We focus on a novel and economical route for the synthesis of Si fertilizer via the calcination method using lithium pyroxene acid-leaching residues as the starting materials.The molar ratio of Si/K/Ca of 1:1.4:0.8,ca...We focus on a novel and economical route for the synthesis of Si fertilizer via the calcination method using lithium pyroxene acid-leaching residues as the starting materials.The molar ratio of Si/K/Ca of 1:1.4:0.8,calcination temperature of 900℃and calcination time of 120 min were identified as the optimal conditions to maximize the available Si content of the prepared Si fertilizer.The performance of the resulting product satisfies the Chinese agricultural standard for silica fertilizers,providing a new solution for the large-scale harmless and sustainable reuse of lithium pyroxene tailings.The X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR)characterization elucidated the formation mechanism of silica fertilizers,and identified KAlSiO_(4)and K_(4)CaSi_(3)O_(9)as the primary silicates products.Observation of the surface morphology of the samples was conducted by scanning electron microscopy(SEM)and X-ray energy dispersive spectrometry(EDS),and compositional analysis of the micro-regions.The acceleration action of CaCO_(3)in the decomposition process of lithium pyroxene acid-leaching residues was demonstrated by the thermogravimetry-differential scanning calorimetry(TG-DSC)test.Determination of heavy metal elements in Si fertilizer was performed by ICP-OES.Potting experiments confirmed that the best growth of pakchoi was achieved when 5 g·kg^(-1)of Si fertilizer was applied.These evidence suggests that the Si fertilizer prepared in this study is a promising candidate for a silica-supplemented soil.展开更多
Aluminum was leached out from coal fly ash by pressure acid-leaching method. The effects of coal fly ash size, sulfuric acid concentration, reaction time and reaction temperature on extraction efficiency of aluminum w...Aluminum was leached out from coal fly ash by pressure acid-leaching method. The effects of coal fly ash size, sulfuric acid concentration, reaction time and reaction temperature on extraction efficiency of aluminum were investigated comprehensively. The phase and morphology of coal fly ash and solid residues after reaction were analyzed by XRD, SEM and IR. The optimal technological conditions for extracting aluminum from coal fly ash were eventually confirmed that coal fly ash with size of 74 μm and sulfuric acid with concentration of 50% are mixed in pressure reaction kettle to react for 4 h at 180 ℃. Under the optimal conditions, the extraction efficiency of aluminum can reach 82.4%.展开更多
Proper treatment of acidleaching tailings(ALTs)of vanadiumbearing stone coal minerals is of great urgency.One approach is adding it into the raw materials during the preparation of lightweight aggregate(LWA).But clay ...Proper treatment of acidleaching tailings(ALTs)of vanadiumbearing stone coal minerals is of great urgency.One approach is adding it into the raw materials during the preparation of lightweight aggregate(LWA).But clay is always needed.In this paper,another solid waste,red mud,was mixed with ALTs as a source of flux components instead of clay.Evaluation of the physical characteristics,morphological structures,as well as crystal phases during the sintering process were investigated.When their mixtures with a proper ratio were sintered at 1080℃,a glassy phase with certain viscosity was formed,and the gases generated simultaneously were encapsulated by the melt.Finally,LWA with a onehour water absorption as low as 1.46%,a bulk density as low as 728.76 kgm 3 and a compressive strength as high as 10.77 MPa was fabricated.展开更多
A large amount of acid-leaching residue is produced during the conventional Zn hydrometallurgy process,and this residue has a large concentration of a variety of valuable metals.The purpose of this study was to evalua...A large amount of acid-leaching residue is produced during the conventional Zn hydrometallurgy process,and this residue has a large concentration of a variety of valuable metals.The purpose of this study was to evaluate the ability of a procedure that entails the use of sulfation roasting,water leaching,and chlorination leaching(blowing oxygen technique)to recover Pb and Ag,followed by cooling crystallization and the replacement of Ag with lead sheet,to realize the full recovery of all valuable metals from zinc acid-leaching residue;consequently,good results were achieved.The best results were obtained under the following conditions:a sulfuric acid at 70%of the raw material quality,roasting temperature of 300°C and roasting time of 2 h,followed by the process of leaching the roasted residue for 1 h by applying a water-to-solid ratio of 5꞉1 at room temperature.The recovery rates of Zn and Fe were 98.69%and 92.36%,respectively.The main parameters of the chlorine salt leaching system were as follows:Cl−concentration of 300 g/L,Fe3+concentration of 25 g/L,acid concentration of 2 mol/L,liquid-to-solid ratio of 9 mL:1 g,temperature of 90℃,and leaching time of 0.5 h;this leaching process was followed by filtration separation.These conditions resulted in high extents of leaching for Pb and Ag(i.e.,98.87%and 96.74%,respectively).Finally,the kinetics of the process of Ag leaching using Cl−ions in an oxygen-rich medium was investigated.It was found that the leaching process was controlled by the diffusion of the product layers,and the activation energy was 19.82 kJ/mol.展开更多
Well-crystallized zeolite beta was synthesized by using acid-leached metakaolin as the silica-alumina source and tetraethylammonium hydroxide structure-directing agent.The influence of the composition of the reaction ...Well-crystallized zeolite beta was synthesized by using acid-leached metakaolin as the silica-alumina source and tetraethylammonium hydroxide structure-directing agent.The influence of the composition of the reaction mixture on product crystallinity was investigated,and the crystallization process was studied by examining solid samples obtained at different synthesis times.Results showed that the acid-leached metakaolin was fully converted into soluble aluminum and silicon species,which is crucial for the formation of well-crystallized zeolite beta.At the beginning of the crystallization process,these soluble aluminum and silicon species formed a aluminum-rich intermediate structure with layer morphology.With the crystallization proceeding,more silicon species were incorporated into the zeolite beta framework and the layered structure was changed into spherical particles of zeolite beta with high SiO 2 /Al 2 O 3 ratio and crystallinity.展开更多
Alkali-leaching and acid-leaching were proposed for the dephosphorization of Changde iron ore, which contains an average of 1.12% for phosphorus content. Sodium hydroxide, sulfuriced, hydrochloric and nitric acids wer...Alkali-leaching and acid-leaching were proposed for the dephosphorization of Changde iron ore, which contains an average of 1.12% for phosphorus content. Sodium hydroxide, sulfuriced, hydrochloric and nitric acids were used for the preparation of leach solutions. The results show that phosphorus occurring as apatite phase could be removed by alkali-leaching, but those occurring in the iron phase could not. Sulfuric acid is the most effective among the three kinds of acid. 91.61% phosphorus removal was attained with 1% sulfuric acid after leaching for 20 rain at room temperature. Iron loss during acid-leaching can be negligible, which was less than 0.25%.The pH value of solution after leaching with1% sulfuric acid was about 0.86, which means acid would not be exhausted during the process and it could be recycled, and the recycle of sulfuric acid solution would make the dephosphorization process more economical.展开更多
The recovery of nickel from laterite ore with sulphuric acid under the effect of microwave irradiation was studied.The experimental results indicated that the extraction rate of nickel was influenced by reaction time,...The recovery of nickel from laterite ore with sulphuric acid under the effect of microwave irradiation was studied.The experimental results indicated that the extraction rate of nickel was influenced by reaction time,sulphuric acid concentration,and temperature,especially by microwave power.The results obtained from the experiments of orthogonal arrays showed that the optimum conditions of sulphuric acid concentration,reaction time,microwave power,and temperature were 25 vol.%,1.5 h,600 W,and 90°C,respectively.Under the optimal conditions,the nickel recovery could reach approximately 90.8%,which was higher than that obtained by conventional water bath heating.Kinetic experiments showed that the leaching of nickel in a sulphuric acid medium was controlled by chemical reaction occurring on the surface of laterite ore.The apparent activation energy was 38.9 kJ/mol.Microwave heating technology is efficient,clean,and easy to control and facilitate continuous processing of materials.展开更多
The recycling of spent lithium-ion batteries(LIBs) is crucial for environmental protection and resource sustainability.However,the economic recovery of spent LIBs remains challenging due to low Li recovery efficiency ...The recycling of spent lithium-ion batteries(LIBs) is crucial for environmental protection and resource sustainability.However,the economic recovery of spent LIBs remains challenging due to low Li recovery efficiency and the need for multiple separation operations.Here,we propose a process involving mixed HCl-H_(2)SO_(4) leaching-spray pyrolysis for recycling spent ternary LIBs,achieving both selective Li recovery and the preparation of a ternary oxide precursor.Specifically,the process transforms spent ternary cathode(LiNi_(x)Co_yMn_(2)O_(2),NCM) powder into Li_(2)SO_(4) solution and ternary oxide,which can be directly used for synthesizing battery-grade Li_(2)CO_(3) and NCM cathode,respectively.Notably,SO_(4)^(2-) selectively precipitates with Li^(+) to form thermostable Li_(2)SO_(4) during the spray pyrolysis,which substantially improves the Li recovery efficiency by inhibiting Li evaporation and intercalation.Besides,SO_(2) emissions are avoided by controlling the molar ratio of Li^(+)/SO_(4)^(2-)(≥2:1),The mechanism of the preferential formation of Li_(2)SO_(4) is interpreted from its reverse solubility variation with temperature.During the recycling of spent NCM811,92% of Li is selectively recovered,and the regenerated NCM811 exhibits excellent cycling stability with a capacity retention of 81.7% after 300 cycles at 1 C.This work offers a simple and robust process for the recycling of spent NCM cathodes.展开更多
文摘We focus on a novel and economical route for the synthesis of Si fertilizer via the calcination method using lithium pyroxene acid-leaching residues as the starting materials.The molar ratio of Si/K/Ca of 1:1.4:0.8,calcination temperature of 900℃and calcination time of 120 min were identified as the optimal conditions to maximize the available Si content of the prepared Si fertilizer.The performance of the resulting product satisfies the Chinese agricultural standard for silica fertilizers,providing a new solution for the large-scale harmless and sustainable reuse of lithium pyroxene tailings.The X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR)characterization elucidated the formation mechanism of silica fertilizers,and identified KAlSiO_(4)and K_(4)CaSi_(3)O_(9)as the primary silicates products.Observation of the surface morphology of the samples was conducted by scanning electron microscopy(SEM)and X-ray energy dispersive spectrometry(EDS),and compositional analysis of the micro-regions.The acceleration action of CaCO_(3)in the decomposition process of lithium pyroxene acid-leaching residues was demonstrated by the thermogravimetry-differential scanning calorimetry(TG-DSC)test.Determination of heavy metal elements in Si fertilizer was performed by ICP-OES.Potting experiments confirmed that the best growth of pakchoi was achieved when 5 g·kg^(-1)of Si fertilizer was applied.These evidence suggests that the Si fertilizer prepared in this study is a promising candidate for a silica-supplemented soil.
基金Project (BO210(2008)) supported by the Foundation of "Hundred Talent Program" of Chinese Academic of SciencesProject (2008-G-158) supported by the Scientific and Technological Project of Qinghai Province, China
文摘Aluminum was leached out from coal fly ash by pressure acid-leaching method. The effects of coal fly ash size, sulfuric acid concentration, reaction time and reaction temperature on extraction efficiency of aluminum were investigated comprehensively. The phase and morphology of coal fly ash and solid residues after reaction were analyzed by XRD, SEM and IR. The optimal technological conditions for extracting aluminum from coal fly ash were eventually confirmed that coal fly ash with size of 74 μm and sulfuric acid with concentration of 50% are mixed in pressure reaction kettle to react for 4 h at 180 ℃. Under the optimal conditions, the extraction efficiency of aluminum can reach 82.4%.
文摘Proper treatment of acidleaching tailings(ALTs)of vanadiumbearing stone coal minerals is of great urgency.One approach is adding it into the raw materials during the preparation of lightweight aggregate(LWA).But clay is always needed.In this paper,another solid waste,red mud,was mixed with ALTs as a source of flux components instead of clay.Evaluation of the physical characteristics,morphological structures,as well as crystal phases during the sintering process were investigated.When their mixtures with a proper ratio were sintered at 1080℃,a glassy phase with certain viscosity was formed,and the gases generated simultaneously were encapsulated by the melt.Finally,LWA with a onehour water absorption as low as 1.46%,a bulk density as low as 728.76 kgm 3 and a compressive strength as high as 10.77 MPa was fabricated.
基金Projects(51804136,52064021,52074136,51564021,52064022)supported by the National Natural Science Foundation of ChinaProjects(2019T120625,2019M652276)supported by the China Postdoctoral Science Foundation+2 种基金Project(20202ACB213002)supported by the Jiangxi Province Science Fund for Distinguished Young Scholars,ChinaProject(2019KY09)supported by the Program for Excellent Young Talents,JXUST Young Jinggang Scholars of Jiangxi Province,Merit-based Postdoctoral Research in Jiangxi Province,ChinaProjects supported by the Distinguished Professor Program of Jinggang Scholars,Chinain Institutions of Higher Learning,Jiangxi Province,China。
文摘A large amount of acid-leaching residue is produced during the conventional Zn hydrometallurgy process,and this residue has a large concentration of a variety of valuable metals.The purpose of this study was to evaluate the ability of a procedure that entails the use of sulfation roasting,water leaching,and chlorination leaching(blowing oxygen technique)to recover Pb and Ag,followed by cooling crystallization and the replacement of Ag with lead sheet,to realize the full recovery of all valuable metals from zinc acid-leaching residue;consequently,good results were achieved.The best results were obtained under the following conditions:a sulfuric acid at 70%of the raw material quality,roasting temperature of 300°C and roasting time of 2 h,followed by the process of leaching the roasted residue for 1 h by applying a water-to-solid ratio of 5꞉1 at room temperature.The recovery rates of Zn and Fe were 98.69%and 92.36%,respectively.The main parameters of the chlorine salt leaching system were as follows:Cl−concentration of 300 g/L,Fe3+concentration of 25 g/L,acid concentration of 2 mol/L,liquid-to-solid ratio of 9 mL:1 g,temperature of 90℃,and leaching time of 0.5 h;this leaching process was followed by filtration separation.These conditions resulted in high extents of leaching for Pb and Ag(i.e.,98.87%and 96.74%,respectively).Finally,the kinetics of the process of Ag leaching using Cl−ions in an oxygen-rich medium was investigated.It was found that the leaching process was controlled by the diffusion of the product layers,and the activation energy was 19.82 kJ/mol.
基金supported by Beijing Natural Science Foundation (Grant No.2093043)the National Natural Science Foundation of China (Grant No.20606038)
文摘Well-crystallized zeolite beta was synthesized by using acid-leached metakaolin as the silica-alumina source and tetraethylammonium hydroxide structure-directing agent.The influence of the composition of the reaction mixture on product crystallinity was investigated,and the crystallization process was studied by examining solid samples obtained at different synthesis times.Results showed that the acid-leached metakaolin was fully converted into soluble aluminum and silicon species,which is crucial for the formation of well-crystallized zeolite beta.At the beginning of the crystallization process,these soluble aluminum and silicon species formed a aluminum-rich intermediate structure with layer morphology.With the crystallization proceeding,more silicon species were incorporated into the zeolite beta framework and the layered structure was changed into spherical particles of zeolite beta with high SiO 2 /Al 2 O 3 ratio and crystallinity.
基金Project (50321402) supported by the National Natural Science Foundation of China project(2004CB619204) supported by Major State Basic Research Development Program of China
文摘Alkali-leaching and acid-leaching were proposed for the dephosphorization of Changde iron ore, which contains an average of 1.12% for phosphorus content. Sodium hydroxide, sulfuriced, hydrochloric and nitric acids were used for the preparation of leach solutions. The results show that phosphorus occurring as apatite phase could be removed by alkali-leaching, but those occurring in the iron phase could not. Sulfuric acid is the most effective among the three kinds of acid. 91.61% phosphorus removal was attained with 1% sulfuric acid after leaching for 20 rain at room temperature. Iron loss during acid-leaching can be negligible, which was less than 0.25%.The pH value of solution after leaching with1% sulfuric acid was about 0.86, which means acid would not be exhausted during the process and it could be recycled, and the recycle of sulfuric acid solution would make the dephosphorization process more economical.
文摘The recovery of nickel from laterite ore with sulphuric acid under the effect of microwave irradiation was studied.The experimental results indicated that the extraction rate of nickel was influenced by reaction time,sulphuric acid concentration,and temperature,especially by microwave power.The results obtained from the experiments of orthogonal arrays showed that the optimum conditions of sulphuric acid concentration,reaction time,microwave power,and temperature were 25 vol.%,1.5 h,600 W,and 90°C,respectively.Under the optimal conditions,the nickel recovery could reach approximately 90.8%,which was higher than that obtained by conventional water bath heating.Kinetic experiments showed that the leaching of nickel in a sulphuric acid medium was controlled by chemical reaction occurring on the surface of laterite ore.The apparent activation energy was 38.9 kJ/mol.Microwave heating technology is efficient,clean,and easy to control and facilitate continuous processing of materials.
基金Fund of University of South China (201RGC013 and 200XQD052)。
文摘The recycling of spent lithium-ion batteries(LIBs) is crucial for environmental protection and resource sustainability.However,the economic recovery of spent LIBs remains challenging due to low Li recovery efficiency and the need for multiple separation operations.Here,we propose a process involving mixed HCl-H_(2)SO_(4) leaching-spray pyrolysis for recycling spent ternary LIBs,achieving both selective Li recovery and the preparation of a ternary oxide precursor.Specifically,the process transforms spent ternary cathode(LiNi_(x)Co_yMn_(2)O_(2),NCM) powder into Li_(2)SO_(4) solution and ternary oxide,which can be directly used for synthesizing battery-grade Li_(2)CO_(3) and NCM cathode,respectively.Notably,SO_(4)^(2-) selectively precipitates with Li^(+) to form thermostable Li_(2)SO_(4) during the spray pyrolysis,which substantially improves the Li recovery efficiency by inhibiting Li evaporation and intercalation.Besides,SO_(2) emissions are avoided by controlling the molar ratio of Li^(+)/SO_(4)^(2-)(≥2:1),The mechanism of the preferential formation of Li_(2)SO_(4) is interpreted from its reverse solubility variation with temperature.During the recycling of spent NCM811,92% of Li is selectively recovered,and the regenerated NCM811 exhibits excellent cycling stability with a capacity retention of 81.7% after 300 cycles at 1 C.This work offers a simple and robust process for the recycling of spent NCM cathodes.
