Minerals
·
2023
·Vol. 13
·期 3
·318
·
IF 2.5
Yingli Chen,Xiyun Yang,Linglong Wu,Lirong Tong,Jing Zhu
This paper describes a leaching-purifying-precipitation process to recover magnesium from serpentine acid-leaching solution and to synthesize high purity Mg(OH)2and 4MgCO3·Mg(OH)2·4H2O. Fe, Al, and Cr in the leaching solution were removed using the oxidation precipitation method with active MgO as a precipitant and H2O2as an oxidant. Ni, Co and Mn were removed by Na2S precipitation to obtain a pure MgSO4solution. Mg2+ions were first precipitated with NH3·H2O to synthesize Mg(OH)2, followed by NH4HCO3precipitation to obtain 4MgCO3·Mg(OH)2·4H2O. A small part of MgSO4coprecipitates with Mg(OH)2to form MgSO4·5Mg(OH)2·3H2O. The Mg(OH)2was aged with a diluted NaOH solution to remove the sulfur; the two-stage precipitation percentage of Mg is 96.3%. Mg(OH)2has a purity of 98.48% with a sulfur content of 0.28%. This process provides a promising method for the high-efficiency recovery of Mg and the large-scale production of the high purity of Mg(OH)2from the serpentine.Keywords:serpentine;two-stage counter current leaching;remove impurity;MgSO4·5Mg(OH)2·3H2O;high purity Mg(OH)2
研究领域:
冶金工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
WASTE MANAGEMENT
·
2019
·
IF 5.431
Xiangdong Meng,Xiaoji Liu,Qunxing Huang,Huaping Gao,Kangrou Tay,Jianhua Yan
As a phosphorus-rich material, low-temperature combustion sewage sludge ash (LTCA) contains over 9 wt% content of phosphorus (P) and a large proportion of impurities, especially the content of Fe arrives at 14.59 wt%. To fully utilize LTCA as a fertilizer, this study investigated a procedure for P recovery from LTCA via struvite crystallization with fewer impurities. The adsorption characteristics of P and Fe by cation exchange resin (CER) were explored by simulating using the macroscopic parametric equation Thomas model. Optimum purification conditions for P-rich leachate by cation exchange column method were determined. Results showed that approximately 97.21 wt% of P was extracted from LTCA at HCl concentration of 0.8 M and liquid/solid ratio of 20.0 ml/g. More than 90 wt% of impurities could be detached by making P-rich leachate flow through cation exchange bed filled by CER at 300 ml/h. The macroscopic parametric equation Thomas model could clearly describe the adsorption characteristics of Fe in P-rich leachate by CER. Theoretical basis for purification of high concentration Fe in P-rich leachate by CER was provided. Approximately 84.04 wt% of total P in LTCA was recovered as struvite crystal which had low concentrations of heavy metals (5.96 mg/kg for Cr, 45.21 mg/kg for Cu, 29.67 mg/kg for Ni, 2.24 mg/kg for Pb, and 290.6 mg/kg for Zn) and could be eco-friendly for agricultural application. X-ray diffraction and SEM-EDS analysis validated the formation of struvite.
研究领域:
环境科学
·
农业科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Zirui Li,Zhengjie Chen,Dong Ouyang,Xiaowei Gan,Junyu Qu,Chenguang Han,Shilong Ye,Wenhui Ma
Spent carbon cathode (SCC) is a recyclable hazardous solid waste generated from electrolytic aluminum production. In this study, a combined leaching process involving mixed molten salt roasting and ultrasonic-thermal pressure was proposed to purify graphite and repair the lattice structure of waste cathodes. The results showed that the mixed molten salt system reduced the reaction temperature of the impurities in the waste cathode and that adding an ultrasonic pretreatment step shortened the subsequent hot-pressing acid leaching time. It also lowered the reaction temperature, and the fixed carbon content of the product increased from 99.81% to 99.86%. X-ray diffraction (XRD), Raman spectroscopy, BET, and particle size tests showed that ultrasonic pretreatment did not damage the graphite crystal structure and even promoted the repair of the graphite lattice while destroying the porous structure of the waste cathode and removing impurities between graphite layers. This study provides a solution to the high energy consumption and graphite structure damage during the recycling of waste cathode graphite and achieves a dual effect of impurity removal and structure repair. It also provides new experimental data for designing other waste graphite purification processes.
研究领域:
环境工程
·
材料科学
·
冶金工程
·
化学工程
·
声学
✓ 已验证
产品关联
DOI
高影响因子
JOM
·
2025
·
IF 2.3
Yan Yaoyu,Sun Shuchen,Wei Jing,Shubo A.,Xiao Faxin,Tu Ganfeng
Manganese is an important strategic resource for the new energy industry, and the preparation of high-purity manganese sulfate is crucial for lithium battery positive electrode materials. This study aims to thoroughly remove Ca 2+ and Mg 2+ impurities in rhodochrosite acid leaching solution, and proposes a directional purification method based on MnF 2 precipitant. Through single factor experiments and response surface optimization, the effects of MnF 2 addition, temperature, pH, and reaction time on impurity removal have been systematically studied. Under the optimized conditions (MnF 2 addition 2.35 times the theoretical value, temperature 86.94 °C, pH 4.0, reaction time 45.92 min), the removal rates of Ca 2+ and Mg 2+ reached 99.93% and 98.98%, respectively. Combining thermodynamic analysis with an E-pH diagram to explore the precipitation mechanism of impurities, the results show that the preferential precipitation of CaF 2 and MgF 2 originates from the strong coordination ability of Ca 2+ /Mg 2+ with F - (hard and soft acids and bases, HSAB, theory) and the ionic radius matching effect (r + /r − = 0.75). In addition, MnF 2 was efficiently recovered by water-washing precipitation–evaporation crystallization method, and battery-grade manganese sulfate was successfully prepared. This study provides theoretical support and technical reference for the efficient purification of rhodochrosite leaching solution and the green preparation of battery-grade manganese sulfate.
研究领域:
冶金工程
·
材料科学
·
化学工程
·
无机化学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）