To realize the comprehensive utilization of ludwigite ore,an integrated and efficient route for the boron and iron separation was proposed in this work,which via soda-ash roasting under CO–CO_(2)–N_(2) atmosphere fo...To realize the comprehensive utilization of ludwigite ore,an integrated and efficient route for the boron and iron separation was proposed in this work,which via soda-ash roasting under CO–CO_(2)–N_(2) atmosphere followed by grind-leaching,magnetic separation,and CO_(2) carbonation.The effects of roasting temperature,roasting time,CO/(CO+CO_(2))composition,and Na_(2)CO_(3) dosage on the boron and iron separation indices were primarily investigated.Under the optimized conditions of the roasting temperature of 850℃,roasting time of 60 min,soda ash dosage of 20 wt%,and CO/(CO+CO_(2)) of 10 vol%,92%of boron was leached during wet grinding,and 88.6%of iron was recovered during the magnetic separation and magnetic concentrate with a total iron content of 61.51 wt%.Raman spectra and^(11)B NMR results indicated that boron exists asB(OH)_(4)^(-) in the leachate,from which high-purity borax pentahydrate could be prepared by CO_(2) carbonation.展开更多
In this study,antimony production from a stibnite concentrate(Sb2S3)was performed in one step using a molten salt electrolysis method and borax as an electrolyte.Electrochemical reduction of the stibnite concentrate w...In this study,antimony production from a stibnite concentrate(Sb2S3)was performed in one step using a molten salt electrolysis method and borax as an electrolyte.Electrochemical reduction of the stibnite concentrate was performed at 800℃under galvanostatic conditions and explained in detail by the reactions and intermediate compounds formed in the borax.The effects of current density(100 800 mA cm^-2)and electrolysis time(10 40 min)on cathodic current efficiency and antimony yields were systematically investigated.During the highest current efficiency,which was obtained at 600 mA cm^-2,direct metal production was possible with 62%cathodic current efficiency and approximately 6 kWh/kg energy consumption.At the end of the 40-min electrolysis duration at 600 mA cm^-2 current density,antimony reduction reached 30.7 g and 99%of the antimony fed to the cell was obtained as metal.展开更多
In this study,for the first time,direct copper production from copper sulfide was carried out via direct electrochemical reduction method using inexpensive and stable molten borax electrolyte.The effects of current de...In this study,for the first time,direct copper production from copper sulfide was carried out via direct electrochemical reduction method using inexpensive and stable molten borax electrolyte.The effects of current density(100–800 mA/cm^2)and electrolysis time(15–90 min)on both the cathodic current efficiency and copper yield were systematically investigated in consideration of possible electrochemical/chemical reactions at 1200℃.The copper production yield reached 98.09%after 90 min of electrolysis at a current density of 600 mA/cm^2.Direct metal production was shown to be possible with 6 kWh/kg energy consumption at a 600 mA/cm2 current density,at which the highest current efficiency(41%)was obtained.The suggested method can also be applied to metal/alloy production from single-and mixed-metal sulfides coming from primary production and precipitated sulfides,which are produced in the mining and metallurgical industries during treatment of process solutions or wastewaters.展开更多
The effect of the borax content and magnesia to phosphate ratio（M/P） on the hydration properties of the magnesium potassium phosphate cement（MKPC） with large volume of fly ash was investigated, and a five-hydratio...The effect of the borax content and magnesia to phosphate ratio（M/P） on the hydration properties of the magnesium potassium phosphate cement（MKPC） with large volume of fly ash was investigated, and a five-hydration-stage for MKPCs was proposed. The results show that MKPC sets rapidly with less than 8% of borax, which is unfavorable to the application of MKPC on construction. Adding more than 8%（including 8%） of borax results in a secondary hydration peak for MKPC, in which the process of hydration can be divided into five stages, namely, pre-induction period, induction period, acceleration period, deceleration period and stable period. M/P ratios could not change the multi-step reactive stages but higher M/P ratios could accelerate the hydration. Borax tends to impact the formation of Mg-containing hydrated products.展开更多
The corrosion of stainless steel was experimentally investigated and analyzed to improve the service-life of the crucible and fixture clamps. Through the experiment, stainless steel was found to satisfy the crucible a...The corrosion of stainless steel was experimentally investigated and analyzed to improve the service-life of the crucible and fixture clamps. Through the experiment, stainless steel was found to satisfy the crucible and fixture clamps materials. As the chromium element mass percentage of the stainless steel increased, the corrosion decreased rapidly at first and then slowly increased. With the corrosion time prolonging, the corrosion growth rate is generally a downward trend. With Chromium 20%, the corrosive were the least. With Nickel element mass percentage increased, the corrosion increased rapidly at first and then decreased rapidly, flatten at the last. It was special that the corrosion had little relationship with the Chromium and Nickel mass percentage when the Nickel percentage is more than 35%. The most remarkable corrosion is corresponding with the Nickel element 12%, the least corrosion with Nickel element 80%. So Nickel element 35% is the most optional.展开更多
Vanadium pentoxide, borax, boron carbide and sodium fluoride were used to grow vanadium carbide coating on surface of Crl2 steel at 950℃ by TD process. The coating of vanadium carbide （VC） extended the serve-life p...Vanadium pentoxide, borax, boron carbide and sodium fluoride were used to grow vanadium carbide coating on surface of Crl2 steel at 950℃ by TD process. The coating of vanadium carbide （VC） extended the serve-life period of Crl2 steel as punching die. Kinetics of vanadium carbide coating growth was brought forward and verified by comparison of the mathematical model with the experimental results. The thickness of coating was illustrated by SEM. The chemical constituent of coating and remnants were tested by X-ray diffraction （XRD） and X-ray energy dispersive spectroscopy （EDS）. To increase the thickness, rare earth silicon powder （FeSiRe23） was added to the borax salt bath. The analysis of XRD revealed that FeSiRe23 increased the depth of vanadium car-bide coating as reducing agent and catalysis.展开更多
The authors investigated lacustrine chemical sediments on terrace-I of DongCo-a salt lake in the interior of the northern Tibetan Plateau and firstly discovered borax and acomplete sedimentary section with five pure m...The authors investigated lacustrine chemical sediments on terrace-I of DongCo-a salt lake in the interior of the northern Tibetan Plateau and firstly discovered borax and acomplete sedimentary section with five pure mirabilite beds. According to the sedimentarycharacteristics of rhythmic layering, palaeotemperatures for the formation of the cold-phasemineral-mirabilite-at the profiles and ^(14)C dating, the authors applied the theory and method ofcomparative salinology in the study of the history of the palaeoclimate and palaeoenvironment ofDong Co in the early and middle Holocene and drew the conclusion that the salt lake had experiencedthe following climatic evolution: the warm and moist stage (>8470 a HP and possibly to 10500 aHP)->cold and dry stage (8470-8170 a BP)->warm and moist stage (8170-7590 a BP)->stage of repeatedclimatic oscillations (7590-7400 a BP, alternation of three dry oscillations and three moistoscillations in a generally cold climatic background)->cold and dry stage (7400-6940 a BP)->warm andmoist stage (6940-6620 a BP)->cold and dry stage (6620-6410 a BP)->warm and moist stage (after 6410a HP).展开更多
This paper investigates the effect of rare earth elements on the kinetic process, microstructure and mechanical properties of vanadization in borax bath. The results show that addition of rare earth elements to vanadi...This paper investigates the effect of rare earth elements on the kinetic process, microstructure and mechanical properties of vanadization in borax bath. The results show that addition of rare earth elements to vanadizing agent has obvious catalytic effect on the rate of vanadization, which has been enchanced by 30%. The wear and corrosion resistance of vanadium carbide layer were prompted by the addition of rare earth to the agent. Through increasing vanadium potential of the agent, activating the surface of workpieces and decreasing the activation energy of diffusion of carbon, rare earth elements accelerate the rate of vanadization process.展开更多
Small-scale gold mining is the largest anthropogenic contributor of mercury pollution on planet Earth. The miners grind gold ore together with mercury in order to recover the fine gold grains. The gold amalgam is burn...Small-scale gold mining is the largest anthropogenic contributor of mercury pollution on planet Earth. The miners grind gold ore together with mercury in order to recover the fine gold grains. The gold amalgam is burned whereby the mercury evaporates and gold is left behind. This processing extracts only a fraction of the gold in the ore and the released mercury causes serious global health and environmental problems. However, a mercury-free method described below has proved to extract up to twice as much gold without need of investment in new processing equipment and without longer processing time. The method has successfully been tested in the Philippines, Indonesia, Tanzania, Bolivia and Zimbabwe.展开更多
It has been worked with textile fabrics of Acrylic 100 % , that have as final use the Tapestry, this fabrics have been impregnated with a two products flame retardant: Commercial Retardant, which is formed by a combin...It has been worked with textile fabrics of Acrylic 100 % , that have as final use the Tapestry, this fabrics have been impregnated with a two products flame retardant: Commercial Retardant, which is formed by a combination of a resin polymeric and acid phosphoric and Borax (Na2B4O5(OH)4.8H2O) with Sodium Hexametaphosphate (Na16P14O43). These Retardants?? has the advantage of the fact that it can be applied to the substrates mixed with water in the relation 1:1, 1:2 or pure. In order to reduce the flammability, Textile fabrics are coated with flame retardants. The flame retardant capabilities, mechanical properties and structural characteristics of the textile fabrics before and after the use of these products were investigated throughout the special textile methods for inflammability and mechanical resistibility. After the use of the flame retardants the mechanical properties of the fabrics were improved or at least remained the same as compared to fabrics without any treatment. The use of Borax / Sodium Hexametaphosphate /Water results in the essential increase of combustion retardation time about 2 minutes as compared with 8 seconds for untreated fabrics.展开更多
In this extensive investigation,the impact of borax decahydrate as a fuel additive in a diesel single-cylinder engine was rigorously examined.Borax decahydrate was introduced at concentrations of 5,15,25 and 35 g in 5...In this extensive investigation,the impact of borax decahydrate as a fuel additive in a diesel single-cylinder engine was rigorously examined.Borax decahydrate was introduced at concentrations of 5,15,25 and 35 g in 500 ml of biodiesel,forming five unique fuel mixtures with conventional diesel:90%diesel+10%spirulina biodiesel(SB10),SB10+1 g borax decahydrate(SB10B1),SB10+3 g borax decahydrate(SB10B3),SB10+5 g borax decahydrate(SB10B5)and SB10+7 g borax decahydrate(SB10B7).The investigation encompassed four diverse loading conditions and yielded insightful findings.Notably,at full load,SB10B3 exhibited a higher cylinder peak pressure than diesel,reaching 69.25 bar.Heat release rate profiles demonstrated superior efficiency for SB10 at 50%load,with a cumulative heat release rate of 950 J/°CA,which is lower than the 1050 J/°CA of diesel.Knock intensity(KI)evaluations revealed that,although SB10 and SB10B1 exhibited higher KI than diesel at full load due to elevated peak pressure,SB10B7 showed no knocking across all loads,indicative of reduced in-cylinder combustion.This meticulous numerical analysis emphasizes the potential of borax decahydrate as a catalyst and enhancer,providing valuable insights into the combustion dynamics of these alternative fuel blends and their viability for sustainable and efficient engine performance.In summary,out of all the blends,SB10B3 could be a potential diesel fuel replacement fuel for compression-ignition engines.展开更多
Based on the inhibition effect on the respiratory chain activity of microorganisms by toxicants, an electrochemical method has been developed to measure the current variation of a mediator in the presence of microorga...Based on the inhibition effect on the respiratory chain activity of microorganisms by toxicants, an electrochemical method has been developed to measure the current variation of a mediator in the presence of microorganisms contacted with a toxicant. Microelectrode arrays were adopted in this study, which can accelerate the mass transfer rate of an anaiyte to the electrode and also increase the total current signal, resulting in an improvement in detection sensitivity. We selected Escherichia coli as the testee and the standard glucose- glutamic acid as an exogenous material. Under oxygen restriction, the experiments in the presence of toxicant were performed at optimum conditions （solution pH 7.0, 37℃ and reaction for 3 hr）. The resulting solution was then separated from the suspended microorganisms and was measured by an electrochemical method, using ferricyanide as a mediator. The current signal obtained represents the reoxidation of ferrocyanide, which was transformed to inhibiting efficiency, IC50, as a quantitative measure of toxicity. The IC50 values measured were 410, 570 and 830 mg/L for sodium nitrite, borax and aluminum potassium sulfate, respectively. The results show that the toxicity sequence for these three food additives is consistent with the value reported by other methods. Furthermore, the order of damage degree to the microorganism was also observed to be： sodium nitrite 〉 borax 〉 aluminum potassium sulfate 〉 blank, according to the atomic force microscopy images of E. coli after being incubated for 3 hr with the toxic compound in buffer solutions. The electrochemical method is expected to be a sensitive and simple alternative to toxicity screening for chemical food additives.展开更多
基金financially supported by the National Key Research and Development Program of China(No.2020YFC1909803)the Basic Science Center Project for the National Natural Science Foundation of China(No.72088101)the Graduate Research and Innovative Project of Central South University(No.506021739)。
文摘To realize the comprehensive utilization of ludwigite ore,an integrated and efficient route for the boron and iron separation was proposed in this work,which via soda-ash roasting under CO–CO_(2)–N_(2) atmosphere followed by grind-leaching,magnetic separation,and CO_(2) carbonation.The effects of roasting temperature,roasting time,CO/(CO+CO_(2))composition,and Na_(2)CO_(3) dosage on the boron and iron separation indices were primarily investigated.Under the optimized conditions of the roasting temperature of 850℃,roasting time of 60 min,soda ash dosage of 20 wt%,and CO/(CO+CO_(2)) of 10 vol%,92%of boron was leached during wet grinding,and 88.6%of iron was recovered during the magnetic separation and magnetic concentrate with a total iron content of 61.51 wt%.Raman spectra and^(11)B NMR results indicated that boron exists asB(OH)_(4)^(-) in the leachate,from which high-purity borax pentahydrate could be prepared by CO_(2) carbonation.
文摘In this study,antimony production from a stibnite concentrate(Sb2S3)was performed in one step using a molten salt electrolysis method and borax as an electrolyte.Electrochemical reduction of the stibnite concentrate was performed at 800℃under galvanostatic conditions and explained in detail by the reactions and intermediate compounds formed in the borax.The effects of current density(100 800 mA cm^-2)and electrolysis time(10 40 min)on cathodic current efficiency and antimony yields were systematically investigated.During the highest current efficiency,which was obtained at 600 mA cm^-2,direct metal production was possible with 62%cathodic current efficiency and approximately 6 kWh/kg energy consumption.At the end of the 40-min electrolysis duration at 600 mA cm^-2 current density,antimony reduction reached 30.7 g and 99%of the antimony fed to the cell was obtained as metal.
文摘In this study,for the first time,direct copper production from copper sulfide was carried out via direct electrochemical reduction method using inexpensive and stable molten borax electrolyte.The effects of current density(100–800 mA/cm^2)and electrolysis time(15–90 min)on both the cathodic current efficiency and copper yield were systematically investigated in consideration of possible electrochemical/chemical reactions at 1200℃.The copper production yield reached 98.09%after 90 min of electrolysis at a current density of 600 mA/cm^2.Direct metal production was shown to be possible with 6 kWh/kg energy consumption at a 600 mA/cm2 current density,at which the highest current efficiency(41%)was obtained.The suggested method can also be applied to metal/alloy production from single-and mixed-metal sulfides coming from primary production and precipitated sulfides,which are produced in the mining and metallurgical industries during treatment of process solutions or wastewaters.
基金Funded by the National Natural Science Foundation of China(No.51472168)Natural Scientific Foundation of Liaoning Province(No.201602646)Open Fund from Liaoning Key Laboratory of Advanced Processing Technology for Metal Materials,Shenyang Ligong University,the Postdoctoral Research Foundation of Shenyang Ligong University
文摘The effect of the borax content and magnesia to phosphate ratio（M/P） on the hydration properties of the magnesium potassium phosphate cement（MKPC） with large volume of fly ash was investigated, and a five-hydration-stage for MKPCs was proposed. The results show that MKPC sets rapidly with less than 8% of borax, which is unfavorable to the application of MKPC on construction. Adding more than 8%（including 8%） of borax results in a secondary hydration peak for MKPC, in which the process of hydration can be divided into five stages, namely, pre-induction period, induction period, acceleration period, deceleration period and stable period. M/P ratios could not change the multi-step reactive stages but higher M/P ratios could accelerate the hydration. Borax tends to impact the formation of Mg-containing hydrated products.
基金Funded by the National Natural Science Foundation of China (No.50675165)the National Key Technology R&D Program (No.2006BAF02A29)
文摘The corrosion of stainless steel was experimentally investigated and analyzed to improve the service-life of the crucible and fixture clamps. Through the experiment, stainless steel was found to satisfy the crucible and fixture clamps materials. As the chromium element mass percentage of the stainless steel increased, the corrosion decreased rapidly at first and then slowly increased. With the corrosion time prolonging, the corrosion growth rate is generally a downward trend. With Chromium 20%, the corrosive were the least. With Nickel element mass percentage increased, the corrosion increased rapidly at first and then decreased rapidly, flatten at the last. It was special that the corrosion had little relationship with the Chromium and Nickel mass percentage when the Nickel percentage is more than 35%. The most remarkable corrosion is corresponding with the Nickel element 12%, the least corrosion with Nickel element 80%. So Nickel element 35% is the most optional.
基金Funded by the National Natural Science Foundation of China (No.50675165)the National Key Technology R&D Program (No.2006BAF02A29)
文摘Vanadium pentoxide, borax, boron carbide and sodium fluoride were used to grow vanadium carbide coating on surface of Crl2 steel at 950℃ by TD process. The coating of vanadium carbide （VC） extended the serve-life period of Crl2 steel as punching die. Kinetics of vanadium carbide coating growth was brought forward and verified by comparison of the mathematical model with the experimental results. The thickness of coating was illustrated by SEM. The chemical constituent of coating and remnants were tested by X-ray diffraction （XRD） and X-ray energy dispersive spectroscopy （EDS）. To increase the thickness, rare earth silicon powder （FeSiRe23） was added to the borax salt bath. The analysis of XRD revealed that FeSiRe23 increased the depth of vanadium car-bide coating as reducing agent and catalysis.
基金National Natural Science Foundation grant 49833010.
文摘The authors investigated lacustrine chemical sediments on terrace-I of DongCo-a salt lake in the interior of the northern Tibetan Plateau and firstly discovered borax and acomplete sedimentary section with five pure mirabilite beds. According to the sedimentarycharacteristics of rhythmic layering, palaeotemperatures for the formation of the cold-phasemineral-mirabilite-at the profiles and ^(14)C dating, the authors applied the theory and method ofcomparative salinology in the study of the history of the palaeoclimate and palaeoenvironment ofDong Co in the early and middle Holocene and drew the conclusion that the salt lake had experiencedthe following climatic evolution: the warm and moist stage (>8470 a HP and possibly to 10500 aHP)->cold and dry stage (8470-8170 a BP)->warm and moist stage (8170-7590 a BP)->stage of repeatedclimatic oscillations (7590-7400 a BP, alternation of three dry oscillations and three moistoscillations in a generally cold climatic background)->cold and dry stage (7400-6940 a BP)->warm andmoist stage (6940-6620 a BP)->cold and dry stage (6620-6410 a BP)->warm and moist stage (after 6410a HP).
文摘This paper investigates the effect of rare earth elements on the kinetic process, microstructure and mechanical properties of vanadization in borax bath. The results show that addition of rare earth elements to vanadizing agent has obvious catalytic effect on the rate of vanadization, which has been enchanced by 30%. The wear and corrosion resistance of vanadium carbide layer were prompted by the addition of rare earth to the agent. Through increasing vanadium potential of the agent, activating the surface of workpieces and decreasing the activation energy of diffusion of carbon, rare earth elements accelerate the rate of vanadization process.
文摘Small-scale gold mining is the largest anthropogenic contributor of mercury pollution on planet Earth. The miners grind gold ore together with mercury in order to recover the fine gold grains. The gold amalgam is burned whereby the mercury evaporates and gold is left behind. This processing extracts only a fraction of the gold in the ore and the released mercury causes serious global health and environmental problems. However, a mercury-free method described below has proved to extract up to twice as much gold without need of investment in new processing equipment and without longer processing time. The method has successfully been tested in the Philippines, Indonesia, Tanzania, Bolivia and Zimbabwe.
文摘It has been worked with textile fabrics of Acrylic 100 % , that have as final use the Tapestry, this fabrics have been impregnated with a two products flame retardant: Commercial Retardant, which is formed by a combination of a resin polymeric and acid phosphoric and Borax (Na2B4O5(OH)4.8H2O) with Sodium Hexametaphosphate (Na16P14O43). These Retardants?? has the advantage of the fact that it can be applied to the substrates mixed with water in the relation 1:1, 1:2 or pure. In order to reduce the flammability, Textile fabrics are coated with flame retardants. The flame retardant capabilities, mechanical properties and structural characteristics of the textile fabrics before and after the use of these products were investigated throughout the special textile methods for inflammability and mechanical resistibility. After the use of the flame retardants the mechanical properties of the fabrics were improved or at least remained the same as compared to fabrics without any treatment. The use of Borax / Sodium Hexametaphosphate /Water results in the essential increase of combustion retardation time about 2 minutes as compared with 8 seconds for untreated fabrics.
文摘In this extensive investigation,the impact of borax decahydrate as a fuel additive in a diesel single-cylinder engine was rigorously examined.Borax decahydrate was introduced at concentrations of 5,15,25 and 35 g in 500 ml of biodiesel,forming five unique fuel mixtures with conventional diesel:90%diesel+10%spirulina biodiesel(SB10),SB10+1 g borax decahydrate(SB10B1),SB10+3 g borax decahydrate(SB10B3),SB10+5 g borax decahydrate(SB10B5)and SB10+7 g borax decahydrate(SB10B7).The investigation encompassed four diverse loading conditions and yielded insightful findings.Notably,at full load,SB10B3 exhibited a higher cylinder peak pressure than diesel,reaching 69.25 bar.Heat release rate profiles demonstrated superior efficiency for SB10 at 50%load,with a cumulative heat release rate of 950 J/°CA,which is lower than the 1050 J/°CA of diesel.Knock intensity(KI)evaluations revealed that,although SB10 and SB10B1 exhibited higher KI than diesel at full load due to elevated peak pressure,SB10B7 showed no knocking across all loads,indicative of reduced in-cylinder combustion.This meticulous numerical analysis emphasizes the potential of borax decahydrate as a catalyst and enhancer,providing valuable insights into the combustion dynamics of these alternative fuel blends and their viability for sustainable and efficient engine performance.In summary,out of all the blends,SB10B3 could be a potential diesel fuel replacement fuel for compression-ignition engines.
基金supported by the National Natural Science Foundation of China (No. 20820102037,20935003)the National Basic Research Program (973) of China (No.2010CB933603)
文摘Based on the inhibition effect on the respiratory chain activity of microorganisms by toxicants, an electrochemical method has been developed to measure the current variation of a mediator in the presence of microorganisms contacted with a toxicant. Microelectrode arrays were adopted in this study, which can accelerate the mass transfer rate of an anaiyte to the electrode and also increase the total current signal, resulting in an improvement in detection sensitivity. We selected Escherichia coli as the testee and the standard glucose- glutamic acid as an exogenous material. Under oxygen restriction, the experiments in the presence of toxicant were performed at optimum conditions （solution pH 7.0, 37℃ and reaction for 3 hr）. The resulting solution was then separated from the suspended microorganisms and was measured by an electrochemical method, using ferricyanide as a mediator. The current signal obtained represents the reoxidation of ferrocyanide, which was transformed to inhibiting efficiency, IC50, as a quantitative measure of toxicity. The IC50 values measured were 410, 570 and 830 mg/L for sodium nitrite, borax and aluminum potassium sulfate, respectively. The results show that the toxicity sequence for these three food additives is consistent with the value reported by other methods. Furthermore, the order of damage degree to the microorganism was also observed to be： sodium nitrite 〉 borax 〉 aluminum potassium sulfate 〉 blank, according to the atomic force microscopy images of E. coli after being incubated for 3 hr with the toxic compound in buffer solutions. The electrochemical method is expected to be a sensitive and simple alternative to toxicity screening for chemical food additives.
