The utilization of alunite ore as a coagulant aid

Alunite, K2SO4 • Al2(SO4)3 • 4Al(OH)3 is a mineral not soluble in water in its original form. It was formed by hydrothermal alteration of tuff. Therefore it contains approximately 50% SiO2. When heated to 700°C, it becomes soluble in water and such soluble components as Al2(SO4)3 and K2SO4 dissolve in water. In the present work, the coagulant characteristics of the calcined alunite were examined and whether or not calcined alunite could be used a coagulant aid was determined. The alunite was crushed and calcined at various temperatures ranging from 600°C to 900°C. The effectiveness of coagulant aid of the calcined alunite using at various doses, together with aluminium sulphate in jar test, was investigated. The jar tests were made in the synthetic water sample prepared in varying its alkalinity and turbidity.