Nickel recovery from synthetic Watts bath electroplating wastewater by homogeneous fluidized bed granulation process

• Nickel recovery from Watts bath electroplating wastewater was done in homogeneous FBR.
• CO3:Ni = 1.5, 300 mg·L−1 nickel influent, and 10.8 carbonate pH as the best condition.
• Calcium ions took effect in recovery and granulation efficiency of nickel carbonate.

This study determined the removal of nickel from a synthetic Watts bath electroplating composition (NiCl2·6H2O, NiSO4·6H2O, and H3BO3) by homogeneous fluidized-bed granulation process. The effects of adding calcium ions present in an electroplating bath while varying influent nickel concentration (200 mg·L−1, 300 mg·L−1, and 400 mg·L−1), [CO32−:Ni2+] molar ratio (1.0, 1.5 and 2.0) and pH of carbonate precipitant (10.5, 10.8, and 11.0) were evaluated. Calcium ion addition was varied at 20 mg·L−1, 50 mg·L−1, and 100 mg·L−1. The best operating conditions were at 300 mg·L−1 influent nickel concentration, [CO32−:Ni2+] molar ratio of 1.5, and pH of 10.8 of the precipitant from different types of water source. The removal of nickel from synthetic Watts bath electroplating wastewater using tapwater was 84.93%, and 92.66% with the addition of Ca2+ ion at 20 mg·L−1. For the synthetic Watts bath electroplating wastewater using reverse osmosis water, nickel removal was 97.08% and 98.51% when pure nickel ion in the solution was used. The characterized granules has low symmetry that confirmed the characteristics of a nullaginite mineral of Ni2(CO3)(OH)2.