Acid Leaching-Based Synthesis of CdS Yellow Ceramic Pigment with Discarded Ni-Cd Batteries

There is increasing interest in the ceramic industry in the development of pigments with intense tonalities that can be produced from low-cost alternative raw materials and also can fulfill technological and environmental requirements. This work reports on the preparation and characterization of CdS yellow ceramic pigment derived from Ni-Cd batteries through an acid leaching process. Cadmium was chemically extracted with HCl and tributylphosphate (TBP) and reacted with H2S to form CdS. The obtained yellow powder is composed of agglomerated particles with nanometer sizes and hexagonal and rod-shaped crystals. Rietveld refinement indicated that these particles consist of cubic and hexagonal CdS. CIELab colorimetric parameters revealed a bright yellow color (L*=77.8, a*=13.7 and b*=76.2), similar to that of commercial Cd Yellow pigment. The extraction of Cd from Ni-Cd batteries could be a low-cost and environmentally friendly solution for the production of CdS-based ceramic pigments.