This study investigates the production of high-quality MgCl2 from recycled waste magnesite powder with an average particle size of d(50) 0.079 mm using the HCl acid leaching method. The experimental parameters were, leaching temperature, leaching time, amount of the acid, liquid-to-solid ratio, scale-up factor, acid concentration, particle size and mixing speed. The experiments were performed under reproducible conditions. The results showed that optimum leaching parameters were: temperature of 70 degrees C, 180 min leaching time, 130 cm(3) acid consumption, 3.6 cm(3)/g liquid-to-solid ratio, scale-up factor of 1, 10.17 M acid concentration, 0.079 mm average particle size and a mixing speed 60 rpm. Under these optimum conditions, the leaching yield was 96.72%. The produced MgCl2 solution contained 0.04% SiO2, 0.36% CaO, 0% Fe2O3, 0% Al2O3, 46.73% MgCl2, 52.87% L.O.I. and 99.60% MgCl2+L.O.I. (= MgCl2 center dot 6H(2)O). These results indicated that high-quality magnesium chloride can be produced from waste magnesite powder.