The prediction of saturated-unsaturated seepage processes is crucial for the in-situ leaching of ionic rare earth ores.Currently,large-scale seepage prediction studies based on Physics-Informed Neural Networks(PINN)are relatively limited.This study constructed a long-term,large-scale neural network prediction model based on PINN for simulating in-situ leaching engineering.The model was applied to investigate the predictions of saturatedunsaturated seepage under different training sample sizes,soil types,and spatiotemporal scales.The results showed that when predicting column leaching experiments,the model achieved an R2 of 0.959 when validated with experimental data and an R2 of 0.98 across different data volumes and soil types in the training set.For a 10 m deep soil column,the model achieved an R2 of 0.90 using only 0.4% of the simulated data for training and increased to 0.98 when the training data volume was raised to 1%,while the maximum error in the wetting front time curve was reduced to 0.36%.This model offers a novel approach and theoretical framework for predicting seepage processes in the in-situ leaching of ionic rare earth ores.
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In the rare-earth electrolysis process,the flow state of the electrolyte significantly affects the electrolysis efficiency.Once the electrolysis cell is energized,bubbles generated at the anode induce the molten electrolyte in motion.As a result,the bubble escape rate from the anode wall surface,which varies with different electrode spacing,plays a crucial role in the electrolytic efficiency.Therefore,this study focused on an 8 kA rare-earth electrolysis cell from a non-ferrous enterprise as the research object to explore the relationship between the bubble flow field and the electrolytic efficiency.Considering that the conventional electrode spacing for an 8 kA cell typically ranges between 80 and 90 mm,five specific cases with electrode spacings(75,80,85,90,and 95 mm)were selected for flow field simulation and analysis to ensure scientific rigor.The experimental results showed that the eddy current in the flow field reached a relatively stable state at about 25 s of the melt redox reaction,and changes in electrode spacing had a significant impact on the maximum flow velocity and the area of eddy current between the anode and cathode electrodes.Specifically,the stable maximum flow velocity of the electrolyte peaked when the electrode spacing was approximately 85 mm.Although the area of the eddy current between the electrodes reached its maximum at an electrode spacing of 95 mm,the small eddy current at the bottom of the cell was segmented by the inter-electrode vortices,which hindered the collection of rare earth metals.The simulation results showed that for an 8 kA Pr-Nd system electrolysis cell,an electrode spacing of approximately 85 mm optimized the flow in the lower part of the melt,thereby maximizing the precipitation and collection efficiency of metallic rare earth.
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The efficient recovery of valuable metal resources,such as iron,nickel,cobalt and copper,from iron-rich nickel slag represents a key technical bottleneck in the comprehensive utilization of nickel slag resources.This study focused on metallized pellets produced by the reduction of modified nickel slag.Firstly,the thermodynamic analysis of the CaO-MgO-SiO2 slag system for these pellets was carried out using FactSage software,and the composition of secondary slags and melt characteristics were determined through phase diagrams and equilibrium calculations.Then,the effects of melting temperature,alkalinity and other factors on the recovery rates of valuable metals,such as iron,nickel,cobalt and copper in metallized pellets were investigated through experiments.The migration and enrichment characteristics of the target metals were also explored during the melting separation process,the optimal processing parameters were identified,and the underlying mechanism was analyzed.Thermodynamic calculations showed that when the slag system alkalinity of modified nickel slag metallized pellets was within the range of 0.70.9,the melting temperature was lower than 1400℃,the viscosity was 0.20.4 Pa·s,and the secondary slag phase was the pyroxene phase.Experimental results showed that when the melting temperature was 1600℃,and the alkalinity was 0.9,the recovery ratio of melted iron reached 95.31%.The enrichment and recovery ratios of nickel,cobalt and copper were all satisfactory.
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xiazailiang-0
Aiming at a zinc sulfate solution containing a Fe2+concentration of 20.3 g/L produced by a zinc hydrometallurgical plant,a new process was developed to oxidize Fe2+to Fe3+using pure oxygen in an autoclave.Secondary zinc oxide powder was utilized as a neutralizing agent to neutralize the acid generated during the iron precipitation stage.The reaction pH value was rigorously controlled within the range of 3.0 to 4.0.Under the conditions of oxygen partial pressure of 0.35 MPa,reaction temperature of 80℃,agitation speed of 450 r/min,and neutralizing agent dosage of 55 g/L,the oxidation and removal of Fe2+from the zinc sulfate solution were achieved within 50 min.The total iron(TFe)concentration in the solution after iron precipitation was less than 2 g/L,and the iron removal efficiency reached 92%.
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xiazailiang-0
The primary impurity minerals in microcrystalline graphite include quartz,mica,chlorite,and sulfide minerals(such as pyrite).Current acid leaching purification processes face challenges,including the low solubility of impurities and the occurrence of secondary precipitation.In this study,hydrochloric acid(HCl)and hydrofluoric acid(HF)were used as the primary leaching agents,and ammonium persulfate((NH4)2S2O8)was introduced to enhance the oxidative properties of the leaching system,thereby strengthening the purification effect.Acid leaching experiments demonstrated that the fixed carbon content of graphite increased from 98.0% to 98.4% with the addition of ammonium persulfate,indicating a significant improvement in the purification efficiency.Thermodynamic analysis revealed that while pyrite cannot spontaneously react with HF and HCl at ambient temperature,the addition of ammonium persulfate promoted its dissolution.Furthermore,it was found that the reaction of mica and chlorite with HF tended to generate potassium hexafluorosilicate(K2SiF6)precipitates.However,the presence of hydrochloric acid in the mixed acid system effectively suppressed the formation of these precipitates to a certain extent,thereby enhancing the purification efficiency.Structural characterization of the purified graphite indicated that the introduction of ammonium persulfate did not adversely affect the surface morphology or the crystalline structure of the microcrystalline graphite.
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xiazailiang-0
The efficient recovery of valuable metal resources,such as iron,nickel,cobalt and copper,from iron-rich nickel slag represents a key technical bottleneck in the comprehensive utilization of nickel slag resources.This study focused on metallized pellets produced by the reduction of modified nickel slag.Firstly,the thermodynamic analysis of the CaO-MgO-SiO2 slag system for these pellets was carried out using FactSage software,and the composition of secondary slags and melt characteristics were determined through phase diagrams and equilibrium calculations.Then,the effects of melting temperature,alkalinity and other factors on the recovery rates of valuable metals,such as iron,nickel,cobalt and copper in metallized pellets were investigated through experiments.The migration and enrichment characteristics of the target metals were also explored during the melting separation process,the optimal processing parameters were identified,and the underlying mechanism was analyzed.Thermodynamic calculations showed that when the slag system alkalinity of modified nickel slag metallized pellets was within the range of 0.70.9,the melting temperature was lower than 1400℃,the viscosity was 0.20.4 Pa·s,and the secondary slag phase was the pyroxene phase.Experimental results showed that when the melting temperature was 1600℃,and the alkalinity was 0.9,the recovery ratio of melted iron reached 95.31%.The enrichment and recovery ratios of nickel,cobalt and copper were all satisfactory.
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xiazailiang-0
Aiming at a zinc sulfate solution containing a Fe2+concentration of 20.3 g/L produced by a zinc hydrometallurgical plant,a new process was developed to oxidize Fe2+to Fe3+using pure oxygen in an autoclave.Secondary zinc oxide powder was utilized as a neutralizing agent to neutralize the acid generated during the iron precipitation stage.The reaction pH value was rigorously controlled within the range of 3.0 to 4.0.Under the conditions of oxygen partial pressure of 0.35 MPa,reaction temperature of 80℃,agitation speed of 450 r/min,and neutralizing agent dosage of 55 g/L,the oxidation and removal of Fe2+from the zinc sulfate solution were achieved within 50 min.The total iron(TFe)concentration in the solution after iron precipitation was less than 2 g/L,and the iron removal efficiency reached 92%.
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xiazailiang-0
The primary impurity minerals in microcrystalline graphite include quartz,mica,chlorite,and sulfide minerals(such as pyrite).Current acid leaching purification processes face challenges,including the low solubility of impurities and the occurrence of secondary precipitation.In this study,hydrochloric acid(HCl)and hydrofluoric acid(HF)were used as the primary leaching agents,and ammonium persulfate((NH4)2S2O8)was introduced to enhance the oxidative properties of the leaching system,thereby strengthening the purification effect.Acid leaching experiments demonstrated that the fixed carbon content of graphite increased from 98.0% to 98.4% with the addition of ammonium persulfate,indicating a significant improvement in the purification efficiency.Thermodynamic analysis revealed that while pyrite cannot spontaneously react with HF and HCl at ambient temperature,the addition of ammonium persulfate promoted its dissolution.Furthermore,it was found that the reaction of mica and chlorite with HF tended to generate potassium hexafluorosilicate(K2SiF6)precipitates.However,the presence of hydrochloric acid in the mixed acid system effectively suppressed the formation of these precipitates to a certain extent,thereby enhancing the purification efficiency.Structural characterization of the purified graphite indicated that the introduction of ammonium persulfate did not adversely affect the surface morphology or the crystalline structure of the microcrystalline graphite.
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xiazailiang-0
The efficient recovery of valuable metal resources,such as iron,nickel,cobalt and copper,from iron-rich nickel slag represents a key technical bottleneck in the comprehensive utilization of nickel slag resources.This study focused on metallized pellets produced by the reduction of modified nickel slag.Firstly,the thermodynamic analysis of the CaO-MgO-SiO2 slag system for these pellets was carried out using FactSage software,and the composition of secondary slags and melt characteristics were determined through phase diagrams and equilibrium calculations.Then,the effects of melting temperature,alkalinity and other factors on the recovery rates of valuable metals,such as iron,nickel,cobalt and copper in metallized pellets were investigated through experiments.The migration and enrichment characteristics of the target metals were also explored during the melting separation process,the optimal processing parameters were identified,and the underlying mechanism was analyzed.Thermodynamic calculations showed that when the slag system alkalinity of modified nickel slag metallized pellets was within the range of 0.70.9,the melting temperature was lower than 1400℃,the viscosity was 0.20.4 Pa·s,and the secondary slag phase was the pyroxene phase.Experimental results showed that when the melting temperature was 1600℃,and the alkalinity was 0.9,the recovery ratio of melted iron reached 95.31%.The enrichment and recovery ratios of nickel,cobalt and copper were all satisfactory.
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