真空蒸馏电解铝废旧阴极炭块分离碳和电解质

Separation of Electrolyte and Carbon from Electrolytic Aluminum Spent Cathode Carbon Block by Vacuum Distillation

对电解铝废旧阴极炭块真空蒸馏分离碳和电解质进行了理论分析和实验研究,考察了蒸馏温度、保温时间对碳和电解质分离效果的影响。理论研究表明,在真空条件下电解铝废旧阴极炭块中的碳和电解质具有分离的可能性。实验结果表明,提高蒸馏温度和延长保温时间,均可提高铝、氟、钠元素的脱除率和渣中碳含量。在蒸馏压力10~30 Pa、蒸馏温度1350℃、保温时间5 h时,蒸馏渣中的碳含量为82.02%,铝脱除率为74.61%,氟脱除率为97.92%,钠脱除率为99.69%。研究表明,添加造孔剂NH4HCO3可提高铝的脱除率,NH4HCO3的添加量为6%时,铝的脱除率高达96%。研究结果可为真空蒸馏分离碳和电解质提供新的方法,对采用真空蒸馏法处理电解铝废旧阴极炭块具有一定的指导意义和应用价值。

The theoretical analysis and experimental study on the separation of carbon and electrolyte by vacuum distillation of electrolytic aluminum waste carbon block were carried out.The effects of distillation temperature and holding time on the separation of carbon and electrolyte were investigated.Theoretical studies have shown that the carbon and electrolyte in the aluminum cathode block of electrolytic aluminum have the possibility of separation under vacuum conditions.The experimental results show that increasing of the distillation temperature and prolonging of the holding time are beneficial to improve the removal rate of aluminum,fluorine and sodium and the carbon content in the slag.At a distillation pressure of 10-30 Pa,a distillation temperature of 1350℃,and a holding time of 5 h,the carbon content in the distillation residue is 82.02%,the aluminum removal rate is 74.61%,the fluorine removal rate is 97.92%and the sodium removal rate is 99.69%.Moreover,experimental studies have shown that the addition of pore-forming agent NH4HCO3 can improve the removal rate of aluminum.When the addition amounts of NH4HCO3 is 6%,the removal rate of aluminum is as high as 96%.The research results can provide a new method for vacuum distillation to separate carbon and electrolyte.It has certain guiding significance and application value for the treatment of electrolytic aluminum waste cathode carbon blocks by vacuum distillation.