Magnesium sedimentation wastewater treatment
In addition to calcium ions, the liquid after magnesium precipitation basically does not contain other metal ions, but the pH value is higher than 11, can not be directly discharged. Part of the magnesium wastewater can be used for lime slurry, and the remaining wastewater can be neutralized and discharged to standard or reused.
Copper loss of extracted residual liquid
After the copper in the extracted residue enters the cobalt hydroxide production process, some of it is discarded directly into the iron slag, and some of it enters the cobalt product, but when it is sold, the copper is a non-valued metal, so it causes copper loss. Copper can be recovered by adding a copper deposition process after the iron removal process.
The production of nickel and cobalt from activated magnesium oxide in DRC shows that it is technically feasible to produce cobalt hydroxide from cobalt-containing extracts by using the process of debinding – one stage magnesium oxide to sink cobalt – two stages of slaked lime to sink cobalt – magnesium.
The two-stage cobalt precipitation process, with one stage using magnesium oxide and the second stage using slaked lime, can produce high-grade cobalt hydroxide (about 32% cobalt) and ensure high recovery of cobalt.
The magnesium precipitation wastewater produced by the whole process is basically free of other metal ions except calcium ions, which can be neutralized and discharged to the standard or reused, without pollution to the environment.