EFFECT OF REACTION CONDITIONS ON DISSOLUTION OF MAGNESIUM, IRON AND CALCIUM DURING LEACHING OF BURNED MAGNESITE IN HYDROCHLORIC ACID
Abstract
Dissolution rates of magnesium, iron and calcium during the leaching of burned magnesite in hydrochloric acid solutions were studied in a laboratory isothermal, mechanically mixed, batch reactor under different reaction conditions (temperature, acid concentration and particle size). It was observed that: (a) In all leaching tests more than 95% of calcium had dissolved before the first sample of solution was withdrawn, i.e. in times shorter than 2 minutes. (b) Dissolution rates of magnesium and iron increased with temperature and decreased with particle size - the latter fact is caused by law porosity of the solid. ( c) HCl concentration had different effects on the rates of dissolution of magnesium and iron: while the rate of dissolution of the magnesium decreased with increasing cHCl , that of iron increased with cHCl at lower conversions (< 0.4) and decreased at higher conversions (> 0.4) - this effect is caused by simultaneous dissolution of iron from different minerals.