CN102786818A

CN102786818A - Method for whitening kaolin by using surface cladding method

Info

Publication number: CN102786818A
Application number: CN2012102324152A
Authority: CN
Inventors: 赵曰浩
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-06-29
Filing date: 2012-06-29
Publication date: 2012-11-21
Anticipated expiration: 2032-06-29
Also published as: CN102786818B

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

A kind ofly utilize surperficial coating method to brighten kaolinic method

Technical field

The invention belongs to field of inorganic nonmetallic material, be specifically related to a kind ofly utilize surperficial coating method to brighten kaolinic method.

Background technology

Kaolin is the aggregate of the hydrous alumino silicates of multi mineral composition, and staple is a kaolinite, it is generally acknowledged that its chemical formula is Al ₂O ₃SiO ₂2H ₂O (crystal water exists with the form of hydroxyl) is made up of through 1: 1 type layer silicate mineral that common oxonium ion key connecting forms a stratiform silicon-oxy tetrahedron and an alumina octahedral.Purified kaolin is white in color; Usually often contain trace quantity minerals such as smectite, illite, pyrite, limonite, carbonaceous and quartz in the kaolin ore; These association materials are dyed various different colours with kaolin; Have a strong impact on kaolinic whiteness and using value, generally must adopt physics and chemical process to remove the impurity in the kaolin, improve its whiteness and using value.Therefore kaolinic whiteness is the important indicator of its purposes of decision and economic worth, therefore considers that from technology and economic overall equilbrium improving kaolinic whiteness also becomes the emphasis in present technique field, difficult point.

Kaolin method of whitening commonly used at present mainly contains:

1. superfine grinding

In the superfine grinding process, material receives the effect of extraneous mechanical force, shows as the increase of material particles refinement, miniaturization and specific surface area on the macroscopic view; And accumulate in granular system inside owing to portion of energy on the microcosmic; Thereby cause the particle lattice distortion, lattice imperfection, amorphization; Generate radical, surface free energy increases.As far as kaolin, the process of its grain refine also is the process that its true density and consolidation 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 the interface has increased its whiteness.(vast stretches of wooded country etc., ultra-fine coal measures satin burns the character and the surface-treated [J] thereof of kaolin particle. University of Science & Technology, Beijing's journal, 1999,21 (6): 516-518).

2. calcining is brightened

Fixed carbon content is generally about 2% (the Coaseries kaolin carbon content is higher) in the kaolin; Be present in the kaolinite xln gap; Make kaolin present grey black or pearl (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 the high-temperature calcination de-carbon to improve its whiteness, and calcining temperature is usually 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, the calcining whitening effect is fairly obvious.

3. chemical removal of iron brightens

The chemical removal of iron method has multiple, and Traditional use vat powder reduction method is promptly used strong reductant V-Brite B and kaolinic red stone effect, is reduced to water-soluble ferrous ion to water-fast ferric iron, can remove through filtering.The whiteness value that this method can reach is not high, and too many because of the factor of relative influence, and reaction process is difficult to be controlled.

Summary of the invention

The technical problem that the present invention will solve provides a kind ofly utilizes surperficial coating method to brighten kaolinic method.

For solving above technical problem, technical scheme of the present invention is: a kind ofly utilize surperficial coating method to brighten kaolinic method, comprise the steps:

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

(2) will go up after the step, the slurry pH value that makes was adjusted to 7-8, high speed ball milling 60-120min, obtaining weight percent concentration is the grout below 10%;

(3) aluminum sulfate or aluminum nitrate are joined in the grout that the step makes, after fully mixing, slowly add ammoniacal liquor, continue stirring reaction after, through leave standstill, filter, drying, the kaolin product after obtaining to brighten.

Said dispersion agent is soda ash light or Sodium hexametaphosphate 99, and its addition is the 0.1-0.2% of kaolin raw material dry weight.

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

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

Said 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.

Said drying is that temperature is 105 ℃, and be 10 hours time of drying.

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

The present invention is on the basis of the kaolin product that traditional technique of preparing is produced; Adopt the mode of high speed ball milling that kaolin is ground; Realize that on the one hand particulate pulverizes, make the kaolin particle surface more lattice imperfection and-OH occur on the other hand, this is the essential condition that realizes that deposition coats; The Al (OH) that adopts the reaction of Tai-Ace S 150 or aluminum nitrate solution and ammoniacal liquor to generate ₃Particulate parcel kaolin particle, its principle is: kaolin is because the characteristics of its crystalline structure cause 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.So before the high speed ball milling, regulate earlier kaolin slurry pH=7-8, be in order to make the kaolin particle surface behind the ball milling electronegative.Add alum liquor and ammoniacal liquor subsequently, reaction as follows take place:

Al ³⁺+OH ^-→Al(OH) ₃↓

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

The invention provides and a kind ofly utilize surperficial coating method to brighten kaolinic method, at first kaolin is carried out the high speed ball milling activation of certain hour, adopt aluminium salt and ammoniacal liquor to carry out liquid deposition again; Accomplished that promptly the kaolin surface is coated the production technique that brightens, it is superfine that this method can be widely used in processing staining impurity disseminated grain size, the unconspicuous chiltern kaolin of chemical removal of iron whitening effect; Can increase the 4-10 degree through coating the kaolin product whiteness that brightens; Can be used as the coating of papermaking and the high quality filler in fields such as plastics, rubber and use, this technical matters is simple, use equipment is less, the production power consumption is lower, and can increase low-quality kaolinic added value greatly; Enlarge low-quality kaolinic range of application; Improve the utilising efficiency of Mineral resources, met the requirement of national energy-saving and emission-reduction, therefore had the vast market space.

Description of drawings

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

Fig. 2 is the kaolin sample SEM picture (* 10000) after processing is brightened in the embodiment of the invention 1 surface coating.

Embodiment

Embodiment 1: do not brighten the kaolin of processing through coating, the blue light whiteness is 80.5.

50g kaolin, 0.05g soda ash light, 70ml zero(ppm) water are mixed, regulate pH=7, ball milling 400r/m, ball milling 60min.Take by weighing 2.5g Tai-Ace S 150 and be dissolved in 20ml zero(ppm) water, solution is added in the kaolin mud (dilution is concentration 10%), continue to stir 15min.Get the ammoniacal liquor 2ml of concentration 20%, dropwise add in the kaolin mud time spent 10min.Reaction is left standstill 30min after finishing.Filter 105 ℃ of freeze-day with constant temperature 10 hours.Record product blue light whiteness 85.5.Coat whitening technology and improve product whiteness 5 degree.

Embodiment 2: do not brighten the kaolin of processing through coating, the blue light whiteness is 79.9.

50g kaolin, 0.05g Sodium hexametaphosphate 99,50ml zero(ppm) water are mixed, regulate pH=8, ball milling 400r/m, ball milling 90min.Take by weighing the 5g aluminum nitrate and be dissolved in 20ml zero(ppm) water, solution is added in the kaolin mud (dilution is concentration 8%), continue to stir 15min.Get the ammoniacal liquor 5ml of concentration 20%, dropwise add in the kaolin mud time spent 10min.Reaction is left standstill 40min after finishing.Filter, 105 ℃ of freeze-day with constant temperature 10 hours record product whiteness 85.2.Coat whitening technology and improve product whiteness 5.3 degree.

Embodiment 3: do not brighten the kaolin of processing through coating, the blue light whiteness is 77.7.

50g kaolin, 0.1g soda ash light, 35ml zero(ppm) water are mixed, regulate pH=8, ball milling 400r/m, ball milling 120min.Take by weighing 7.5g Tai-Ace S 150 and be dissolved in 20ml zero(ppm) water, solution is added in the kaolin mud (dilution is concentration 5%), continue to stir 15min.Get the ammoniacal liquor 7.5ml of concentration 20%, dropwise add in the kaolin mud time spent 15min.Reaction is left standstill 30min after finishing.Filter, 105 ℃ of freeze-day with constant temperature 10 hours are beaten powder, record product whiteness 86.6, coat whitening technology and improve product whiteness 8.9 and spend.

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

Can find out that from accompanying drawing 2 embodiment of the invention 1 is not obvious through the laminated structure that the surface coats the kaolin sample after brightening processing, particle surface is wrapped in by a surface sediments, and surface irregularity is uneven.

Claims

1. one kind is utilized surperficial coating method to brighten kaolinic method, comprises the steps:

2. the surperficial coating method of utilization according to claim 1 brightens kaolinic method, it is characterized in that: said dispersion agent is soda ash light or Sodium hexametaphosphate 99, and its addition is the 0.1-0.2% of kaolin raw material dry weight.

3. the surperficial coating method of utilization according to claim 1 brightens kaolinic method, and it is characterized in that: the concentration of said kaolin grout is preferably 5%-10%.

4. the surperficial coating method of utilization according to claim 1 brightens kaolinic method, it is characterized in that: the addition of said Tai-Ace S 150 or aluminum nitrate and kaolinic weight percent are 0.1-0.3: 1.

5. the surperficial coating method of utilization according to claim 1 brightens kaolinic method, and it is characterized in that: said 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.

6. the surperficial coating method of utilization according to claim 1 brightens kaolinic method, it is characterized in that: said drying is that temperature is 105 ℃, and be 10 hours time of drying.

7. brighten kaolinic method according to the surperficial coating method of the arbitrary described utilization of claim 1-6, it is characterized in that: the scope that said kaolin product whiteness can be enhanced is the 4-10 degree.