Effect of Mechanical Activation on the Thermal Oxidation of Sphalerite

We consider the effect of mechanical activation on the particle size and strain of natural sphalerite particles and demonstrate that mechanical activation of the mineral for 20 min in a high-energy planetary mill reduces the crystallite size to 20 nm and that in this process the lattice strain in sphalerite reaches 0.73–0.85%. Thermogravimetry, calorimetry, and mass spectrometry have been used to study sphalerite oxidation processes during nonisothermal heating to a temperature of 1000°C in flowing air before and after mechanical activation. Mechanical activation of sphalerite has been shown to lead to a slight increase in the rate of sulfate formation, a decrease in the temperature and enthalpy of the thermal effects involved, and release of sulfur dioxide as a product of interaction with oxygen starting at a temperature of 150°C.