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The kinetics of the leaching of natural magnesite with hydrochloric or nitric acid has been studied. Relatively high values of the apparent activation energy (from 46.5 to 70.0 kJ mol−1), but especially the low values of the apparent reaction order for H+ cations, $n$ n , have shown that the whole process is controlled by the surface chemical reaction. The value of $n$ n decreases continuously with increasing activity of H+ cations in the range of pH 5 to −1.4. At ${\rm{pH}}\,\lt 2.6$ pH < 2.6 there is a transition from the kinetic regime characterized by $n \cong $ n ≅ 0.5 to another one with $n$ n close to zero. [ABSTRACT FROM AUTHOR]