Effect of the nickel molar content on the preparation and properties of spinel-type black ceramic pigment by microwave processing from stainless steelmaking dust

Abstract

The transformation of stainless steel dust(SSD) rich in transition metal elements into Fe-Cr-Ni series spinel-type black ceramic pigment can solve a number of problems associated with traditional high-temperature SSD treatment while also maximizing resource efficiency and harmlessness utilization. Microwave heating and calcination at 900 °C using SSD, Cr2O3, and NiO as the main raw materials, altering the molar ratio of Fe and Cr in the raw materials to 1, and gradually adding NiO, were used to make black spinel ceramic pigments in this study. The solid solution phase is gradually replaced by the spinel phase as the amount of NiO added increases, and the primary phases are Ni(FeCr)O4 and NiCr2O4. The generated pigment phases are completely transformed to spinel when the Fe/Cr/Ni molar ratio is altered to 1:1:0.5. Because NiO can react with spinel in SSD, increasing the NiO content of the raw material will increase the intensity of the spinel phase diffraction peak. According to morphological examination, the prepared spinel pigments have a characteristic polyhedral shape. Furthermore, as the amount of NiO increases, so does the average grain size of the spinel phase, the orbital hybridization effect, the degree of atomic inversion in tetrahedra and octahedra, and oxygen vacancies and deficiencies, resulting in an increase in visible light absorbance and a decrease in band gap width. The prepared spinel pigments are fired in ceramics and exhibit good color rendering and adaptation properties.