The enhancement of chalcopyrite bioleaching with an enriched microbial community by acidified seawater was studied,and the enhancing mechanism was analyzed.The microbial community was enriched at the Dabaoshan mine si...The enhancement of chalcopyrite bioleaching with an enriched microbial community by acidified seawater was studied,and the enhancing mechanism was analyzed.The microbial community was enriched at the Dabaoshan mine site,and the treated ore sample had high concentrations of chalcopyrite and galena.The experimental results show that copper extraction from chalcopyrite with an enriched microbial community in seawater was promoted from 13.1%to 62.1%by acidification in comparison with that without acidification.Further analyses of the solutions,solid residues and microbial compositions by scanning electron microscopy,X-ray diffraction,Raman spectroscopy,Fourier transform infrared spectroscopy and 16 S rDNA sequencing revealed the promoting effects of acidified seawater.This acidification can increase the biodissolution of chalcopyrite to increase the concentration of iron ions and maintain the redox potential in the range of 360−410 mV.The latter produces an optimal redox environment conducive to chalcopyrite dissolution via Cu_(2)S.The adaptability of the microbial community to a high-salt environment is improved.Chloride ions at 580 mmol/L improve the leaching kinetics of chalcopyrite by increasing the porosity and noncrystallinity of the intermediate elemental sulfur.This study provides a promising way to bioleaching copper minerals using seawater for areas with freshwater shortages.展开更多
Objective:Psoriasis is associated with lipid metabolism disorders,but the underlying mechanisms remain unclear.This study aims to investigate the role of trimethylamine Noxide(TMAO)in lipid metabolism dysregulation in...Objective:Psoriasis is associated with lipid metabolism disorders,but the underlying mechanisms remain unclear.This study aims to investigate the role of trimethylamine Noxide(TMAO)in lipid metabolism dysregulation in psoriasis.Methods:An imiquimod(IMQ)-induced psoriasis-like mouse model was used to assess lipid metabolism parameters,TMAO levels,and liver flavin monooxygenase 3(FMO3)mRNA expression.Blood samples from healthy individuals and psoriatic patients were collected to measure serum TMAO levels and lipid profiles.To clarify the role of TMAO in the lipid metabolism disorder of mice with psoriasis model,exogenous TMAO,choline,or 3,3-dimethyl-1-butanol(DMB)were administered via intraperitoneal injections or diet in IMQ-treated mice.Liver tissues from the mouse models were subjected to RNA sequencing to identify TMAO-regulated signaling pathways.Results:IMQ-induced psoriatic mice exhibited abnormal glucose,insulin,and lipid levels.IMQ treatment also downregulated the hepatic mRNA expression of glucose transporter 2(Glut2)and silence information regulator 1(Sirt1),while upregulating glucose transporter 4(Glut4)and peroxisome proliferator-activated receptor gamma(PPARγ).Elevated serum TMAO levels were observed in both psoriatic patients and IMQ-treated mice.Additionally,liver FMO3 mRNA expression was increased in the psoriatic mouse model.In patients,TMAO levels positively correlated with Psoriasis Area and Severity Index(PASI)scores,serum triglyceride(TG),and total cholesterol(TC)levels.The intraperitoneal injection of TMAO exacerbated lipid dysregulation in IMQ-treated mice.A choline-rich diet further aggravated lipid abnormalities and liver injury in psoriatic mice,whereas DMB treatment alleviated these effects.RNA-Seq analysis demonstrated that TMAO upregulated hepatic microRNA-122(miR-122),which may suppress the expression of gremlin 2(GREM2),thus contributing to lipid metabolism disorder.Conclusion:TMAO may promote lipid metabolism dysregulation in psoriasis by modulating the hepatic miR-122/GREM2 pathway.展开更多
With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysi...With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysis of PET to DMT is achieved over Cu-Mg-Al oxide catalyst.Next,terephthalic acid(TPA)is prepared by DMT hydrolysis.It is found that hydrolysis of DMT to TPA can be promoted by introducing trace amount of water in this catalyst system.CuO-MgO-4.5Al_2O_(3)catalyst demonstrates the excellent catalytic performance for the depolymerization of PET with high conversion rate and TPA yield(100%and 99.5%,respectively)after reaction at 160℃for 6 h,which provides a new idea for the depolymerization of PET.展开更多
Three zincand cobaltcoordination polymers,namely{[Zn_(2)(μ_(6)-adip)(phen)_(2)]·4H_(2)O}_(n)(1),{[Co_(2)(μ_(6)-adip)(bipy)_(2)]·4H_(2)O}_(n)(2),and[Co_(2)(μ4-adip)(μ-bpa)_(2)]_(n)(3)have been constructed...Three zincand cobaltcoordination polymers,namely{[Zn_(2)(μ_(6)-adip)(phen)_(2)]·4H_(2)O}_(n)(1),{[Co_(2)(μ_(6)-adip)(bipy)_(2)]·4H_(2)O}_(n)(2),and[Co_(2)(μ4-adip)(μ-bpa)_(2)]_(n)(3)have been constructed hydrothermally using H4adip(H4adip=5,5′-azanediyldiisophthalic acid),phen(phen=1,10-phenanthroline),bipy(bipy=2,2′-bipyridine),bpa(bpa=bis(4-pyridyl)amine),and zinc and cobalt chlorides at 160℃.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses,and single-crystal X-ray diffrac-tion analyses.Single-crystal X-ray diffraction analyses revealed that three compounds crystallize in the orthorhom-bic system Pnna(1 and 2)or P21212(3)space groups.All compounds exhibit 3D frameworks.The catalytic perfor-mances in the Henry reaction of these compounds were investigated.Compound 3 exhibited an effective catalytic activity in the Henry reaction at 70℃.CCDC:2339391,1;2339392,2;2339393,3.展开更多
Three zinc(Ⅱ),cobalt(Ⅱ),and nickel(Ⅱ)coordination polymers,namely[Zn(μ^(3-)cpna)(μ-dpea)_(0.5)]_(n)(1),[Co(μ^(3-)cpna)(μ-dpey)_(0.5)]_(n)(2),and[Ni(μ^(3-)cpna)(μ-dpey)_(0.5)(H_(2)O)]_(n)(3),have been construc...Three zinc(Ⅱ),cobalt(Ⅱ),and nickel(Ⅱ)coordination polymers,namely[Zn(μ^(3-)cpna)(μ-dpea)_(0.5)]_(n)(1),[Co(μ^(3-)cpna)(μ-dpey)_(0.5)]_(n)(2),and[Ni(μ^(3-)cpna)(μ-dpey)_(0.5)(H_(2)O)]_(n)(3),have been constructed hydrothermally using H_(2)cpna(5-(4-carboxyphenoxy)nicotinic acid),dpea(1,2-di(4-pyridyl)ethane),dpey(1,2-di(4-pyridyl)ethylene),and zinc,cobalt,and nickel chlorides at 160℃.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses,and single-crystal X-ray diffraction analyses.Single-crystal X-ray diffraction analyses revealed that three compounds crystallize in the triclinic system,space group P1.Compounds 1-3 show 2D layer structures.The catalytic activities in the Knoevenagel condensation reaction of these compounds were investigated.Compounds 1 and 2 exhibit effective catalytic activities in the Knoevenagel condensa-tion reaction at room temperature.For this reaction,various parameters were optimized,followed by the investiga-tion of the substrate scope.CCDC:2335676,1;2335677,2;2335678,3.展开更多
This paper is aimed to present a clean,inexpensive and sustainable method to synthesize high purity lithium sulfide(Li_(2)S)powder through hydrogen reduction of lithium sulfate(Li_(2)SO_(4)).A three-step reduction pro...This paper is aimed to present a clean,inexpensive and sustainable method to synthesize high purity lithium sulfide(Li_(2)S)powder through hydrogen reduction of lithium sulfate(Li_(2)SO_(4)).A three-step reduction process has been successfully developed to synthesize well-crystallized and single-phase Li_(2)S powder by investigating the melting,sintering and reduction behavior of the mixtures of Li_(2)SO_(4)-Li_(2)S.High purity alumina was found to be the most suitable crucible material for producing high purity Li_(2)S,because it was not attacked by the Li_(2)SO_(4)-Li_(2)S melt during heating,as compared with other materials,such as carbon,mullite,quartz,boron nitride and stainless steel.The use of synthesized LizS resulted in higher purity and substantially higher room temperature ionic conductivity(2.77 mS·cm^(-1))for the argyrodite sulfide electrolyte Li_(6)PS_(5)Cl than commercial Li_(2)S(1.12 mS·cm^(-1)).This novel method offers a great opportunity to produce battery grade Li_(2)S for sulfide solid electrolyte applications.展开更多
Preparation of high purity ruthenium nitrosyl nitrate using spent Ru-Zn/ZrO_(2)catalyst was studied,including melting and leaching to obtain potassium ruthenate solution,reduction,dissolving,concentrating and drying t...Preparation of high purity ruthenium nitrosyl nitrate using spent Ru-Zn/ZrO_(2)catalyst was studied,including melting and leaching to obtain potassium ruthenate solution,reduction,dissolving,concentrating and drying to obtain ruthenium trichloride,nitrosation and hydrolysis to obtain ruthenium nitrosyl hydroxide,removing of K^(+)and Cl^(-),and neutralization with nitric acid.The effects of temperature,concentration,time and pH on the yield and purity of intermediates and final product were studied,and the optimum process conditions were obtained.The yield of ruthenium nitrosyl nitrate is 92%,the content of ruthenium in high purity product is 32.16%,and the content of Cl^(-)and K^(+)are much less than 0.005%.The reaction kinetics of ruthenium nitrosyl chloride to ruthenium nitrosyl hydroxide was studied.The reaction orders of Ru(NO)Cl_(3)at 40,55 and 70℃are 0.39,0.37 and 0.39,respectively,while those of KOH are 0.16,0.15 and 0.17,respectively.The activation energy is-2.33 k J/mol.展开更多
A small molecular organic depressor glycerine-xanthate was synthesized. The effect of glycerine-xanthate on the flotation of sulfide minerals was investigated based on a function of pH value and concentration of glyce...A small molecular organic depressor glycerine-xanthate was synthesized. The effect of glycerine-xanthate on the flotation of sulfide minerals was investigated based on a function of pH value and concentration of glycerine-xanthate through flotation experiments in the presence and absence of Cu^2＋. The results show that glycerinee-xanthate has a strong dressing effect on marmatite at pH〉6 and on arsenopyrite in weak acid and base conditions with butyl-xanthate as collector. In the presence of glycerine -xanthate, marmatite is activated by addition of Cu^2＋, but arsenopyrite cannot be activated and remains unfloatable. So the selective separation can be achieved for two minerals. The depression of glycerine-xanthate on sulfide minerals was discussed based on the radical electronegative calculation and the theory of HSAB. Infrared spectrum shows that there are some -OH and-CSS-in glycedne-xanthate molecule, which competes with butyl-xanthate on the mineral surface. As a result of many hydrophilic groups in glycerine-xanthate, the surfaces of marmatite and arsenopyrite become hydrophilic, thus the flotation of marmatite and arsenopyrite is depressed. The collector is adsorbed preferentially on the surface of marmatite and it shows a better floatability in the presence of Cu^2＋, whereas, the surface of arsenopyrite absorbs glycerine-xanthate and the flotation of arsenopyrite is depressed by glycerine-xanthate.展开更多
The crystal structure,formation kinetics and micro-morphology of CaO·SiO2 during high-temperature sintering process were studied in low-calcium system by XRD,FT-IR,Raman and SEM-EDS methods.When the molar ratio o...The crystal structure,formation kinetics and micro-morphology of CaO·SiO2 during high-temperature sintering process were studied in low-calcium system by XRD,FT-IR,Raman and SEM-EDS methods.When the molar ratio of CaCO3 to SiO2 is 1.0,β-2CaO·SiO2 forms firstly during the heating process,and then CaO·SiO2 is generated by the transformation reaction of pre-formed 2CaO·SiO2 with SiO2.3CaO·SiO2 and 3CaO·2SiO2 do not form either in the heating or sintering process.Rising the sintering temperature and prolonging the holding time promote the phase transition of 2CaO·SiO2 to CaO·SiO2,resulting in the sintered products a small blue shift and broadening in Raman spectra.The content of CS can reach 97.4%when sintered at 1400℃ for 1 h.The formation kinetics of CaO·SiO2 follows the second-order chemical reaction model,and the corresponding apparent activation energy and pre-exponential factor are 505.82 kJ/mol and 2.16×10^14 s^−1 respectively.展开更多
Cu-Cr-O nanocomposites that can be used as additives for the catalytic combustion of AP(ammonium perchlorate)-based solid-state propellants were synthesized via a citric acid(CA) complexing approach. Techniques of TG-...Cu-Cr-O nanocomposites that can be used as additives for the catalytic combustion of AP(ammonium perchlorate)-based solid-state propellants were synthesized via a citric acid(CA) complexing approach. Techniques of TG-DTA, XRD as well as TEM were employed to characterize the thermal decomposition procedure, crystal phase, micro-structural morphologies and grain size of the as-synthesized materials respectively. The results show that well-crystallized Cu-Cr-O nanocomposites can be produced after the CA-Cu-Cr precursors are calcined at 500 ℃ for 3 h. Phase composition of the as-obtained Cu-Cr-O nanocomposites depends on the molar ratio of Cu to Cr in the starting reactants. Addition of the as-synthesized Cu-Cr-O nanocomposites as catalysts enhances the burning rate as well as lowers the pressure exponent of the AP-based solid-state propellants considerably. Noticeably, catalyst with a CuCr molar ratio of 0.7 exhibits promising catalytic activity with high burning rate and low pressure exponent at all pressures, due to the effective phase interaction between the spinel CuCr2O4 and delafossite CuCrO2 contained in the as-synthesized Cu-Cr-O nanocomposites.展开更多
For the sake of understanding the deterioration behavior of concrete in actual railway tunnel structures subjected to aggressive sulfate medium in practice,detailed field investigations and tested analysis on sprayed ...For the sake of understanding the deterioration behavior of concrete in actual railway tunnel structures subjected to aggressive sulfate medium in practice,detailed field investigations and tested analysis on sprayed concrete linings of approximately 40-year-old railway tunnels in environments containing sulfate ion were carried out,respectively.The results show that the deterioration of concretes in the investigated area is serious,which involves complicated physicochemical process between the sulfate salt and concrete.Among them,the secondary sulfateminerals such as gypsum formation under very high concentration sulfate ion condition by accumulating and evaporation process dominate,followed by the crystallization of sulfate salt and formation of thaumasite.展开更多
Simultaneous equilibrium was applied to the thermodynamic analysis and calculation of Bi（Ⅲ）-X（Cl-, NO-3）-H2O systems, based on which the diagrams of the logarithm of equilibrium concentration of Bi（Ⅲ） of serie...Simultaneous equilibrium was applied to the thermodynamic analysis and calculation of Bi（Ⅲ）-X（Cl-, NO-3）-H2O systems, based on which the diagrams of the logarithm of equilibrium concentration of Bi（Ⅲ） of series precipitation vs pH value of these two systems at 25 ℃ were obtained, and the pH ranges of the stable zones of various precipitations were analyzed and determined. In Bi（Ⅲ）-Cl--H2O system, the variations of c0(Bi3+) and （c0（Cl-）） have little effect on the equilibria of Bi（OH）3-solution and BiOOH-solution, but has great influence on the （equilibrium） of BiOCl-solution. However, in Bi（Ⅲ）-NO-3-H2O system, the variations of c0(Bi3+) and c0（NO-3） have little effect on equilibria of Bi（OH）3-solution, BiOOH-solution and Bi2O3-solution. When pH value is high, Bi2O3 is the thermodynamic stable phase, its stable zone is the widest, almost including the stable zones of BiOCl or （BiONO3,） （Bi（OH）3） and BiOOH. Bi（OH）3 cannot be obtained from Bi（Ⅲ）-Cl--H2O system, even strong alkaline media. Bi2O3 can be obtained from the solution directly, and highly pure BiOCl or BiONO3 can also be obtained through strictly controlling pH value.展开更多
基金Project(2022YFC2105300)supported by the National Key Research and Development Program of ChinaProjects(41802038,51774342)supported by the National Natural Science Foundation of China。
文摘The enhancement of chalcopyrite bioleaching with an enriched microbial community by acidified seawater was studied,and the enhancing mechanism was analyzed.The microbial community was enriched at the Dabaoshan mine site,and the treated ore sample had high concentrations of chalcopyrite and galena.The experimental results show that copper extraction from chalcopyrite with an enriched microbial community in seawater was promoted from 13.1%to 62.1%by acidification in comparison with that without acidification.Further analyses of the solutions,solid residues and microbial compositions by scanning electron microscopy,X-ray diffraction,Raman spectroscopy,Fourier transform infrared spectroscopy and 16 S rDNA sequencing revealed the promoting effects of acidified seawater.This acidification can increase the biodissolution of chalcopyrite to increase the concentration of iron ions and maintain the redox potential in the range of 360−410 mV.The latter produces an optimal redox environment conducive to chalcopyrite dissolution via Cu_(2)S.The adaptability of the microbial community to a high-salt environment is improved.Chloride ions at 580 mmol/L improve the leaching kinetics of chalcopyrite by increasing the porosity and noncrystallinity of the intermediate elemental sulfur.This study provides a promising way to bioleaching copper minerals using seawater for areas with freshwater shortages.
基金supported by the National Natural Science Foundation(82173426)the Natural Science Foundation of Hunan Province(2023JJ30984),China。
文摘Objective:Psoriasis is associated with lipid metabolism disorders,but the underlying mechanisms remain unclear.This study aims to investigate the role of trimethylamine Noxide(TMAO)in lipid metabolism dysregulation in psoriasis.Methods:An imiquimod(IMQ)-induced psoriasis-like mouse model was used to assess lipid metabolism parameters,TMAO levels,and liver flavin monooxygenase 3(FMO3)mRNA expression.Blood samples from healthy individuals and psoriatic patients were collected to measure serum TMAO levels and lipid profiles.To clarify the role of TMAO in the lipid metabolism disorder of mice with psoriasis model,exogenous TMAO,choline,or 3,3-dimethyl-1-butanol(DMB)were administered via intraperitoneal injections or diet in IMQ-treated mice.Liver tissues from the mouse models were subjected to RNA sequencing to identify TMAO-regulated signaling pathways.Results:IMQ-induced psoriatic mice exhibited abnormal glucose,insulin,and lipid levels.IMQ treatment also downregulated the hepatic mRNA expression of glucose transporter 2(Glut2)and silence information regulator 1(Sirt1),while upregulating glucose transporter 4(Glut4)and peroxisome proliferator-activated receptor gamma(PPARγ).Elevated serum TMAO levels were observed in both psoriatic patients and IMQ-treated mice.Additionally,liver FMO3 mRNA expression was increased in the psoriatic mouse model.In patients,TMAO levels positively correlated with Psoriasis Area and Severity Index(PASI)scores,serum triglyceride(TG),and total cholesterol(TC)levels.The intraperitoneal injection of TMAO exacerbated lipid dysregulation in IMQ-treated mice.A choline-rich diet further aggravated lipid abnormalities and liver injury in psoriatic mice,whereas DMB treatment alleviated these effects.RNA-Seq analysis demonstrated that TMAO upregulated hepatic microRNA-122(miR-122),which may suppress the expression of gremlin 2(GREM2),thus contributing to lipid metabolism disorder.Conclusion:TMAO may promote lipid metabolism dysregulation in psoriasis by modulating the hepatic miR-122/GREM2 pathway.
文摘With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysis of PET to DMT is achieved over Cu-Mg-Al oxide catalyst.Next,terephthalic acid(TPA)is prepared by DMT hydrolysis.It is found that hydrolysis of DMT to TPA can be promoted by introducing trace amount of water in this catalyst system.CuO-MgO-4.5Al_2O_(3)catalyst demonstrates the excellent catalytic performance for the depolymerization of PET with high conversion rate and TPA yield(100%and 99.5%,respectively)after reaction at 160℃for 6 h,which provides a new idea for the depolymerization of PET.
文摘Three zincand cobaltcoordination polymers,namely{[Zn_(2)(μ_(6)-adip)(phen)_(2)]·4H_(2)O}_(n)(1),{[Co_(2)(μ_(6)-adip)(bipy)_(2)]·4H_(2)O}_(n)(2),and[Co_(2)(μ4-adip)(μ-bpa)_(2)]_(n)(3)have been constructed hydrothermally using H4adip(H4adip=5,5′-azanediyldiisophthalic acid),phen(phen=1,10-phenanthroline),bipy(bipy=2,2′-bipyridine),bpa(bpa=bis(4-pyridyl)amine),and zinc and cobalt chlorides at 160℃.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses,and single-crystal X-ray diffrac-tion analyses.Single-crystal X-ray diffraction analyses revealed that three compounds crystallize in the orthorhom-bic system Pnna(1 and 2)or P21212(3)space groups.All compounds exhibit 3D frameworks.The catalytic perfor-mances in the Henry reaction of these compounds were investigated.Compound 3 exhibited an effective catalytic activity in the Henry reaction at 70℃.CCDC:2339391,1;2339392,2;2339393,3.
文摘Three zinc(Ⅱ),cobalt(Ⅱ),and nickel(Ⅱ)coordination polymers,namely[Zn(μ^(3-)cpna)(μ-dpea)_(0.5)]_(n)(1),[Co(μ^(3-)cpna)(μ-dpey)_(0.5)]_(n)(2),and[Ni(μ^(3-)cpna)(μ-dpey)_(0.5)(H_(2)O)]_(n)(3),have been constructed hydrothermally using H_(2)cpna(5-(4-carboxyphenoxy)nicotinic acid),dpea(1,2-di(4-pyridyl)ethane),dpey(1,2-di(4-pyridyl)ethylene),and zinc,cobalt,and nickel chlorides at 160℃.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses,and single-crystal X-ray diffraction analyses.Single-crystal X-ray diffraction analyses revealed that three compounds crystallize in the triclinic system,space group P1.Compounds 1-3 show 2D layer structures.The catalytic activities in the Knoevenagel condensation reaction of these compounds were investigated.Compounds 1 and 2 exhibit effective catalytic activities in the Knoevenagel condensa-tion reaction at room temperature.For this reaction,various parameters were optimized,followed by the investiga-tion of the substrate scope.CCDC:2335676,1;2335677,2;2335678,3.
基金Fiscal Year 2023-2024 High-Level and Growth Research and Development Subsidy for supporting the research and development activities for small and medium-size enterprise(SMEs),which is administered by Chiba Industry Advancement Center(Grant No.2066 and 2027)。
文摘This paper is aimed to present a clean,inexpensive and sustainable method to synthesize high purity lithium sulfide(Li_(2)S)powder through hydrogen reduction of lithium sulfate(Li_(2)SO_(4)).A three-step reduction process has been successfully developed to synthesize well-crystallized and single-phase Li_(2)S powder by investigating the melting,sintering and reduction behavior of the mixtures of Li_(2)SO_(4)-Li_(2)S.High purity alumina was found to be the most suitable crucible material for producing high purity Li_(2)S,because it was not attacked by the Li_(2)SO_(4)-Li_(2)S melt during heating,as compared with other materials,such as carbon,mullite,quartz,boron nitride and stainless steel.The use of synthesized LizS resulted in higher purity and substantially higher room temperature ionic conductivity(2.77 mS·cm^(-1))for the argyrodite sulfide electrolyte Li_(6)PS_(5)Cl than commercial Li_(2)S(1.12 mS·cm^(-1)).This novel method offers a great opportunity to produce battery grade Li_(2)S for sulfide solid electrolyte applications.
基金Project(22178392)supported by the National Natural Science Foundation of China。
文摘Preparation of high purity ruthenium nitrosyl nitrate using spent Ru-Zn/ZrO_(2)catalyst was studied,including melting and leaching to obtain potassium ruthenate solution,reduction,dissolving,concentrating and drying to obtain ruthenium trichloride,nitrosation and hydrolysis to obtain ruthenium nitrosyl hydroxide,removing of K^(+)and Cl^(-),and neutralization with nitric acid.The effects of temperature,concentration,time and pH on the yield and purity of intermediates and final product were studied,and the optimum process conditions were obtained.The yield of ruthenium nitrosyl nitrate is 92%,the content of ruthenium in high purity product is 32.16%,and the content of Cl^(-)and K^(+)are much less than 0.005%.The reaction kinetics of ruthenium nitrosyl chloride to ruthenium nitrosyl hydroxide was studied.The reaction orders of Ru(NO)Cl_(3)at 40,55 and 70℃are 0.39,0.37 and 0.39,respectively,while those of KOH are 0.16,0.15 and 0.17,respectively.The activation energy is-2.33 k J/mol.
基金Project(50234010) supported by the National Natural Science Foundation of China
文摘A small molecular organic depressor glycerine-xanthate was synthesized. The effect of glycerine-xanthate on the flotation of sulfide minerals was investigated based on a function of pH value and concentration of glycerine-xanthate through flotation experiments in the presence and absence of Cu^2＋. The results show that glycerinee-xanthate has a strong dressing effect on marmatite at pH〉6 and on arsenopyrite in weak acid and base conditions with butyl-xanthate as collector. In the presence of glycerine -xanthate, marmatite is activated by addition of Cu^2＋, but arsenopyrite cannot be activated and remains unfloatable. So the selective separation can be achieved for two minerals. The depression of glycerine-xanthate on sulfide minerals was discussed based on the radical electronegative calculation and the theory of HSAB. Infrared spectrum shows that there are some -OH and-CSS-in glycedne-xanthate molecule, which competes with butyl-xanthate on the mineral surface. As a result of many hydrophilic groups in glycerine-xanthate, the surfaces of marmatite and arsenopyrite become hydrophilic, thus the flotation of marmatite and arsenopyrite is depressed. The collector is adsorbed preferentially on the surface of marmatite and it shows a better floatability in the presence of Cu^2＋, whereas, the surface of arsenopyrite absorbs glycerine-xanthate and the flotation of arsenopyrite is depressed by glycerine-xanthate.
基金Projects(51674075,51774079)supported by the National Natural Science Foundation of ChinaProject(2018YFC1901903)supported by the National Key R&D Program of ChinaProject(N182508026)supported by the Fundamental Research Funds for the Central Universities of China。
文摘The crystal structure,formation kinetics and micro-morphology of CaO·SiO2 during high-temperature sintering process were studied in low-calcium system by XRD,FT-IR,Raman and SEM-EDS methods.When the molar ratio of CaCO3 to SiO2 is 1.0,β-2CaO·SiO2 forms firstly during the heating process,and then CaO·SiO2 is generated by the transformation reaction of pre-formed 2CaO·SiO2 with SiO2.3CaO·SiO2 and 3CaO·2SiO2 do not form either in the heating or sintering process.Rising the sintering temperature and prolonging the holding time promote the phase transition of 2CaO·SiO2 to CaO·SiO2,resulting in the sintered products a small blue shift and broadening in Raman spectra.The content of CS can reach 97.4%when sintered at 1400℃ for 1 h.The formation kinetics of CaO·SiO2 follows the second-order chemical reaction model,and the corresponding apparent activation energy and pre-exponential factor are 505.82 kJ/mol and 2.16×10^14 s^−1 respectively.
基金Project (2003AA305820) supported by the National High-Tech Research and Development Program of ChinaProject(2006) supported by the Postdoctoral Foundation of Central South University, China
文摘Cu-Cr-O nanocomposites that can be used as additives for the catalytic combustion of AP(ammonium perchlorate)-based solid-state propellants were synthesized via a citric acid(CA) complexing approach. Techniques of TG-DTA, XRD as well as TEM were employed to characterize the thermal decomposition procedure, crystal phase, micro-structural morphologies and grain size of the as-synthesized materials respectively. The results show that well-crystallized Cu-Cr-O nanocomposites can be produced after the CA-Cu-Cr precursors are calcined at 500 ℃ for 3 h. Phase composition of the as-obtained Cu-Cr-O nanocomposites depends on the molar ratio of Cu to Cr in the starting reactants. Addition of the as-synthesized Cu-Cr-O nanocomposites as catalysts enhances the burning rate as well as lowers the pressure exponent of the AP-based solid-state propellants considerably. Noticeably, catalyst with a CuCr molar ratio of 0.7 exhibits promising catalytic activity with high burning rate and low pressure exponent at all pressures, due to the effective phase interaction between the spinel CuCr2O4 and delafossite CuCrO2 contained in the as-synthesized Cu-Cr-O nanocomposites.
基金Project(2008G025-C) supported by the Ministry of Railway of ChinaProject(50708114) supported by the National Natural Science Foundation of China
文摘For the sake of understanding the deterioration behavior of concrete in actual railway tunnel structures subjected to aggressive sulfate medium in practice,detailed field investigations and tested analysis on sprayed concrete linings of approximately 40-year-old railway tunnels in environments containing sulfate ion were carried out,respectively.The results show that the deterioration of concretes in the investigated area is serious,which involves complicated physicochemical process between the sulfate salt and concrete.Among them,the secondary sulfateminerals such as gypsum formation under very high concentration sulfate ion condition by accumulating and evaporation process dominate,followed by the crystallization of sulfate salt and formation of thaumasite.
文摘Simultaneous equilibrium was applied to the thermodynamic analysis and calculation of Bi（Ⅲ）-X（Cl-, NO-3）-H2O systems, based on which the diagrams of the logarithm of equilibrium concentration of Bi（Ⅲ） of series precipitation vs pH value of these two systems at 25 ℃ were obtained, and the pH ranges of the stable zones of various precipitations were analyzed and determined. In Bi（Ⅲ）-Cl--H2O system, the variations of c0(Bi3+) and （c0（Cl-）） have little effect on the equilibria of Bi（OH）3-solution and BiOOH-solution, but has great influence on the （equilibrium） of BiOCl-solution. However, in Bi（Ⅲ）-NO-3-H2O system, the variations of c0(Bi3+) and c0（NO-3） have little effect on equilibria of Bi（OH）3-solution, BiOOH-solution and Bi2O3-solution. When pH value is high, Bi2O3 is the thermodynamic stable phase, its stable zone is the widest, almost including the stable zones of BiOCl or （BiONO3,） （Bi（OH）3） and BiOOH. Bi（OH）3 cannot be obtained from Bi（Ⅲ）-Cl--H2O system, even strong alkaline media. Bi2O3 can be obtained from the solution directly, and highly pure BiOCl or BiONO3 can also be obtained through strictly controlling pH value.
