TRANSACTIONS OF THE INDIAN INSTITUTE OF METALS
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2025
·Vol. 78
·期 4
·1-10
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IF 1.6
Pan Qi,Zhu Zhen,Lin Xiaocheng,Guo Bao,Jiang Kaixi
It is a waste of gallium resource to discard the high aluminum-containing gallium electrolyte. The Ga/Al separation is difficult by only using lime precipitation because of high gallium loss rate. The present study employs an adsorption resin LSC-600P to recover gallium in the simulated gallium electrolyte and then uses lime to remove aluminum, leaving only alkali solution recycled. The results showed that the aluminum removal rate in the gallium electrolyte was 93.12% under the conditions of reaction temperature of 85 °C, addition of lime 2 times to the theoretical molar ratio of calcium to aluminum, reaction time of 3 h and stirring speed of 600 r/min. In the experiments of gallium adsorption, after six adsorption–desorption cycles, the adsorption rate of gallium by LSC-600P resin still reached 98.6%, and the adsorption rate of aluminum was lower than 4.5%. In the desorption process, the desorption rate of gallium was more than 98%, and the aluminum content in the stripping solution after desorption was almost negligible. The resin exhibits high adsorption affinity for gallium while demonstrating minimal adsorption for aluminum.
研究领域:
冶金学
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环境工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Kai Gao,Xingyu Liu,Shaochun Hou,Guoguang Zhang,Zongyang Da,Shengfeng Ma,Chunlei Guo,Weihua Guan
The concentration of rare earth elements (lanthanum, cerium, and praseodymium) within rare earth polishing powder waste (REPPW) typically exceeds 50 %, with the majority of impurities comprised of silicon and aluminum-related compounds. Transforming REPPW into recycled rare earth polishing powders that adhere to polishing standards in an eco-friendly and economically viable way presents a significant challenge in the industry. Traditional acid or alkaline processes predominantly recover rare earth elements as oxides, which are underutilized due to their high costs. Considering the varying forms of impurities and rare earth compounds found in REPPW, this research introduces a novel physicochemical decontamination and continuous chemical transformation process aimed at producing regenerated rare earth polishing powders. Under optimal conditions, the physicochemical two-step decontamination process achieved a rare earth recovery rate surpassing 92 %, while silicon and aluminum removal rates reached 86.12 %. During the continuous chemical transformation of REPPW, the rare earth phases in an alkaline setting followed the sequence REOF (CeO 2 ) → RE(OH) 3 → RECO 3 OH→RECO 3 F→CeLa 2 O 3 F 3 (CeO 2 ), which not only facilitated phase reorganization but also enhanced the particle surface structure. Notably, these chemical transformations did not disrupt the rare earth distribution; instead, they indirectly boosted product purity and uniformly dispersed within the regenerated polishing powder particles, thereby improving polishing efficiency. Consequently, the adoption of this innovative regeneration process for polishing powders holds substantial importance for the sustainable utilization of rare earth resources.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Chunling Chen,Hui Long,Yangyang Luo,Kuantao Zhang,Chongyu Du,Hongyan Pan,Qian Lin,Zheng Chen
The purification of wet-process phosphoric acid has always posed a challenge for both academic and industrial researchers. In order to address this issue, a treatment unit was developed to mitigate magnesium and aluminum impurities from industrial semi-aqueous wet process phosphoric acid (SWPPA) (39.4 wt% P 2 O 5 ) through ralstonite precipitation using Na + /F − as the precipitator (F − provided by HF). Thermodynamic analysis, DFT calculation and separation experiments results were used to investigate the impact of sodium sources properties on impurities removal rates and H 3 PO 4 yield. Additionally, the effects of reaction temperature, reaction time, precipitating agent dosage, and aging time on precipitation efficiency were also examined. The results show that the ability of sodium source to ionize Na + and react with H 3 PO 4 and HF plays a crucial role in determining the impurity removal performance of magnesium and aluminum. The precipitants NaCl and Na 2 CO 3 exhibit the highest removal rates for magnesium and aluminum, which is attributed to the easy ionization of Na + ions. In comparison to Na 2 CO 3 , the higher H 3 PO 4 yield with NaCl as precipitator can be achieved due to its lower nucleation rate and higher crystal growth rate in the phosphoric acid system. NaCl and HF as precipitants effectively reduces the concentrations of magnesium and aluminum in the untreated SWPPA solution from 23.47 g MgO/kg P 2 O 5 to 3.29 g MgO/kg P 2 O 5 , 48.98 g Al 2 O 3 /kg P 2 O 5 to 15.54 g Al 2 O 3 /kg P 2 O 5 . The removal rates for magnesium and aluminum are found to be 85.98% and 68.27%, respectively, with minimal residue of Na + /F − .
研究领域:
化学工程
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材料科学
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产品关联
DOI
高影响因子
MINERALS ENGINEERING
·
2025
·
IF 5
Hao Fu,Xuesong Jiang,Xiaotian Chen,Zhenyi Hu,Jifei Sun,Zongrong Zhou,Ling Wang,Boyuan Ban,Jian Chen
Al is one of the most difficult to remove impurities from quartz. Even with HF, only a limited removal efficiency was demonstrated. This study proposes a novel and environmentally friendly strategy centered on a combined process of ball milling, Na 2 CO 3 roasting, fluorine-free acid leaching, and chlorination roasting. The core innovation lies in the strategic induction of a consecutive and reversible phase transformation cycle (α-quartz → cristobalite → α-quartz), which serves as an internal grain refiner to achieve continuous microstructure refinement, thereby constructing abundant fast pathways for impurity migration. A comprehensive XRD analysis was introduced to observe the microstructure evolution. The results indicate that Na 2 CO 3 promotes the phase transformation from α-quartz into cristobalite at a relatively low temperature, while chlorination roasting facilitates the reverse transformation back to α-quartz. It revealed that these two distinct phase transformations not only disrupt the crystal integrity but also lead to significant microstructure refinement accompanied by abundant lattice defects. Through these defects, Al impurities rapidly migrate to the quartz particle surface, where they react with the acid solution and HCl gas, enabling efficient removal. Under the optimal process, the Al removal rate reached 90.5 %, the total impurity removal rate attained 98 %, and the quartz purity increased from 99.683 wt% to 99.994 wt%. This work highlights the crucial role of reversible phase transformation-induced grain refinement as an efficient strategy for lattice impurity removal, offering a green and high-performance alternative to HF-based purification with demonstrated advantages in environmental safety, energy efficiency, and product yield.
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高影响因子
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