Preparation of Fe–Cr–Ni–Mn Black Ceramic Pigment from Stainless Steelmaking Dust

The rich transition metal elements in stainless steelmaking dust, such as Fe, Cr, Ni, and Mn, can be used to prepare black ceramic pigments. The stainless steelmaking dust can be ultilized to prepare cobalt-free black ceramic pigments. According to the color mechanism of Fe–Cr–Ni–Mn black pigment, an appropriate amount of chemical reagents Fe₂O₃, Cr₂O₃, MnO and NiO was added into stainless steel making dust in a mixed mass ratio of 6:1:1:1. The chromaticity value vibration rules of black ceramic pigments prepared under different conditions were investigated, and the coloring mechanism of the pigments was discussed as well. The results show that a high firing temperature or a long holding time causes the decomposition of Cr-containing spinel phase, adversely affecting the coloring properties of the pigment. The optimum firing process of the pigment is the firing temperature of 1175 ℃, the holding time of 30 min, and the furnace cooling method. The L^*, a^* and b^* values of the prepared pigment are 37.20, 0.13 and 0.02, respectively, and the main phases in the pigment are Fe₂O₃ and mixed spinels. The absorbance of the pigment to each visible light wavelength band is basically the same, and the bandgap of the pigment is 0.88 eV. The color of the pigment is black. The average grain size of spinels is only 26.795 nm, and the pigment has a superior thermal stability at 20–1100 ℃. The ceramic has a good color performance when the pigment is used to prepare the ceramic. It is indicated that the prepared black ceramic pigment with the superior coloring property has a promising application potential.