Method for enriching platinum group metal and rare earth in failed automobile exhaust purification catalyst

Abstract

The invention relates to a method for enriching platinum group metal and rare earth in a failed automobile exhaust purification catalyst. The metod comprises the steps that the failed automobile exhaust purification catalyst is finely ground and then is subjected to pressure leaching in a sodium hydroxide solution, gamma-A12O3 in the crystal is partially dissolved, and cordierite carrier in the catalyst is converted into sodalite which is easy to dissolve in an acidic system; acid leaching is carried out on the produced pressure leaching residue, rare earth elements enter the acid leaching solution, and platinum, palladium and rhodium elements are remained in the residue, so that separation of platinum, palladium and rhodium and rare earth is realized; and sodium sulfate is added into theacidic leaching solution to form a rare earth sulfate complex salt precipitate, rare earth elements are recycled, and acidic insoluble residues are further treated to recycle platinum, palladium and rhodium metal. The leaching rate of lanthanum and yttrium reaches 95% or more, platinum, palladium and rhodium in the failed automobile tail gas purification catalyst is enriched by 13 times or more, the subsequent extraction of noble metal is facilitated, and the comprehensive recovery rate of lanthanum and yttrium elements reaches 90% or more.

Description

technical field [0001] The invention relates to a hydrometallurgical process in the field of metallurgy, and is a method for effectively enriching platinum group metals and rare earths in exhaust gas purification catalysts of exhausted vehicles. Background technique [0002] Auto catalysts are an important way to control vehicle exhaust emissions and reduce pollution in the fuel locomotive industry. The current mainstream automotive catalyst is made of carrier (2MgO 2A1 2 o 3 ·5SiO2 2 or 2FeO·2A1 2 o 3 0.5SiO2 2 ), surface coating (γ-A1 2 o 3 ), active materials (Pt, Pd and Rh) and additives (Ce, La, Ba, Sr, Zr and other rare earth or alkaline earth element oxides), in which the content of precious metals is generally above 0.05%, and contains about 4%~ 8% rare earth elements. At present, the annual output of platinum group metals in the world is about 300 tons, 90% of which come from countries such as Russia and South Africa. The reserves and output of platinum gro...

AI Technical Summary

Problems solved by technology

This invention does not need to add any additional collectors and is easy to operate, but it needs to use high-temperature melting furnaces such as plasma electric furnaces, which has a large demand for energy consumption. At the same time, this method has certain limitations. Additional collectors are required to extract valuable metals

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