Abstract
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.
Highlights
Ceramic pigments consist mostly of metallic oxides due to their high thermal and chemical stability
The brown color of the the effect of multiples ions in the extraction in strong acid precipitate indicates the possible presence of iron (Fe2O3). solution, using hydrochloric acid media in the extraction we suggest that the leaching of the metal grid of cadmium and TBP as organic phase to obtain a complex releases Fe ions into the solution and this occurs throughout
CdS-based yellow ceramic pigments were synthesized from cadmium extracted from discarded Ni-Cd batteries
Summary
Ceramic pigments consist mostly of metallic oxides due to their high thermal and chemical stability. The possible color pigments based on Cd range from yellow (CdS), through orange, to red-brown, gray and black (CdSe); all very intense. They are expensive, these pigments are much desired by the ceramic industry. The main methods of recycling batteries involve three distinct routes: i) Unity operations of mining treatment, where the components of batteries are physically separated for further recovering through other chemical processes; ii) Pyrometallurgical approach, where the components are distilled at high temperatures; and iii) Hydrometallurgical approach, through acid leaching of the metallic elements 15. Further studies have revealed the formation of coordinate complex between CdCl2 and solvent and the presence of other metal species may induce the formation of MCl3- complexes and MCl4- complexes, according to the reaction 21: 2CdCl2 ) CdCl+ + CdCl3-
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