熔盐电解二氧化硅制备低硼磷铝硅合金

Preparation of Al-Si Alloy with Low Concentration of Boron and Phosphorus by Molten Salt Electrolysis of Silica

分别采用高纯石墨和Fe-Ni合金为阳极,在960℃的冰晶石熔盐中电解SiO2制备低硼磷铝硅合金,研究电流密度和SiO2添加量对电流效率、阴极产物成分和B,P杂质含量的影响规律,并利用XRD和SEM表征阴极产物的物相组成和微观形貌.结果表明,以石墨为阳极时,当电流密度从0. 5 A/cm^2增大到0. 9 A/cm^2时,阴极产物中w[Si]从0. 75%增大到15. 17%,电流效率从2. 58%增大到38. 06%;B和P的最低质量分数分别为3×10^-6和7×10^-6.以Fe-Ni合金为阳极时,当SiO2添加量从2%增大到6%时,阴极产物中w[Si]从3. 19%增大到19. 86%,电流效率从12. 43%增大到70. 48%;B和P的最低质量分数分别为6×10^-6和11×10^-6;阴极产物的物相组成为铝、硅和铝硅合金.

Low-boron(B)/phosphorus(P)Al-Si alloys were prepared by electrolysis of silica in cryolite melts at 960 ℃ using high-purity graphite and Fe-Ni alloy as anodes.The effects of current density and the addition amount of silica to the melts on current efficiency, cathode composition, and impurity(B and P)contents were investigated.The phase composition and microstructure of the cathode product were characterized by XRD and SEM.The results showed that when using graphite anode, the silicon contents in the cathode product increased from 0.75 % to 15.17 % as the current density increased from 0.5 A/cm 2 to 0.9 A/cm^ 2, and the current efficiency increased from 2.58 % to 38.06 %.The minimum contents of B and P were 3 ×10^-6 and 7×10^-6 , respectively.Using Fe-Ni alloy anode, the silicon contents in the cathode product increased from 3.19 % to 19.86 %, and the current efficiency increased from 12.43 % to 70.48 % when the addition amount of silica increased from 2 % to 6 %.The minimum contents of B and P were 6×10 ^-6 and 11×10^-6 , respectively.The phase compositions of the cathode product were Al, Si, and Al-Si alloy.