Historical use and future development of chemicals for solid–liquid separation in the mineral processing industry

From their ancient beginnings to the present day, coagulants and flocculants, used to enhance solid–liquid separation by particle aggregation, are described; particular reference is given to developments in the mineral processing industry. The impact of polyacrylamide-based flocculants on technical effectiveness, disposal possibilities and environmental control, over the last 40 years, has had a profound effect on the efficiency and design of solid–liquid separation equipment. Recent developments, in terms of molecular architecture, offer new horizons for the future at a time when requirements for separating solid particles from liquid are becoming more demanding in the minerals industry.