Preparation method of palladium chloride

The invention discloses a preparation method of palladium chloride, and relates to the technical field of chlorine fertilizers, and the preparation method comprises the following steps: adding iron powder to form an iron powder mixture after hydrochloric acid and a waste catalyst are moderated, filtering after the iron powder mixture is placed and cooled, and washing filter residues with hydrochloric acid to obtain crude palladium; the preparation method comprises the following steps: mixing aqua regia and crude palladium, standing for a period of time for dissolving, heating the crude palladium dissolved by the aqua regia, carrying out aqua regia dissolving reaction by virtue of a reactor with a temperature sensor and a control system, adding concentrated hydrochloric acid in the reaction process for saltpetering, and repeating the saltpetering process, so as to obtain a saltpetered solution. And in the aqua regia dissolving process, the reaction is carried out at the optimal temperature, so that the quality