熔盐电沉积法制备铝钙合金中的反电动势实验研究

Study on back electromotive force in preparation of Al-Ca alloys by molten salt electrodeposit

铝钙合金是理想的脱氧、脱碳、脱硫剂,在冶金工业中作还原剂和添加剂,起到去硫脱氧及净化作用。以易得的CaO代替了CaCl2为原料电解,以石墨为阳极,上浮铝液作为阴极,电解温度在740℃下,在CaCl2-CaF2-BaF2体系中熔盐电解法制得到铝钙合金的过程。采用熔盐电解监控仪测量电解过程中的反电动势、槽电压、电流等工艺参数及电解波形图,通过电位控制法调节Li2CO3的加料周期,重点对反电动势进行了深入的探讨。研究发现,反电动势和槽电压均随阳极电流密度增加而增加,但当电流密度超过0.3 A/cm2以后,反电动势和槽电压增长趋势减缓;临界电流密度经测量为2.548 A/cm2;加入1%CaO后反电动势降低0.5 V,通过控制电位法测得加料周期为30 min。

Calcium-aluminum alloy as the reducing agent and additives is an ideal deoxidizer,decarbonizer and desulfurizer in the metallurgical industry,which plays the role of desulfurization and deoxidation.The technical process is that Al-Ca alloys are prepared by taking the aluminum liquid as cathode,graphite as anode and a mixture of CaCl2-CaF2-BaF2 as molten salt electrolyte in a laboratory cell at 740 ℃.The technological parameters such as back electromotive force,cell voltage,current and electrolysis waveform are measured by testing the device of molten salt electrolysis.The period of CaO feeding is adjusted by the method of electric potential control.Especially,the back electromotive force is discussed in details.The results indicate that the back electromotive force and cell voltage increase with the increasing of current density.After the current density is more than 0.3 A/cm2,the growth of back electromotive force and cell voltage are delayed.The critical current density measured is 2.548 A/cm2.The back electromotive force decreases by 0.5 V after adding 1% CaO and the feeding period is 30 min measured by the method of electric potential control.