Title: Study of the Possibility of Precipitation/Purification of Heavy Non-ferrous Metals from Technological Solutions
Authors: Khojiev Sh.T., Mutalibkhonov S.S., Khudoymuratov Sh.J.
Volume: 10
Issue: 1
Pages: 101-105
Publication Date: 2026/01/28
Abstract:
Purification of zinc sulfate leach liquors is traditionally performed by cementation with zinc dust (metallic Zn), especially for Cu, Cd, Co, and Ni, but this route can be costly, generate hydrogen, and create difficult-to-handle residues. This review evaluates whether ZnO (or ZnO-bearing solids such as zinc calcine/roasting dust/secondary zinc oxide powder) can replace zinc dust during precipitation-based purification of zinc leach solutions containing CuSO4, FeSO4, NiSO4, CdSO4, and CoSO4. Ten Scopus-indexed journal papers were analyzed with an emphasis on mechanisms, operating windows, impurity selectivity, and industrial practicality. The literature shows that ZnO is highly effective as a neutralizing agent for controlled hydrolysis routes that remove iron (goethite/jarosite/hematite pathways) and can support co-precipitation of some impurities under pH/Eh control, but ZnO cannot directly substitute zinc dust for reductive cementation of Cu/Cd/Co/Ni because ZnO lacks reducing power. Viable "ZnO-based" purification is therefore best positioned as (i) iron control (Fe removal) and (ii) pH-driven precipitation/co-precipitation, optionally combined with oxidation, seed management, ultrasound, or hydrothermal transformation to produce filterable residues and reduce zinc losses.