Abstract |
Precipitation behavior of heavy metals (Ni, Co, Cd, Cu, and Zn) was studied extensively in single- and multi-metal systems. Kinetic studies showed that NiS oxidation (as a function of pH, oxygen, and reaction time) caused the dissolution of NiS. CoS precipitation would require high pH, short detention times, or closed reactors (under N2 atmosphere). In the multi-metal systems without nickel, CdS and ZnS precipitation were the same as in their single-metal systems; however, the precipitations were affected in nickel, CdS and ZnS precipitation were the same as in their single-metal systems; however, the precipitations were affected in nickel-containing systems because of NiS oxidation. Results of CdS precipitation from multi-metal systems (with or without nickel) were substantially better than the single-metal case. |