Preparation of ceramic tiles with black pigments using stainless steel plant dust as a raw material

Stainless steel plant dust is typically considered as a hazardous solid waste for its significant levels of harmful heavy metals. However, it also contains valuable elements such as Cr and Fe. According to the coloring mechanism of Fe-Cr-based black pigment, reagent grade Cr2O3 was added in the stainless steel plant dust to adjust the ratios of Fe and Cr in the mixture. It was thereafter sintered to prepare a black pigment. The obtained black pigment was used as a coloring reagent and added into the ceramic base body to produce ceramic tiles. The results show that black pigment can be synthesized with stainless steel plant dust and reagent grade Cr2O3 after it was sintered at 1200 °C for 30 min. The optimal process parameters of black ceramic tiles are sintering at 1200 °C for 30 min with 8% of pigment addition. The compressive strength of the ceramic tiles exceeds the Chinese national standard of the minimum compressive strength of polished tiles, and the leachable toxic substances also meet the national limits.