Physicochemical Properties Of Industrial Aluminum Electrolytes Enriching Li And K

Due to the high content of impurities of domestic alumina, the potassium salt and lithium salt are enriched in the electrolytes with the cell running, so that the composition and physic-chemical properties of electrolytes have been changed. To understand the characteristic of the properties deeply, and to achieve stability produce and energy consume decline, based on the electrolyte system (2.2-2.7)NaF·AlF3-5%CaF2-2.5%Al2O3-0.5%MgF2-(0-4%)LiF-(0-4%) KF, effects of potassium salt, lithium salt and CR on liquidus temperature and alumina solubility of electrolytes have been studied in the present work. Moreover, a new kind of lithium salt of LiAlO2has been explored. The main conclusions can be drawn as follows:1) Basic data of liquidus temperatures of the system (2.2-2.7)NaF·AlF3-5%CaF2-2.5%Al2O3-0.5%MgF2-(0-4%)LiF-(0-4%)KF has been measured. Effects of potassium salt, lithium salt, and cryolite ratio on liquidus temperature have been revealed. The complex effects of these three facts on liquidus temperatures depend on the composition of electrolytes. Liquidus temperatures decrease by0.97-4.50℃with addition of1%KF, and it decreases by5.13-10.74℃with addition of1%LiF. With CR increasing, liquidus temperatures increase gradually.2) Basic data of alumina solubility of the system (2.2-2.7)NaF·AlF3-5%CaF2-2.5%Al2O3-0.5%MgF2-(0-4%)LiF-(0-4%)KF under different temperatures has been measured. Effects of potassium salt, lithium salt, cryolite ratio, and temperature on alumina solubility have been revealed. At certain temperature, alumina solubility is increased by potassium salt, and the role can be weakened by lithium salt. As for the system of low lithium salt, increasing of CR weakens the role of potassium salt to alumina solubility; alumina solubilities of the system including4%KF and0-1%LiF are about7%.3) Effects of LiAlO2on liquidus temperature and alumina solubility of industrial electrolyte have been studied. Liquidus temperature decreases by1.2-5.5℃with addition of1%LiAlO2. If the alumina concentration is calculated by the total oxygen concentration, LiAlO2increases alumina concentration. When adding3%LiAlO2into the experimental electrolyte, the alumina concentration increases up to6.44%, and it will be6.67%if continuely adding3%KF.60Pictrues,34Tables and71References.