By mineral liberation analyzer （MLA） automated quantitative system, the niobium-tantalum ore in this study was classified as refractory mineral of low-grade which was mainly composed of fergusonite, polycrase, ilmen...By mineral liberation analyzer （MLA） automated quantitative system, the niobium-tantalum ore in this study was classified as refractory mineral of low-grade which was mainly composed of fergusonite, polycrase, ilmenorutile, and bastnasite. Most of niobium and rare earth metals were dis- seminated in these minerals （particle sizes of 95 % rare earth elements 〈40 μm）, which cannot be concentrated through traditional floatation process and treated by the current hydrofluoric acid leaching in industry application. It is nec- essary to develop a new approach to recovery these valuable metals. In this study, an improved method is proposed to extract these metals, which includes acid roasting and sulfuric acid leaching. The influence of mineralogy, acid concentra- tion, leaching temperature, leaching time, and liquid to solid ratio was experimentally studied. It is observed that after the ground ore （-74 μm） was roasted at 350 ℃ for 2 h with sulfuric acid （18.4 mol.L- 1） in the ore to acid mass ratio of 1：1, and then the roasting residue reacted with 25 % sulfuric acid at 90 ℃ for 2 h, the recovery rate of rare earth elements reaches 〉90 %, and the leaching extent of niobium can reach 84 %.展开更多
Zinc silicate ore was characterized mineralogically and the results showed that zinc exists mainly as hemimorphite and smithsonite in the sample.Sulfuric acid pressure leaching of zinc silicate ore was carried out to ...Zinc silicate ore was characterized mineralogically and the results showed that zinc exists mainly as hemimorphite and smithsonite in the sample.Sulfuric acid pressure leaching of zinc silicate ore was carried out to assess the effect of particle size,sulfuric acid concentration,pressure,reaction time and temperature on the extraction of zinc and the dissolution of silica.Under the optimum conditions employed,up to 99.25% of zinc extraction and 0.20% silica dissolution are obtained.The main minerals in leaching residue are quartz and small amounts of undissolved oxide minerals of iron,lead and aluminum are associated with quartz.展开更多
The decomposition of copper anode slime heated by microwave energy in a sulfuric acid medium was investigated. Leaching experiments were carried out in a multi-mode cavity with microwave assistance. The leaching proce...The decomposition of copper anode slime heated by microwave energy in a sulfuric acid medium was investigated. Leaching experiments were carried out in a multi-mode cavity with microwave assistance. The leaching process parameters were optimized using response surface methodology（RSM）. Under the optimized conditions, the leaching efficiencies of copper and tellurium were 99.56% ± 0.16% and 98.68% ± 0.12%, respectively. Meanwhile, a conventional leaching experiment was performed in order to evaluate the influence of microwave radiation. The mechanism of microwave-assisted leaching of copper anode slime was also investigated. In the results, the microwave technology is demonstrated to have a great potential to improve the leaching efficiency and reduce the leaching time. The enhanced recoveries of copper and tellurium are believed to result from the presence of a temperature gradient due to the shallow microwave penetration depth and the superheating at the solid-liquid interface.展开更多
This research work deals with the extraction of nickel from a low grade nickel laterite ore, taken from a deposit located in southwestern of Iran, through agitation leaching at atmospheric pressure. The assaying and m...This research work deals with the extraction of nickel from a low grade nickel laterite ore, taken from a deposit located in southwestern of Iran, through agitation leaching at atmospheric pressure. The assaying and mineralogical studies carried out on the nickel laterite sample, showed the 0.88% Ni, and principally consisted of oxide and silicate crystalline phases i.e. dolomite, quartz, magnetite, and goethite. Among numerous factors affecting such process, four major parameters i.e. temperature, agitator speed(r/min), leaching agents and their concentration were considered in a two-level full factorial experimental design. The agitation leach tests showed that the ore could be leached at atmospheric pressure with sulfuric acid while citric acid was almost unpromising. Analysis of variance(ANOVA) using DX7 software was employed to identify effective parameters. Sulfuric acid concentration and temperature were the most effective parameters on Ni extraction. Furthermore, the factorial models for experiment responses were developed. The results showed 83% Ni extraction after 4 h leaching, under optimized conditions i.e.temperature at 95 ℃, acid concentration at 5 N and agitator speed at 1000 r/min. This study revealed that factorial experimental design can be implemented to identify effective parameters on the agitation leaching process of nickel laterite.展开更多
High pressure roll grinding（HPRG）and ball milling were compared to investigate the influence of mechanical activation on the acid leaching dephosphorization of a high-phosphorus iron ore concentrate,which was manufa...High pressure roll grinding（HPRG）and ball milling were compared to investigate the influence of mechanical activation on the acid leaching dephosphorization of a high-phosphorus iron ore concentrate,which was manufactured through magnetizing roasting-magnetic separation of high-phosphorus oolitic iron ores.The results indicated that when high-phosphorus iron ore concentrates containing 54.92 mass% iron and 0.76 mass% phosphorus were directly processed through acid leaching,iron ore concentrates containing 55.74mass%iron and 0.33mass%phosphorus with an iron recovery of 84.64%and dephosphorization of 63.79% were obtained.When high-phosphorus iron ore concentrates activated by ball milling were processed by acid leaching,iron ore concentrates containing56.03mass%iron and 0.21mass% phosphorus with an iron recovery of 85.65% and dephosphorization of 77.49%were obtained.Meanwhile,when high-phosphorus iron ore concentrates activated by HPRG were processed by acid leaching,iron ore concentrates containing 58.02mass%iron and 0.10mass% phosphorus were obtained,with the iron recovery reaching 88.42% and the dephosphorization rate reaching 88.99%.Mechanistic studies demonstrated that ball milling can reduce the particle size,demonstrating aprominent reunion phenomenon.In contrast,HPRG pretreatment contributes to the formation of more cracks within the particles and selective dissociation of iron and P bearing minerals,which can provide the favorable kinetic conditions to accelerate the solid-liquid reaction rate.As such,the crystal structure is destroyed and the surface energy of mineral particles is strengthened by mechanical activation,further strengthening the dephosphorization.展开更多
基金financially supported by the National Science & Technology Pillar Program(No.2012BAB10B00)
文摘By mineral liberation analyzer （MLA） automated quantitative system, the niobium-tantalum ore in this study was classified as refractory mineral of low-grade which was mainly composed of fergusonite, polycrase, ilmenorutile, and bastnasite. Most of niobium and rare earth metals were dis- seminated in these minerals （particle sizes of 95 % rare earth elements 〈40 μm）, which cannot be concentrated through traditional floatation process and treated by the current hydrofluoric acid leaching in industry application. It is nec- essary to develop a new approach to recovery these valuable metals. In this study, an improved method is proposed to extract these metals, which includes acid roasting and sulfuric acid leaching. The influence of mineralogy, acid concentra- tion, leaching temperature, leaching time, and liquid to solid ratio was experimentally studied. It is observed that after the ground ore （-74 μm） was roasted at 350 ℃ for 2 h with sulfuric acid （18.4 mol.L- 1） in the ore to acid mass ratio of 1：1, and then the roasting residue reacted with 25 % sulfuric acid at 90 ℃ for 2 h, the recovery rate of rare earth elements reaches 〉90 %, and the leaching extent of niobium can reach 84 %.
基金Project(2007CB613605) supported by the National Basic Research Program of China
文摘Zinc silicate ore was characterized mineralogically and the results showed that zinc exists mainly as hemimorphite and smithsonite in the sample.Sulfuric acid pressure leaching of zinc silicate ore was carried out to assess the effect of particle size,sulfuric acid concentration,pressure,reaction time and temperature on the extraction of zinc and the dissolution of silica.Under the optimum conditions employed,up to 99.25% of zinc extraction and 0.20% silica dissolution are obtained.The main minerals in leaching residue are quartz and small amounts of undissolved oxide minerals of iron,lead and aluminum are associated with quartz.
基金financially supported by the National Science and Technology Support Program of China during the 12th Five-Year Plan Period (No. 2012BAE06B05)the Fundamental Research Funds for the Central Universities of China (No. N130602004)
文摘The decomposition of copper anode slime heated by microwave energy in a sulfuric acid medium was investigated. Leaching experiments were carried out in a multi-mode cavity with microwave assistance. The leaching process parameters were optimized using response surface methodology（RSM）. Under the optimized conditions, the leaching efficiencies of copper and tellurium were 99.56% ± 0.16% and 98.68% ± 0.12%, respectively. Meanwhile, a conventional leaching experiment was performed in order to evaluate the influence of microwave radiation. The mechanism of microwave-assisted leaching of copper anode slime was also investigated. In the results, the microwave technology is demonstrated to have a great potential to improve the leaching efficiency and reduce the leaching time. The enhanced recoveries of copper and tellurium are believed to result from the presence of a temperature gradient due to the shallow microwave penetration depth and the superheating at the solid-liquid interface.
文摘This research work deals with the extraction of nickel from a low grade nickel laterite ore, taken from a deposit located in southwestern of Iran, through agitation leaching at atmospheric pressure. The assaying and mineralogical studies carried out on the nickel laterite sample, showed the 0.88% Ni, and principally consisted of oxide and silicate crystalline phases i.e. dolomite, quartz, magnetite, and goethite. Among numerous factors affecting such process, four major parameters i.e. temperature, agitator speed(r/min), leaching agents and their concentration were considered in a two-level full factorial experimental design. The agitation leach tests showed that the ore could be leached at atmospheric pressure with sulfuric acid while citric acid was almost unpromising. Analysis of variance(ANOVA) using DX7 software was employed to identify effective parameters. Sulfuric acid concentration and temperature were the most effective parameters on Ni extraction. Furthermore, the factorial models for experiment responses were developed. The results showed 83% Ni extraction after 4 h leaching, under optimized conditions i.e.temperature at 95 ℃, acid concentration at 5 N and agitator speed at 1000 r/min. This study revealed that factorial experimental design can be implemented to identify effective parameters on the agitation leaching process of nickel laterite.
基金Item Sponsored by National Torch Program Project of China(2011GH561685)
文摘High pressure roll grinding（HPRG）and ball milling were compared to investigate the influence of mechanical activation on the acid leaching dephosphorization of a high-phosphorus iron ore concentrate,which was manufactured through magnetizing roasting-magnetic separation of high-phosphorus oolitic iron ores.The results indicated that when high-phosphorus iron ore concentrates containing 54.92 mass% iron and 0.76 mass% phosphorus were directly processed through acid leaching,iron ore concentrates containing 55.74mass%iron and 0.33mass%phosphorus with an iron recovery of 84.64%and dephosphorization of 63.79% were obtained.When high-phosphorus iron ore concentrates activated by ball milling were processed by acid leaching,iron ore concentrates containing56.03mass%iron and 0.21mass% phosphorus with an iron recovery of 85.65% and dephosphorization of 77.49%were obtained.Meanwhile,when high-phosphorus iron ore concentrates activated by HPRG were processed by acid leaching,iron ore concentrates containing 58.02mass%iron and 0.10mass% phosphorus were obtained,with the iron recovery reaching 88.42% and the dephosphorization rate reaching 88.99%.Mechanistic studies demonstrated that ball milling can reduce the particle size,demonstrating aprominent reunion phenomenon.In contrast,HPRG pretreatment contributes to the formation of more cracks within the particles and selective dissociation of iron and P bearing minerals,which can provide the favorable kinetic conditions to accelerate the solid-liquid reaction rate.As such,the crystal structure is destroyed and the surface energy of mineral particles is strengthened by mechanical activation,further strengthening the dephosphorization.
