A roasting-leaching test was carried out for the efficient utilization of clay-type lithium ore in the central region of Yunnan province.The test used the mixed acid of sulfuric acid and phosphoric acid as the leachin...A roasting-leaching test was carried out for the efficient utilization of clay-type lithium ore in the central region of Yunnan province.The test used the mixed acid of sulfuric acid and phosphoric acid as the leaching agent.Under the conditions of roasting temperature of 600℃,roasting time of 1 h,liquid-solid ratio of 5:1,volume ratio of H_(2)SO_(4)solution to H_(3)PO_(4)solution of 45:5,leaching time of 2 h and leaching temperature of 80℃,the leaching rate of lithium was as high as 97.83%.The leaching mechanism was studied by SEM,pore property analysis,XRD and XPS.It was found that the morphology of the ore changed obviously after roasting and leaching,and a certain degree of collapse and fragmentation occurred,which provided favorable spatial conditions for the leaching of lithium.The porosity,total intrusion volume and total pore area also increased after roasting and leaching,thus promoting the leaching of Li^(+).The results showed that chemical reaction taken placed during the roasting and leaching.The phase of the sample changed from chlorite,kaolinite and diaspore(boehmite)mainly to corundum,hematite,periclase and quartz after roasting.However,after leaching,no new phase was produced in the ore sample,and no S and P elements were found on the surface of the ore sample,indicating that the leaching mechanism of lithium might be the ion exchange between H^(+)and Li^(+).展开更多
The structural complexity of lithium-bearing clay minerals and limitations of conventional characterization methods impede efficient lithium extraction from montmorillonite-type ores.This study employs density functio...The structural complexity of lithium-bearing clay minerals and limitations of conventional characterization methods impede efficient lithium extraction from montmorillonite-type ores.This study employs density functional theory to elucidate structure-activity relationships governing lithium occurrence in montmorillonite,with particular emphasis on octahedral locking mechanisms and interfacial reaction barriers.Systematic calculations reveal four potential lithium occurrence sites:Al-O octahedra,Si-O tetrahedral lattices,interlayer sites and Li substituted H site.Lithium demonstrates optimal stability within Mg-Al-O octahedral lattices,exhibiting the lowest interaction energy(−672.982 kJ/mol)and substantial Mulliken charge transfer(2.35 e),confirming this configuration as the primary hosting environment.Density of states analysis uncovers critical electronic structure features:the 1s orbital of lithium remains energetically isolated from the Fermi level,explaining its chemical inertness and resistance to direct leaching.Conversely,the reactive 2p orbital of oxygen near the Fermi level facilitate surface interactions with flotation reagents.These electronic signatures imply the feasibility of flotation recovery alongside hydrometallurgical approaches.The octahedral locking mechanism originates from Li-induced dynamic symmetry reconstruction.This process achieves energy minimization through bond-angle regularization,while the notable contraction of Al-O/Mg-O bonds enhances electrostatic coupling.These synergistic effects ultimately establish a structural-charge dual-locking mechanism.This study delivers atomic-level insights into lithium occurrence mechanisms,addressing critical gaps in clay-type lithium mineralogy and revealing structure-activity relationships that guide sustainable lithium recovery via interface regulation.展开更多
基金supported by Yunnan Fundamental Research Projects(grant No.202201BE070001-016)project from Technology Innovation Center for Comprehensive Utilization of Strategic Mineral Resources,Ministry of Natural Resources(grant No.CCUM-KY-2308)+1 种基金National Natural Science Foundation of China(grant No.52304288)project“Study on high efficiency utilization of multicomponent in clay lithium ore with low temperature roasting”from Xing Dian Talent Program of Yunnan province.
文摘A roasting-leaching test was carried out for the efficient utilization of clay-type lithium ore in the central region of Yunnan province.The test used the mixed acid of sulfuric acid and phosphoric acid as the leaching agent.Under the conditions of roasting temperature of 600℃,roasting time of 1 h,liquid-solid ratio of 5:1,volume ratio of H_(2)SO_(4)solution to H_(3)PO_(4)solution of 45:5,leaching time of 2 h and leaching temperature of 80℃,the leaching rate of lithium was as high as 97.83%.The leaching mechanism was studied by SEM,pore property analysis,XRD and XPS.It was found that the morphology of the ore changed obviously after roasting and leaching,and a certain degree of collapse and fragmentation occurred,which provided favorable spatial conditions for the leaching of lithium.The porosity,total intrusion volume and total pore area also increased after roasting and leaching,thus promoting the leaching of Li^(+).The results showed that chemical reaction taken placed during the roasting and leaching.The phase of the sample changed from chlorite,kaolinite and diaspore(boehmite)mainly to corundum,hematite,periclase and quartz after roasting.However,after leaching,no new phase was produced in the ore sample,and no S and P elements were found on the surface of the ore sample,indicating that the leaching mechanism of lithium might be the ion exchange between H^(+)and Li^(+).
基金support by Yunnan Provincial Science and Technology Department(grant No.202301AS070033)is sincerely appreciated。
文摘The structural complexity of lithium-bearing clay minerals and limitations of conventional characterization methods impede efficient lithium extraction from montmorillonite-type ores.This study employs density functional theory to elucidate structure-activity relationships governing lithium occurrence in montmorillonite,with particular emphasis on octahedral locking mechanisms and interfacial reaction barriers.Systematic calculations reveal four potential lithium occurrence sites:Al-O octahedra,Si-O tetrahedral lattices,interlayer sites and Li substituted H site.Lithium demonstrates optimal stability within Mg-Al-O octahedral lattices,exhibiting the lowest interaction energy(−672.982 kJ/mol)and substantial Mulliken charge transfer(2.35 e),confirming this configuration as the primary hosting environment.Density of states analysis uncovers critical electronic structure features:the 1s orbital of lithium remains energetically isolated from the Fermi level,explaining its chemical inertness and resistance to direct leaching.Conversely,the reactive 2p orbital of oxygen near the Fermi level facilitate surface interactions with flotation reagents.These electronic signatures imply the feasibility of flotation recovery alongside hydrometallurgical approaches.The octahedral locking mechanism originates from Li-induced dynamic symmetry reconstruction.This process achieves energy minimization through bond-angle regularization,while the notable contraction of Al-O/Mg-O bonds enhances electrostatic coupling.These synergistic effects ultimately establish a structural-charge dual-locking mechanism.This study delivers atomic-level insights into lithium occurrence mechanisms,addressing critical gaps in clay-type lithium mineralogy and revealing structure-activity relationships that guide sustainable lithium recovery via interface regulation.
