Novel processes for preparing high-purity anhydrous YCl3 and Mg-Y alloys

The process for preparing high-purity anhydrous yttrium chloride was investigated using a complex salt containing an excess of yttrium oxychloride. By studying the conversion of yttrium oxychloride, it was determined that the key to preparing high-purity anhydrous yttrium chloride lay in the synergistic actions of gas-solid and solid-solid reactions. On this basis, a purity control strategy involving the adjustment of the height-diameter ratio of the sample was proposed to inhibit hydrolysis and enhance the conversion rate. By adopting the purity control strategy, high-purity anhydrous yttrium chloride with a yttrium oxychloride content below 0.1 wt.% was obtained at 600°C when the height-diameter ratio of the samples exceeded 1.42. Finally, the experiments on preparing Mg-Y alloys through molten salt electrolysis validated the impact of the YCl3 purity on the electrolysis process. When the high-purity anhydrous yttrium chloride obtained by this strategy was utilized, the current efficiency could reach 83.7%.