Preparation of Black Ceramic Tiles with Chromium Slag and Copper Smelting Waste Slag

Chromium slag and copper smelting waste slag are solid wastes generated in the process of industrial production of chromium salt and copper metal, respectively. In this study, chromium slag and copper smelting waste slag were used as raw materials to produce black ceramic tiles. It can not only reduce environmental pollution but also increase their utilization value. The chromaticity values of ceramic tiles (L*, a*, and b*), which are color models developed by the International Commission on Illumination, were measured using a colorimeter. The phases and microstructure of the ceramic tile were analyzed by X-ray diffractometer (XRD), scanning electron microscope and energy-dispersive X-ray spectrometry (SEM-EDS), respectively. The effects of different process parameters on the coloring performance of ceramic tiles were also investigated. The results show that the color of ceramic tile is the best when the Fe/Cr ratio is 1.5, the sintering temperature is 1200 degrees C, the holding time is 30 min and the ceramic tile is cooled in the furnace. The values of L*, a*, and b* are, respectively, 22.5, 0, and -1.6. The compressive strength of ceramic tile and the leaching concentration of Cr(VI) are 127.2 MPa and 3.31 mg/L, respectively, which can meet the relevant national standards.

Automated summary

Chromium slag and copper smelting waste slag were used as raw materials to produce black ceramic tiles, reducing environmental pollution and increasing their utilization value. The color characteristics, phases, and microstructure of the ceramic tiles were analyzed, and the effects of different process parameters were investigated. The results showed that the optimal conditions for coloring the ceramic tiles were an Fe/Cr ratio of 1.5, sintering temperature of 1200 degrees C, holding time of 30 min, and cooling in the furnace. The ceramic tiles met the relevant national standards for compressive strength and leaching concentration of Cr(VI).