Si-Mn alloy dust is the solid waste produced in the process of ferroalloy smelting, which contains a large amount of manganese and a small amount of zinc, lead and alkali metals. In order to better recycle the valuable metals in the dust and reduce the harm of zinc, lead and alkali metals to the smooth smelting process, the Si-Mn alloy dust is pressed into blocks, and the volatilization removal and dynamics law of zinc, lead, potassium and sodium during carbothermal reduction reaction of the blocks are studied. The results show that high temperature is beneficial to the volatilization of zinc, lead, potassium and sodium during carbothermal reduction reaction. When the temperature is 1 550 ℃, zinc and lead volatilize quickly, and they are completely volatilized in about 5 minutes, with the volatilization rates of 99.74% and 99.00% respectively, and the volatilization rates of potassium and sodium are 97.65% and 96.66% respectively when they are heated for 30 minutes. Avrami-Erafeev model can well describe the volatilization of zinc, which is controlled by the gasification reaction of carbon. Jander's three-dimensional diffusion model can well describe the volatilization of lead, potassium and sodium, and its volatilization is controlled by gas phase diffusion. The volatilization activation energies of zinc, lead, potassium and sodium are 26.16, 95.77, 175.06 and 261.09 kJ/mol, respectively.