Hydrophobic flocculation pretreatment was performed to assess its effect on the recovery of fine cuprite in sulfidation-flotation. The results of the micro-flotation experiment showed that cuprite recovery is related ...Hydrophobic flocculation pretreatment was performed to assess its effect on the recovery of fine cuprite in sulfidation-flotation. The results of the micro-flotation experiment showed that cuprite recovery is related to the particle size, and that an excessive content of fine particles(<18 μm) impacted the recovery of coarse particles. When hydrophobic flocculation pretreatment was used, the recovery of fine cuprite in sulfidation-flotation increased from 60.3% to 86.3% under optimum conditions(pH 9.5; sodium oleate concentration, 2 × 10^(-4) mol×L^(-1); stirring time, 6 min; stirring speed, 1600 r×min^(-1)). The laser particle size analysis and optical microscopy results indicate that hydrophobic flocculation pretreatment effectively reduces the content of fine cuprite, and augments the apparent particle size in the pulp. We performed the Derjaguin–Landau–Verwey–Overbeek(DLVO) theory and extended DLVO theory calculations to further support the interpretation of the results.展开更多
Hydrogen peroxide was used as an oxidant to modify the cuprite surface and enhance its sulfidization.Surface-adsorption and infrared spectroscopy measurements indicated that the modification of the cuprite surface wit...Hydrogen peroxide was used as an oxidant to modify the cuprite surface and enhance its sulfidization.Surface-adsorption and infrared spectroscopy measurements indicated that the modification of the cuprite surface with hydrogen peroxide before sulfidization increased the adsorption capacity of xanthate.Zeta potential,scanning electron microscopy-energy dispersive X-ray spectroscopy,X-ray photoelectron spectroscopy,and time-of-flight secondary ion mass spectrometry results showed that the modification with hydrogen peroxide increased the contents of S^(2−)and Sn^(2−)species on the cuprite surface.Microflotation tests showed that the recovery of cuprite increased from 61.74%to 83.30%after the modification of the surface with hydrogen peroxide.These results confirm that the modification of the cuprite surface with hydrogen peroxide enhances the sulfidization of cuprite,which in turn improves its flotation.展开更多
The direct sulfidization of cuprite is inefficient because cuprite is a copper-oxide mineral with a strong surface hydrophilicity.In this study,oxidant was used to modify cuprite surfaces to regulate the sulfidization...The direct sulfidization of cuprite is inefficient because cuprite is a copper-oxide mineral with a strong surface hydrophilicity.In this study,oxidant was used to modify cuprite surfaces to regulate the sulfidization of cuprite.Microflotation tests showed that the flotation recovery of pre-oxidized cuprite was nearly25% higher than that of direct sulfidization flotation,which indicates that the cuprite surface activity was enhanced after pre-oxidation by Cu(Ⅰ) species(weak affinity with sulfur ions) transformation to Cu(Ⅱ)species(strong affinity with sulfur ions).Zeta potential,scanning electron microscopy-energy dispersive X-ray spectroscopy,X-ray photoelectron spectroscopy,and time-of-flight secondary ion mass spectrometry results showed that pre-oxidation improved cuprite sulfidization and promoted the formation of copper-sulfide species on the cuprite surfaces.The mineral surface stability and thus,xanthate species adsorption on the cuprite surfaces were improved.The surface-adsorption measurements and infrared spectroscopy showed that a large amount of xanthate species was adsorbed onto the sulfidized cuprite surfaces after pre-oxidation,which enhanced the cuprite hydrophobicity and improved the cuprite flotation.展开更多
Cuprite is a difficult oxide to leach under acidic conditions(for the maximum extraction of50%).In this research,the feasibility of leaching cuprite in an ammoniacal medium was studied.The working conditions addressed...Cuprite is a difficult oxide to leach under acidic conditions(for the maximum extraction of50%).In this research,the feasibility of leaching cuprite in an ammoniacal medium was studied.The working conditions addressed here were the liquid/solid ratio(120:1-400:1mL/g),stirring speed(0-950r/min),temperature(10-45℃)and NH4OH concentration(0.05-0.15mol/L).In addition,different ammoniacal reagents(NH4F and(NH4)2SO4)were analyzed.The experiments were performed in a2L reactor with a heating mantle and a condenser.The most important results were that the maximum leaching rate was obtained at pH10.5,0.10mol/L NH4OH,45℃,4h,850r/min and a liquid/solid ratio of400:1,reaching a copper extraction rate of82%.This result was related to the non-precipitation of copper in solution by the formation of copper tetra-amine (Cu(NH2)4^2+).The liquid/solid ratio and stirring speed were essential for increasing the cuprite leaching.The maximum leaching rate was achieved at higher temperatures;however,significant copper leaching rate occurred at temperatures near the freezing point of water(17.9%over4h).Increasing NH4OH concentration and decreasing particle size increased the cuprite leaching rate.The two ammoniacal reagents(NH4F and(NH4)2SO4)had low extraction rate of copper compared with NH4OH.The kinetic model representing cuprite leaching was a chemical reaction on the surface.The order of the reaction with respect to the NH4OH concentration was1.8,and it was inversely proportional to the radius of the ore particles.The calculated activation energy was44.36kJ/mol in the temperature range of10-45℃.展开更多
Cuprite (Cu2O) particles are synthesized by hydrothermal method. Most crystalline particles have long column morphology. Particles which are regarded as assembling of the crystallites in definite directions are observ...Cuprite (Cu2O) particles are synthesized by hydrothermal method. Most crystalline particles have long column morphology. Particles which are regarded as assembling of the crystallites in definite directions are observed. The typical example is the particles formed by assembling six columns in three perpendicular directions. The cone surfaces are visible at the tops of the columns. The results revealed that the coalescence of the crystallites did happen under hydrothermal conditions in which the crystallite connected with other crystallite on certain structure compatible surfaces to form a crystalline particle with a special morphology. This phenomenon is called the second kind of coalescence. The Cu2O structure unit is determined by its crystal structure. It is concluded that the tetragonal prism and three tetragonal prism-like growth units are the favorable units after stability energy calculation was performed on different kinds of growth units. It is believed that the first kind of coalescence exists commonly. The second kind of coalescence is unlikely to occur for all crystallites under hydrothermal conditions. The occurrence is dependent on the crystal structure.展开更多
The empirical relation of between the transition temperature of optimum doped superconductors T<sub>co</sub> and the mean cationic charge , a physical paradox, can be recast to strongly support fractal the...The empirical relation of between the transition temperature of optimum doped superconductors T<sub>co</sub> and the mean cationic charge , a physical paradox, can be recast to strongly support fractal theories of high-T<sub>c</sub> superconductors, thereby applying the finding that the optimum hole concentration of σ<sub>o</sub> = 0.229 can be linked with the universal fractal constant δ<sub>1</sub> = 8.72109… of the renormalized quadratic Hénon map. The transition temperature obviously increases steeply with a domain structure of ever narrower size, characterized by Fibonacci numbers. However, also conventional BCS superconductors can be scaled with δ<sub>1</sub>, exemplified through the energy gap relation k<sub>B</sub>T<sub>c</sub> ≈ 5Δ<sub>0</sub>/δ<sub>1</sub>, suggesting a revision of the entire theory of superconductivity. A low mean cationic charge allows the development of a frustrated nano-sized fractal structure of possibly ferroelastic nature delivering nano-channels for very fast charge transport, in common for both high-T<sub>c</sub> superconductor and organic-inorganic halide perovskite solar materials. With this backing superconductivity above room temperature can be conceived for synthetic sandwich structures of less than 2+. For instance, composites of tenorite and cuprite respectively tenorite and CuI (CuBr, CuCl) onto AuCu alloys are proposed. This specification is suggested by previously described filamentary superconductivity of “bulk” CuO1﹣x samples. In addition, cesium substitution in the Tl-1223 compound is an option.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 51374079 and 51504053) the Hundred, Thousand and Ten Thousand Talent Project of Liaoning Province (No. 2014921014)the Postdoctoral Science Foundation of China (No. 2015M571324)
文摘Hydrophobic flocculation pretreatment was performed to assess its effect on the recovery of fine cuprite in sulfidation-flotation. The results of the micro-flotation experiment showed that cuprite recovery is related to the particle size, and that an excessive content of fine particles(<18 μm) impacted the recovery of coarse particles. When hydrophobic flocculation pretreatment was used, the recovery of fine cuprite in sulfidation-flotation increased from 60.3% to 86.3% under optimum conditions(pH 9.5; sodium oleate concentration, 2 × 10^(-4) mol×L^(-1); stirring time, 6 min; stirring speed, 1600 r×min^(-1)). The laser particle size analysis and optical microscopy results indicate that hydrophobic flocculation pretreatment effectively reduces the content of fine cuprite, and augments the apparent particle size in the pulp. We performed the Derjaguin–Landau–Verwey–Overbeek(DLVO) theory and extended DLVO theory calculations to further support the interpretation of the results.
基金Project funded by Ten Thousand Talent Plans for Young Top-notch Talents of Yunnan Province, China (No. YNWR-QNBJ-2018-051)。
文摘Hydrogen peroxide was used as an oxidant to modify the cuprite surface and enhance its sulfidization.Surface-adsorption and infrared spectroscopy measurements indicated that the modification of the cuprite surface with hydrogen peroxide before sulfidization increased the adsorption capacity of xanthate.Zeta potential,scanning electron microscopy-energy dispersive X-ray spectroscopy,X-ray photoelectron spectroscopy,and time-of-flight secondary ion mass spectrometry results showed that the modification with hydrogen peroxide increased the contents of S^(2−)and Sn^(2−)species on the cuprite surface.Microflotation tests showed that the recovery of cuprite increased from 61.74%to 83.30%after the modification of the surface with hydrogen peroxide.These results confirm that the modification of the cuprite surface with hydrogen peroxide enhances the sulfidization of cuprite,which in turn improves its flotation.
基金the Project funded by Ten Thousand Talent Plans for Young Top-notch Talents of Yunnan Province (Grant No. YNWR-QNBJ-2018-051)。
文摘The direct sulfidization of cuprite is inefficient because cuprite is a copper-oxide mineral with a strong surface hydrophilicity.In this study,oxidant was used to modify cuprite surfaces to regulate the sulfidization of cuprite.Microflotation tests showed that the flotation recovery of pre-oxidized cuprite was nearly25% higher than that of direct sulfidization flotation,which indicates that the cuprite surface activity was enhanced after pre-oxidation by Cu(Ⅰ) species(weak affinity with sulfur ions) transformation to Cu(Ⅱ)species(strong affinity with sulfur ions).Zeta potential,scanning electron microscopy-energy dispersive X-ray spectroscopy,X-ray photoelectron spectroscopy,and time-of-flight secondary ion mass spectrometry results showed that pre-oxidation improved cuprite sulfidization and promoted the formation of copper-sulfide species on the cuprite surfaces.The mineral surface stability and thus,xanthate species adsorption on the cuprite surfaces were improved.The surface-adsorption measurements and infrared spectroscopy showed that a large amount of xanthate species was adsorbed onto the sulfidized cuprite surfaces after pre-oxidation,which enhanced the cuprite hydrophobicity and improved the cuprite flotation.
文摘Cuprite is a difficult oxide to leach under acidic conditions(for the maximum extraction of50%).In this research,the feasibility of leaching cuprite in an ammoniacal medium was studied.The working conditions addressed here were the liquid/solid ratio(120:1-400:1mL/g),stirring speed(0-950r/min),temperature(10-45℃)and NH4OH concentration(0.05-0.15mol/L).In addition,different ammoniacal reagents(NH4F and(NH4)2SO4)were analyzed.The experiments were performed in a2L reactor with a heating mantle and a condenser.The most important results were that the maximum leaching rate was obtained at pH10.5,0.10mol/L NH4OH,45℃,4h,850r/min and a liquid/solid ratio of400:1,reaching a copper extraction rate of82%.This result was related to the non-precipitation of copper in solution by the formation of copper tetra-amine (Cu(NH2)4^2+).The liquid/solid ratio and stirring speed were essential for increasing the cuprite leaching.The maximum leaching rate was achieved at higher temperatures;however,significant copper leaching rate occurred at temperatures near the freezing point of water(17.9%over4h).Increasing NH4OH concentration and decreasing particle size increased the cuprite leaching rate.The two ammoniacal reagents(NH4F and(NH4)2SO4)had low extraction rate of copper compared with NH4OH.The kinetic model representing cuprite leaching was a chemical reaction on the surface.The order of the reaction with respect to the NH4OH concentration was1.8,and it was inversely proportional to the radius of the ore particles.The calculated activation energy was44.36kJ/mol in the temperature range of10-45℃.
基金This work was supported by the National Natural Science Foundation of China(Grant No.59832080)Natural Science Foundation of Jiangxi Province(No.0111015).
文摘Cuprite (Cu2O) particles are synthesized by hydrothermal method. Most crystalline particles have long column morphology. Particles which are regarded as assembling of the crystallites in definite directions are observed. The typical example is the particles formed by assembling six columns in three perpendicular directions. The cone surfaces are visible at the tops of the columns. The results revealed that the coalescence of the crystallites did happen under hydrothermal conditions in which the crystallite connected with other crystallite on certain structure compatible surfaces to form a crystalline particle with a special morphology. This phenomenon is called the second kind of coalescence. The Cu2O structure unit is determined by its crystal structure. It is concluded that the tetragonal prism and three tetragonal prism-like growth units are the favorable units after stability energy calculation was performed on different kinds of growth units. It is believed that the first kind of coalescence exists commonly. The second kind of coalescence is unlikely to occur for all crystallites under hydrothermal conditions. The occurrence is dependent on the crystal structure.
文摘The empirical relation of between the transition temperature of optimum doped superconductors T<sub>co</sub> and the mean cationic charge , a physical paradox, can be recast to strongly support fractal theories of high-T<sub>c</sub> superconductors, thereby applying the finding that the optimum hole concentration of σ<sub>o</sub> = 0.229 can be linked with the universal fractal constant δ<sub>1</sub> = 8.72109… of the renormalized quadratic Hénon map. The transition temperature obviously increases steeply with a domain structure of ever narrower size, characterized by Fibonacci numbers. However, also conventional BCS superconductors can be scaled with δ<sub>1</sub>, exemplified through the energy gap relation k<sub>B</sub>T<sub>c</sub> ≈ 5Δ<sub>0</sub>/δ<sub>1</sub>, suggesting a revision of the entire theory of superconductivity. A low mean cationic charge allows the development of a frustrated nano-sized fractal structure of possibly ferroelastic nature delivering nano-channels for very fast charge transport, in common for both high-T<sub>c</sub> superconductor and organic-inorganic halide perovskite solar materials. With this backing superconductivity above room temperature can be conceived for synthetic sandwich structures of less than 2+. For instance, composites of tenorite and cuprite respectively tenorite and CuI (CuBr, CuCl) onto AuCu alloys are proposed. This specification is suggested by previously described filamentary superconductivity of “bulk” CuO1﹣x samples. In addition, cesium substitution in the Tl-1223 compound is an option.
