Effect of additive on copper removal from spent lithium-ion batteries by ammoniacal leaching

Ammoniacal solution containing ammonia and ammonium sulfate was used as leaching media for copper removal from spent lithium-ion batteries (LIBs). Effects of calcined temperature, amount of ammonium persulfate and leaching temperature on the leaching rate of copper, lithium and cobalt were investigated when ammonium persulfate was adopted as leaching additive. The experimental results showed that the leaching rate of copper was enhanced when ammonium persulfate was added to the ammoniacal solution, and could be affected greatly by leaching temperature. All copper in spent LIBs could be leached out with a leaching rate of 100% copper under the optimized conditions while the leaching rate of cobalt was still low. At low temperature(40 ℃) amounts of ammonium persulfate added had no obvious effect on the leaching rate of copper. Furthermore, cobalt-containing phases in leached residue were confirmed to be mainly Co3O4、LiCoO2 by XRD analysis.