Method for secondary aluminum ash harmless use

A secondary aluminum and secondary technology, applied in chemical instruments and methods, inorganic chemistry, applications, etc., can solve the problems of low decomposition amount of aluminum nitride, difficult utilization of aluminum nitride, and environmental pollution, so as to avoid pollution, The effect of realizing resource utilization and improving economic benefits

Inactive Publication Date: 2018-12-21
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the current use of acid to directly treat the secondary aluminum ash or to wash the secondary aluminum ash with water for a short time and then use acid treatment, the decomposition of aluminum nitride is very low in these two methods, and it is difficult to use aluminum nitride
Both salt and aluminum nitride in secondary aluminum ash are available resources, if not recycled, it will not only cause waste of resources, but also pollute the environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Add water and secondary aluminum ash to the reaction kettle at a liquid-solid ratio of 5:2, heat and stir at 75°C for leaching for 4 hours; perform solid-liquid separation after water immersion to obtain primary filtrate and primary filter residue, and the primary filtrate is evaporated to recover salt , water vapor is used in the water immersion process to heat and replenish water, the ammonia gas generated in the water immersion process will escape, the ammonia gas will be recovered, and absorbed by water to prepare ammonia water. The primary filter residue is transported to the acid leaching reaction kettle, and the hydrochloric acid with a concentration of 18wt% and the primary filter residue are heated and stirred in the reaction kettle according to the liquid-solid ratio of 5:2. The leaching temperature is 75°C, and the leaching time is 1h. After leaching, filter , to obtain the secondary filtrate and secondary filter residue, which can be used for brick making aft...

Embodiment 2

[0030] The secondary aluminum ash used for leaching raw materials is the product obtained after the primary aluminum ash is crushed and screened. Add water and secondary aluminum ash to the reaction kettle at a liquid-solid ratio of 5:2, heat and stir at 70°C for leaching for 2 hours; perform solid-liquid separation after water immersion to obtain primary filtrate and primary filter residue, and the primary filtrate is evaporated to recover salt , water vapor is used in the water immersion process to heat and replenish water, the ammonia gas generated in the water immersion process will escape, the ammonia gas will be recovered, and absorbed by water to prepare ammonia water. The primary filter residue is transported to the acid leaching reaction kettle, and the hydrochloric acid with a concentration of 17wt% and the primary filter residue are heated and stirred in the reaction kettle according to the liquid-solid ratio of 5:1. The leaching temperature is 70°C, and the leaching...

Embodiment 3

[0032]The secondary aluminum ash used for leaching raw materials is the product obtained after the primary aluminum ash is crushed and screened. Add water and secondary aluminum ash to the reaction kettle at a liquid-solid ratio of 5:1, heat and stir at 100°C for 6 hours; perform solid-liquid separation after water immersion to obtain primary filtrate and primary filter residue, and the primary filtrate is evaporated to recover salt , water vapor is used in the water immersion process to heat and replenish water, the ammonia gas generated in the water immersion process will escape, the ammonia gas will be recovered, and absorbed by water to prepare ammonia water. The primary filter residue is transported to the acid leaching reaction kettle, and the hydrochloric acid with a concentration of 20wt% and the primary filter residue are heated and stirred in the reaction kettle according to the liquid-solid ratio of 5:2. The leaching temperature is 80°C, and the leaching time is 1h. ...

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PUM

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Abstract

The invention discloses a method for secondary aluminum ash harmless use. The method comprises the following steps: mixing water with secondary aluminum ash, heating, stirring, leaching, and carryingout solid-liquid separation after water leaching so as to obtain primary filtrate and primary filter residues; heating and evaporating the primary filtrate so as to obtain a soluble salt; mixing the primary filter residues with an acid, heating and stirring to achieve leaching; after acid leaching, and carrying out solid-liquid separation so as to obtain secondary filtrate and secondary filter residues; manufacturing bricks with the secondary filter residues; adjusting the pH value of the secondary filtrate within 2.5-3.0; heating and aging the secondary filtrate after the pH value is adjusted, thereby obtaining aluminum polychlorid. By adopting the method, the aluminum element in secondary aluminum ash can be utilized to the maximum extent, aluminum nitride which is hard to react with theacid can be converted into aluminum hydroxide which is easy to react with the acid through high-temperature water leaching, dissolution of the aluminum element in the secondary aluminum ash can be improved, and the content of aluminum oxide in a prepared aluminum polychlorid product can be increased; in addition, a salt solvent and a nitrogen element in the secondary aluminum ash can be recycled,and damage of leaching residues upon the environment can be reduced.

Description

technical field [0001] The invention relates to the field of recycling and utilization of waste resources in the aluminum industry, in particular to a method for harmless utilization of secondary aluminum ash. Background technique [0002] Aluminum ash is a kind of dross floating on the aluminum liquid in the electrolytic tank produced during the aluminum electrolysis process. Aluminum ash is mainly divided into primary aluminum ash (white ash) and secondary aluminum ash (black ash). Primary aluminum ash is the aluminum slag produced in the process of producing aluminum from primary aluminum. Its main components are metallic aluminum and aluminum oxide, and the metallic aluminum content can reach 30-70%. Secondary aluminum ash is the residue of primary aluminum ash or other waste aluminum after extracting metal aluminum by physical or chemical methods. The content of metal aluminum is low and the composition is relatively complex. It mainly contains a small amount of alumin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/56C01C1/02C04B33/132
CPCC01C1/022C01F7/56C04B33/132Y02P40/60
Inventor 石晴张国范杨群李祺
Owner CENT SOUTH UNIV
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