Comprehensive recovery method for rare earth, aluminum and silicon in aluminum-silicon waste

Abstract

The invention discloses a comprehensive recovery method for rare earth, aluminum and silicon in aluminum-silicon waste. The method comprises the following steps that 1, the aluminum-silicon waste is subjected to acid leaching to obtain acid leaching liquid containing rare earth and aluminum and silicon-rich slag; 2, a precipitant is added into the acid leaching liquid containing the rare earth and the aluminum, and rare earth compound salt precipitate and aluminum-containing filtrate are obtained; and 3, sodium metaaluminate or aluminum sulfate is prepared from the aluminum-containing filtrate. By means of the method, rare earth and aluminum are thoroughly separated, the yield and purity of the rare earth and the aluminum are greatly improved, meanwhile, valuable recovery of silicon is completed, and comprehensive recycling of main elements in the aluminum-silicon waste is truly achieved. The recovery technological process has the advantages of being low in alkali consumption, low in water consumption, low in waste water discharge amount and the like, and meanwhile has the characteristics that the fixed investment is low, the production cost is low, and industrialized production can be easily achieved.

Description

technical field [0001] The invention belongs to the field of solid waste recovery, in particular to a method for recovering rare earth, aluminum and silicon from rare earth-containing aluminum-silicon materials. Background technique [0002] As a high-tech element, rare earths are widely used in the field of catalysts. In the 1960s, rare earth-Y type molecular sieves were widely used in heavy oil catalytic cracking, and then rare earths were also used in other molecular sieve catalysts. At present, the domestic consumption of rare earths in the field of petrochemical catalysis accounts for more than 10% of the total consumption of rare earths, and tens of thousands of tons of rare earths are used in the petrochemical industry every year in the world. [0003] With the increasing shortage of resources, the recovery of valuable rare earth components from the petrochemical catalyst preparation process or catalyst waste has good social and economic benefits. Chinese patent CN1...

AI Technical Summary

Problems solved by technology

Chinese patent CN1686813 discloses a method for preparing polyaluminium chloride by using waste molecular sieve catalysts, which can recycle aluminum in waste materials, but this patent does not involve the recovery of high-priced rare earth elements

According to Chinese patent CN1686813 and experimental research, the aluminum element in the molecular sieve waste has high activity and is easy to dissolve in the direct acid leaching process. Rare earth and aluminum have the characteristics of co-dissolution, which not only consumes a large amount of acid for leaching, but also for subsequent impurity removal and single rare earth extraction. Separation brings great trouble

[0006] For rare earth wastes containing aluminum and silicon, such as fluorescent powder wastes, rare earths and materials with low aluminum dissolution activity, there is also a process for extracting rare earths by alkaline treatment in China. Patent CN200810029417.5 proposes a similar method. Alumina raw material has applicability, but there are problems of long process and low yield of rare earth

[0007] However, the above methods mainly focus on the separation and recovery of rare earths, while a large amount of aluminum and silicon materials cannot be effectively utilized

At the same time, it is difficult to achieve the complete separation of rare earth and aluminum by the method of the prior art, the alkali consumption and water consumption in the whole process flow are large, and the environmental pollution is serious

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