The ion exchange model of the leaching process was determined via batch leaching experiments using the Kerr model, with the selectivity coefficient experimentally determined to be 12.59×10^-10 L^2/g^2. Solute tra...The ion exchange model of the leaching process was determined via batch leaching experiments using the Kerr model, with the selectivity coefficient experimentally determined to be 12.59×10^-10 L^2/g^2. Solute transport laws of ammonium ions (NH4 +) and rare earth ions (RE^3+) in column leaching were described by the convection-dispersion equation (CDE). The source and sink in the CDE were determined by the Kerr model. The CDE with strong nonlinearity was solved using the sequential non-iterative method. Compared with the breakthrough curve of RE^3+, the correlation coefficient between the simulated and experimental curves reached 0.8724. Therefore, this method can simulate the one-dimensional column leaching of weathered crust elution-deposited rare earth ore. Moreover, the effects of different concentrations of ammonium sulfate ((NH4)2SO4) solution on the leaching rate of rare earth were analyzed. The optimal concentration of the (NH4)2SO4 solution had a linear relationship with the rare earth grade.展开更多
Column leaching experiments with ion adsorption-type rare earth ores for different lixiviant concentrations and different column heights were carried out.A mathematical model of column leaching was constructed based o...Column leaching experiments with ion adsorption-type rare earth ores for different lixiviant concentrations and different column heights were carried out.A mathematical model of column leaching was constructed based on the experimental data.Two parameters(a and b)in the model were determined according to the following methodology:the ore column was divided into several units;each unit was treated with multiple leaching steps.The leaching process was simulated as a series of batch leaching experiments.Parameter a of the model was determined based on the selectivity coefficient of the balanced batch leaching experiment.Further,the influences of ammonium sulfate concentration,rare earth grade,column height,permeability coefficient,and hydrodynamic dispersion coefficient on the extraction were analyzed.Relationships between parameter b,the ammonium sulfate concentration,and the physical and mechanical properties of the ore column,were examined using dimensional analysis.It was determined that the optimal ammonium sulfate concentration for different column heights(2.5,5.0,7.5,and 10.0 cm)using the mathematical model were 5.9,6.2,7.3,and 7.7 g/L,respectively.The mathematical model can be used to estimate the breakthrough curve,leaching rate,and leaching period of rare earth ores,to achieve optimal extraction.展开更多
基金Projects(51664015,41602311,51774156) supported by the National Natural Science Foundation of China
文摘The ion exchange model of the leaching process was determined via batch leaching experiments using the Kerr model, with the selectivity coefficient experimentally determined to be 12.59×10^-10 L^2/g^2. Solute transport laws of ammonium ions (NH4 +) and rare earth ions (RE^3+) in column leaching were described by the convection-dispersion equation (CDE). The source and sink in the CDE were determined by the Kerr model. The CDE with strong nonlinearity was solved using the sequential non-iterative method. Compared with the breakthrough curve of RE^3+, the correlation coefficient between the simulated and experimental curves reached 0.8724. Therefore, this method can simulate the one-dimensional column leaching of weathered crust elution-deposited rare earth ore. Moreover, the effects of different concentrations of ammonium sulfate ((NH4)2SO4) solution on the leaching rate of rare earth were analyzed. The optimal concentration of the (NH4)2SO4 solution had a linear relationship with the rare earth grade.
基金the National Natural Science Foundation of China(Nos.51664015,41602311,and 51774156)the Jiangxi University of Science and Technology Qingjiang Youth Elite Support Program(No.JXUSTQJBJ2016007).
文摘Column leaching experiments with ion adsorption-type rare earth ores for different lixiviant concentrations and different column heights were carried out.A mathematical model of column leaching was constructed based on the experimental data.Two parameters(a and b)in the model were determined according to the following methodology:the ore column was divided into several units;each unit was treated with multiple leaching steps.The leaching process was simulated as a series of batch leaching experiments.Parameter a of the model was determined based on the selectivity coefficient of the balanced batch leaching experiment.Further,the influences of ammonium sulfate concentration,rare earth grade,column height,permeability coefficient,and hydrodynamic dispersion coefficient on the extraction were analyzed.Relationships between parameter b,the ammonium sulfate concentration,and the physical and mechanical properties of the ore column,were examined using dimensional analysis.It was determined that the optimal ammonium sulfate concentration for different column heights(2.5,5.0,7.5,and 10.0 cm)using the mathematical model were 5.9,6.2,7.3,and 7.7 g/L,respectively.The mathematical model can be used to estimate the breakthrough curve,leaching rate,and leaching period of rare earth ores,to achieve optimal extraction.
