Problem Statement (Relevance). When processing sulfide zinc concentrates according to conventional calcination hydrometallurgical technology, a significant part of zinc remains in the insoluble residue. Zinc cake, where precious metals are concentrated, is subjected to the Waelz process. During the Waelz process, coke breeze is added to the cake to reduce zinc and distill it into the gas phase; noble metals and copper remain in technological waste, called as clinker. Coke breeze added to the charge burns out by about 50%; therefore, the residual carbon-bearing content in the clinker can be 25-40%wt. Clinker yield reaches 27-30% by weight of the processed concentrate, and the copper content is 1-3%, zinc is 2-4% gold is about 2-5 g/t, silver is up to 200 g/t depending on the composition of the original raw materials. It is known that enterprises in Russia and abroad have accumulated tens of millions of tons of clinker, whose processing is an important task to extract valuable components. The conventional processing of clinker as part of the charge of copper smelters is accompanied by certain technological difficulties, and most importantly, does not make it possible to selectively and rather quickly convert precious metals and copper into commercial products. The known technologies for recovery of copper and noble metals by enrichment and hydrometallurgical methods do not provide satisfactory performance. Objective. The paper is aimed at studying the reasons for the unsatisfactory recovery of noble metals and copper from clinker by hydrometallurgical methods. Result. It has been found that coke remaining in clinker has sorption properties. The removal of coke from clinker contributes to increasing gold recovery by leaching of initial clinker with thiourea solutions from 45 to 87%. Gold recovery increases from 59 to 93% after preliminary leaching of copper.