Method for preparing polyaluminum chloride and co-producing baking-free environment-friendly brick from aluminum ash

Abstract

The invention provides a method for preparing polyaluminum chloride and co-producing an unfired environment-friendly brick from aluminum ash. The method comprises the following steps: ball-milling the aluminum ash, and screening; adding the screen underflow into water to obtain aluminum mortar; hydrochloric acid is added into the aluminum mortar, and acid leaching liquid and acid leaching residues are obtained through separation; adjusting the pH value of the pickle liquor, polymerizing and curing to obtain polyaluminum chloride; the baking-free environment-friendly brick is prepared by taking the acid leaching residues as raw materials. According to the method disclosed by the invention, the screen underflow is added into the water for denitrification and defluorination, so that the aluminum ash can be prevented from polluting underground water and soil, the aluminum ash subjected to denitrification and defluorination is used for producing the polyaluminum chloride, the content of Alb (Al13) in an optimal coagulation form is up to 60%, and high value and resource utilization of the aluminum ash are realized; meanwhile, the prepared baking-free brick is excellent in performance, the compressive strength is as high as 30MPa, the production cost is low, the energy consumption is low, the manufacturing process is simple, the environmental pollution caused by the waste aluminum ash slag can be preferentially reduced, and the full-quantitative comprehensive utilization of the aluminum ash is realized.

Description

technical field [0001] The invention relates to the technical field of comprehensive utilization of solid wastes, in particular to a method for preparing polyaluminum chloride co-production-free environment-friendly bricks with aluminum ash. Background technique [0002] The primary and secondary aluminum industries produce 3%-5% and 8%-15% of primary aluminum ash and secondary aluminum ash respectively for every ton of molten aluminum produced. At present, the annual emission of aluminum ash in my country exceeds 3 million tons. Aluminum ash mainly contains metal aluminum, aluminum oxide, aluminum nitride, fluoride salt and chloride salt. The composition is complex, the danger is high, and the storage location is high. Long-term accumulation of large amounts can easily cause heavy metal pollution in water and soil, soil salinity and alkali. change. When it rains or the air is humid, it is very easy to cause groundwater, soil pollution and air pollution. At present, most o...

AI Technical Summary

Problems solved by technology

After ball milling and sorting, the aluminum ash is sieved and returned to the furnace. The remaining aluminum ash under the sieve still contains 20-30% metallic aluminum. This part of the aluminum is low in aluminum content, and aluminum is mainly composed of corundum, magnesium aluminum spinel, AlN, metallic Al and Al(OH) 3 There are other forms, and metal aluminum is no longer recovered, but can be used to produce polyaluminum chloride, but the corundum-type Al 2 o 3 with MgAl 2 o 4 , SiO 2 The structure is relatively stable, and it is difficult to be effectively used to produce polyaluminum chloride because it is difficult to dissolve in acid

[0006] At present, there are many methods of using aluminum ash to prepare polyaluminium chloride and non-burning environmental protection bricks, but most of the technologies for preparing polyaluminium chloride by using aluminum ash still produce a large amount of waste residue, and the full quantitative system application of aluminum ash has not been realized. Part of the technology of using aluminum ash to prepare non-burning environmentally friendly bricks has failed to achieve high-value utilization of aluminum ash. It is important to use

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