Preparation of Aluminum-Yttrium Master Alloy from Yttrium Smelting Slag
A certain quantity of rare-earth fluorides and rare-earth metals are generally left in the corresponding yttrium smelting slag,making the yttrium smelting slag a good recovering value.However,the cost of wet recov-ery processes for high-abundance and cheap yttrium smelting slag is high but the value of the obtained product is low,which hinders the recovery of yttrium smelting slag.In this work,a sophisticated recovery system was de-signed,and the residual rare-earth elements in smelting slag were recovered and transformed into rare-earth met-als.Moreover,the obtained rare-earth metals are promoted to diffuse into the molten aluminum during the ther-mal reduction process,thereby obtaining an aluminum-yttrium master alloy product in one step.The results indi-cate that the residual YF3 in yttrium smelting slag reaches 12.51％,and lots of small-sized yttrium metals are found to be included in the slag.The corresponding recovery experiments find that when the smelting tempera-ture was set at 1550 ℃ and the addition amount of metallic calcium is 1.15 times the theoretical value,the re-covery rate of yttrium element from the smelting slag reaches 85％.The main precipitates in the obtained alumi-num-yttrium master alloy are Al3Y5,Al43Y6W4,and Al4Ca.These results are of great significance for developing a new recovery method for rare-earth smelting slag and promoting the efficient utilization of rare earth resources.
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