Study of the phase composition and metal speciation of aged Elektrotsink clinker

Abstract

The depletion of natural reserves and the accumulation of large-tonnage waste containing significant quantities of non-ferrous and precious metals make the processing of man-made raw materials increasingly critical. Unlike ores and concentrates whose mineral structure is often well understood, data on the phase properties of metallurgical waste are quite scarce. This information can serve as a starting point for selecting a rational and effective technology for recovering precious elements from such waste. The processing of zinc clinker, which is one of the most large-tonnage non-ferrous wastes, is discussed using the Elektrotsink dumps as an example. Modern methods are used to study the material and phase compositions of an increment clinker sample and the speciation of precious elements such as copper, zinc, gold, and silver. The main phases (up to 40%) are simple and complex iron oxides and silicates and quartz SiO₂ (up to 15%). The total fraction of copper, zinc, and iron sulfides does not exceed 15%. The content of these elements does not exceed several percent. Particular attention is paid to the phases that determine the quantitative indicators of the concentration and hydrometallurgical processes in clinker processing: carbon (coke) and ferrites. The composition of clinker is highly heterogeneous, with intergrowths of different phases of variable composition. The content of precious elements in different clinker samples can vary widely.