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 leaching.Firstly,the thermodynamic analysis of roasting reacti...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 leaching.Firstly,the thermodynamic analysis of roasting reaction was carried out,then the effects of roasting factors on leaching REEs,Li and F in slag were investigated.In 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 analyzed.The results show that the synergistic roasting and activation of molten salt slag by CaO and Al_(2)(SO_(4))_(3)are thermodynamically feasible.The 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 activation.After leaching,the leaching residue is mainly strip CaSO4,indicating that REES,Li and F can be fully extracted from molten salt slag.展开更多
A method of activation roasting followed by acid leaching using titanium slag was introduced to prepare Ti-rich material. The effects of HaPO4 dosage, roasting temperature, and roasting time on TiO2 grade were investi...A method of activation roasting followed by acid leaching using titanium slag was introduced to prepare Ti-rich material. The effects of HaPO4 dosage, roasting temperature, and roasting time on TiO2 grade were investigated. A Ti-rich material containing 88.54% TiO2, 0.42% （CaO＋MgO） was obtained when finely ground titanium slag was roasted with 7.5% H3PO4 at 1000 ℃ for 2 h, followed by a two-stage leaching in boiling dilute sulfuric acid for 2 h. The XRD patterns show that the product is titanium dioxide with a rutile structure. Mechanism studies show that structures of anosovite solid solution and silicate minerals are destroyed in the roasting process. As a result, titanium components in titanium slag are transformed into TiO2 （futile） while impurities are transformed into acid-soluble phosphate and quartz.展开更多
Simultaneously preparing sodium silicate solution with high modulus and obtaining aluminum concentrate with high Al/Si ratio from activated roasting clinker is the key to a new method for clean utilization of coal fly...Simultaneously preparing sodium silicate solution with high modulus and obtaining aluminum concentrate with high Al/Si ratio from activated roasting clinker is the key to a new method for clean utilization of coal fly ash.This study systematically investigates the leaching mechanism of SiO_(2) from activated roasting clinker in sodium silicate solution and proposes an optimized leaching process.The colloidal particles formed by the condensation of siloxane groups increase the diffusion resistance of the leaching agent in the capillary pores,and the SiO_(2) deep inside the pores is difficult to contact with the leaching agent,which is an important reason for the insufficient leaching of SiO_(2) in high modulus sodium silicate solution.A two-stage countercurrent leaching process proposed can simultaneously prepare sodium silicate solution with modulus greater than 2.5 and aluminum concentrate with high Al/Si ratio exceeding 11.This work provides a potential application solution for the development of clean and economically feasible technologies for the utilization of fly ash.展开更多
基金Project supported by the National Key R&D Program"Solid Waste Recycling"Key Project(2020YFC1909000,2020YFC1909003)the National Natural Science Foundation of China(52064019)the Key Fund of Jiangxi Provincial Department of Science and Technology(2019ACBL20015)。
文摘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 leaching.Firstly,the thermodynamic analysis of roasting reaction was carried out,then the effects of roasting factors on leaching REEs,Li and F in slag were investigated.In 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 analyzed.The results show that the synergistic roasting and activation of molten salt slag by CaO and Al_(2)(SO_(4))_(3)are thermodynamically feasible.The 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 activation.After leaching,the leaching residue is mainly strip CaSO4,indicating that REES,Li and F can be fully extracted from molten salt slag.
基金Project(NCET-10-0834) supported by the Program for New Century Excellent Talents in University,China
文摘A method of activation roasting followed by acid leaching using titanium slag was introduced to prepare Ti-rich material. The effects of HaPO4 dosage, roasting temperature, and roasting time on TiO2 grade were investigated. A Ti-rich material containing 88.54% TiO2, 0.42% （CaO＋MgO） was obtained when finely ground titanium slag was roasted with 7.5% H3PO4 at 1000 ℃ for 2 h, followed by a two-stage leaching in boiling dilute sulfuric acid for 2 h. The XRD patterns show that the product is titanium dioxide with a rutile structure. Mechanism studies show that structures of anosovite solid solution and silicate minerals are destroyed in the roasting process. As a result, titanium components in titanium slag are transformed into TiO2 （futile） while impurities are transformed into acid-soluble phosphate and quartz.
基金Project(52374362)supported by the National Natural Science Foundation of ChinaProject(2022YFC3900901)supported by the National Key Research and Development Program of China。
文摘Simultaneously preparing sodium silicate solution with high modulus and obtaining aluminum concentrate with high Al/Si ratio from activated roasting clinker is the key to a new method for clean utilization of coal fly ash.This study systematically investigates the leaching mechanism of SiO_(2) from activated roasting clinker in sodium silicate solution and proposes an optimized leaching process.The colloidal particles formed by the condensation of siloxane groups increase the diffusion resistance of the leaching agent in the capillary pores,and the SiO_(2) deep inside the pores is difficult to contact with the leaching agent,which is an important reason for the insufficient leaching of SiO_(2) in high modulus sodium silicate solution.A two-stage countercurrent leaching process proposed can simultaneously prepare sodium silicate solution with modulus greater than 2.5 and aluminum concentrate with high Al/Si ratio exceeding 11.This work provides a potential application solution for the development of clean and economically feasible technologies for the utilization of fly ash.
