US3894927A

US3894927A - Recovery of metal values from ocean floor nodule ores by halidation in molten salt bath

Info

Publication number: US3894927A
Application number: US309738A
Authority: US
Inventors: William S Kane; Hugh L Mccutchen; Paul H Cardwell
Original assignee: Deepsea Ventures Inc
Current assignee: Deepsea Ventures Inc
Priority date: 1972-11-27
Filing date: 1972-11-27
Publication date: 1975-07-15
Anticipated expiration: 1992-07-15

Abstract

This invention provides a process for removing metal values from ocean floor nodule ores comprising contacting the nodule ore with a molten bath of an alkali metal halide and/or an alkaline earth metal halide to form the halides of the manganese, copper, cobalt and nickel present in the ore, and separating the thus formed halides from the reaction mixture, as by vaporization. The mixture of halides can then be separated into the individual halides, e.g. by dissolving in water and separating by extraction. Preferably the ore is first dehydrated and the ore can be contacted with a reducing agent to reduce the manganese present to the divalent state.

Description

United States Patent [191 Kane et a1.

i 1 RECOVERY OF METAL VALUES FROM OCEAN FLOOR NODULE ORES BY HALIDATION IN MOLTEN SALT BATH [21] Appl. No.: 309,738

[ 1 July 15, 1975 1.421667 8/1922 McKirahan 75/113 3,471,285 10/1969 Rolf 75/80 3,499,754 3/1970 Colombo et a1. 423/138 3,751,554 8/1973 Bare et all t l 75/103 3,752,745 8/1973 Kane et al 423/139 Primary Examiner0. R. Vertiz Assistant Examiner-Brian E. Hearn Attorney, Agent, or Firm-Barry G. Magidoff [57] ABSTRACT This invention provides a process for removing metal values from ocean floor nodule ores comprising contacting the nodule ore with a molten bath of an alkali [52] metal halide and/or an alkaline earth metal halide to 75H 75 form the halides of the manganese, copper, cobalt and [5 [1 Int Cl czzd 3/00 nickel present in the ore, and separating the thus [58] Fieid 139 46 formed halides from the reaction mixture, as by vapor- 75/113 1 l 82 1 ization. The mixture of halides can then be separated 106 into the individual halides, e.g. by dissolving in water and separating by extraction. 5 References Cited Preferably the ore is first dehydrated and the ore can UNITED STATES PATENTS be contacted with a reducing agent to reduce the I 3'9 858 10/19 Ed d 423/44 manganese present to the divalent state.

W3! 5 1,368,885 2/1921 Bradford 75/113 28 Claims, 1 Drawing Figure aim pee (muJnzr /{,a'60

hen/awn? l mm: A?

f'l/AIVAZE #00 my! [MAM/J6? [ES/004' [YE/ll C/IlUI/DE a a (00 :0 mun- Mora tznucrlaw ixnrnz'rm /P467 fl'M/flr/r/av nPrxrnu/zaw Its Ave [a C0 fifn A! (a: (12 Kilt/an (11 RECOVERY OF METAL VALUES FROM OCEAN FLOOR NODULE ORES BY I-IALIDATION IN MOLTEN SALT BATH balt. as the main ingredients, followed by chromium. zinc, tin. vanadium, and many more elements, including the rare metals silver and gold. In addition to the crystals of compounds of valuable metals present. there with the increased awareness on the part of both the is also a larg q n i y f i r g ngue. material intipublic and the metals industry of the ecological dangers mately admixed in the nodule ore. This silt or gangue that can arise from continued surface mining of mineris sand and clay, and includes the usual oxides of silicon als and the increased problems of pollution caused by and aluminum in varying proportions and some carbonthe refining procedures required for most ores mined ates. from the land. industry has been interested for several The precise chemical composition of the nodules years now in the mining of minerals from the sea. This ary p n ing p n heir lo tion in h ocean. The has been an extremely elusive target up to the present. variation apparently is caused by differences in temper- The directions taken have included both attempts to ature in various places. differences in composition of wrest minerals directly from solution in sea water and sea water. perhaps Caus d by t Pr ssur and temperathe mining of ores which are available on the floor 0f ture variation at different depths, and composition of the ocean. These ores do not require any digging into adjacent land areas; variations in the amount of oxygen the earth's crust; the ocean floor ores can merely be which is present in the water in different locations and scooped up or in other ways removed from the ocean perhaps other variables not readily apparent to observfloor without actuall rendin the r h f ers. Generally, however, in almost all cases the metals Ocean floor nodules were first collected in the first which are P major Proportions are manganese half of the 1870s, Th h v b di d b many and iron. The following table (taken from an article enworkers in an attempt to determine their composition. titled The Geochemistry of Manganese Nodules and and after their composition had been determined, to try Associated Deposits from the Pacific and Indian to decipher ways to wrest from their peculiar structure ans" by Cl' n-afl and T001118 in Deep a Research the valuable metals contained therein. It is presently (1 l m 1 p g P rg m n Press believed that these nodules are actually creations of the (Great Britain) ShOWS the relative COmPOSlKlOHS 0f the sea; they are somehow grown from the metal commost valuable metals contained in nodules taken from pounds which are dissolved in sea water, generally in different areas within the Pacific and Indian Oceans.

Table l L.O.I. 30.87 25.50 22.12 24.78 24.75 27.21 28.73 25.89 27.18

Depth l. Mid-Pacific Mountains (5 samples) 5. Northeast Pacific (10 samples) 2. West Pacific (23 samples) 6. Southeast Pacific (8 samples) 3. Central Pacific (9 samples) 7. South Pacific 1 1 samples) 4. Southern Borderland Seamount Province (5 samples) 8. West Indian Ocean (10 samples) 9. East Indian Ocean 14 samples) the form of the metal oxides. Nodules are also found in the Atlantic ocean; how- The metal values in the nodules are almost excluever. it has been found that generally these nodules sively in the form of the oxides and moreover are prescontain lower proportions of the more valuable metals ent in a very peculiar physical configuration. The physiand correspondingly higher proportions of the less cle cal and chemical structure of the nodules are believed Sirable m tals hich Cannot be readily refined and to be a dir r l f the conditi under which th which have little or no value. such as the alkaline earth were created and to which they have been exposed t ssince their creation. First. the nodules have never been exposed to temperatures other than those at the bottom Because of the peculiar and intricate crystal structure of the ocean at the location at which they were formed. of the ocean floor nodules. the common refining tech- They have an extremely large surface area, often better niques used for the refining of land ores are not generthan 50% porosity. and they are thus a relatively chemially suitable for the nodules. The art has struggled with cally reactive ore. various schemes for refining these nodules but only a The nodules are formed in an extremely complex few processes have been devised WhlCI'l permit the crystal matrix ofiron and manganese oxides: tiny grains commercial refining of these nodules to obtain ecoof each oxide of a size and type which are substantially nomically significant quantities of the valuable metals impossible to separate with presently available physical contained therein in the necessary degree of purity. means. These iron and manganese oxides form the crystalline structure within which are held. by means not precisely known, other metal compounds, most likely oxides. including those of nickel. copper and co- Mero. US. Pat. No. 3.169,856, had devised a scheme for a very peculiar type of nodule wherein the separate mineral phases of manganese and iron contain different metals; specifically it was stated that nickel and copper were contained only in the manganese phase of the material whereas cobalt was present solely in the iron phase. Apparently, according to Mero, the oxides were in solid solution therein. The Mero material. if he was correct in his analysis, was very unusual. Mero describes one method for breaking up the nodule matrix of the peculiar type of nodules he was working with. Mero differentially leaches nickel from the nodule leaving the cobalt, which can be removed by a subse quent leaching; thus separating nickel values from cobalt values.

Ocean floor nodule ores have also been refined by hydrochlorinating i.e. reacting the ore with HCl to prepare the chlorides of manganese, nickel, copper and cobalt, and forming an aqueous solution of the mixed chlorides of the desired metals. The mixed chloride solutions are then separated by liquid ion exchange procedures to obtain separate streams of copper, nickel, cobalt and manganese chlorides, which can then be reduced to form the elemental metal. See for example, Chemical and Engineering News, May 10, 1971, pages 56 and 57.

Land ores have also been refined using chloridation techniques, some of which have been utilized on a commercial basis. Several plants have been constructed utilizing sodium chloride or calcium chloride as a chloridating agent for reaction with pyrites ore. Generrally the ore is initially roasted to remove excess sulfur content from the pyrites, the roasted cinder" is then reacted with sodium chloride or calcium chloride at elevated temperatures, eg about 2,000 F. The metal halides thus formed, derived from pyrites, include lead chloride, silver chloride, bismuth chloride and zinc chloride. The mixed halides are then dissolved to form an aqueous solution and the individual halides separated by various methods. See for example, Chemical Engineering, Apr. 8, 1968, pages ll4-l 16 Japanese Process Makes Blast Furnace Feed From Pyrites Concentrate." Generally this process has been commonly used for removing non-ferrous metal from pyrites ore to purify the pyrites ore so that it can be used as a raw material in iron production. The non-ferrous metals which are removed become a valuable by-product of this process. The chlorides can be separated from the pyrites cinder by leaching the cinder or by carrying out the halidation reactions at sufficiently high tempera tures to volatilize the non-ferrous chlorides, then condensing and collecting them after separation from the cinder.

Various land-based manganiferous ores have also been reacted on an experimental basis using both sodium chlorides and calcium chlorides. These reactions have been carried out at temperatures sufficiently high to vaporize both the iron and manganese chlorides which are formed. Generally temperatures above about 1100' C. are utilized. The chloride vapors are swept from the furnace with a stream of an inert gas, such as dry nitrogen, and the chloride vapors are then readily condensed as a dry product. The mixed chlorides can then be dissolved in water and, by varying the pH of the solution, separated by sequential precipitation of, first, ferrous hydroxide Fe (OH) followed by precipitation of manganous hydroxide at a higher pH. See for example, Review of Major Proposed Processes for Recovering Manganese from U.S. Resources, Information Circular 8160, U.S. Department of Interior, Bureau of Mines. 2. Chloride and Fixed Nitrogen Processes" by Norman et al.

Other chloridation techniques have also been carried out on landbased ores. For example, nickel and cobalt have been separated from iron present in lateritic ores by first reacting the ore with carbon monoxide to form the corresponding carbonyl compounds followed by treatment with chlorine. See for example, U.S. Pat. No. 2,998,3ll to lllis. Other iron-nickel ores, which also contain only a minor proportion of manganese, have also been refined by chloridizing using a mixture of HCI and water vapor to selectively form chlorides of nickel and cobalt to the exclusion of iron and chromium. The nickel chloride and cobalt chloride are then leached with water (U.S. Pat. No. 2,766,115 to Graham et al.).

The manganiferous materials which have been chloridated by the use of metal salts in the past have contained manganese and iron in the lowest or divalent state. The major portion of the manganese and iron present in the ocean floor nodule ores are in their highest valence states, tetravalent and trivalent, respectively.

Nickeliferous ores containing various proportions of nickel and cobalt have also been chloridated utilizing a metal chloride as the chloride source. In one process, the ore is first oxidized and then selectively chloridated so that nickel and cobalt chlorides are volatilized and separated from the gangue fraction of the ore. Daubenspeck in U.S. Pat. No. 2,733,983, asserts that the use of ferric chloride as the chloridizing agent for chloridating the dehydrated oxidized ore results in a particularly effective reaction in that ferric oxide remains substantially unreacted and presumably results in greater efficiency for the process. However, this procedure is initially carried out at a low temperature, below the volatization point of nickel and cobalt halide. The ferric chloride which is assertedly more volatile than nickel and cobalt chloride is first removed at a lower temperature after which the remaining solid mass is heated until the nickel and cobalt chlorides are evaporated. The chloridation step is carried out at a temperature in the range of from about 600 to 700 C., so as to insure the chlorination of nickel and cobalt and avoid the chlorination of the gangue faction including the iron.

Another high temperature process, following which the metal chlorides are vaporized and collected by condensation or sublimation, involves the reaction of an oxidic" iron ore with chlorine and a solid carboncontaining reducing agent.

Nickel-containing ores which contain cobalt and iron, but generally not the high proportion of manganese found in the nodules, have also been initially refined by roasting under reduction conditions, such as in the presence of producer gas. See for example, U.S. Pat. No. 2,913,334. Similarly, metal oxide-containing ores, which can contain certain manganese, nickel, cobalt and iron compounds have been roasted with sulfur or sulfide-containing materials and then leached to remove the valuable metals as dissolved salt. in the nodules, these oxides are all found intimately combined together in different proportions and in a unique form together with a host of other metals, especially copper.

The art did not, however, have a simple direct method for initially refining ocean floor nodules, ores which contain high proportions of iron and manganese in an unusual physical state, so as to separate out iron from the remaining metals which are present in high concentration.

As a result of the rather unusual composition and physical structure of the nodule ore, the initial attempts to halidate the nodule ores utilizing a metal salt were unsuccessful. It has been found, however, that when the metal halides are maintained in a molten condition and the nodule ore is dispersed in the melt, the halidation reaction is effected.

in accordance with the present invention, ocean floor nodule ore containing chemically-combined nickel, copper and cobalt dispersed in a crystal lattice formed of chemically-combined manganese and iron and having a high oxygen content, can be refined by separating out the manganese, nickel, cobalt and copper values by a process comprising:

1. Contacting the nodule ore with a halide of an alkali or alkaline earth metal at a temperature sufficient to form a molten bath of said halide and to convert the manganese. nickel, copper and cobalt values to the corresponding halides and,

2. Separating the manganese, nickel, copper and cobalt halides thus formed from the remaining portions of the nodule ore.

Preferably, the yield of manganese values removed from the ores can be improved by reacting the ore with a reducing medium so as to reduce tetravalent manganese to divalent manganese, thus increasing the amount of manganous halide formed.

The halides separated from the ore, i.e., manganese, nickel, copper and cobalt halides are preferably dissolved into an aqueous solution and the individual halides of nickel, copper and cobalt separated therefrom by liquid ion exchange procedures. The metal values can then be reduced, e.g. by electrolysis.

A surprising advantage of this metal halide halidation reaction is that the high proportion of iron present in the nodule (whether in the original trivalent state or reduced to the divalent state) is not converted to the corresponding iron halide under the conditions of this process.

When the manganese values are to be reduced to the divalent state, the reduction reaction and the halidation reaction can be carried out substantially simultaneously by mixing together the reducing agent, the halidating salt and the nodule ore. Generally, however, the reduction reaction and the halidation reaction are carried out most efficiently under different reaction conditions, especially as regards temperature. Therefore, preferably, the manganese is first reduced and then halidated, changing the conditions for reaction as required.

Generally, both of the manganese reduction and the halidation reactions are substantially independent of pressure; the temperature of reaction is, however, significant in obtaining the greatest effective yield for each reaction.

The most efficient temperature for the reduction reaction is dependent upon the reducing agent used. Generally, stronger reducing agents, i.e. agents which are highly effective in reducing tetravalent manganese to the divalent state, and which also reduce the other metal values present, can be UllllZed at temperatures as low as 250C. to obtain effective reduction of manganese to the divalent state. Examples of such stronger reducing agents are elemental carbon, or hydrogen, or carbon monoxide.

Weaker reducing agents, i.e. compounds such as, for example, the hydrocarbons, which are less effective in reducing the manganese, and also the other metal values, are used at higher temperatures, e.g. 500C. Generally, the higher the temperature. the greater the degree of reduction in a given period of time.

It has been found that at too elevated a temperature the ultimate yield of desired metal values from this process is decreased. This temperature differs depending upon the reducing agent used. Generally, a temperature greater than about 800C is not used regardless of the reducing agent selected. Preferably temperatures not greater than about 700C, and optimally not greater than about 600C, should be utilized for the reduction step.

Generally any reducing agent having sufficient reducing strength to reduce tetravalent manganese to divalent manganese can be utilized. However, the reaction of the reducing agent with the ore should not result in the formation of any metal compounds which are not readily converted to halides in accordance with the present process. For example, elemental carbon in the form of coal, coke, graphite, etc. can be utilized, as well as carbon compounds, such as especially carbon monoxide and the hydrocarbons, including those derived from petroleum or other natural mineral products. Any source of elemental carbon can be utilized, pure carbon in any physical state including amorphous or graphitic carbon or natural or semi-manufactured carbonaceous materials such as coal, peat, charcoal and coke. Wood or other organic sources can be utilized as a source for the reducing action of carbon. Any hydrocarbon can be used: aromatic, aliphatic or cycloaliphatic, or compounds having combinations of these groups, without interfering with the reducing action. The higher condensed ring aromatic materials have the highest proportion of carbon among the hydrocarbons and, therefore, provide the greatest unit weight effectiveness as a reducing medium. Gaseous materials such as hydrogen and carbon monoxide, and mixed manufactured materials, such as reformer gas, i.e., a mixture of hydrogen and carbon monoxide, can also be readily utilized as a reducing agent.

Materials such as HCl and HBr can also be utilized as the reducing agent. This results in a combined procedure wherein the HCl is both the reducing agent and the halogen source for the manganese values, and the metal halide salt halidates the remaining desirable metal values in the nodule ores.

The majority of the manganese in the nodule ore is in the tetravalent state and it has been found that the tetravalent manganese combines more slowly than divalent manganese with the alkali metal halide or alkaline earth metal halide to form a volatile managanese halide salt. Accordingly, if it is desired to obtain substantially pure manganese halide and to reduce the amount of manganese in admixture with the halides of copper, nickel and cobalt, the reducing step can be omitted. The ore is halidated using the halide salt to remove substantially all of the nickel, copper and cobalt values plus a lesser quantity of manganese. The remaining ore can then be reduced and reacted with additional halide so that substantially pure manganese halide is separated from the ore. Alternatively, the reaction time can be increased so that the amount of manganese halide is increased, without a reducing agent.

Prior to initiating the halidation reaction utilizing a metal halide it is desirable to dehydrate the nodule ore. This can be done by maintaining the ore for a sufficient period at a temperature sufficient to evaporate the moisture. Generally. the drying temperature should be at least about lC. and preferably in the range from about 150 to about 300C. and optimally at least about 200C. The dehydration can be carried out after the ore is admixed with the metal halide. This can be accomplished, for example, by mixing the ore and metal halide at a temperature below halidation initiation temperature, generally below the melting point of the halide, so that halidation does not occur before the water is driven off. Alternatively, the ore can be added to the molten metal halide and the moisture from the ore, which is immediately vaporized, is withdrawn from the reactor. lt is desirable to eliminate the moisture in the ore in order to avoid hydrolysis of the halides during halidation.

Generally, when carrying out the halidation reaction, the reaction temperature is sufficient to fuse or melt the alkaline earth metal halide or alkali metal halide. This temperature varies depending upon the specific salt or mixture of salts utilized. lt had been found that although most of the individual metal halides melt at temperatures of 700C. or higher; mixtures of alkali metal halides and/or alkaline earth metal halides which form eutectics melt at substantially lower temperatures, eg in the range of from about 340 to 500C. at the eutectic composition. The following Table II lists the melting points for selected individual salts and binary and ternary eutectic mixtures:

These values obtained from the text. Phase Diagrams for Ccrumists. i964 and N69 Supplementv Levin el all, (American Ceramic Society, Columbus. Ohio).

The halidation reaction should be carried out at or above the melting point of the metal halide halidation reagent used. Accordingly, a minimum temperature sufficient to maintain a fused bath of molten or semimolten metal halides must be present. Generally a temperature of at least about 340C. is utilized, depending upon the salt or salts used, and generally not above about l200C. and preferably a temperature not greater than about 700C. Optimally, a temperature in the range of from about 450 to about 600C. is utilized.

As can be seen from Table ll, above, eutectic mixtures of halide salts can be used in order to operate within the relatively lower temperature range. Generally such a low melting temperature mixture of halides, preferably contains at least one alkaline earth metal halide and at least one alkali metal halide. Alternatively, in another preferred variation, only one of the alkali metal or alkaline earth metal halides are present and a eutectic mixture can be formed with another metal salt, such as a metal halide formed from the metal values in the nodules, for example, manganous chloride, as shown in Table II. Mixtures of salts in proportions other than at a eutectic point generally have an intermediate melting temperature.

Diluent salts can also be present in the molten mixture of metal halides. However, these usually do not interfere with the process of this invention. Some diluents, however, do form eutectics with alkali metal halides or with alkaline earth metal halides and thus reduce the temperature required to form the molten halide.

As explained above, the reaction between nodule ore and an alkaline earth metal halide or an alkali metal halide involves the manganese, cobalt, nickel and copper values present in the nodule ores plus certain other metals which are present in even smaller proportions such as zinc, lead and cadmium.

The amount of alkali and/or alkaline earth metal halide salt which is mixed with the nodule ore should be sufficient to form a fluid mixture with the ore when the halide salt is fused, or melted. Accordingly, there is at least an equal weight ratio of alkali metal and/or alkaline earth metal halide-to-nodule ore present in the reactor. Preferably up to about l0 parts of halide by weight to one part of nodule ore is utilized and opti mally from about 2 to about 8 parts of halide by weight to one part of nodule ore. Greater percentages of alkali metal and/or alkaline earth metal halide can of course be utilized if desired; however, it would normally be an unnecessary increase in volume of material being handled in the reactor and, therefore, an unnecessary increase in the cost of the process.

Generally, the most useful halides include the iodides, bromides and chlorides; the chlorides and bromides are generally the most effective halidation agents. Generally the chloride salts are the most avail able commercially and, therefore, would be available at the lowest cost and most economically useful. The halides of the alkali metals, such as lithium, sodium, potassium and cesium can be used, although the sodium and potasium salts are generally available at the lowest cost and, therefore, preferred. Sodium chloride, for example, can be obtained directly from sea water. Useful alkaline earth metal halides include salts of calcium, magnesium, barium and strontium. Generally calcium and magnesium halides are the most readily available. The most commonly available salts include magnesium chloride, calcium chloride, sodium chloride and potassium chloride.

Subsequent to completion of the halidation reaction, the desirable halides that are formed from the metal values in the nodule, especially nickel, cobalt, copper and, manganese halides, are separated from the fluid reaction mass. Preferably, the separation can be accomplished by vaporization of the preferred metal halides at elevated temperatures. Generally, temperatures of at least about 600C are used, and preferably not higher than about l200C; optimally, metal halide vaporization temperatures are in the range of from about 800 to about l000C for the desired metal halides.

The temperature need not be at the boiling point of the halide at the given pressure if a carrier gas is used to carry off the metal halides as they are vaporized. The carrier gas is preferably inert in the process of this invention and thus includes such materials as nitrogen, carbon dioxide, or any of the Noble gases, such as helium, neon or argon. Air also can be utilized as a carrier gas; under the conditions of this reaction, air is inert to the metal halides being vaporized. The vaporized halides are preferably condensed as a mixture and dissolved with water to form an aqueous solution of these mixed halides. Alternatively, the metal halide vapor can be fractionated and several solutions obtained carrying different portions of the various metal values.

Preferably, the metal halides are condensed by di rectly spraying water into the condenser. The water cools the halides. condensing them and eventually cooling them to a point where liquid water is formed and the halides are immediately dissolved therein. Alternatively, of course, the halides can be condensed onto a condenser plate by indirect cooling followed by leaching from the plate by water. Generally, the preferred halides of copper, cobalt, nickel and manganese are soluble in water and there is no problem in forming a solution by either method. Generally, the bromides and chlorides are the most readily soluble in water and are the preferred halides to be used in this process for this additional reason.

Alternative methods for separating the halides from the nodule ore include contacting the entire reaction mixture of halides and nodule ore with water in order to dissolve the desired metal halides together with the alkali metal and alkaline earth metal compounds present. Generally, the alkali metal and alkaline earth metal halides can be readily separated from the copper. cbalt, nickel and any manganese halides. The alkali metal and alkaline earth metal salts generally do not interfere with the various separation procedures for the manganese, nickel, copper and cobalt even if mixed in solution therewith.

Generally, it is unnecessary to decrease pressure in the vaporization stage. Although the lower pressure aids in the vaporization of the halides, it has been found that the use of an inert carrier gas is at least as effective and certainly far less expensive than maintaining a vacuum under these high temperature conditions. However, if desired, the pressure can be maintained below atmospheric. The use of decreased pressure in the reaction vessel will prevent the leakage of any vapors, exteriorly from the reactor. Alternatively, maintenance of pressure in the vessel above atmospheric will prevent any atmospheric air leak into the reactor.

This procedure can be carried out in a single batch reactor where the temperature is gradually raised after the complete charge is added. This charge or reaction mixture includes, if desired. a reducing agent, at least one halide salt and the nodule ore. The charge is mixed and the temperature gradually raised first to a point sufficient to dry the ore, next, if desired, to a temperature sufficient to reduce the manganese to the divalent state, and then, to the halidation temperature. The reduction step can be omitted as described above, or can occur after an initial halidation and be followed by a subsequent halidation, by omitting the reducing agent from the initial charge and introducing the reducing agent after the initial halidation reaction.

Useful reactor vessels include kettles for use under both batch or continuous operation. In continuous operation the reaction mass is moved from kettle to kettle as the temperatures increase. Preferably, however, a continuously rotating kiln can be utilized with the temperature gradually increasing along the length of the kiln. The temperature at the entry end of the kiln being sufficient to evaporate moisture from the ore and the period of time within that portion of the kiln being sufficient to result substantially in complete dehydration.

The kiln can empty directly into a kettle maintained at a temperature sufficient to melt the alkali metal and- /or alkaline earth metal halide present. The molten halide is mixed with the nodule ore and the metal values in the ore are halidated. The temperature of the halidated reaction mass can then be increased to effect vaporization at a relatively rapid rate. A continuous flow of an inert carrier gas is passed over the molten mass in the vaporization stage to carry away the vapors as they are formed: in this manner the temperature of the molten mass need not be at the boiling point of the halide in order to effect an economical rate of vaporization. Generally, the vapor pressures of any alkali metal and/or alkaline earth metal compounds present are low at the temperatures at which the desired metal halides vaporize at an economical rate, thus separation is achieved.

The vapors are removed overhead and passed to a condenser where the halide salts are condensed and the non-condensible carrier gases passed through and if desired recycled for further use as a carrier gas. The condensed halides are then dissolved into an aqueous solution and the individual halides separated out by known methods. The particular ratio of metal values found in the nodule ores, i.e. the relative percentage of nickel, copper, cobalt and manganese, make it extremely efficient to separate each metal value utilizing liquid ion exchange procedures.

The aqueous solution of mixed halides generally can contain up to about 225 g/liter of manganese, as metal, if manganese is present, but preferably contains manganese in concentrations from about 50 to about 225 g/l, as metal, and optimally in a concentration of from about to about 200 g/l by weight of metal. The concentrations of other metals are proportional to their concentration in the nodules and thus in the halide vapors removed overhead from the vaporization zone following halidation.

The aqueous solution of the mixed metal halides is generally not neutral; it is preferably acidic having a pH not greater than about 4 and preferably not greater than about 3. Optimally the maximum pH of the leach liquid is about 2; the lower pH tends to substantially increase the proportion of copper halide which can be dissolved. At higher pH, it is believed that the copper halide tends to hydrolyze, forming insoluble products, separating out from the leach solution. The condenser spray or leach water should then be acidic.

Because of the rather complex mixture of materials which are obtained from such ocean floor nodules, many of the standard hydrometallurgical methods for separating out metal halides are not directly applicable because of the presence of various interfering ions. However, the following procedures can be utilized for obtaining at least the pure cobalt, copper, nickel and manganese halides.

In the preferred system for separating the halides, the copper halide is first removed from the aqueous solu tion. In describing the process, the chlorides are used as an example of the halides.

A group of materials known to the art as liquid ion exchange agents can be utilized for the extraction of copper. Such materials include a group of substituted 8-hydroxyquinolines, a-hydroxy oximes and naph thenic acids. The oximes and quinolines generally are preferred because of their ability to separate more cleanly the various metal salts and because the same compound can be used to extract each of the other metals from solution.

The 8-hydroxyquinoline compounds, which are especially useful for the separation of the metal halides in accordance with the present process, can generally be defined by the following formula:

1 6 R a 9 R RJ wherein each of the R groups can be hydrogen or a hydrocarbyl group, or inertly substituted hydrocarbon groups, such as alkenyl, alkyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or combinations thereof, such as alkaryl, aralkyl, aralkenyl, alkyl-cycloalkyl, etc.

At least one of the R groups, however, must be a hydrocarbon group. Any inert substituent can be present, as long as it does not adversely affect the solubility of the substituted S-hydroxyquinolines in organic solvents nor adversely affect the solubility in the organic solvent of the metal chelate formed therefrom.

The resulting metal chelate must remain soluble at least to the extent of approximately 2% by weight in the organic solvent.

The preferred position of the hydrocarbyl substituent on the S-hydroxyquinoline nuclear structure is such as to preferentially complex with the desired metal ion in the aqueous solution. The sum of the carbon atoms in the R groups must be at least about 8 and can be as high as 24 or more. The preferred R groups are alkylbenzyl groups or beta-alkenyl groups containing from l2 to 18 carbon atoms, preferably attached at the R, R, or R position. The optimum position for substitution is at the R" position to obtain the highest degree of efficiency. For a more complete description of these hydrocarbylsubstituted S-hydroxyquinolines see Republic of South Africa specification No. 69/4397 to Budde Jr., et al. assigned to Ashland Oil, Inc.

Representative compounds useful in this invention and within the scope of the above general formula are: 7octylbenzyl-8-hydroxyquinoline, 7-dodecylbenzyl-8- hydroxyquinoline, 7-nonylbenzyl8-hydroxyquinoline, 7-ditertiarybutylbenzyl-8-hydroxyquinoline, 7- hexadecyI-S-hydroxyquinoline, 7-octadecyl-8- hydroxyquinoline, 7-hexadecenyl-8-hydroxyquinoline,

7-dibenzyl-8-hydroxyquinoline, 7- dimethyldicyclopentadienyl-8-hydroxyquinoline, 7- dicyclopentadienyl-S-hydroxyquinoline, 7- dodecylphenyl-8hydroxyquinoline, 7-

phenyldodecenyl-S-hydroxyquinoline, and the like where one or more of the hydrocarbyl groups, R, are attached to ring carbon atoms in the 2nd, 3rd, 4th, 5th and 6th positions. Mixtures of these 8- hydroxyquinoline derivatives can be used if desired.

The S-hydroxyquinolines are preferably utilized in solution in organic solvents, preferably hydrocarbon or chlorinated hydrocarbon solvents. Such preferred solvents include benzene, toluene, xylene, the various commercial mixtures of aromatic hydrocarbon solvents available on the market, aliphatic hydrocarbon solvents such as hexane-heptane mixtures, light fuel oil, kerosene and other hydrocarbons. Chlorinated such hydrocarbon solvents such as chlorobenzene, are useful in this regard. Generally liquid aliphatic, cycloaliphatic, aromatic, cycloaliphatic-aromatic or aliphaticaromatic hydrocarbons or chlorinated such hydrocarbons can be preferably utilized. Optimally, the solvents have specific gravities in the range of from about 0.65 to 0.95 and mid-boiling points in the range of from about to 6l5F. (ASTM distillation). However, substantially any liquid can be used as a solvent that meets the following criteria: 1) a solvent for the extracting agent; 2) a solvent for the metal-containing chelate; 3) immiscible with water, and 4) readily separable from water. The extracting compound and the metal containing such compound are both preferably soluble in the solvent to the extent of at least 2% by weight.

The second preferred type of metal extractant are the alpha-hydroxy oximes, which are disclosed inter alia in U.S. Pat. Nos. 3,224,873, 3,276,863 and 3,479,378. These materials have the general formula:

wherein the R", R and R groups can be any of a variety of organic, hydrocarbon radicals such as aliphatic and alkyl aryl radicals. R can also be hydrogen. Preferably R and R are unsaturated hydrocarbon or branched chain alkyl groups containing from about 6 to about 20 carbon atoms. R" and R" are also preferably the same, and when alkyl are preferably linked to the central carbon atoms by a secondary carbon atom. R is preferably hydrogen or unsaturated hydrocarbon or branched chain alkyl group containing from about 6 to about 20 carbon atoms. The oxime preferably contains a total of from about 14 to about 40 carbon atoms. Useful R", R and R groups include in addition to hydrogen, the monoand polyunsaturated groups such as heptenyl, octenyl, decenyl, octadecenyl, octadecynyl and ethyl octadecenyl Alkyl groups include Z-ethylhexyl, 2,3-diethylheptyl, Z-butyldecyl, 2- butylhexadecyl, 2,4-ethylbutyldodecyl, 4- butylcyclohexyl, and the like. Examples of the preferred alpha hydroxy oximes include l9-hydroxyhexatriaconta-9, 27-diene-l 8-oxime; 5, l O-diethyl-S- hydroxytetradecan-7-oxime; 5,8-diethyl-7-hydroxydodecane-fi-oxime.

These alpha-hydroxy oximes are also utilized in an organic, water-immiscible solvent, in which they should be soluble to an extent of at least about 2% by weight. The useful solvents are set forth above for use with the B-hydroxyquinoline compounds. The alpha-hydroxy oximes or the S-hydroxyquinolines can be present in the solvent in amounts of from about 2 to about 50% by weight, based on the total solution, but preferably in amounts of from about 2 to about l5% by weight.

Solutions of the extracting agents which are known as chelating agents, or liquid ion exchange agents", generally are improved in their extracting efficiency by the presence of materials known as conditioners. Such conditioners include, long chain aliphatic alcohols, such as capryl alcohol. isodecanol, tridecyl alcohol and 2-ethylhexanol. The conditioners act, it is believed, by improving the phase-separating properties of the organic solvent from the aqueous leach liquid. The conditioners can be present in amounts of up to about 20% by volume of solution, and generally are aliphatic or cycloaliphatic alcohols containing from about 6 to about l6 carbon atoms.

The above two types of liquid ion exchange materials are especially preferred for the separation of the metal halides found in the leach liquid obtained from ocean floor nodules because a single reagent can be utilized for the selective removal of all of the important metal values from the solution of mixed halides. Thus, by utilizing either an a-hydroxy oxime or an 8- hydroxyquinoline, a single extraction medium can be utilized for removing, in seriatim, all of the desired metal halides. It is unnecessary to utilize a multiple extractant system when utilizing these materials, but it is merely necessary to vary the pH of the aqueous solution of mixed halides following each successive extraction. Other extraction materials which can be used to separate one or more of the metals include the organic phosphates and amines, and naphthenic acid.

Beginning with an aqueous leach liquid containing dissolved copper halide, cobalt halide, nickel halide and manganese halide as the primary solutes, plus a variety of other metal halides in relatively smaller concentrations, the extraction of the individual metals can preferably be carried out by the following general procedure with oxime or hydroxy-quinoline liquid ion exchange agents as the extracting solution:

1 adjust the pH of the mixed halide aqueous solution to a desirable pH, 2) mix the aqueous solution with an immiscible organic liquid containing an extractant specific to a metal at that pH; preferably, copper is extracted initially at a pH of not greater than about 2.5, preferably from about 1.5 to about 2.5, and optimally of from about 1.8 to 2.2; the best results are obtained at a pH of about 2; 3) separate the aqueous raffinate from step 2), adjust the pH as necessary, and mix the raffinate with an immiscible organic liquid containing an extractant specific to another metal at the pH of the aqueous phase. Generally, nickel is extracted at a pH of from about 3 to about 6 and preferably about 3 to about 3.5 with chelating, or liquid ion exchange agents, and cobalt is extracted at a pH of from about 3.5 to 7, preferably from 3.5 to about 6, optimally from 3.5 to about 5 and the most economical results at from 3.5 to about 4.5. At too high a pH, the manganese, nickel and cobalt tend to precipitate and this is preferably avoided. Further, increasing pH too much is expensive, in using up basic reagents.

Alternatively, cobalt is first extracted using a secondary, tertiary or quaternary amine extractant.

The tertiary amines are preferred for extracting cbalt, and especially the trialkyl amines, containing from about 6 to about l2 carbon atoms in each group, such as triisooctyl amine, triisodecyl amine and tricapryl amine. The amine extractant is dissolved in an inert organic liquid in which both the amine and the amine metal salt are soluble in concentrations of at least 2% by weight. There can also be present a conditioner such as one or more of the higher alcohols described above. The higher alcohols are preferably present in concentrations of from about to about 30 volume percent. The organic solvents are selected on the same basis as those defined above for use with the oximes and hydroxyquinolinesv Aromatic and aliphatic petroleum hydrocarbons are preferred. Nickel is then extracted from the aqueous raffinate using an a-hydroxy oxime or 8- hydroxyquinoline, as defined above at a pH of from about 3 to about 3.5.

Preferably, the cobalt and nickel are extracted simultaneously and then selectively stripped from the extracting phase. The ratio of cobalt and nickel removed from the leach liquid by the extractant is determined by the pH, i.e. the relative proportions of nickel and cobalt can be the same as that which is present in the leach liquid or it can have a greater proportion of nickel or a greater proportion of cobalt. Generally the higher the pH the greater the proportion of cobalt extracted. It is preferred, usually, to remove the nickel and cobalt in the same proportions as the metals are present in the leach liquid. Therefore, the pH for this ratio should be maintained during the extraction.

it is usually necessary to add continually alkaline material during the extraction stages in order to maintain the desired pH. The chelating agents act by releasing hydrogen ions when extracting metals, and thus the pH would tend to decrease during extraction. Caustic soda solution is preferably used. The sodium ion generally does not interfere with the further processing of any metal salt. However, other useful basic materials include generally ammonium and alkali metal oxides and hydroxides, alkaline earth metal hydroxides and oxides and their corresponding carbonates, such as calcium hydroxide, potassium hydroxide, lithium hydroxide, lithium carbonate, magnesium carbonate, calcium carbonate, and ammonium hydroxide and carbonate, basic manganese compounds, such as the hydroxide and manganese carbonate can be used. Buffering agents can also be added; however, this can add an undesirable impurity to the leach liquid.

Each extraction step can be carried out with one or more extraction stages until the desired amount of metal is extracted.

4) The metal-containing organic extractant phases are stripped of the metal values by contacting with an aqueous stripping solution, generally an acidic solution is used. Generally, following stripping the extracting solution can be recycled to the process.

Copper can be readily stripped from the extract phase by any mineral acid, in an aqueous solution, having hydrogen ion concentrations of from about IN to about lON and preferably from about 2N to about 6N. The concentration of hydrogen ion must be at least slightly in excess (preferably 5%) of the stoichiometric amount needed to substitute for the metal in the extract. The preferred acids include sulfuric acid, nitric acid, and hydrochloric acid. As the acid used determines the metal salt to be formed, this can be a basis for selecting the acid, if a particular salt is desired.

The cobalt can be stripped from the ammine extract using a weakly acidic, i.e. pH of from about 2 to about 3.5, water solution.

Where nickel and cobalt are extracted together from the aqueous solution using an oxime or hydroxyquinoline, the nickel can first be stripped from the extract phase using relatively weakly acidified water, containing an acid such as the mineral acids or the stronger organic acids, such as chloracetic acid, in a concentration of from about 0.0lN to about 3N acid and preferably from 0.1N to about LON. Cobalt can then be stripped from the chelate using a more strongly acidified chloride ion-containing aqueous solution, having concen tration of at least 6N in hydrogen ion and 6N in chloride ion. Strong hydrochloric acid, containing at least about by weight HCl is preferred.

The aqueous raffinate remaining after the cobalt and nickel are removed from the halide solution contains substantially all of the manganese halide which was leached from the nodule plus small amounts of the halides of other metals. The leach liquid can bc utilized per se to obtain relatively impure manganese, the degree of impurities being very slight. However, if a high quality manganese is needed, it is advisable to separate the manganese from the other metals. This can be done in various ways. such as by sulfide precipitation of the other metal values present. The remaining manganese halide in solution can then be utilized for the preparation of manganese metal by any conventional reducing means. The presence of any alkali metal or alkaline earth metal values results in no interference at this point.

All of the solutions which are obtained by the extracting methods can be further treated by conventional means to obtain the metal from the salts either from the solution directly or by first drying the solution and then treating the metal salt.

Other methods of separating individual metal halides from solutions of mixed metal halides can be utilized. Such methods include utilizing other types of extracting solutions than those described above, or it can include other types of separating procedures such as are generally well known in analytical chemistry for separating various ions, including resinous ion exchange materials. It is believed that the above-described extracting processes are the most economical procedures to be followed based upon the concentrations and kinds of metals which are present in the nodules and which are transferred into the leach liquid once they have been halidated according to the process of this invention.

The solution of the individual metal salts can then be treated in a conventional manner to obtain the elemental metals, if desired. For example, manganese chloride can be reduced to manganese either in a aqueous electrolytic cell, in a fused salt electrolytic cell or by reduction with a less noble metal, e.g. aluminum, magnesium or sodium. Nickel and cobalt salts can be reduced to metal from aqueous solutions in electrolytic cells as can be copper. These are conventional procedures well known to the art and form no part of this invention. Other, nonelectrolytic, processes include. for example, cementation, by passing a solution of copper, for example, over iron or any other less noble metal. Similarly, the solution of copper salt can be dried, the salt oxidized to cupric oxide and then reduced, for example, with carbon. Nickel and cobalt can also be reduced other than by electrolysis: forming the oxides and reducing as above, or by passing hydrogen through the aqueous solution thereof.

The drawing accompanying this application is a flow diagram showing the preferred procedures for the process of the present invention.

Referring to the drawing, nodule ore which is obtained from the ocean floor, either as individual pebble-size rocks or as portions of sheath-like layers formed on the ocean floor, are comminuted, e.g. crushed and ground, to a particle size not greater than about 10 mesh. As shown in this procedure, coal, as the source of the reducing agent carbon, and an alkali metal and/or alkaline earth metal halide are mixed with the ground nodules in a pre-heated zone in which the temperature is in the range of from about to about 250 C. during which time water vapor and carbon dioxide are driven off. The dry preheated mixture of nodule ore, metal halide and reducing agent, is then passed into a three-zone furnace. The first zone is maintained at a temperature range of from about 250 to about 500C, but below the melting point of the metal halide. In this zone any manganese present in the nodule ore is reduced from the tetravalent state to the divalent state. In the second zone of the furnace, to which the reaction mixture is passed, the reaction mass is heated to above the fusion point of the metal halide salt so as to form a fluid. mixture wherein the ground nodule ore is dispersed in the molten metal halide. The molten mass is next passed through the third zone in the furnace where the temperature is further increased to at least about 600C and preferably to at least about 800C. so as to vaporize the manganese halide, copper halide, cobalt halide, nickel halide and other metal halides formed in the second section of the furnace from the metal values in the ore. A stream of nitrogen is passed over the molten reaction mass to carry off the vapors, as they vaporize, to a spray tower condenser. Solid material which is primarily the residue from the ore and the coal, comprising silt plus the iron values present in the nodule ores, primarily in the form of Fe 0 can be removed from the molten mass on a regular basis. The metal halid vapors passing overhead from the furnace pass into a spray tower condenser in which the vapors and liquid water are contacted. Liquid water sprayed into the tower first cools and condenses the halide vapors and eventually dissolves the condensed metal halides. The solution of the metal halides in the water (the leach liquid) is then passed to the separation stages to separate out the desired metal halides individually. Liquid ion exchange procedures are shown in the drawing.

The leach liquor is first contacted with a first liquid ion exchange reagent to remove copper values. The raffinate from this cooper extraction stage is then contacted with a second ion exchange reagent to remove cobalt and to a third to remove nickel, leaving the manganese in the final raffinate from the liquid ion exchange. The separated metal halide can then be reduced to obtain the elemental metal. Copper, cobalt and nickel are shown as being reduced in an aqueous electrolytic cell. As shown, the final raffinate containing manganese halide is first purified, e.g., by treatment with hydrogen sulfide, before the manganese halide is reduced. Manganese halide first is crystallized and then reduced by chemical means to form manganese metal.

In considering the process of the above invention it is surprising that the desired copper, cobalt, nickel and manganese halides are not obtained mixed with iron. It has been found that under the conditions of the present invention, ferric oxide is more stable than the corresponding halide and, therefore, the relatively nonvolatile iron oxide remains and is not converted to the relatively volatile iron halide. The copper, cobalt, manganese and nickel halides, however, are preferentially formed from the corresponding oxides, which are generally presumed to be present in the nodule ores, and, therefore, these relatively volatile compounds can be readily removed and separated from the iron and other materials present in the nodule ore.

17 The following examples set forth preferred embodiments of the present invention, but are exemplary and not exclusive of the full scope of this invention.

EXAMPLE 1 Samples of ocean floor nodule ore ground to a maximum particle size of 25 mesh and having the following composition were obtained:

COMPONENTS PARTS BY WEIGHT Manganese 2 Iron Nickel Copper Cobalt A sample, 17 grams, measured dry, of the above material was mixed with 100 grams of a mixture of halides comprising 48% sodium chloride by weight and 52% by weight magnesium chloride. The resulting mixture was heated in a preheater to a temperature of about 200C. and maintained for a period of l hour. Substantially all of the moisture in the ore was expelled. The dried material was then passed to a furnace where it was heated to 600C. to form a liquid mass in which the particulate nodule ore was dispersed.

The molten mixture was maintained at 600C. for 6 hours, after which time a test sample of the reaction mixture was removed, cooled and leached with water. The cooled sample was analyzed for the metal values remaining in the nodules to determine the percentage of the metal values originally present in the nodule converted to the corresponding chlorides. The results are set forth in Table III.

Table Ill OF METAL PRESENT IN METAL NODULE CONVERTED TO CHLORIDE 4O Manganese 35.5 Iron 0.0 Nickel 76.5 Copper 92.3 Cobalt 72.5

The molten reaction mixture was then heated to l,000C. and nitrogen carrier gas passed over the surface of the molten mixture.

The vapors were removed overhead and condensed in a jet condenser to form an aqueous solution. The jet spray was water having a pH of about 2, containing HCl. The molten mixture was maintained at l,0O0C for a period of 5 hours after which time substantially no further halides were vaporized. The amount of metal halides in the aqueous solution removed from the jet condenser was measured, and it was found that better than 95% of the metal halides formed in the halidation zone were vaporized, condensed and dissolved in water by the above procedure. As shown by Table Ill above, this process results in substantially complete separation of the desirable metal values from the iron and gangue fractions present in the nodule. It further shows that a portion of the tetravalent manganese present in the nodules is converted to manganese dichloride.

ore having the composition set forth in Example l, was placed in a kiln and heated to about 600C and maintained at that temperature for about minutes during which time carbon monoxide at a rate of 2.4 liter/hr STP, was passed through the bed of nodule ore. A portion of the nodule ore was removed and analyzed. It was found that approximately of the manganese present in the nodules had been reduced from the tetravalent state, i.e., as MnO to the divalent state, i.e., as MnO. This also substantially completely dehydrates the nodule ore to an anhydrous condition.

The reduced nodule ore sample was then mixed with 39 g. of sodium chloride, and the resulting mixture heated in a furnace to 900C to form a molten mixture in which the nodules were dispersed throughout molten sodium chloride. The molten mixture was maintained at 900C for 10 hours during which time a nitrogen carrier gas was passed over the mixture and the vaporized chlorides as formed were carried off overhead and condensed in a jet condenser to form an aqueous solution having a pH of about 2, as in Example 1. The con densed product was analyzed, and it was found that the following amounts of the desirable metal values in the ore had been converted to chlorides and vaporized:

Table IV 7? OF METAL PRESENT IN NODULES The aqueous solution from the process of Example 2 has the following composition:

GRAMS PER LlTER AS COMPONENT METAL Manganese chloride 200 Cop er chloride 9.33 Nic el chloride 9.97 Cobalt chloride L88 The aqueous solution, or leach liquid, is passed countercurrently to an organic extracting liquid through 5 mixer-settler stages, at an organic-to-aqueous ratio of 6:315 by volume. The organic extraction liquid is a solution of 10% by volume of an alpha-hydroxyoxime (5,8-diethyl-7-hydroxy dodecane-6-oxime, known as LIX64N plus 20% by volume isodecanol, in kerosene solvent, i.e., a mixture of aromatic petroleum hydrocarbons having a boiling point range of 4l0460F and a specific gravity of 0.81.

The copper content of the aqueous raftinate following the five stages of separation is only 0.00l grams per liter. There is substantially no manganese, nickel or cobalt found in the organic extract phase. The aqueous solution at the start of the extraction stages has a pH of about 2, as set out in Example 2, and caustic is added during extraction to maintain that pH.

Following the separation from the final settling stage, the organic extract is stripped of copper by spent acid solution from a copper aqueous electrolysis cell having a hydrogen ion concentration of 3N. utilizing countercurrent flow through 5 stages of a mixer-settler series. The aqueous raftinate from the copper extraction step is adjusted to a pH of about 4.5 by the addition of 2N caustic solution. The resulting aqueous solution was extracted in a five-stage mixer-settler system, with a solution of l% by volume 7- 3-(5,5,7,7-tetramethyl-loctenyl)-8-hydroxyquinoline plus 20% by volume isodecanol in kerosene to extract nickel and cobalt.

The nickel is stripped from the organic extract phase using the spent solution from a nickel electrolysis cell to which hydrochloric acid is added to a concentration of hydrogen ion of 3N in order to insure stripping of all of the nickel. The organic liquid and stripping acid are passed countercurrently through mixer-settler stages at an organic-to-aqueous liquid ratio of 2:1, by volume. Substantially all of the nickel is removed from the organic phase.

The cobalt is next stripped from organic extract phase utilizing an aqueous solution containing by wt. HCl, in five mixer-settler stages at an organiczaqueous ratio of 2:l by volume. The cobalt is extracted from the 20% HCI solution using a kerosene solution containing l()% by volume triisoctyl amine(TlOA) at an organiczaqueous volume ratio of 2: l. The cobalt is stripped from the TlOA solution utilizing spent aqueous electrolyte from a cobalt electrolysis cell in 3 mixer-settler stages with a l :2 organiczaqueous phase ratio, by volume.

The raffinate from the cobalt extraction contains primarily manganese chloride. Hydrogen sulfide is passed through the raffinate to precipitate the various other metal values present, leaving a substantially pure solu tion of manganese chloride.

There is thus obtained as a result of this process four separate final streams each containing substantially pure metal chloride: copper chloride, nickel chloride, cobalt chloride and manganese chloride. Each of these aqueous solutions can be further treated by known methods to reduce the salts to the respective elemental metal.

Manganese is preferentially reduced in a fused salt electrolytic cell or in an aluminum reduction cell. The copper, nickel and cobalt are preferably electrolyzed in aqueous electrolytic cells.

The embodiments of this claimed are as follows:

1. A process for the recovery of meta] values from ocean floor nodule ore, the ore comprising as primary components compounds of copper, cobalt and nickel; the process comprising the steps of l reacting the nodule ore with a halide reactant comprising at least one halide of a metal selected from the group consisting of the alkali metal halides and the alkaline earth metal halides, by dispersing the ore in a molten salt bath of the halide reactant, the weight ratio of halide reactant to nodule ore in the bath being at least about one, to form the halides of manganese, copper, cobalt and nickel and a reacted ore residue, including the iron; and 2) separating said halides of manganese, copper, cobalt and nickel from the reacted nodule ore residue.

2. The process of claim I wherein the halides of manganese, cobalt and nickel are separated from the reacted nodule ore in an aqueous solution.

3. The process of claim 1 wherein the halides of manganese, copper, cobalt and nickel are separated by vaporization from the molten mass and condensed.

invention which are 4. The process of claim 3 wherein the condensed manganese. copper, nickel and cobalt halides are dissolved in an aqueous leach liquid to form an aqueous solution of said mixed halides.

5. The process of claim 3 wherein the halides are condensed by direct contact with a spray of water to form an aqueous solution of manganese halide, cobalt halide, nickel halide and copper halide.

6. The process of claim 3 wherein an inert carrier gas is passed over the molten mass to aid in the removal of vaporized halides.

7. The process of claim 1 wherein the halides are selected from the group consisting of chlorides and bromides.

8. The process of claim 7 wherein the halides are chlorides.

9. The process of claim I, wherein the halide reactant comprises an eutectic mixture comprising at least two halide salts.

10. The process of claim 1, comprising, in addition, prior to reaction with the halide reactant, reducing the nodule ore by mixing the ore with a carbonaceous material at a temperature of from about 250 to about 600C, to reduce the tetravalent manganese present in the nodule ore to divalent manganese.

11. The process of claim 10, wherein the reducing agent is selected from the group consisting of carbon, hydrocarbons, hydrogen and carbon monoxide.

12. The process of claim I, wherein the reactant halide is present in an amount of from about I to about l0 parts by weight per part by weight of nodule ore present.

13. The process of claim 3, comprising, in addition, leaching the condensed halides to form an aqueous solution thereof and separating the individual metal halides from the solution by consecutive extraction with selective liquid extraction agents.

14. The process of claim 13, wherein the extraction agents are liquid ion exchange compounds.

15. The process of claim 14, wherein the individual metal halides are reduced to the elemental metal by electrolysis.

16. A process for the recovery of metal values from ocean floor nodule ore, the ore comprising as primary components, the oxides of manganese and iron and as secondary components compounds of copper, cobalt and nickel; the process comprising the steps of 1) reducing the nodule ore at a temperature in the range of from about 250 to about 600C with a reducing agent selected from the group consisting of carbon, hydrocarbons, hydrogen and carbon monoxide, to reduce the manganese present in the nodule ore to divalent manganese; 2) reacting the reduced nodule ore with a halide reactant comprising at least one halide of a metal selected from the group consisting of the alkali metal halides and the alkaline earth metal halides, by dispersing the ore in a molten salt bath of the halide reactant, the weight ratio of halide reactant to nodule ore in the bath being at least about one to form the halides of manganese, copper. cobalt and nickel and a reacted ore residue, including the iron; and 3) separating said halides of manganese, copper, cobalt and nickel from the reacted nodule ore residue.

17. The process of claim 16, wherein the halides are chlorides.

18. The process of claim 17, wherein the halides of manganese, copper, cobalt and nickel are vaporized.

the vapors separated from the molten material and condensed.

19. The process of claim 18, comprising flowing an inert carrier gas in contact with the vaporized mixed metal halides to increase the rate of removal of the vaporized metal halides and removing a mixture of the carrier gas and the vaporized halides.

20. The process of claim 19, wherein the carrier gas is selected from the group consisting of nitrogen, carbon dioxide, the noble gases and hydrogen.

21. The process of claim 20, wherein the halide reactant comprises an eutectic mixture comprising at least one alkali metal chloride and at least one alkaline earth metal chloride.

22. The process of claim 16, wherein the temperature is maintained below l,200C.

23. The process of claim 17, wherein the halidation reaction, Step 2, is carried out at a temperature in the range of from about 340 to, about 700C.

24. The process of claim 19, wherein the vaporization of the halides is carried out at a temperature of at least about 600C.

25. The process of claim 18, wherein the halide vapors are condensed by direct contact with a spray of water.

26. A process for the recovery of metal values from ocean floor nodule ore, the ore comprising as primary components, the oxides of manganese and iron and as secondary components compounds of copper, cobalt and nickel; the process comprising the steps of 1) reducing the nodule ore with a reducing agent selected from the group consisting of carbon, hydrocarbons, hydrogen and carbon monoxide, to reduce the manganese present in the nodule ore to divalent manganese; 2) reacting the reduced nodule ore with a halide reactant comprising at least one halide of a metal selected from the group consisting of the alkali metal halides and the alkaline earth metal halides, by dispersing the ore in a molten salt bath of the halide reactant, the weight ratio of halide reactant -tonodule ore in the bath being at least about one, to form the halides of manganese, copper, cobalt and nickel and a reacted ore residue, including the iron; and 3) vaporizing the halides of manganese, copper, cobalt and nickel and separating the vapors from the molten bath and reacted ore residue.

27. A process for the recovery of metal values from ocean floor nodule ore, the ore comprising as primary components, the oxides of manganese and iron and as secondary components compounds of copper, cobalt and nickel; the process comprising the steps of I) reducing the nodule ore with a reducing agent selected from the group consisting of carbon, hydrocarbon, hy drogen and carbon monoxide, to reduce the manganese present in the nodule ore to divalent manganese, 2) reacting the reduced nodule ore with a halide reactant comprising at least one halide of a metal selected from the group consisting of the alkali metal halides and the alkaline earth metal halides, dispersing the ore in a molten salt bath of the halide reactant, the weight ratio of halide reactant -tonodule ore in the bath being at least about one, to form the molten halides of manganese, copper, cobalt and nickel as a salt bath product, and a reacted ore residue, including the iron, dispersed in the salt bath product, 3) cooling the salt bath product to form a solid mixture comprising the halides of manganese, copper, cobalt and nickel and the ore residue; 4) leaching the solid mixture with water to form an aqueous solution of the halides; and 5) separating the aqueous solution of the halides from the waterinsoluble reacted ore residue.

28. A process for the recovery of metal values from ocean floor nodule ore, the ore comprising as primary components, the oxides of manganese and iron and as secondary components compounds of copper, cobalt and nickel; the process comprising the steps of 1) reacting the nodule ore with a halide reactant comprising at least one halide of a metal selected from the group consisting of the alkali metal halides and the alkaline earth metal halides, by dispersing the ore in a molten salt bath of the halide reactant, the weight ratio of halide reactant-to-nodule ore in the bath being at least about one, to form the molten halides of manganese, copper, cobalt and nickel as a salt bath product, and a reacted ore residue, including the iron, dispersed in the salt bath product; 2) cooling the salt bath product to form a solid mixture comprising the halides of manganese, copper, cobalt and nickel and the ore residue; 4) leaching the solid mixture with water to form an aqueous solution of the halides; and 5) separating the aqueous solution of the halides from the water-insoluble reacted ore residue.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 1 3, 894,927

DATED 1 July 15, 1975 'NVENTOR(5) 1 WILLIAM s. KANE; HUGH L. MCCUTCHEN; PAUL H.

. CARDWELL It rs certrfred that error appears In the above-rdentrtred patent and that sard Letters Patent are hereby corrected as shown below:

Column 22, line 41 (Claim 28, line 17) change "4)" line 20) change "5)" Erigncd and Scaled this sixth D of January 1976 [SEAL] A tres t:

C. MARSHALL DANN Arresting Officer

Claims

1. A PROCESS FOR THE RECOVERY OF METAL VALUES FROM OCEAN FLOOR NODULE ORE, THE ORE COMPRISING AS PRIMARY COMPONENTS COMPOUNDS OF COPPER, COBALT AND NICKEL, THE PROCESS COMPRISING THE STEPS OF 1) REACTING THE NODULE ORE WITH A HALIDE REACTANT COMPRISING AT LEAST ONE HALIDE OF A METAL SELECTED FROM THE GROUP CONSISTING OF THE ALKALI METAL HALIDES AND THE ALKALINE EARTH METAL HALIDES, BY DISPERSING THE ORE IN A MOLTEN SALT BATH OF THE HALIDE REACTANT, THE WEIGHT RATIO OF HAIDE REACTANT - TO - NODULE ORE IN THE BATH BEING AT LEAST ABOUT ONE, TO FORM THE HALIDES OF MANGANESE, COPPER, COBALT AND NICKEL AND A REACTED ORE RESIDUE, INCLUDING THE IRON, AND 2) SEPARATING SAID HALIDES OF MANGANESE, COPPER, COBALT AND NICKEL FROM THE REACTED NODULE ORE RESIDUE.

2. The process of claim 1 wherein the halides of manganese, cobalt and nickel are separated from the reacted nodule ore in an aqueous solution.

4. The process of claim 3 wherein the condensed manganese, copper, nickel and cobalt halides are dissolved in an aqueous leach liquid to form an aqueous solution of said mixed halides.

8. The process of claim 7 wherein the halides are chlorides.

9. The process of claim 1, wherein the halide reactant comprises an eutectic mixture comprising at least two halide salts.

10. The process of claim 1, comprising, in addition, prior to reaction with the halide reactant, reducing the nodule ore by mixing the ore with a carbonaceous material at a temperature of from about 250* to about 600*C, to reduce the tetravalent manganese present in the nodule ore to divalent manGanese.

12. The process of claim 1, wherein the reactant halide is present in an amount of from about 1 to about 10 parts by weight per part by weight of nodule ore present.

16. A process for the recovery of metal values from ocean floor nodule ore, the ore comprising as primary components, the oxides of manganese and iron and as secondary components compounds of copper, cobalt and nickel; the process comprising the steps of 1) reducing the nodule ore at a temperature in the range of from about 250* to about 600*C with a reducing agent selected from the group consisting of carbon, hydrocarbons, hydrogen and carbon monoxide, to reduce the manganese present in the nodule ore to divalent manganese; 2) reacting the reduced nodule ore with a halide reactant comprising at least one halide of a metal selected from the group consisting of the alkali metal halides and the alkaline earth metal halides, by dispersing the ore in a molten salt bath of the halide reactant, the weight ratio of halide reactant - to - nodule ore in the bath being at least about one to form the halides of manganese, copper, cobalt and nickel and a reacted ore residue, including the iron; and 3) separating said halides of manganese, copper, cobalt and nickel from the reacted nodule ore residue.

17. The process of claim 16, wherein the halides are chlorides.

18. The process of claim 17, wherein the halides of manganese, copper, cobalt and nickel are vaporized, the vapors separated from the molten material and condensed.

22. The process of claim 16, wherein the temperature is maintained below 1,200*C.

23. The process of claim 17, wherein the halidation reaction, Step 2, is carried out at a temperature in the range of from about 340* to, about 700*C.

24. The process of claim 19, wherein the vaporization of the halides is carried out at a temperature of at least about 600*C.

26. A process for the recovery of metal values from ocean floor nodule ore, the ore comprising as primary components, the oxides of manganese and iron and as secondary components compounds of copper, cobalt and nickel; the process comprising the steps of 1) reducing the nodule ore with a reducing agent selected from the group consisting of carbon, hydrocarbons, hydrogen and carbon monoxide, to reduce the manganese present in the nodule ore to divalent manganese; 2) reacting the reduced nodule ore with a halide reactant comprising at least one halide of a metal selected from the group consisting of the alkali metal halides and the alkaline earth metal halides, by dispersing the ore in a molten salt Bath of the halide reactant, the weight ratio of halide reactant -to- nodule ore in the bath being at least about one, to form the halides of manganese, copper, cobalt and nickel and a reacted ore residue, including the iron; and 3) vaporizing the halides of manganese, copper, cobalt and nickel and separating the vapors from the molten bath and reacted ore residue.

27. A process for the recovery of metal values from ocean floor nodule ore, the ore comprising as primary components, the oxides of manganese and iron and as secondary components compounds of copper, cobalt and nickel; the process comprising the steps of 1) reducing the nodule ore with a reducing agent selected from the group consisting of carbon, hydrocarbon, hydrogen and carbon monoxide, to reduce the manganese present in the nodule ore to divalent manganese, 2) reacting the reduced nodule ore with a halide reactant comprising at least one halide of a metal selected from the group consisting of the alkali metal halides and the alkaline earth metal halides, dispersing the ore in a molten salt bath of the halide reactant, the weight ratio of halide reactant -to- nodule ore in the bath being at least about one, to form the molten halides of manganese, copper, cobalt and nickel as a salt bath product, and a reacted ore residue, including the iron, dispersed in the salt bath product, 3) cooling the salt bath product to form a solid mixture comprising the halides of manganese, copper, cobalt and nickel and the ore residue; 4) leaching the solid mixture with water to form an aqueous solution of the halides; and 5) separating the aqueous solution of the halides from the water-insoluble reacted ore residue.