Separation of Rare Earth-rich Phase from Low Rare Earth-bearing Slag by Natural Gravity
In order to recover rare earth(RE)resources from slag with low RE content,a separation method for the RE-rich phase from slag by natural gravity was attempted in this paper.After the RE-rich phase crystallization was completed,the viscosity of the upper slag was adjusted by adding a fluxing agent,and thereby the gravity deposition of the RE-rich crystalline phase was realized.The results showed that the suitable holding temperature for the excellent deposition of the RE-rich phase was different for the different slag compositions.For the slags with P2O5,the suitable temperature range is 1300 ℃ to 1350 ℃,the La2O3 content in the bottom layer reached to 35.21％to 37.12％,and the enrichment factor was 2.24 to 2.49,and the deposition rate of the precipitated phase was up to 91％.For the slags with CaF2,the deposition effect was enhanced in case of holding at 1200 ℃ compared with 1350 ℃.However,the deposition effect of the slags with CaF2 was inferior to that of the slags with P2O5.With increasing B2O3 content from 0 to 3％,the deposition effect of the RE-rich phase gradually increased.At adding 3％B2O3,La2O3 content in the bottom deposition layer of the slag was 37.12％and the enrichment fac-tor was 2.24.
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