Ascorbic acid was used as leaching agent to investigate the dissolution kinetics of natural magnesite ore. The effects of various reaction parameters such as acid concentration, liquid-solid ratio, particle size, stirring speed, and temperature were determined on dissolution kinetics of the magnesite ore. It was found that the dissolution rate increased with increase in acid concentration, liquid-solid ratio, stirring speed, and temperature and decrease in the particle size of the ore. The graphical and statistical methods were applied to analyze the kinetic data, and it was evaluated that the leaching process was controlled by the chemical reaction, that is, . The activation energy of the leaching process was found to be 57.244？kJ？mol？1 over the reaction temperature range from 313 to 343？K. 1. Introduction Magnesium is the third most commonly used structural metal after iron and aluminum. The applications of magnesium involve aerospace, automobiles, flash photography, flares, pyrotechnics, Grignard reagent, refractory materials, food, fertilizers, medicinal products, paper, textile, alloy formation, to remove sulfur in the production of iron and steel, fireproof, and so forth as described by Jones et al. [1]. With increase in population, there is continuous increase in demand of magnesium and its compounds. To overcome the increasing demand of magnesium and its compounds there is a need to explore ores of magnesium (magnesite, dolomite, etc.). These ores may vary in composition from deposit to deposit resulting differences in acidulation processes. These rocks generally contain impurities such as calcium, iron, and silica which can cause adverse effects on the applications of magnesium and its compounds. The leaching and dissolution studies of different ores with different leaching agents are available in the literature [2–11]. On industrial scales different leaching agents are used to leach ores of various compositions to get different metals and their compounds. Inorganic/organic acids or bases and their salts can be used for leaching of magnesite rocks to get magnesium and its compounds.From the dissolution studies of magnesite rocks by inorganic acids such as HCl, H2SO4, it was found that the dissolution reaction was chemically controlled [12, 13]. The inorganic acids are regarded as good leaching agents when relatively fast reaction rates are required. However, the use of inorganic acids as leaching agents affords certain limitations, like less selectivity, scaling problems, high CO2 pressure, corrosion, environmental problems, froth formation,
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