Synthesis of ceramic pigments from industrial wastes: Red mud and electroplating sludge. (October 2018)

• Record Type: Journal Article
• Authors: Carneiro, J.; Tobaldi, D.M.; Capela, M.N.; Novais, R.M.; Seabra, M.P.; Labrincha, J.A.
• Is Part Of: Waste management. Volume 80(2018)
• Page Start: 371
• Page End: 378
• Publication Date: 2018-10
• Subjects: Bauxite residue -- Electroplating sludge -- Black pigment -- Waste valorisation -- Ceramic glaze; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2018.09.032
• Languages: English
• ISSNs: 0956-053X

Abstract

Highlights: Red mud and electroplating sludge combined to prepare ceramic pigments. Dark pigments with structure based on a chrome-iron-nickel spinel. Waste-based pigments display good color stability in ceramic glazes. Stability/tinting strength of waste-based pigments competitive with commercial ones. Abstract: The perception of industrial waste has changed, in the last decades, from an economic and environmental problem to a potential raw material. In this work, the synthesis of a stable pigment was prepared by combining two hazardous and unexplored wastes: red mud (RM, rich in Fe) and electroplating sludge (ES, rich in Ni/Cr). The wastes were mixed in different proportions and calcined at 1200 °C. Black and brown pigments were obtained from the mixture of RM/ES in 1:3 and 1:1 wt proportions, respectively. The color was given by the chrome-iron-nickel spinels, based on Ni 2+ 3 T1g ( 3 F) transitions (≈13, 000 cm −1 ), Cr 3+ 4 A2g → 4 T1g ( 4 F) transitions (≈24, 400 cm −1 ) and Fe 3+ (≈15, 000–≈22, 500 cm −1 ). The achieved coloring strength and thermal stability on various ceramic glazes render excellent prospects for the industrial application of such waste-based pigments.