A kind of method for bleaching high-concentration kaolin pulp
Technical field
The present invention relates to the chemical bleaching method in a kind of kaolin product production, particularly a kind of bleaching method of high density kaolin ore pulp.
Background technology
Kaolin is mainly used in ceramic industry, coating, refractory materials, papermaking, paint, rubber, senior porcelain, electric wire, industrial plastic, chemical engineering industry filler and printing ink, food, makeup, medicine etc.China's kaolin resource mainly contains three major types, a kind of is to be the ore type kaolin that the elevated temperature heat crack filling of representative becomes the ore deposit with Suzhou kaolin, this kaolin mostly is tubulose, columnar crystal structure, minority is the tabular crystal structure, need carry out classification again after the Mechanical Crushing, be fit to be processed into the product that petrochemical catalyst is used.Second kind is Coaseries kaolin, its crystalline structure has needle-like, sheet, column, tubulose are also arranged, polluted by coal because of it becomes in the process of ore deposit, must become another kind of mineral material after the processing through the further processing of calcining back, how aspect loading material of rubber, high-grade paint, to use, also have minority to use on papermaking paint, its tooling cost applies being restricted than grittiness kaolin height.The third is to be the chiltern type kaolin through the weathering sedimentary mineralization of representative with Maoming kaolin, its crystalline structure mostly is sheet, needle-like, tubular structure are also arranged, the kaolin of tabular crystal structure is processed into high-grade coating papermaking paint product, product granularity, spend certainly, index request height such as sticking concentration.
The chiltern type kaolin in Maoming mainly adopts the mining of hydrodynamic cleaning method, because pulp density low (pulp density is generally 8~15%), bleaching method direct adding sulfuric acid, the vat powders of adopting stir bleaching more in the production, because kaolin ore pulp concentration is low, take a policy behind the powder because vat powder is met the water capacity under acidic conditions hydrolysis easily takes place carry out autoreaction, therefore production capacity is little, and the production unit energy consumption is big, the medicine consumption is big, and is unfavorable for that follow-up filter-press dehydration technique processes; The kaolin ore pulp bleaching high to concentration, because its viscosity is big, stirring is difficult, difficulty is bleached the vat powder uniform distribution, as adding with the water dissolution vat powder, because autoreaction was carried out in easy generation hydrolysis after vat powder was met water, its character is extremely unstable, and bleaching effect is passed the anxious utmost point in time and descended, after 30 minutes ore pulp has not been had bleaching action, and vat powder adding consumption is big.
It is a kind of with the technology of complexometry from the removing iron by kaolin bleaching that patent CN89107952.1 provides, and preferred complexing agent, lattice reagent, reductive agent and dispersion agent and their composition proportion reach the deironing bleaching, the reagent combination complexity.Patent application CN200410052171.5 provides a kind of production method of superfine kaolin, the pulp density of chemical bleaching low (6~12%), add sulfuric acid, vat powder and alkaline agent bleaching, patent application CN200710053033.2 provides a kind of high sticking concentration production technology, patent application CN200710053034.7 provides a kind of paper making and cloth coating production technology, all be to adopt hydraulicefficiency machinery method exploitation kaolin ore and make the kaolin ore pulp, major technique is not in bleaching, adopt traditional chemical bleaching method, had the same shortcoming of above-mentioned technology.
Summary of the invention
The object of the present invention is to provide a kind of method for bleaching high-concentration kaolin pulp, guarantee bleaching effect, cut down the consumption of energy and reagent consumption, save production cost.
Purpose of the present invention can realize by following technical measures: the dry mining kaolin ore, remove impure mineral, raw ore adds entry, Sodium hexametaphosphate 99, sodium hydroxide mixing, mixing solid content is 65~70%, carries out high speed dispersion and smashes slurry, removes coarse sand through three grades of spiral sand removing machines, the scraper plate machine is removed fine sand, ultra-fine mill, the spiral shell classification of crouching obtains the high density ore pulp, and is as follows to the blanching step of high density ore pulp:
(1) the preparation vat powder aqueous solution: add alkali earlier and obtain alkaline water in water, the powder that takes a policy again carries out stirring and dissolving, and making its vat powder volumetric concentration is 10~15%, and regulating the vat powder pH value of aqueous solution is 7.0~8.0;
(2) the vat powder aqueous solution mixes with the kaolin high concentration ore pulp: respectively the vat powder aqueous solution, kaolin high concentration ore pulp are sent in the same pipeline by pump, mixed when carrying, kaolin ore pulp concentration is 25~30%;
(3) leave standstill bleaching: deliver to slurry can with the kaolin high concentration ore pulp after the vat powder aqueous solution, leave standstill bleaching in jar, bleaching time is 15~20 hours, and the pH value of regulating slurries after bleaching is finished is 2.5~3.0.
In step (1), the add-on of alkali is as the criterion 7.0~8.0 with the pH value of vat powder dissolving rear solution, described alkaline agent is made up of sodium hydroxide (caustic soda) and yellow soda ash (soda ash), the weight proportion of sodium hydroxide and yellow soda ash is 0.33~0.47: 10, the weight proportion of vat powder and alkaline agent is 100: 10.3~10.5 in the vat powder aqueous solution, the vat powder properties of Aqueous Solution of preparation is stable, can be used for the bleaching of kaolin ore pulp in 3 hours.
In step (2), the add-on of the vat powder aqueous solution is 1.4~2.3% of a kaolin high concentration ore pulp.
After step (3) was finished, ore pulp whiteness 〉=87.0 that obtain were floated the width of cloth and are reached 19%, were finished product after dehydration press filtration, ultra-fine mill, drying.
The invention has the beneficial effects as follows: technical scheme is reasonable in design, and operation is easy to control, process stabilizing, the high density ore pulp of bleaching helps follow-up filter-press dehydration processing, has improved the production production capacity, has reduced energy consumption and reagent consumption, reduce production cost, stablized the kaolin product quality.
Embodiment
The geographic chiltern type in dry mining Maoming, crystalline structure are flaky kaolin, remove impure mineral, add and carry out high speed dispersion after entry, Sodium hexametaphosphate 99, sodium hydroxide mix and smash slurry, remove coarse sand through three grades of spiral sand removing machines, the scraper plate machine is removed fine sand, ultra-fine mill, the spiral shell classification of crouching obtains the high density ore pulp, and pulp density is 25~30%.Set up vat powder dissolving vessel and slurry can, the vat powder dissolving vessel connects the pipeline of carrying high density kaolin ore pulp by pipeline through pump, connects slurry can, and embodiment is as follows in bleaching:
Embodiment one: at pack into 3 cubic metres in clear water of vat powder dissolving vessel, add 0.99 kilogram in sodium hydroxide again, 30 kilograms in yellow soda ash, stirring and dissolving 8 minutes, the powder that takes a policy again stirs dissolving in 15 minutes for 300 kilograms, the vat powder volumetric concentration is 10%, and the pH value is 7.1, and the vat powder aqueous solution for preparing is standby.Respectively the vat powder aqueous solution, kaolin high concentration ore pulp are sent in the same pipeline by pump, when carrying, mix, the flow of pumping kaolin high concentration ore pulp is per hour 70 cubic metres, the flow of the pumping vat powder aqueous solution is per hour 1.61 cubic metres, deliver to slurry can and leave standstill bleaching, bleaching the pH value of regulating slurries after 20 hours is 2.5, and ore pulp whiteness 87.0 degree that obtain can be given following process.
Embodiment two:
At pack into 1.1 cubic metres in clear water of vat powder dissolving vessel, add 0.7 kilogram in sodium hydroxide again, 15 kilograms in yellow soda ash, stirring and dissolving 5 minutes, the powder that takes a policy again stirs dissolving in 12 minutes for 150 kilograms, and the vat powder volumetric concentration is 15%, the pH value is 8.0, and the vat powder aqueous solution for preparing is standby.Respectively the vat powder aqueous solution, kaolin high concentration ore pulp are sent into same pipe-line blending by pump, the flow of pumping kaolin high concentration ore pulp is per hour 70 cubic metres, the flow of the pumping vat powder aqueous solution is per hour 0.98 cubic metre, deliver to slurry can and leave standstill bleaching, bleaching the pH value of regulating slurries after 15 hours is 3.0, more than ore pulp whiteness 87.0 degree that obtain, be finished product after dehydration press filtration, ultra-fine mill, drying, quality product reaches standard-required.