Method for preparing high-whiteness aluminium hydroxide micropowder from Bayer process sodium aluminate solution

A Bayer method sodium aluminate and aluminum hydroxide technology, applied in the field of aluminum hydroxide micropowder preparation, can solve problems such as research, purification and decolorization of sodium aluminate solution, lack of guiding significance for large-scale industrial production, etc., and achieve low production costs , low energy consumption and stable product quality

Active Publication Date: 2012-06-20
河南能源集团研究总院有限公司 +1
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  • Summary
  • Abstract
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AI Technical Summary

Problems solved by technology

[0008] Some of the above methods have not carried out detailed research on the purification and decolorization of high-concentration sodium aluminate solution in the Bayer process. The process of preparing active seed crystals does not use sodium bicarbonate, and there is no change in the seeding process after the preparation of active seed crystals. In-depth research, lack of guiding significance for large-scale industrial production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Pipette 5000mL sodium aluminate solution, (solution composition is Na 2 o k 110g / L, Al 2 o 3 120g / L, α k :1.40) into the beaker, add calcium oxide (CaO) according to the solid-to-liquid ratio of 15g / L, heat in a water bath, stir vigorously (rotation speed: 180rpm), heat the solution in a water bath to 80°C, and then add 300mL of 20% hydrogen peroxide dropwise Solution, after reacting for 2 hours, centrifuging liquid-solid separation, taking the clear night to test the absorbance value of 0.189.

[0025] 5gNaHCO 3Dissolve in 50mL of aqueous solution to obtain a 100g / L solution, heat it to 30°C in a water bath, and then take 100mL of the sodium aluminate solution that was decolorized and purified in the first step in the separatory funnel. Under the condition of rapid stirring (400rpm), the purified sodium aluminate solution was slowly added dropwise, and the reaction time was 1.5h to prepare active seed crystals. After the reaction was completed, it was aged at this...

Embodiment 2

[0027] Get 8L factory sodium aluminate solution (solution composition is Na 2 o k 160.81g / L, Al 2 o 3 173.48g / L, α k :1.53) into the stainless steel bomb, add 2 Φ20mm and 2 Φ5mm steel balls to strengthen stirring, after sealing, put it in a water bath, add calcined dolomite (CaCO 3 · MgCO 3 , the calcination temperature is 900°C, which is above its decomposition temperature), and at the same time, 800mL of 30% hydrogen peroxide solution is added dropwise, heated to 90°C in a constant temperature water bath, and the vigorous stirring speed is 400rpm. After 2.5h of reaction, use a sand core Funnel suction filtration, take clear liquid, test clear night absorbance value is 0.145, organic carbon concentration is 0.376g / L.

[0028] 20gNaHCO 3 Dissolve in 100mL of aqueous solution to obtain a 200g / L suspension, heat to 45°C in a water bath, and then take 400mL of decolorized and purified sodium aluminate solution in a separatory funnel. Under the condition of rapid stirring (...

Embodiment 3

[0030] Take 5000mL factory sodium aluminate solution (solution composition is Na 2 o k 166.81g / L, Al 2 o 3 173.48g / L, α k :1.68) into the stainless steel bomb, add 2 Φ20mm and 2 Φ5mm steel balls to strengthen the stirring, after sealing, put it into the glycerin bath, add the calcined dolomite (CaCO 3 · MgCO 3 , the calcination temperature is 900°C, which is above its decomposition temperature), heated to 120°C in a constant temperature oil bath, and the vigorous stirring speed is 400rpm. After reacting for 2 hours, filter it with a sand core funnel, take the clear liquid, and test the light absorption of the clear night The value is 0.237.

[0031] 25gNaHCO 3 Dissolve in 250mL of aqueous solution to obtain a 250g / L suspension, heat it to 60°C in a water bath, and then take 750mL of decolorized and purified sodium aluminate solution in a separatory funnel. Under the condition of rapid stirring (520rpm), slowly add sodium aluminate solution dropwise, the reaction time is...

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Abstract

A method for preparing high-whiteness aluminium hydroxide micropowder from Bayer process sodium aluminate solution is disclosed, which comprises the following steps of: (1) performing purification and decoloration on Bayer process high-concentration sodium aluminate solution at first; (2) preparing high-whiteness seed crystal by the purified and decoloured sodium aluminate solution; (3) adding the high-whiteness seed crystal slurry prepared in the step (2) in the high-concentration sodium aluminate solution purified and decoloured in the step (1), and performing seed precipitation to prepare high-whiteness aluminium hydroxide micropowder; and (4) performing surface modification on the filtered and washed high-whiteness aluminium hydroxide micropowder, so as to prevent the agglomeration of the aluminium hydroxide micropowder during drying process. In the method for preparing high-whiteness aluminium hydroxide micropowder from Bayer process sodium aluminate solution disclosed by the invention, the high-whiteness aluminium hydroxide micropowder is prepared by using high-concentration sodium aluminate solution during production process for alumina using Bayer process, leading out the high-concentration sodium aluminate solution via a lateral line, and performing the processes of purification and decoloration for solution, preparation for active seed crystal, seed precipitation for the high-concentration sodium aluminate solution and the like, and seed precipitation mother solution is returned to the present production process for alumina simultaneously.

Description

technical field [0001] The invention belongs to the technical field of aluminum hydroxide micropowder preparation, and in particular relates to a method for producing high-white aluminum hydroxide micropowder by a Bayer process. Background technique [0002] High-white aluminum hydroxide micropowder is a high-end product in the alumina industry with high added value. It is widely used in flame retardants, fillers for artificial agate and artificial marble, paper-making fillers, toothpaste fillers, pharmaceutical raw materials, and chemical raw materials. [0003] In the field of flame retardants alone, the annual demand for aluminum hydroxide micropowder is about 700,000 tons. The European Union, Japan, and the United States have banned halogen flame retardants since 2006. The implementation of safety regulations in these countries has made aluminum hydroxide developed in Europe and the United States. The application in the country is more and more extensive. At the same tim...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/14
Inventor 李伍成李小斌蒋元力刘桂华赵东峰齐天贵邢奇生周秋生贾金才彭志宏丁建础张秀全李峰杰李壮陈湘根陈涛
Owner 河南能源集团研究总院有限公司
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