Research On Comprehensive Utilization Of The Spent Cathode Of Aluminium Cell

With China’s capacity of electrolytic aluminum increasing, the spent aluminumcell cathode material is also growing. The spent cathode material contains lots ofsoluble fluoride and a dash of cyanide which belong to the dangerous solid waste.Meanwhile, the spent cathode material mainly consists of carbon materials andpermeated electrolyte, etc., which can be exploited as a kind of resource. Therefore,the comprehensive utilization of spent cathode material is the main direction topollution prevention and resource utilization in electrolytic aluminum enterprises.The spent aluminum cell cathode were chosen from Shanxi Guanlv Co.,Ltd. forexperimental materials in this paper. The basic physical and chemical properties,include the phase, chemical composition, resistivity and combustion characteristics.According to the property of the spent cathode determined that the carbonaceousmaterials and electrolyte composition were selected by flotation method, and thenanalyzed the products to utilize.The main conclusions are as follows:(1) The spent aluminum cell cathode material is mainly composed of C、Na3AlF6、NaF、CaF2、Al2O3, etc., in which the carbon content is30%~66%. There isa clear interface between the carbonaceous and electrolytic materials in spentaluminum cell cathode materials.(2)The resistivity increases with electrolyte penetrate, which leads the cell to stop.The electrolyte osmosis and the resistivity increase from bottom to top. According tothe test, the resistivity increased from2.7×10-5~3.1×10-5Ω·m to3.2×10-1~3.7×10-1Ω·m,higher than the original resistivity1.0×10-5~1.5×10-5Ω·m. The temperature should be controlled at500~800℃to degradable carbon in the cell cathode material while ithigher cause electrolyte volatilization and lower will be ineffective to degradablecarbon.(3)The optimal sorting parameters are determined as follous:85.75%of grindingfineness is-200mesh, modifies the quantity of Na2SiO3by500g/t,the dosage ofkerosene collector is500g/t and the2#frother is100g/t. Once roughing and thirdconcentrating and once scavenging were taken for tests. The carbon concentrate gradeis81.08%and recovery is82.83%.This study can be used for separating and utilizing spent aluminum cell cathode.This can provide the basis for environmental protection and resource recycling.