Method for comprehensively recycling mixed secondary aluminum dross

A secondary aluminum and mixed technology, applied in chemical instruments and methods, ammonia compounds, alkali metal chlorides, etc., can solve the problems of unconsidered treatment and recycling, low recovery rate, insufficient decomposition of aluminum nitride, etc. , to achieve the effect of green recycling

Inactive Publication Date: 2019-04-26
平罗县中兴碳素有限公司 +1
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  • Summary
  • Abstract
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  • Application Information

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Problems solved by technology

[0008] But there are many deficiencies in the above-mentioned technology: 1, the treatment and recycling of chloride salt and fluoride salt in the aluminum ash are not considered, which easily causes secondary pollution in production; 2, the decomposition of aluminum nitride in the aluminum ash is not sufficient, and the recycling 3. The recycling process is complicated, and a large amount of acidic waste liquid is difficult to handle; 4. The use of fire method requires a large amount of fuel consumption, which is poor in industrial practicability and economy

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  • Method for comprehensively recycling mixed secondary aluminum dross

Examples

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Embodiment 1

[0033] A method for recycling multiple elements of mixed secondary aluminum ash, comprising the following steps:

[0034] a) Catalytic deamination step: the mixed secondary aluminum ash is placed in a closed container, and water and 4wt% NaF are added thereto as a catalyst at 95°C under stirring conditions to form a mixture, and the liquid-solid ratio is controlled to be 6, and the reaction After leaching for 8 hours, after the reaction is completed, the solid-liquid separation will obtain the filtrate and high-alumina solid material, and the high-alumina solid material will be directly returned to the Bayer processing system for the production of alumina products;

[0035] b) Ammonia gas recovery step: In the above-mentioned catalytic deamination step, aluminum nitride in the secondary aluminum ash is completely decomposed to generate ammonia gas under high temperature conditions, and the released ammonia gas is passed into the recovery device, and the concentration of sprayin...

Embodiment 2

[0039] A method for recycling multiple elements of mixed secondary aluminum ash, comprising the following steps:

[0040] a) Catalytic deamination step: place the mixed secondary aluminum ash in a closed container, add water and 3wt% NaF and KF mixture thereinto as a catalyst at 90°C under stirring conditions to form a mixture, and control the liquid-solid ratio to 8. Reaction and leaching for 6 hours. After the reaction is completed, solid-liquid separation is obtained to obtain the filtrate and high-alumina solid material, which is used to produce high-grade refractory materials;

[0041] b) Ammonia gas recovery step: In the above-mentioned catalytic deamination step, aluminum nitride in the secondary aluminum ash is completely decomposed to generate ammonia gas under high temperature conditions, and the released ammonia gas is passed into the recovery device, and the concentration of spraying in the recovery device is 0.5% dilute sulfuric acid collects the escaping ammonia ...

Embodiment 3

[0045] A method for recycling multiple elements of mixed secondary aluminum ash, comprising the following steps:

[0046] a) Catalytic deamination step: place the mixed secondary aluminum ash in a closed container, add water and 2wt% AlF as a catalyst at 80°C under stirring conditions to form a mixture, control the liquid-solid ratio to 5, and react Leach for 10 hours, and after the reaction is completed, the solid-liquid separation is obtained to obtain the filtrate and high-alumina solid material, which is used to produce various alumina products;

[0047] b) Ammonia gas recovery step: in the above-mentioned catalytic deamination step, aluminum nitride in the secondary aluminum ash is completely decomposed to generate ammonia gas under high temperature conditions, and the released ammonia gas is passed into the recovery device, and the concentration of spraying in the recovery device is 0.8% dilute sulfuric acid collects the escaping ammonia gas to obtain an ammonium sulfate...

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Abstract

The invention relates to a method for comprehensively recycling mixed secondary aluminum dross. The method comprises the following recycling processes: step (1) adding water into mixed secondary aluminum dross for catalytic deamination reaction, decomposing aluminum nitride to generate ammonia gas to overflow, performing solid-liquid separation to obtain filtrate and high aluminum solids after reaction; step (2) completely decomposing aluminum nitride in secondary aluminum dross to generate ammonia gas, feeding the overflowed ammonia gas into a sulfuric acid solution, collecting the overflowedammonia gas to obtain an ammonium sulfate solution; and step (3) performing staged evaporation and crystallization on the filtrate obtained by solid-liquid separation by using an evaporation crystallizer, performing first-stage evaporation crystallization to obtain a mixture of NaF and KF, performing second-stage evaporation crystallization to obtain a mixture of NaCl and KCl. The method providedby the invention not only fully recycles elements Al, N, F and Cl in the secondary aluminum dross, but also does not generate any secondary wastes in the whole process, and realizes green recycling of secondary resources of aluminum.

Description

technical field [0001] The invention relates to a method for comprehensive recovery and utilization of mixed secondary aluminum ash, which relates to a comprehensive utilization of solid waste resources in the aluminum industry, in particular to a method for multiple element recovery and utilization of mixed secondary aluminum ash. technical background [0002] Aluminum ash is a huge amount of hazardous solid waste produced in the aluminum industry, which is produced in all production processes where aluminum is melted. The main sources include oxides, additives, infusible inclusions floating on the surface of aluminum melt in the process of electrolytic aluminum, aluminum processing and casting, and secondary aluminum production, as well as reaction products produced by physical and chemical reactions with additives. Therefore, aluminum ash contains a large amount of fluoride Toxic and harmful substances such as , chloride and nitrogen compounds pose a huge threat to the na...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01C1/242C01D3/04
CPCC01C1/242C01D3/04
Inventor 刘风琴吕晗谢明壮王焕雪赵洪亮刘伟董文湘张拥军付小亮
Owner 平罗县中兴碳素有限公司
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