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Effect of roasting activation of rare earth molten salt slag on extraction of rare earth,lithium and fluorine

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Journal of Rare Earths 2023年第2期41卷 300-308页

作者： Zhifang Tong Xiaofei Hu Hao Wen Faculty of Materials metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341099China

A new process was proposed to extract rare earth elements(REEs),Li and F from electrolytic slag of rare earth molten salt by synergistic roasting and acid ***,the thermodynamic analysis of roasting reaction was carried out,then the effects of roasting factors on leaching REEs,Li and F in slag were *** additions,the mineral phase and morphology of molten salt slag,roasting slag and acid leaching slag were characterized,and the migration mechanism of REES,Li and F minerals in roasting and leaching process was *** results show that the synergistic roasting and activation of molten salt slag by CaO and Al_(2)(SO_(4))_(3)are thermodynamically *** optimum roasting conditions are as follows:molten salt slag of 20 g,Al_(2)(SO_(4))_(3)of 31.25 g and CaO of 6.25 g,roasting temperature of 1173.15 K and reaction time of 2 h,under this condition,the leaching rates of Nd,Pr,Gd,Li and F are 92.47%,91.56%,91.08%,96.69%and 96.8%,respectively.X-ray powder diffraction(XRD)and scanning electron microscopy-energy dispersive X-ray spectroscopy(SEM-EDS)analysis show that the rare earth fluoride(REF3)in molten salt slag transforms into soluble rare earth oxide(REO)after roasting and *** leaching,the leaching residue is mainly strip CaSO4,indicating that REES,Li and F can be fully extracted from molten salt slag.

关键词： Rare earth molten salt electrolytic slag Thermodynamic analysis Activation roasting Efficient extraction

Theoretical Foundation of Carbonation Pellet process for Ferrous Sludge recycling

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Journal of Iron and Steel Research International 2011年第12期18卷 27-31页

作者： HU Chang-qing HAN Tao ZHANG Yu-zhu ZHANG Zhi-xia College of metallurgy and Energy Hebei United University Tangshan 063009 Hebei China Hebei Key Laboratory of Modern metallurgy Technology Tangshan 063009 Hebei China

For the recycling of ferrous sludge from steel industry,the carbonation pellet process should be considered as a ＂green＂ process,since no impurities are added as well as CO2 can be sequestrated and *** the thermodynamic calculation,the carbonation reaction can occur spontaneously and is an exothermic *** on the kinetic analysis through unreacted core model,the interfacial chemical reaction was the rate controlling step in the initial fast stage of carbonation,and the CO2 diffusion through the CaCO3 product layer was the rate controlling step in the following extremely slow *** the carbonation bonded mechanism,the pellet strength was gained by the formation and growing of CaCO3 product *** the interfacial chemical reaction was the critical stage of the entire carbonation process,the emphasizes should be focused on the improvement of sorbent activity and the optimization of process parameters,such as pore structure,pore surface area,and total pressure,CO2 partial pressure,reaction temperature,etc to accelerate the reaction rate and to improve the quality of carbonation pellets.

关键词： CO2 sequestration ferrous sludge carbonation pellet thermodynamics kinetics unreacted core model

Chromium recycling from Argon-oxygen Decarburization Dust in Hot metal Pre-dephosphorization process

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Journal of Iron and Steel Research International 2016年第9期23卷 867-873页

作者： Dong-ping ZHAN Yang-peng ZHANG Zhou-hua JIANG De-wei WANG Hui-shu ZHANG School of metallurgy Northeastern University metallurgical Engineering College Liaoning Institute of Science and Technology

The chromium recycling from the stainless steel dust of an argon-oxygen decarburization （AOD） furnace during a hot metal pretreatment process was investigated. Experiments at different temperatures or with different amounts of AOD dusts were carried out in a laboratory furnace equipped with MoSi2 heating elements and subsequently industrial experiments were conducted in a stainless steelmaking factory, in order to study the thermodynamic mechanism of C and Si reacted with Cr2O3 to get Cr from AOD dust. The results showed that the reaction between C and Cr2 O1 occurred below 1572.18 K. Although its reducing ability was weaker than that of Si, C enabled the Cr in Cr2O3 in the AOD dust to be recycled using the Si in the slag. By combining the AOD dust added in an earlier stage, the hot metal pretreatment slag added in a later stage could not only recycle Cr from AOD dust but also remove Si, S, and P. Higher hot metal temperatures resulted in higher Cr content and lower remained P concentration in the molten iron.

关键词： stainless steelmaking AOD dust chromium recycling hot metal pre-dephosphorization

Two-stage reduction for the preparation of ferronickel alloy from nickel laterite ore with low Co and high MgO contents

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International Journal of Minerals,metallurgy and Materials 2017年第5期24卷 512-522页

作者： Yong-qiang Chen Hong-liang Zhao Cheng-yan Wang School of metallurgical and Ecological Engineering University of Science and Technology Beijing Key Lab of Rare & Precious metals Green recycling and Extraction

The preparation of ferronickel alloy from the nickel laterite ore with low Co and high MgO contents was studied by using a pre-reduction-smelting method. The effects of reduction time, calcination temperature, quantity of reductant and calcium oxide (CaO), and pellet diameter on the reduction ratio of Fe and on the pellet strength were investigated. The results show that, for a roasting temperature > 800 A degrees C, a roasting time > 30 min, 1.5wt% added anthracite coal, 5wt% added CaO, and a pellet size of similar to 10 mm, the reduction ratio of Fe exceeds 70% and the compressive strength of the pellets exceeds 10 kg per pellet. Reduction smelting experiments were performed by varying the smelting time, temperature, quantity of reductant and CaO, and reduction ratio of Fe in the pellets. Optimal conditions for the reduction smelting process are as follows: smelting time, 30-45 min; smelting temperature, 1550A degrees C; quantity of reductant, 4wt%-5wt%; and quantity of CaO, 5wt%; leading to an Fe reduction ratio of 75% in the pellets. In addition, the mineral composition of the raw ore and that during the reduction process were investigated by process mineralogy.

关键词： pre-reduction smelting ferronickel alloy nickel laterite ore

recycling rare earth from ultrafine NdFeB waste by capturing fluorine ions in wastewater and preparing them into nano-scale neodynium oxyfluoride

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Journal of Rare Earths 2022年第5期40卷 815-821,I0005页

作者： He Sun Tuoyao Wang Chengxiang Li Yusheng Yang Department of Chemistry Baotou Teachers’CollegeBaotou 014030China School of Energy and Environment Inner Mongolia University of Science and TechnologyBaotou 014010China Key Laboratory of Integrated Exploitation of Bayan Obo Multi-metal Resources School of Material and MetallurgyInner Mongolia University of Science and TechnologyBaotou 014010China Collaborative Innovation Center of Integrated Exploitation of Bayan Obo Multi-metal Resources Inner Mongolia University of Science and TechnologyBaotou 014010China

Ultrafine NdFeB waste is a relatively clean waste produced during NdFeB magnet *** wastewater is a common type of industrial wastewater,such as stainless steel pickling *** this work,rare earth element neodynium was recycled from ultrafine NdFeB waste by capturing fluorine ions in the fluorine-containing wastewater and prepared into neodynium *** reaction process was investigated through UV-Vis-NIR,thermogravimetry/differential thermogravimetry(TG/DTG),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).The neodymium hydroxide in the ultrafine NdFeB waste reacted with fluorine ions to form Nd(OH)_(2) F,and Nd(OH)_(2) F was then transformed into neodymium oxyfluoride after *** formed neodymium oxyfluoride is found to be particles with rhombohedral structure and a particle size of around 50 *** reaction kinetics of forming Nd(OH)_(2) F was *** reaction kinetic equation was established and the reaction activation energy was *** effect of fluorine ion concentration on the reaction rate and products was *** results show that the reaction rate increases with the increase of fluorine ion concentration in the range of 0.01-1.5 mol/L,but it has little *** addition,the fluorine ion concentration affects the crystallinity of formed neodymium *** recycling process not only realizes the sustainable utilization of rare earths,but also reduces the concentration of fluorine ions in the fluorine-containing wastewater,achieving two goals with one stone.

关键词： recycling Ultrafine NdFeB waste Capturing fluorine ions Neodymium oxyfluoride Rare earths

recycling high density tungsten alloy powder by oxidization reduction process

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中国有色金属学会会刊：英文版 2002年第3期12卷 450-453页

作者：张兆森陈立宝贺跃辉黄伯云 State Key Laboratory for Powder metallurgy Central South University Changsha 410083 China

The processes of directly recycling high density tungsten alloy by oxidation reduction technique were investigated. The particle size of recycled powder is fine, and the shape of powder particle is regular when the final reduction temperature is 850?℃, in which the average size of the tungsten alloy particles reduced is about 1.5?μm. The average size of the alloy particles increase to 6?μm and 9?μm when increasing the reduction temperature to 900?℃ and 950?℃, respectively. However, if the reduction temperature is higher than 900?℃, the surface feature of powder is complicated. Increasing reduction temperature from 900?℃ to 950?℃, the content of oxygen of recycled powder decreases from 0.231?4% to 0.170?0%, and powder particles grow slightly. It has been also found that the chemical composition of the recycled alloy powder is the same as the initial powder.

关键词：合金粉末钨合金氧化还原过程再生高密度合金

Kinetic model of chromium release from argon oxygen decarburisation(AOD)slag in a neutral leachate

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Journal of Iron and Steel Research International 2020年第11期27卷 1303-1310页

作者： Ya-nan Zeng Qian-qian Ren Bao Liu Jun-guo Li School of metallurgy and Energy North China University of Science and TechnologyTangshan 063200HebeiChina

Valorisation of argon oxygen decarburisation(AOD)slag,a suitable recycling resource,is limited by the release of a notable amount of heavy metals,such as *** mineralogical component of AOD slag was characterised by X-ray diffraction and scanning electron microscopy-energy-dispersive X-ray *** explore the release kinetics of chromium from AOD slag,neutral leaching tests were performed at various *** results indicated the existence of two leaching stages:quick and slow leaching *** 2 h,the chromium release fraction increased sharply as the leaching time *** the leaching time in creased,the chromium release rate gradually *** on the shrinking core model,chromium release kinetic models for the quick and slow leaching stages from the AOD slag were independently *** chromium release was controlled by solid product diffusion during the quick leaching stage and a complicated process in the slow leaching *** activation energy of chromium leaching was calculated based on the Arrhenius *** product diffusion was the velocity-determining step during the 2 h leaching *** the slow leaching stage,chromium release was controlled by complicated hybrid control dominated by solid product diffusion.

关键词： Kinetic model Chromium release Shrinking core model-AOD slag

Thermodynamic modeling of antimony removal from complex resources in copper smelting process

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Transactions of Nonferrous metals Society of China 2022年第12期32卷 4113-4128页

作者： Song-song WANG Qin-meng WANG Xue-yi GUO Qing-hua TIAN Sheng-li QU Zhi WANG Ming-xing HUANG School of metallurgy and Environment Central South UniversityChangsha 410083China National&Regional Joint Engineering Research Center of Nonferrous metal Resources recycling Changsha 410083China Shandong Humon Smelting Co. Ltd.Yantai 264109China Dongying Fangyuan Nonferrous metals Co. Ltd.Dongying 257091China

This work investigated the reaction mechanism of Sb in copper smelting process. The difference of multi-phase distribution of Sb in four typical copper smelting processes was analyzed. A multi-phase equilibrium model of the oxygen-enriched bottom-blow copper smelting process was developed. The impacts of Cu, S, and Sb concentrations in raw materials on Sb distribution in multiphases were researched. This model was also used to investigate the effect of process factors such as copper matte grade, oxygen-enriched concentration, smelting temperature, and oxygen/ore ratio(ratio of oxygen flow rate under standard conditions to concentrate charge rate) on Sb distribution behavior. The results showed that calculation data were in good agreement with the actual production results and literature data. Increasing the Cu content and decreasing the S and Sb contents in the concentrate, increasing the copper matte grade, oxygen/enriched concentration, and oxygen-ore ratio, and at the same time appropriately reducing the smelting temperature are conducive to the targeted enrichment of Sb into the slag. Modeling results can provide theoretical guidance for the clean and efficient treatment of complex resources and the comprehensive recycling of associated elements.

关键词： copper oxygen-enriched smelting Sb reaction mechanism distribution behavior

Sustainable recycling of titanium from TiO_(2) in spent SCR denitration catalyst via molten salt electrolysis

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Journal of Energy Chemistry 2021年第7期30卷 557-563页

作者： Xuyang Bai Xiaojia Shang Heli Wan Yusi Che Bin Yang Jilin He Jianxun Song Henan Province Industrial Technology Research Institute of Resources and Materials Zhengzhou University450001 ZhengzhouHenanChina National Engineering Laboratory of Vacuum metallurgy Kunming University of Science and Technology650093 KunmingYunnanChina State Key Laboratory of Complex Nonferrous metal Resources Clean Utilization 650093 KunmingYunnanChina

Spent catalyst used for denitration by selective catalytic reduction(spent SCR denitration catalysts) is one of the important urban mines due to the high content of TiO_(2)(~85 wt%) and the massive accumulation amount(over 100,000 tons),therefore,value-added reutilization of titanium in spent SCR catalysts is considerably *** this paper,a novel method is proposed for converting the titanium oxide in spent SCR denitration catalysts to metallic ***,titanium dioxide(TiO_(2)) was firstly obtained from spent SCR denitration catalysts after removing the impurities by hydrometallurgy ***,TiO_(2) is converted to Ti_(2)CO by carbothermic reduction method,and Ti_(2)CO was further purified by oleic acid ***,by utilizing the as-prepared Ti_(2)CO as the consumable anode in the NaCl-KCl molten salt,high-purity metallic titanium was deposited at cathode,all confirming the feasibility for the conversion of low-grade TiO_(2) in the spent catalysts,from 60 wt% to high-purity metallic Ti(99.5 wt%), furthermore,the energy consumption of this process is 3950 kWh tonne-1 Ti,which is lower than that of most traditional titanium metallurgy *** method herein can provide new insights for the value-added recycling of titanium resources in urban mines.

关键词： Spent SCR denitration catalyst Hydrometallurgy Impurity Ti_(2)CO Molten salt