Harmless treatment method for aluminum ash

Abstract

A harmless treatment method for aluminum ash comprises the following steps: (1) mixing the aluminum ash with water, performing stirring to form a slurry, and grading the slurry to obtain a fine particle slurry; or mixing the graded aluminum ash with water, and performing stirring for forming a slurry to obtain the fine particle slurry; (2) adding a leaching agent, and carrying out a leaching reaction to obtain a nonmetal slurry; and (3) carrying out ball-milling deamination on the oxidized slurry, and washing, filtering, washing and drying the deaminated slurry to obtain harmless aluminum ash.The method has the advantages of high safety coefficient in the production process, simplicity, low cost, and suitableness for industrial production; and the obtained harmless aluminum contains, by mass, 95% of Al2O3, 0.02% or below of aluminum nitride, 0.01% or less of metallic aluminum and 0.2% or less of salt, meets the bauxite ore standard of GB / T 24483-2009, and can be used as a raw materialof a water purifying agent, ceramic, glass, a refractory material, a building material or electrolytic aluminum.

Description

Technical field [0001] The invention relates to a method for treating aluminum ash, in particular to a method for harmless treatment of aluminum ash. Background technique [0002] Aluminum ash is the product of cooling and processing of smelting slag produced in the production process of electrolytic aluminum or aluminum casting. It contains aluminum and a variety of valuable elements, mainly composed of metal aluminum, aluminum nitride, aluminum oxide, other metal oxides and salt fluxes. For example, the composition of 6 series alloy aluminum ash of a certain aluminum factory is: Al 2 O 3 54.71%, AlN 20%, MgO 6.21%, Fe 2 O 3 2.67%, KCl 3.69%, NaCl 4.28%, SiO 2 6.64%, CaO 1.8%. [0003] The high content of metallic aluminum and alumina in aluminum ash is a valuable renewable resource, while the deliquescent of metallic aluminum and aluminum nitride in aluminum ash will produce and release hydrogen and ammonia gas, which is a malodorous The gas is flammable and explosive, and th...

AI Technical Summary

Problems solved by technology

However, none of the above-mentioned wet treatment processes for producing water purifiers mentions the problem that aluminum ash releases flammable and explosive hydrogen and ammonia when it encounters acid, and the ammonium chloride residue produced by the neutralization of ammonia and acid will cause water purifiers to The ammonia nitrogen in it is unqualified, the reaction equation is: 2Al+6HCl→2AlCl 3 +3H 2 ↑, AlN+3H 2 O→Al(OH) 3 +NH 3 ↑, NH 3 +HCl→NH 4 Cl

[0007] CN105271327A discloses a method for harmless treatment and recycling of aluminum ash, and discloses a method for deammonization by water immersion. However, since the product formed by the hydrolysis of aluminum nitride on the surface of aluminum ash particles is aluminum hydroxide, the aluminum ash particles The tight package prevents the continuous penetration of water, which leads to a very long hydrolysis process of aluminum ash under natural conditions. Aluminum hydroxide is an amphoteric compound. Therefore, there is a problem of slow reaction speed in deamination by water immersion. Aluminum oxide is dissolved to accelerate the decomposition of aluminum nitride

[0008] CN105347361A discloses a treatment method for comprehensive utilization of aluminum ash, which uses a catalyst that can accelerate deamination, but there will be catalyst residues in the regenerated product, and it is necessary to increase the washing process

Although the hydrolysis reaction of aluminum nitride can be accelerated in the initial stage, because the inclusions produced by hydrolysis will prevent the penetration of water, the reaction rate will decrease in the later stage, and aluminum nitride still cannot be completely decomposed.

[0010] CN108893615A discloses a method for recovering metal aluminum from aluminum ash, which is to use a ball mill to add water and wet mill to carry out deep aluminum extraction. However, it has not been noticed that wet milling will produce flammable and explosive ammonia and hydrogen (hydrogen explosion limit is 4.0-75.6%, ammonia 15.7-27.4%), and issues derived from gas collection and gas treatment

However, there are also the problems of long and incomplete deamination time