Method for dissolving out precious metal in waste automobile exhaust purification catalyst

The invention provides a method for dissolving out precious metal in a waste automobile exhaust purification catalyst. The method comprises the following steps of firstly, carrying out sulfating roasting on the waste automobile exhaust purification catalyst, performing diluted acid leaching on a roasted product after roasting, adding alkali into leached filter residue for roasting, performing water leaching on the roasted product after adding the alkali for roasting, leaching ou precious metal in residues obtained after most base metal is removed through acid and an oxidizing agent, mixing leaching residues obtained after most platinum group metal is leached out with sodium peroxide and sodium hydrogen sulfate to be roasted at the proper temperature, and enabling the roasted product to be subjected to acid leaching again to further dissolve out the precious metal. The method has the advantages of being low in energy consumption, simple and convenient in process, small in reagent dosage, low in residue amount