PRODUCTION OF AL-Y ALLOY VIA ELECTROLYSIS OF KF-NaF-ALF-YO MELT

One of the ways to increase the efficiency of aluminum production is the use of low-temperature electrolytes and the production of demand aluminum master alloys. Earlier it was noted that it is effective to obtain aluminium master alloys via electrolysis of low-temperature electrolytes, allowing to arrange production without the need to obtain individual alloying elements and aluminium. It is relevant both from the practical and scientific point of view is the study of the possibility of obtaining aluminium master alloys with such electronegative elements as scandium, yttrium, strontium and calcium, etc. In this paper, the possibility of obtaining the Al-Y master alloy during electrolysis of a low-temperature electrolyte based on the KF-AlF system with the addition of YO at a temperature of 800C was studied. For this purpose, the kinetics of the cathode process on a molybdenum and glassy carbon electrode was studied in the melt under study with different oxide content using chronovoltammetry method. It is shown that the addition of YO practically does not affect the voltampere dependences and the mechanism of the process, increasing the cathodic currents of reduction of aluminium and yttrium ions, as well as the anodic currents of oxidation of cathodic reaction products. Based on electrochemical measurements, it was assumed that the co-reduction of aluminum with yttrium is possible at current densities above 0.4-0.5 A/cm. The process of obtaining Al-Y alloys in the KF-NaF-AlF melt with the addition of 1 wt% YO under conditions of aluminothermic synthesis and galvanostatic electrolysis of the melt at a cathodic current density of 0.5 and 1.0 A/cm was studied. As a result of aluminothermic reduction, an alloy with an yttrium content of no more than 0.07 wt.% was obtained, while during electrolysis, Al-Y master alloys with an yttrium content from 0.75 to 1.28 wt.% were obtained. The obtained values correspond to the extraction of yttrium from its oxide of 4.4; 47.5 and 81.3. It is suggested that the increase of synthesis duration and periodic loading of YO into the melt will allow to obtain Al-Y master alloys with increased yttrium content.