Abstract: Based on the results of laboratory research，Taking magnesium chloride and carbide slag as raw materials，the test conditions for the preparation of crude magnesium by silicon thermal reduction method were investigated.The experiment showed that: under the conditions of the calcium magnesium ratio of 0.83，the calcination temperature of 900 ℃，and the calcination period of 1.5 h，crude magnesium reduction yield was 80.93% on average.Compared with the crude magnesium production processes by Pidgeon method with dolomite as raw materials，the silicon thermal reduction method with magnesium chloride and carbide slag as raw materials makes full use of secondary resources and reduces the destruction of the environment by the exploitation of resources.It eliminated the discharge of carbon dioxide，reduced the energy consumption in the process，and improved the flexibility of the production process.Therefore，after removing the impurities of carbide slag，this process has a good prospect for industrialization.

Key words: Magnesium chloride in saline lake, Carbide slag, Silicothermic reduction process, Crude magnesium, Dolomite, Pidgeon