Selective recovery of chromium from ferronickel slag via alkaline roasting followed by water leaching

Chromium was selectively recovered from ferronickel slag by roasting the slag with addition of Na2O2, followed by water leaching. The thermodynamic analysis revealed that in the presence of Na2O2 at appropriate temperatures, the Cr2O3 in the ferronickel slag can be converted to NaCrO2, instead of Na2CrO4, which prevents the formation of highly toxic Cr (VI). The experimental results confirmed that under the optimal alkaline roasting and water...