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Method for safely and efficiently producing sand-like alumina from aluminum ash

A technology of alumina and aluminum ash, which is applied in the field of aluminum metallurgy, can solve the problems of affecting the normal operation of alumina, poor physical indicators of products, and high impurity content of products, and achieve the effects of industrial application, reduction of energy consumption, and improvement of environmental protection

Active Publication Date: 2017-06-13
CENT SOUTH UNIV +1
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  • Summary
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

Most of the organic matter in bauxite enters the sodium aluminate solution during the dissolution process, and various organic additives will also remain in the sodium aluminate solution. These organic matters are transformed during alumina production and circulated in the mother liquor. Accumulated during the process, resulting in many kinds of organic matter and high concentration in the sodium aluminate solution, which has led to difficulty in desiliconization, difficulty in slurry separation, low decomposition rate, high impurity content in the product, poor physical indicators of the product, etc., seriously affecting the normal operation of alumina , it is urgent to reduce the concentration of organic matter in sodium aluminate solution

Method used

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  • Method for safely and efficiently producing sand-like alumina from aluminum ash
  • Method for safely and efficiently producing sand-like alumina from aluminum ash
  • Method for safely and efficiently producing sand-like alumina from aluminum ash

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preparation example Construction

[0048] b Preparation of aluminum hydroxide: filter the crude liquid (leaf filter, leaf filter) to obtain semen, after the semen is cooled, add seed crystals to the semen to decompose [NaAl(OH) 4 Decomposed into Al(OH) 3 ] Obtain aluminum hydroxide slurry, after classification, get sandy aluminum hydroxide product and seed crystal, filter, wash product, get sandy aluminum hydroxide, lotion and mother liquor, return and continue to add to the seminal fluid of cooling for seed crystal Precipitation of aluminum hydroxide;

[0049] c Sandy alumina Preparation of alumina: Calcining sandy aluminum hydroxide to obtain sandy alumina.

[0050] Among them, the mother liquor is evaporated and concentrated to obtain the concentrated mother liquor (the recycle mother liquor prepared) and the evaporative salt containing sodium carbonate. In the pure Bayer process, water is added to dissolve and evaporate the precipitated salt, and lime is added for causticization to obtain caustic soda for...

Embodiment 1

[0052] refer to figure 1 , figure 2 , a method for safely and efficiently producing sandy alumina using aluminum ash provided by the present invention, the specific steps are as follows:

[0053] 1) Take 100mL sodium aluminate solution (Na 2 o k =160g / L, Al 2 o 3 =90.8g / L, a k =2.90), add aluminum ash to the sodium aluminate solution, add aluminum ash every 5 minutes each time, the amount of each addition is 10 g / L, the total amount of aluminum ash added is 150 g / L, stir at 25 ° C for 10 h , after filtration, a section of eluate (Na 2 o k =165.7g / L, Al 2 o 3 =166.2g / L, a k =1.64, SiO 2 1.7g / L) and aluminum ash, collected hydrogen 22.5L, ammonia concentration 4.5%;

[0054] 2) Add evaporating salt in the Bayer process to the above-mentioned filtered aluminum ash (containing liquid), then add lime with 3% of the mass of aluminum ash as an additive, mix evenly to obtain raw slurry, and oxidize in the raw slurry Sodium (Na 2 o k ) to the total amount of alumina a...

Embodiment 2

[0058] refer to figure 1 , figure 2 , a method for safely and efficiently producing sandy alumina using aluminum ash provided by the present invention, the specific steps are as follows:

[0059] 1) Take 100mL sodium aluminate solution (Na 2 o k =130g / L, Al 2 o 3 =71g / L, a k =3.00), add aluminum ash to the sodium aluminate solution, add aluminum ash every 3min, the amount of each addition is 30 g / L, the total amount of aluminum ash added is 130 g / L, stir at 90°C for 10h, After filtration, a section of eluate (Na 2 o k =141.1g / L, Al 2 o 3 =158.2g / L, a k =1.47, SiO 2 =1.4g / L) and aluminum ash, collected hydrogen 14.8L, ammonia concentration 7.8%;

[0060] 2) Add the evaporating salt in the Bayer process to the above-mentioned filtered aluminum ash (containing liquid), and then add a mixture of lime, calcium aluminate and calcium-silicon slag with 5% of the mass of the aluminum ash slag as an additive and mix evenly to obtain a raw material. Sodium oxide (Na 2 ok ...

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Abstract

The invention provides a method for safely and efficiently producing sand-like alumina from aluminum ash. The method comprises the steps as follows: 1) aluminum ash is added to a sodium aluminate to react with the sodium aluminate solution, then solid-liquid separation is performed, a first-section digestion liquid and aluminum ash residues are obtained, and hydrogen and ammonia gas are comprehensively utilized; 2) alkali and an additive are added to the aluminum ash residues, raw slurry is obtained, and thus chlorine and fluorine elements are prevented from entering tail gas; 3) the raw slurry is sintered and clinker is obtained; 4) the clinker is added to an adjustment liquid for digestion, and second-section digestion slurry is obtained; 5) the first-section digestion liquid and the second-section digestion slurry are mixed in a Bayer process digestion slurry dilution system for production of the sand-like alumina by the Bayer process system. Nitrogen, fluorine, chlorine, hydrogen and other harmful elements in the aluminum ash are disposed safely, the concentration of organic matter in a Bayer process solution is decreased, and aluminum components are recovered efficiently and economically; for the aluminum ash, the method has the characteristics of safety, high efficiency, low cost and the like; for the Bayer process system, the yield is increased, the solution is purified, and the production efficiency is significantly improved.

Description

technical field [0001] The invention relates to the technical field of aluminum metallurgy, in particular to a method for safely and efficiently producing sandy alumina by using aluminum ash. Background technique [0002] Aluminum ash is the waste produced in the process of aluminum electrolysis and aluminum melting and casting, the main component is α-Al 2 o 3 , as well as aluminum, aluminum nitride, silicon, aluminum-silicon, aluminum-titanium alloys, chloride salts, fluoride salts, etc., are complex and difficult-to-handle solid wastes. The production of aluminum ash at home and abroad is large, the environmental risk is great, and it is recognized as hazardous waste. The output of aluminum electrolysis and aluminum processing in my country is large, the output of aluminum ash is large, and the stockpile is large. Therefore, it is urgent to develop new technologies for comprehensive utilization of aluminum ash that are safe, efficient and clean. [0003] Aluminum ash h...

Claims

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Application Information

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IPC IPC(8): C01F7/14C01B3/08C01B3/06C01C1/02
CPCC01B3/06C01B3/08C01C1/026C01F7/0693C01F7/14Y02E60/36Y02P20/50
Inventor 刘桂华郝红杰李小斌刘定明黄文强黄源齐天贵晏华钎彭志宏陈映周秋生段昌祥熊德芬
Owner CENT SOUTH UNIV
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