In this study, the dissolution of electro-filter magnesite dust samples that were collected from different places in an electrostatic bag house in HCl solution was investigated. The effects of sample composition and variations in the leaching parameters, such as reaction temperature, time, and acid concentration, were studied to elucidate the kinetics of the dust dissolution. The results obtained in this study clearly indicate that the dissolution of the magnesite dust increased with increasing acid concentration and leaching temperature. However, the tests on the effect of temperature, carried out at a constant reagent concentration of 0.5 M HCl, showed that the contribution of the increase in temperature on the dissolution rate was more powerful than that of the reagent concentration. At a temperature range between 290 and 318 K, the rate constants k were calculated as a function of temperature, and the following values were obtained: k = 2.71 x 10(8) exp(-7550/T) min(-1) for EFDS-1, k = 1.31 x 10(7) exp(-6520/T) min(-1) for EFDS-2 and k = 2.99 x 10(10) exp(-8780/T) min(-1) for EFDS-3. As a kinetic model to analyze the kinetic data, the shrinking-core model was proposed for the dissolution mechanism. The reaction was controlled by diffusion through the ash layer. The related activation energies were calculated to be 54.24 kJ mol(-1) for EFDS-1, 62.77 kJ mol(-1) for EFDS-2, and 73 kJ mol(-1) for EFDS-3.