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that:  (a) In all leaching tests more than 95% of calcium had dissolved before the first sample of solution was withdrawn, i.e. in times shorter than 2 minutes.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.