CN102786818B

CN102786818B - Method for whitening kaolin by using surface cladding method

Info

Publication number: CN102786818B
Application number: CN201210232415.2A
Authority: CN
Inventors: 赵曰浩
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-06-29
Filing date: 2012-06-29
Publication date: 2014-02-19
Anticipated expiration: 2032-06-29
Also published as: CN102786818A

Abstract

The invention relates to a method for whitening kaolin by using a surface cladding method. The method comprises adding water and a dispersant into the kaolin to prepare slurry with a concentration of 40 to 60 %, adjusting a pH value to 7 to 8, and ball milling for 60 to 120 minutes with a high speed so as to fully activate the surface of the kaolin particles; and then adding an aluminum sulfate or aluminum nitrate solution into the kaolin slurry, fully mixing with stirring, slowly adding ammonia water, continuing to stir and react, standing, filtering and drying to obtain the highly whitened kaolin product. Through detection, the surface of the kaolin product is coated with an Al(OH)3 deposited layer which can shield dyeing substances in the kaolin and significantly improve whiteness of the product. The whitened kaolin through cladding can be used as papermaking paint, and especially as high-quality filling materials in the fields of plastic, rubber, etc. The implementation of the method can greatly increase added value of the low-quality kaolin, enlarge application scope of the low-quality kaolin and improve utilization efficiency of mineral resources.

Description

The coated method in a kind of utilization surface brightens kaolinic method

Technical field

The invention belongs to field of inorganic nonmetallic material, be specifically related to the coated method in a kind of utilization surface and brighten kaolinic method.

Background technology

Kaolin, is the aggregate of the hydrous alumino silicates of multi mineral composition, and main component is kaolinite, it is generally acknowledged that its chemical formula is Al ₂o ₃siO ₂2H ₂o (crystal water exists with the form of hydroxyl), 1: the 1 type layer silicate mineral being formed by common oxonium ion key connecting by a stratiform silicon-oxy tetrahedron and alumina octahedral forms.Pure kaolin is white in color, conventionally in kaolin ore, often contain the trace quantity minerals such as montmorillonite, illite, pyrite, limonite, carbonaceous and quartz, these attendants are dyed various different colours by kaolin, have a strong impact on kaolinic whiteness and using value, generally must adopt physics and chemistry method to remove the impurity in kaolin, improve its whiteness and using value.Therefore kaolinic whiteness is the important indicator that determines its purposes and economic worth, and therefore from technology and economic overall equilbrium, considering to improve kaolinic whiteness also becomes the emphasis of the art, difficult point.

Conventional kaolin method of whitening mainly contains at present:

1. superfine grinding

In Jet Crushing, material is subject to the effect of extraneous mechanical force, in macroscopic view, show as the increase of material particles refinement, miniaturization and specific surface area, and on microcosmic because portion of energy accumulates in granular system inside, thereby cause particle lattice distortion, lattice imperfection, amorphization, generate radical, surface free energy increases.For kaolin, the process of its grain refine is also the process that its true density and strict density reduce.Because density reduces and has increased its scattering of light space, its optical scattering coefficient is increased, the scattering of light of air one particle interface has simultaneously increased opaqueness, and the luminous reflectance on interface has increased its whiteness.(vast stretches of wooded country etc., ultra-fine coal measures satin burns character and the surface modification [J] thereof of kaolin particle. University of Science & Technology, Beijing's journal, 1999,21 (6): 516-518).

2. calcining is brightened

In kaolin, fixed carbon content is generally 2% left and right (Coaseries kaolin carbon content is higher), be present in kaolinite xln gap, make kaolin present grey black or canescence (Zou Zhengguang etc., kaolinic fine processing and the application in novel material [J] thereof. Technical Colleges Of Guilin's journal, 2004,24 (4): 205-210).This kaolin often adopts high-temperature calcination de-carbon to improve its whiteness, and calcining temperature is conventionally at 800-900 ℃.In heat-processed, the carbonaceous of various forms is finally with CO ₂form discharge.Kaolin calcination de-carbon process is the process that increases whiteness, and especially for Coaseries kaolin, calcining whitening effect is fairly obvious.

3. chemical removal of iron brightens

Chemical removal of iron method has multiple, traditional employing vat powder reduction method, uses strong reductant V-Brite B and kaolinic ferric oxide effect, and water-fast ferric iron is reduced to water-soluble ferrous ion, can remove after filtration.The whiteness value that this method can reach is not high, and because of the factor of relative influence too many, the more difficult control of reaction process.

Summary of the invention

The technical problem to be solved in the present invention is to provide the coated method in a kind of utilization surface and brightens kaolinic method.

For solving above technical problem, technical scheme of the present invention is: the coated method in a kind of utilization surface brightens kaolinic method, comprises the steps:

(1) kaolin raw material and dispersion agent are added to water and be made into the slurry that weight percent concentration is 40-60%;

(2) slurry pH value upper step being made is adjusted to after 7-8, high speed ball milling 60-120min, and obtaining weight percent concentration is the grout below 10%;

(3) Tai-Ace S 150 or aluminum nitrate are joined in the grout that upper step makes, after being fully uniformly mixed, slowly add ammoniacal liquor, continue after stirring reaction, through standing, filter, dry, obtain the kaolin product after brightening.

Described dispersion agent is anhydrous sodium carbonate or Sodium hexametaphosphate 99, and its addition is the 0.1-0.2% of kaolin raw material dry weight.

The concentration of described kaolin grout is preferably 5%-10%.

The addition of described Tai-Ace S 150 or aluminum nitrate and kaolinic weight percent are 0.1-0.3: 1.

Described ammoniacal liquor is pressed NH ₃: Al ₂(SO ₄) ₃mol ratio is 3-5: 1 or NH ₃: Al (NO ₃) ₃mol ratio is 2-4: 1 adds.

Described being dried as temperature is 105 ℃, be 10 hours time of drying.

The scope that above-mentioned kaolin product whiteness can be enhanced is 4-10 degree.

On the basis of the kaolin product that the present invention produces at traditional technique of preparing, adopt the mode of high speed ball milling to grind kaolin, realize on the one hand the pulverizing of particle, make on the other hand kaolin particle surface occur more lattice imperfection and-OH, this is to realize the coated essential condition of deposition; The Al (OH) that adopts Tai-Ace S 150 or aluminum nitrate solution and ammoniacal liquor reaction to generate ₃particulate parcel kaolin particle, its principle is: kaolin is because the feature of its crystalline structure causes in acidic medium, and kaolin crystal bottom surface is electronegative and end face is positively charged, and in alkaline medium, whole kaolin surface is all electronegative.Therefore first regulate kaolin slurry pH=7-8 before high speed ball milling, be in order to make the kaolin particle surface band negative electricity after ball milling.Add subsequently alum liquor and ammoniacal liquor, reaction as follows occur:

Al ³⁺+OH ^-→Al(OH) ₃↓

Due to the Al (OH) that above-mentioned reaction generates when the pH=7-8 ₃deposit seeds surface band positive electricity, so Al (OH) ₃under electrostatic adsorption, be adsorbed to kaolin particle surface, form white coating layer, coloring matter in kaolin is played to bridging effect, product whiteness is obviously improved.

The invention provides the coated method in a kind of utilization surface and brighten kaolinic method, first kaolin is carried out the high speed ball milling activation of certain hour, adopt again aluminium salt and ammoniacal liquor to carry out liquid deposition, completed the coated production technique brightening in kaolin surface, it is superfine that the method can be widely used in processing staining impurity disseminated grain size, the unconspicuous sandy kaoline of chemical removal of iron whitening effect, through the coated kaolin product whiteness brightening, can increase 4-10 degree, can be used as coating and the plastics of papermaking, the high quality filler in the fields such as rubber is used, this technical matters is simple, use equipment is less, produce power consumption lower, and can greatly increase low-quality kaolinic added value, expand low-quality kaolinic range of application, improved the utilising efficiency of Mineral resources, meet the requirement that national energy-saving reduces discharging, therefore there is the wide market space.

Accompanying drawing explanation

Fig. 1 is the SEM picture (* 10000) of the embodiment of the present invention 1 kaolin raw sample;

Fig. 2 is the surperficial coated kaolin sample SEM picture (* 10000) after processing that brightens of the embodiment of the present invention 1.

Embodiment

Embodiment 1:, through the coated kaolin that brightens processing, Blue Whiteness is not 80.5.

50g kaolin, 0.05g anhydrous sodium carbonate, 70ml distilled water are mixed, regulate pH=7, ball milling 400r/m, ball milling 60min.Take 2.5g Tai-Ace S 150 and be dissolved in 20ml distilled water, solution is added in kaolin mud (dilution is concentration 10%), continue to stir 15min.Get the ammoniacal liquor 2ml of concentration 20%, dropwise add in kaolin mud used time 10min.After reaction finishes, standing 30min.Filter 105 ℃ of freeze-day with constant temperature 10 hours.Record product Blue Whiteness 85.5.Coated whitening technology improves product whiteness 5 degree.

Embodiment 2:, through the coated kaolin that brightens processing, Blue Whiteness is not 79.9.

50g kaolin, 0.05g Sodium hexametaphosphate 99,50ml distilled water are mixed, regulate pH=8, ball milling 400r/m, ball milling 90min.Take 5g aluminum nitrate and be dissolved in 20ml distilled water, solution is added in kaolin mud (dilution is concentration 8%), continue to stir 15min.Get the ammoniacal liquor 5ml of concentration 20%, dropwise add in kaolin mud used time 10min.After reaction finishes, standing 40min.Filter, 105 ℃ of freeze-day with constant temperature 10 hours, record product whiteness 85.2.Coated whitening technology improves product whiteness 5.3 degree.

Embodiment 3:, through the coated kaolin that brightens processing, Blue Whiteness is not 77.7.

50g kaolin, 0.1g anhydrous sodium carbonate, 35ml distilled water are mixed, regulate pH=8, ball milling 400r/m, ball milling 120min.Take 7.5g Tai-Ace S 150 and be dissolved in 20ml distilled water, solution is added in kaolin mud (dilution is concentration 5%), continue to stir 15min.Get the ammoniacal liquor 7.5ml of concentration 20%, dropwise add in kaolin mud used time 15min.After reaction finishes, standing 30min.Filter, 105 ℃ of freeze-day with constant temperature 10 hours, beat powder, record product whiteness 86.6, and coated whitening technology improves product whiteness 8.9 and spends.

The laminated structure that can find out the embodiment of the present invention 1 kaolin raw sample from accompanying drawing 1 is clear, and particle surface is smooth smooth;

From accompanying drawing 2, can find out the embodiment of the present invention 1 through surface the coated laminated structure that brightens the kaolin sample after processing not obvious, particle surface is wrapped in by a surface sediments, surface irregularity is uneven.

Claims

1. utilize the coated method in surface to brighten a kaolinic method, comprise the steps:

(3) Tai-Ace S 150 or aluminum nitrate are joined in the grout that upper step makes, after being fully uniformly mixed, slowly add ammoniacal liquor, continue after stirring reaction, through standing, filter, dry, obtain the kaolin product after brightening;

Described dispersion agent is anhydrous sodium carbonate or Sodium hexametaphosphate 99, and its addition is the 0.1-0.2% of kaolin raw material dry weight;

The addition of described Tai-Ace S 150 or aluminum nitrate and kaolinic weight percent are 0.1-0.3: 1;

Described ammoniacal liquor is pressed NH ₃: Al ₂(SO ₄) ₃mol ratio is 3-5: 1 or NH ₃: Al (NO ₃) ₃mol ratio is 2-4: 1 adds;

Described being dried as temperature is 105 ℃, be 10 hours time of drying;

The scope that described kaolin product whiteness can be enhanced is 4-10 degree.

2. the coated method in utilization according to claim 1 surface brightens kaolinic method, it is characterized in that: the concentration of described kaolin grout is preferably 5%-10%.