The environmental sustainability of synthetic wollastonite using waste from zirconium oxychloride production.

A reasonable and economic process to achieve the comprehensive utilization of waste from production of zirconium oxychloride would benefit sustainable development of zirconium industries and reduce environmental pollution. In this paper, wollastonite was prepared from spent caustic liquor and zirconium-containing silicon slag at low temperature. The effects of CaO/SiO 2 mole ratio, reaction temperature, reaction time, and rotation rate on the crystallization and morphology of wollastonite were systemically investigated. The optimal conditions for desilication were confirmed as a CaO/SiO 2 mole ratio of 1.0, a reaction temperature of 90 °C, a desilication time of 60 min, and a rotation rate of 200 r/min. Wollastonite was subsequently prepared by calcination of the obtained calcium silicate hydrate at 1000 °C for 1.0 h. The developed process achieved good performance of wollastonite and alkali liquor with a low silicate content, which met the standard of an industrial-grade product. [ABSTRACT FROM AUTHOR]