US931515A - Method of treating corrosive gaseous fumes or smoke. - Google Patents

Description

. ofTre-ating. Corrosive Gaseous Fumes jor.

- Sn1oke';-.and I do hereby declare the follow- UNITED STATES PATENT oFFIoE.

CLARENCE B. SPRA'GUE, OF SALT s LTINe, REFINING &

LAKE CITY, UTAH, ASSIGNOR TO UNITED STATE MINING COMPANY, A CORPORATION OF MAINE.

METHOD onranarmeoonnoslvn Gaseous FUMES R 'sMoKE.

To all a concemu' p Be it knownthat I, CLARENCE B. SPBAGUE,

a citizen ofothe United States, residing at ,-Salt. Lake City, in the county of Salt Lakehave invented. certain and State 'of Utah, new and useful Improvements" in-Methods ing to be. a full, clear, of the. invention, skilled 'inY-the art exact desqription {snake andluse the samefi ff corros ve 'gaseous fumes or smoke such as- -are produced in the IOaStIIIg'DI othertreat The invention relates to the treatment of ii v.Jnoving from the smokevaluable metals and ..1netallic compoundsor compounds andsubsin-noes which mi ht he injurious to vegetable'aud annual lite if allowed -.to escape, into the atmo.sphere;

, #It iswell known tlu-itvthe gaseous fumes or tain' large quantities of sulfur dioxidwhich emsts 1n the smoke 1n a gaseous state. 1 It is not the purpose of thepresent invention to remove this. gas from the smoke.- The smoke producedin the, treat-mentgof inanyY-sulfid ores, either loecausefl of ,the composition of the ore or because; of the character ofthe treatment to which the. ores are subjected,-

also contains more or less sulfuric acid and other corrosive compounds which exist 1n the gaseous roducts as aivapor Oran a finely sion. These minute particles of condensed.

sulfuric acid and other solublecorrosive, compoundscollect upon the minute particlesof solidanatter known as fume, which are always present in the smoke, and are deposited with the fume upon;the surrounding V vegetation when :the smoke is dicharged into ,t-hesatmosphere, and have an 1n ur1ous cor-v .rosive action upon suchvegetation. The solidi-tune, in tIddlt-IOII to valuable-me'tals and metallic compounds,{also frequently contains poisonous compounds of arsenic and other substances which notonly are injurious'to vegetation-but also render "any vegetation upon which they may collect unfit for;

food or fodder.

lt'is the object'of, the

such as 'will enable others .t'oiwhich it appertains to I *fthrough cotton-or woolen filtering fabric.

solid state held in suspen- Specification 01 Letters Patent. p .Tatented Aug. 17, 1909. Appllhation'aflledjlanuary 27, 19419. Serial-1Y0. 474,392. I I

from the smoke produced in the roasting or other treatment ;of such sulfid ores so "that the smoke maygbedischarged intoth'e atmosphere withoutfin jury to the surrounding vegetation, and any values contained in the fumema'y be reclaimed if desired. In cases Where the gaseous fumes or smoke predlicedin the treatment of ores are free from sulfuric acid and other corrosive comlpou'ndsy-it has been the'practice. to-some' ex- :tentto remove the. fume by filtration bags for the-purpose ofrecove'ring the values contained in the fume. It has heretofore been considered impracti'cable,':-however, to successfully filter the smoke [producedinthe treatment of man of the sulfid ores 'smok esproduced in the roasting and smelting of the sulfid' ores of lead and copper, tecause-of the inevitable presence in the sn'ioke of sulfuric"lat-idjaml'other corrosive (.Oll'iand especially thev pounds which would quickly destroy the i have discovered that the minute particles =0f sulfuric acid or vother- "corrosive C0311- pounds held in suspensionin thewsmokc from ore roasting and otherfurnaces may be successfully neutralized so as to enable-the filtration of the smoke through the fabric" by minglingu itlrthe smokei a pulverulentf attested by the sulfur dioxidan'd-which is neutralizing agent which is, practically un held in suspension inthe'smoke 'for a suffi '0 ion t length of time to hnitewith the corrosive compounds therein. The smoke thus neutralized may :then -;be passed throughcloth bagswvithout injuryto the ba'gs,"and

thus the solid fume be completely-removed I therefrom. The invention-in its broader aspects contemplatesmingling the -pulveruy lent neutralizing agent, with the smoke in any suitable manner. v p Y I have also' foundthat a substantially complete neuti-alizationiof the smoke may be successfull 'veruleut neu .i'alizing agent into-the smoke fabric, and.-

further feature of theiii-vention,- p Y The neutrahzmgf agent may bejmingled with the smoke ata-ny desired point, andthe smoke, -'after it is .eooledto a temperature present invention to: removethe corrosive constituents and fume which .wil'lnot injurious-1y affect the fabric on its way; from the furnacekto the filtering 131118 manner of m ngling the neutralizing agent with the smoke forms a effected by introduclug'a .pul- '-1o0 through which it is ,to be filtered, is passed .relation to form non-corrosive compounds.

The acidity of any acid salts held in suspension in the fumes or gas will also be neutral ized by the neutralizing agent, and any soluble salts or heavy metals, such as iron or copper, whichhave become moist or adhesive, and which wouldhave a destructive or corrosive action, Wlll be decomposed by the neutralizing agent, and non-corrosive and.

unobjectionable compounds formed. The smoke as it comes 'to the filtering fabric wlll therefore contain no corrosive compounds, and may be filtered through the fabric without injury thereto. By this treatment, there fore, metals, -metallic compounds, and poisonous and 1n urious compounds contained within the fume, and the corrosive and in- JllI'lOIlS compounds held in suspension,-are removedfrom the smoke before it is Cl1S' charged into the atmosphere. The-danger of injury to vegetation is thus eliminated or reduced to a minimum, and the solid fume is collected so that any values contained therein may bereclaimed if desired by the proper subsequent treatment.

The invention in its broader aspectscontemplates the use of any suitableneutralizing agent which in a pulverulent form has the property of neutralizing acids and the' acidity of acid salts, or of decomposing the soluble salts-of heavy metals such as iron and co per when in solution. Oxid of zinc, oxid of magnesia, oxid orhydroxid of calcium, oXid or hydroxid of barium, thecarbonate and bicarbonate of .said bases, or the oxids, hydroxids, carbonates or bicarbonates of sodium and potassium have this property to a greater or less degree, and are adapted for use as the neutralizing agent. I have found, however, that zinc oxid is especially effective in securing a complete neutralization of the corrosive compounds in the smoke when mingled with the smoke in a .pulverulent form, and the use of this oxid, either alone or in connection with other neutraliz- -ing compounds as the neutralizing agent constitutes a further feature of the invention.

In cases where the' quantities of sulfuricacid and other corrosive com ounds in the smoke are comparatively sma l, I prefer to use pulverulent zinc oxid alone to neutralize the smoke, since a comparatively small quantity of this oxid when mingled with the smoke will effectively and completely neutralizethe sulfuric acid and other corrosive compounds. In cases where the per cent. of sulfuric acid and corrosive compounds is comparatively, large, I have found that an effective and-complete neutralization of. the smoke may be secured by introducing into the smoke finely divided slaked lime and at the same time or thereafter introducing a small amount of zinc oxid. The slaked lime unites with the greater portionof the sulfuric acid and other corrosive compounds contained within the smoke, and the zinc -oxid completes the neutralization by uniting with whatever corrosive compounds would remain in the smoke but for its introduction.

In practicing the invention, the, neutralizing agent may be introduced into the smoke on its way from the furnace to the filtering fabric at any. desired-point, and'in any-suitable manner. For instance, it may be successfully introduced I into a flue through which the smoke passes by blowing it into the flue, or by an ordinary roller feed, the velocity of the gases being such in either case. that the neutralizing agent is held in suspension in the smoke a suliicient length of time to unite with the corrosive compounds therein. The neutralizing agent may also be successfully introduced into the smoke by feeding-it into the inlet of the fan which blows the gases into the bag-house where thesmoke is filtered. In the latter case, the solid particles of the neutralizing agent are held in suspension a suflicient length of time to efiect the thorough neutralization of the corrosive compounds before the smoke comes in contact with the filter bags.

- In using zinc oxid as the neutralizing agent, it may be advantageously intermingled with the smoke by providing a spe cial furnace in which suitable uantities of zinc ore are roasted, and disc iarging the zinc oxid produced in this furnace into the flue through which the. smoke'to be treated passes. The zinc oxid fume produced inthe furnace, and discharged into the fiue,.is in a state of fine subdivision, and is thoroughly intermingled with the gases and their accompanying fume. .The oxid, therefore, is

brought into intimate relation'with the fine particles of sulfuric acid or other corrosive compound held in suspension in the gases, or

which may have collected on the particles of to form non-corrosive compounds. Thesulfur dioXid in the gases ispractically without efiect on the zinc oXid, and the zinc oXid therefore need be present only in sufficient quantities to neutralize the sulfuric acid and corrosive compounds.

thoroughly mixed with the gases, and arefume, and combines with thesecompounds The form of apparatus utilized in practicing the invention is not material, and it may be ofany well known or usual constructi'on.

\ Having set forth the nature andobject of the invention, what I claim-is:- .3 j Y 1. The method of treatingcorrosive gaseous fumes or smoke from ore treating furnaces for the purpose of removing injurious or valuable compounds therefrom consisting in introducing into from the furnace a pulverulent neutralizing j agent which is held in suspension in the' the smoke on-its way smoke and unites with the, corrosive com pounds therein to form non-corrosive compounds, substantially as described.

2. The method of treating corrosive'gase ous fumes ,or naces for the purpose of removing injurious or valuable compounds therefrom, consisting in introducing into the smoke on its way from the furnace a pulverulent neutralizing agent which is held in suspension in the smoke and unites with the corrosive compounds therein to form non-corrosive com' pounds, and thereafter filtering the smoke to remove the fume, substantially'as describeda 3. The method of treating corrosive gaseous fumes or smoke fromore treating-fur naces for the purpose of removing injurious or valuable compounds therefrom, consisting in introducing into the 7 from the furnace a pulverulent neutralizin agent comprising zmc oxid, which is held in suspension in the 'smoke and unites with the corrosive compounds to forlnnon-cor rosive, compounds, and thereafter filtering the smoke to remove the fume,substantially as described. I

4. The method of neutralizing the cor rosive constituents of corrosive gaseous fumes or smoke consisting in mingling therewith a pulverulent neutralizing agent which is.

held in suspension therein and unites with the corrosive compounds to form non-corrosive compounds, substantially as described.

smoke from ore treating fursmoke on .its way- 5. The method of treating corrosive gaseous fumes or smoke for the purpose of removlng in urious .or

smoke a pulverulent neutralizlng'agent, such as pulverulent lime, which unites with the major portion of the corrosive compounds, completing the neutralization by mingling pulverulent, zinc oxid "with the smoke, and

tering fabric to remove tially as described.

7 The method of treating corrosive gasefumes or smoke for the purpose of rethe fume, substanous moving injurious or valuable compoun'ds therefrom, consistlng 1n mingling therewlth "a pulverulent neutralizing agent which unites with the corrosive compounds in the smoke to form non-corrosive compounds, and thereafter filtering the fume, substantially as described.

8. Themethod oftreatingcorrosive gaseousfumes or smoke for the purpose of removing injurious 'or valuable compounds therefrom,

a pulverulent neutralizing agent comprising which unites with the corrosive compounds in the "smoke to form non-corconsisting in mingling therewith rosive compounds, and thereafter filtering the smoke to remove, the fume, substantially as described. I

-- In testimony whereof I aflix my signature,

in. presence of two' witnesses.

' CLARENCE B. SPRAGUE.

Witnesses:

' ANDREW Ho'wA'r,

R. 'H. BU'rrnRFmLn.

valuable compounds-- therefrom consisting in mingling with the.

thereafter passing the smoke through a filsmoke to remove the a