Preparation of calcium sulfate whiskers by carbide slag through hydrothermal method

Abstract

In this work, a series of calcium sulfate whiskers were prepared successfully using carbide slag as raw material through hydrothermal method. The prepared gypsum observed is hemihydrate calcium sulfate and the formation of the calcium sulfate whiskers are influenced by preparation parameters. The optimal preparation conditions are as follows: seriflux concentration, 4 %; hydrothermal reaction time, 10 h; hydrothermal reaction temperature, 130°C; seriflux pH, 7; calcium‐magnesium ratio, 12 : 1. Some nanowires appear when seriflux pH is very low (e.g. 1). The length‐diameter ratio of the whiskers is about 60‐80.