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7146140 
Journal Article 
Recovery of silver from zinc cakes 
Lucheva, BI; Iliev, PK; Stefanova, VlP; , 
2015 
Yes 
Bulgarian Chemical Communications
ISSN: 0861-9808 
BULGARIAN ACAD SCIENCE 
SOFIA 
47 
112-117 
WOS:000377711800020 
The present experimental study investigates the feasibility of thiosulfate recovery of silver from zinc cakes produced in the process of wet recovery of zinc cakes at the KCM Ltd in Bulgaria. The impact of various factors on the rate of silver recovery through thiosulfate leaching is studied. It is found that the rate of silver recovery is 70-74 % within the temperature range of 30-50 degrees C at 20% pulp density and leaching time of 30 min, irrespective of the solution pH. The behavior of copper, lead, zinc and iron during thiosulfate extraction is also observed. The thiosulfate solution pH is maintained to 7-8 in order to reduce by hydrolization the concentration of the metals that have been transferred to the solution except silver. After subsequent precipitation of the silver by means of Na2S, silver concentrate is produced. The possibility of regeneration of the thiosulfate solution is discussed. The solid residue from thiosulfate leaching contains 10-40 g/t silver and can be processed by a Waelz process. 
zinc cake; silver; thiosulfate leaching 
8th National Conference on Chemistry 
Sofia, BULGARIA