Efficient removal of Al(III) and P507 from high concentration MgCl2 solution based on in-situ reaction strategy
(1. National Engineering Research Center for Rare Earth, GRIREM Advanced Materials Co., Ltd., Beijing 100088, China;
2. School of Metallurgy, Northeastern University, Shenyang 110819, China;
3. General Research Institute for Nonferrous Metals, Beijing 100088, China;
4. GRIMAT Engineering Institute Co., Ltd., Beijing 101407, China)
2. School of Metallurgy, Northeastern University, Shenyang 110819, China;
3. General Research Institute for Nonferrous Metals, Beijing 100088, China;
4. GRIMAT Engineering Institute Co., Ltd., Beijing 101407, China)
Abstract: For a highly efficient recycling of a wastewater containing a high concentration of MgCl2, Al(III) and P507 were scheduled to be removed in advance. In this study, the in-situ removal of Al(III) and P507 from a high concentration MgCl2 solution at different pH values and Al/P molar ratios was investigated. The results showed that P507 formed organic complexes of Alx(OH)yz+-P507 at pH of 2.0-4.0. At pH of 4.0-5.0, Al(III) precipitated and transferred into Al(OH)3 with a flocculent amorphous morphology. Active sites on the Al(OH)3 surface enhanced the removal efficiency of P507. At pH of 6.0-6.5, Al(III) and Mg(II) formed layered crystalline Al(OH)3 and MgAl2(OH)8 with small pore channels and fewer active sites, resulting in a reduced removal efficiency of P507. When the Al/P molar ratio exceeded 13 and the pH was between 4.0 and 5.0, the removal rates of both Al(III) and P507 were higher than 98%, while the concentration loss of Mg(II) was only 0.2%-0.9%.
Key words: in-situ removal; Al(III); P507; MgCl2 solution; pH; Al/P molar ratio