zinc cakes are subjected to sulphate leaching at 80-90°C over the reducing agent that provide the reducing potential of leaching solution exceeding +0.8 V. Said solution is fed for zinc extraction while insolubler esidue is subjected to flotation by xant hate at pH = 8-9. Foam product is subjected to cleaner flotation at pH =
3.5-5. Note here that sodium dialkyl dithiophosphate is used as the collect or at the flowrate of 50-500 g/t. Flotation concentrate is directed for extraction of noble metals. Ther ougher t ailings are fed to the leade xtraction. The cleaner flotation tailings are used for zinc extraction in the main production.