Study of the silver ions cementation after mechanical activation of cementator

Abstract

Thiosulphate leaching of silver is a proposed alternative to cyanide or thiourea leaching for certain types of refractory silver ores and secondary resources. Traditional method for the recovery of rare metals from various sources by hydrometallurgy is leaching followed by cementation onto zinc powder and electrowinning. Silver cementation is an inexpensive and simple way to deposit thin metal films. Cementation of silver onto zinc powder, treated by mechanical activation, from thiosulphate solutions was studied by measuring Ag+ ions concentration in the solution. The high energy attrition and planetary ball milling in methanol was applied for the mechanical activation of zinc powder. The changes in the particle size distribution and surface area of cementator, occurring during mechanical treatment have been registered. The observed changes in the physicochemical properties illustrate the possibility of applying activation to modify the surface and/or volume properties of zinc powder and its further application in well-known hydrometallurgical process of cementation. The study was also focused on the changes in the concentration of zinc and pH as a function of reaction time. The morphology of cementation products on zinc powder was also investigated.