Abstract: The zinc content of a copper smelting slag is 5.15%，and the zinc is mainly in the form of zinc oxide，followed by a small amount of zinc sulfide and zinc silicate. In order to determine the develop⁃ ment and utilization scheme of the secondary resource，the vacuum carbothermal reduction test was carried out. The results showed that: ① with the increase of carbon content，the volatilization rate of zinc increases significantly at first and then slows down. The reaction system increased from natural alkalinity to alkalinity 0.6，and the volatilization rate of zinc increased significantly to above 90%. ② With the initial vacuum of 10 Pa，the temperature of 1 000 ℃ for 0.5 h，the alkalinity of the reaction system of 0.6，and the carbon content of 1.9 times of the theoretical amount，the volatilization rate of zinc is 97.72%. CaO can not only promote the reduction of ZnS and Zn₂SiO₄，but also avoid the sintering of slag. ③ Under the condition of 1.9 times the theoretical carbon content，the main phases in the reduction slag are CaFe+2SiO₄，Fe₃O₄ and Fe，which creates the conditions for the subsequent recovery of iron from the slag.

Key words: vacuum carbothermal reduction, zinc, copper smelting slag, calcium oxide