Abstract:Alkali fusion purification process of spent cathode carbon from aluminum electrolysis was optimized by response surface method(RSM). Based on Box-Behnken Design (BBD), effects of temperature, time, and initial mass ratio of alkali to material on purification effect by alkali melting were studied. Secondary mathematical model between factors and carbon content was obtained. Residue carbon content is 95.47%, with 0.61 percent point different from predicted value, under the optimum conditions including temperature of 550 ℃, time of 180 min, and mass ratio of alkali to material of 2. Experimental results are similar to those predicted by the model, indicating the model can be used to optimize purification process of spent cathode carbon.