Preparation of strontium carbonate from celestite

A novel method for the preparation of strontium carbonate from celestite or e has been investigated. The ore is reduced by brown coal at a temperature of 1000 degrees C for a period of 3 h. The reduced product is leached with water at a liquid : solid ratio of 3 : 1 at 90 degrees C and the slurry is then leached with hydrochloric acid at a solid : liquid ratio of 2 : 1. By controlling the pH at 1.5-2 and adding 20% H2O2 at the rate of 0.5 dm(3)/m( 3) of solution the oxidation process HS- --> S degrees is accomplished. Bar ium is precipitated with dilute sulphuric acid; and more than 90% Ca2+ + Mg 2+ land Fe) is removed when the pH is increased to 12. Addition of 1.2 time s the theoretically required amount of NH4HCO3 at a solution strength of 2 mol/l at 60 degrees C and at pH in the range 9-11 results in the precipitat ion of SrCO3. The precipitate is washed and dried at 220-250 degrees C. The proposed flowsheet is simple, has low consumption of acid and alkaline rea gents, gives a high recovery of strontium and accepts a wide range of raw m aterial.