| The boron powder is applied extensively to each field such as the metallurgy, chemical industry, electron. Boron is produced usually by heating reduction with magnesium, hydride sodium reducing process, boron halogenation decompose and melt salt electrolysis. At present, heating reduction with magnesium is still the popular method. But is tedious, low in purity, and removing the metal boride of reductive products takes a long time,and cost a lot. Moreover melt salt electrolysis has such advantage as simple process, high purity and low cost. So melt salt electrolysis was chosen in our work.In this paper,the experimental apparatus of electrolysis was designed.The system of melt salt was chosen, thermodynamical analysis and calculation of theoretical decomposition voltage was carried out,which proved the feasibility of the experiment and offered the basis for the choice of experiment voltage. Liquidus temperature was determined by the cooling curve method, which could provide a foundation for the choice of experimental temperature.High pure boron was produced by molten salt electrolysis. The consumption of the graphite anode in the molten salt electrolysis process was analyzed,which provided a foundation for choosing materials.Current efficiency is an important production target. The reasons of the falling of current efficiency and reactive mechanism were analysed to confirm the formula of current efficiency .Also the influences of experiment temperature, electrolytic time, current density of cathode and distance of poles were investigated.The optimal operation was that the reaction temperature was 760~790℃, the electrolytic time was 2.5~3 hour, current density of cathode was 0.8-1.14A/cm2, distance of poles was 4cm. Under this reaction condition, current efficiency and the purity of boron were high.
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