The equilibrium between the gas-liquid phases of the system of HCl-RECl3-H2O was analyzed,and the possibility of hydrochloric acid recovery from rare earth chloride solutions by vacuum membrane distillation （VMD） wa...The equilibrium between the gas-liquid phases of the system of HCl-RECl3-H2O was analyzed,and the possibility of hydrochloric acid recovery from rare earth chloride solutions by vacuum membrane distillation （VMD） was experimentally studied in the laboratory scale. The results indicate that increasing initial concentrations of both hydrochloric acid and rare earth increase recovery ratio of hydrochloric acid,and recovery ratio of 80% can be achieved. Concentrated multiple of rare earth shows great influence on recovery ratio,leakage ratio of rare earth is less than 2% generally,and pure acid can be acquired in the permeate side. The two factors,namely flux and leakage ratio,which may determine the future use of VMD were also discussed.展开更多
Background:A ruptured hepatocellular carcinoma(HCC)is often fatal.In addition to surgery and transarterial embo?lization,radiofrequency ablation(RFA)might be another option for treating a ruptured HCC.Unfortunately,co...Background:A ruptured hepatocellular carcinoma(HCC)is often fatal.In addition to surgery and transarterial embo?lization,radiofrequency ablation(RFA)might be another option for treating a ruptured HCC.Unfortunately,conven?tional RFA has a limited ablation zone;as such,it is rarely used to treat ruptured tumors.Case presentation:This case was a 60?year?old man who had a large,ruptured HCC in which hydrochloric acid(HCl)?enhanced RFA successfully controlled the bleeding and made the tumor completely necrotic.Conclusion:Considering the effectiveness of HCl?enhanced RFA in achieving hemostasis and tumor ablation,it might be a new option for treating large,ruptured HCCs.展开更多
BACKGROUND To report on the use of percutaneous hydrochloric acid(HCl) enhanced radiofrequency ablation(HRFA) for the treatment of large(maximum diameter ≥5 cm) hepatocellular carcinoma(HCC) in the caudate lobe.CASE ...BACKGROUND To report on the use of percutaneous hydrochloric acid(HCl) enhanced radiofrequency ablation(HRFA) for the treatment of large(maximum diameter ≥5 cm) hepatocellular carcinoma(HCC) in the caudate lobe.CASE SUMMARY Between August 2013 and June 2016, three patients with a large HCC(maximum diameter: 5.0, 5.7, and 8.1 cm) in the caudate lobe were treated by transarterial chemoembolization followed by computer tomography(CT) guided RFA using a monopolar perfusion RF electrode, which was enhanced by local infusion of 10%HCl at 0.2 mL/min(total volume, 3 to 12 mL). The output power of HRFA reached 100 W, and the average ablation time was 39 min(range, 15 to 60 min).Two patients each underwent one session of HRFA and one patient two sessions.After treatment, CT/magnetic resonance imaging showed that all the three lesions were completely ablated. There was no major complication. Two patients had asymptomatic bile duct dilatation. One patient died of tongue cancer 24 mo after ablation. The remaining two patients were alive and no area of enhancement is detected in the caudate lobe at 28 and 60 mo after ablation, respectively.CONCLUSION Percutaneous CT-guided HRFA is safe and efficacious in treating large HCC in the caudate lobe.展开更多
The effect of hydrochloric acid concentration on stainless steel (Fe6956) at temperature range 303 - 333 ± 1 K has been studied using weight loss, thermometric and electrochemical polarization techniques. The cor...The effect of hydrochloric acid concentration on stainless steel (Fe6956) at temperature range 303 - 333 ± 1 K has been studied using weight loss, thermometric and electrochemical polarization techniques. The corrosion rate of the stainless steel was found to be dependent on both temperature variation and acid concentration. The potentiostatic study showed that the active passive transition depends strongly on acid concentration while the weight loss measurements revealed that 2 M HCl at temperature 333 K had an appreciable corrosion rate which corresponds to 14.04 × 10﹣3 reaction number (RN) got from thermometric monitoring. Arrhenius equation and transition state theory were used to calculate kinetic and thermodynamic parameter such as Ea, ΔH* and ΔS*. Results obtained showed that corrosion reaction of Fe6956 in HCl is spontaneous and there is good agreement between the data got from the techniques employed.展开更多
The effects of La 3+ ion and chelate reagent 8 hydroxyquinoline on the corrosion rate of zinc in hydrochloric acid were investigated by using weight loss method and electrochemical method. It is found that in a specif...The effects of La 3+ ion and chelate reagent 8 hydroxyquinoline on the corrosion rate of zinc in hydrochloric acid were investigated by using weight loss method and electrochemical method. It is found that in a specific concentration range of La 3+ ion and 8 hydroxyquinoline, the obvious corrosion inhibition synergism is obtained. The mechanism of corrosion inhibition synergism was discussed on basis of adsorption theory.展开更多
This article reports the extraction of zirconium(IV) from aqueous HCl solution by tri-octyl amine(TOA),Cyanex 921,and their binary mixture using kerosene as the diluent.The efect of some parameters on the extraction o...This article reports the extraction of zirconium(IV) from aqueous HCl solution by tri-octyl amine(TOA),Cyanex 921,and their binary mixture using kerosene as the diluent.The efect of some parameters on the extraction of Zr(IV) was investigated such as equilibration time,aqueous phase acidity,extractant molarity,chloride ion concentration,nature of diluents,and temperature.The extraction of Zr(IV) was found to be 99% from 7.5 M HCl using the mixture of extractants containing 0.1 M TOA and 0.02 M Cyanex 921 in kerosene.Kerosene was found to be the efective diluent for the extraction of Zr(IV) with the binary mixture of TOA and Cyanex 921.The positive enthalpy change and positive entropy change in the binary extraction system show the endothermic process with an increase in entropy.Stripping of Zr(IV) from the loaded organic phase containing the mixture of TOA(0.1 M) and Cyanex 921(0.02 M) indicates that HNO3and Na2CO3are the best stripping agents.展开更多
The possibility of the recovery of hydrochloric acid from rare earth (RE) chloride solutions was first experimen-tally studied by batch vacuum membrane distillation (VMD). The recovery by continuous VMD was also studi...The possibility of the recovery of hydrochloric acid from rare earth (RE) chloride solutions was first experimen-tally studied by batch vacuum membrane distillation (VMD). The recovery by continuous VMD was also studied to devise methods that enabled the operation of VMD setup in a stable condition as well as to increase the membrane-operating life The results indicated that HCl separation with RE by VMD was possible, and the recovery ratio of 80% could be achieved by batch VMD. In continuous VMD, when the temperature of circular solutions, circular rate, and downstream pressure was 62-63°C, 5.4 cm/s, and 9.33 kPa, respectively, the HCl concentration in circular solutions and the processing capacity per membrane area were obtained. The mathematical results were in accordance with the experimental ones.展开更多
Vapor-liquid equilibria for water+hydrochloric acid+magnesium chloride and water+hydrochloric acid+calcium chloride systems at atmospheric pressure were measured using a Othmer-type equilibrium still. The experimental...Vapor-liquid equilibria for water+hydrochloric acid+magnesium chloride and water+hydrochloric acid+calcium chloride systems at atmospheric pressure were measured using a Othmer-type equilibrium still. The experimental data are correlated using a modified Meissner’s method. Satisfactory agreements are obtained between the experimental and the calculated results.展开更多
A novel,unsymmetrical diglycolamide,N,N'-dibutyl-N,N'-di(1-methylheptyl)-diglycolamide(DBD1MHDGA),was synthesized.The extraction of rare earth elements(REEs) from a hydrochloric acid medium with DBD1 MHDGA was...A novel,unsymmetrical diglycolamide,N,N'-dibutyl-N,N'-di(1-methylheptyl)-diglycolamide(DBD1MHDGA),was synthesized.The extraction of rare earth elements(REEs) from a hydrochloric acid medium with DBD1 MHDGA was investigated.The results of the extraction experiments indicated that the distribution ratios of RE(Ⅲ) ions increase with an increase in HC1 concentration,atomic number,and extractant concentration.The calculated thermodynamic data show that the extraction process is an exothermic reaction.The organic phase loaded rare earth ions were characterized by infrared spectroscopy.The composition of the extracted complex was determined.展开更多
The hydrochloric acid recovery from rare earth chloride solutions by continuous vacuum membrane distillation was first experimentally studied, then material balance of the process was calculated, and the equations whi...The hydrochloric acid recovery from rare earth chloride solutions by continuous vacuum membrane distillation was first experimentally studied, then material balance of the process was calculated, and the equations which mathematically stimulate the process were lastly achieved. The results indicate a given RE concentration in circular solutions means its constant HCl concentration during the continuous VMD process, furthermore, increasing RE concentration in feed solutions increases the processing capacity per membrane of the experimental set-up. When keeping constant RE concentration in feed solutions, increasing RE concentration in circular solutions decreases its HCl concentration, and HCl recovery ratio increases accordingly, however, processing capacity per membrane of the experimental set-up decreases at the same time. The mathematical results are in accordance with experimental results.展开更多
In order to amend the superficial performance of palygorskite and improve its application, the natural palygorskite(NP) was treated in the dipping and ionic exchanging experiments using 6mol/L hydrochloric acid trea...In order to amend the superficial performance of palygorskite and improve its application, the natural palygorskite(NP) was treated in the dipping and ionic exchanging experiments using 6mol/L hydrochloric acid treatment. The performance and pore structure of the treated palygorskite(TP) were investigated by means of microscope analyses, FT-IR, XRF, BET-SSA and full hole distribution analytical techniques. The results show that the hydrochloric acid treatment can make the gracile and aggregating compact crystal bundles inside palygorskite clay broken and dispersed, the roughness of microcrystalline surface increases, which not only can dissolve or remove dolomite but vary the superficial performance of palygorskite to some degree. The specific surface area and pore volume increase a lot, while the mean pore size decreases. The pore structure of TP changes remarkably compared with that of NP after 6mol/L hydrochloric acid treatment, and the relevant physicochemical performance can be improved.展开更多
Response surface methodology (RSM) and Artificial neural network (ANN) were used for the simulation and optimization of galena dissolution in hydrochloric acid. The galena ore was characterized for structure elucidati...Response surface methodology (RSM) and Artificial neural network (ANN) were used for the simulation and optimization of galena dissolution in hydrochloric acid. The galena ore was characterized for structure elucidation using FTIR, SEM and X-ray diffraction spectroscopic techniques and the results indicate that the galena ore exists mainly as lead sulphide (PbS). A feed-forward neural network model with Leverberg-Marquardt back propagating training algorithm was used to predict the response (lead yield). The leaching temperature, acid concentration, solid/liquid ratio, stirring rate and leaching time were defined as input variables, while the percentage yield of lead was labelled as output variable. The multilayer perceptron with architecture of 5-9-1 provided the best performance. All the process variables were found to have significant impact on the response with p-values of 2 of 0.991 and 1.00, respectively. A non-dominated optimal response of 85.25% yield of lead at 343.96 K leaching temperature, 3.11 M hydrochloric acid concentration, 0.021 g/ml solid/liquid ratio, 362.27 rpm stirring speed and 87.37 min leaching time was established as a viable route for reduced material and operating cost using RSM.展开更多
Corrosion of metal components constitutes a major challenge in many engineering systems, with appropriate design, proper material selection, and heat treatment as commonly used control strategies. In this study, the c...Corrosion of metal components constitutes a major challenge in many engineering systems, with appropriate design, proper material selection, and heat treatment as commonly used control strategies. In this study, the corrosion behaviour of heat-treated (annealed, normalised, hardened, and tempered) NST 37-2 steel in three concentrations (1.0, 1.5 and 2.0 M) of hydrochloric acid solution was investigated using weight loss and electrode-potential methods. Results showed that corrosion rate increased with increase in acid concentration. The decreasing order of corrosion resistance was Tempered > Annealed > Normalised > Hardened > Untreated. The surface pictures of the heat-treated and untreated samples showed uniform and pitting corrosion with the latter becoming more pronounced as concentration increased.展开更多
ASTM A182 F51 duplex stainless steel with a 50:50 ratio of austenite to ferrite microstructure is a material used in mechanical engineering.Its uses include the manufacturing of equipment and components subject to aci...ASTM A182 F51 duplex stainless steel with a 50:50 ratio of austenite to ferrite microstructure is a material used in mechanical engineering.Its uses include the manufacturing of equipment and components subject to acidification or acid stimulation for oil and gas industries.During acid stimulation or acidification,hydrochloric acid(HCl)solution with concentrations ranging from 5%to 28%(by volume)is injected into the limestone(CaCO3)and dolomite(CaCO3·MgCO3)reservoir rock to restore permeability and consequently increase oil well productivity.Therefore,it is important to use a corrosion inhibitor,such as propargyl alcohol,to prevent or inhibit the aggressive attack of HCl on duplex stainless steel.The present study evaluates the corrosion resistance of ASTM A182 F51 stainless steel using gravimetric(mass loss)and electrochemical(polarization)tests.Studies were completed with and without the addition of 500 and 1,000 mg/L propargyl alcohol in HCl solutions with concentrations of 10%and 15%(by volume)at temperatures of 25,40 and 55°C.The good protection by propargyl alcohol of duplex steel immersed in HCl is observed.展开更多
This study was carried out to investigate the interaction of oxalic acid with hydrochloric acid to attain the better performance for iron dissolution in comparison to absence of oxalic acid. The effects of oxalic acid...This study was carried out to investigate the interaction of oxalic acid with hydrochloric acid to attain the better performance for iron dissolution in comparison to absence of oxalic acid. The effects of oxalic acid on ratio of hydrochloric acid, acid concentration, ratio of liquid to solid, temperature and dissolution time are investigated for the dissolution of Fe and Ti from ilmenite to produce synthetic rutile. The DX7 software basing on an experimental design method with the central composite of response surface design is applied to specify the effects of the parameters and to optimize the leaching process. The optimum condition was determined by analysis of variance (ANOVA), indicating that the ratio of oxalic acid to hydrochloric acid for Fe dissolution and acid concentration for Ti dissolution were the most effective parameters. The results showed that the dissolution of Fe and Ti in 30% (w/w) hydrochloric acid solution was only 48.65% and 5.14%, respectively, while at the same condition and in the presence of oxalic acid with twice the ratio, these values are increased to 78.65% and 12.06%, respectively. The optimum values of parameters were as follows: oxalic acid to hydrochloric acid ratio (2:1), acid concentration (30%), ratio of liquid to solid (10), temperature (160 °C), and dissolution time (3 h). By applying the optimized parameters, Fe and Ti dissolution of 97.15% and 2.8% were predicted by the software with a desirability of 0.745. The results of leaching tests indicated that the Fe and Ti dissolution of 97.58% and 2.43%, were achieved, respectively, which are very close to the predicted value.展开更多
The influence of hydrochloric or sulphuric acid treatment on the electro-physical properties of superthin basalt fiber (STBF) made from Armenian basalt rocks was studied. Specific electric resistance for direct and al...The influence of hydrochloric or sulphuric acid treatment on the electro-physical properties of superthin basalt fiber (STBF) made from Armenian basalt rocks was studied. Specific electric resistance for direct and alternating currents, dielectric parameters of ε, and ε,, were measured. It is shown that specific resistance and dielectric parameters of super-thin basalt fiber change essentially after hydrochloric or sulphuric acid treatment. The temperature dependences of these parameters were studied, too, and their non–monotonic behavior was observed. The probable variation of mentioned STBF parameters is explained by different water absorption capacity of pores as a result of acid treatment.展开更多
文摘The equilibrium between the gas-liquid phases of the system of HCl-RECl3-H2O was analyzed,and the possibility of hydrochloric acid recovery from rare earth chloride solutions by vacuum membrane distillation （VMD） was experimentally studied in the laboratory scale. The results indicate that increasing initial concentrations of both hydrochloric acid and rare earth increase recovery ratio of hydrochloric acid,and recovery ratio of 80% can be achieved. Concentrated multiple of rare earth shows great influence on recovery ratio,leakage ratio of rare earth is less than 2% generally,and pure acid can be acquired in the permeate side. The two factors,namely flux and leakage ratio,which may determine the future use of VMD were also discussed.
基金supported by grants from the National Natural Science Foundation of China (No. 81371652)the Science and Technology Planning Project of Guangdong Province (No. 2012B031800120)
文摘Background:A ruptured hepatocellular carcinoma(HCC)is often fatal.In addition to surgery and transarterial embo?lization,radiofrequency ablation(RFA)might be another option for treating a ruptured HCC.Unfortunately,conven?tional RFA has a limited ablation zone;as such,it is rarely used to treat ruptured tumors.Case presentation:This case was a 60?year?old man who had a large,ruptured HCC in which hydrochloric acid(HCl)?enhanced RFA successfully controlled the bleeding and made the tumor completely necrotic.Conclusion:Considering the effectiveness of HCl?enhanced RFA in achieving hemostasis and tumor ablation,it might be a new option for treating large,ruptured HCCs.
基金the National Natural Science Foundation of China,No.81771955
文摘BACKGROUND To report on the use of percutaneous hydrochloric acid(HCl) enhanced radiofrequency ablation(HRFA) for the treatment of large(maximum diameter ≥5 cm) hepatocellular carcinoma(HCC) in the caudate lobe.CASE SUMMARY Between August 2013 and June 2016, three patients with a large HCC(maximum diameter: 5.0, 5.7, and 8.1 cm) in the caudate lobe were treated by transarterial chemoembolization followed by computer tomography(CT) guided RFA using a monopolar perfusion RF electrode, which was enhanced by local infusion of 10%HCl at 0.2 mL/min(total volume, 3 to 12 mL). The output power of HRFA reached 100 W, and the average ablation time was 39 min(range, 15 to 60 min).Two patients each underwent one session of HRFA and one patient two sessions.After treatment, CT/magnetic resonance imaging showed that all the three lesions were completely ablated. There was no major complication. Two patients had asymptomatic bile duct dilatation. One patient died of tongue cancer 24 mo after ablation. The remaining two patients were alive and no area of enhancement is detected in the caudate lobe at 28 and 60 mo after ablation, respectively.CONCLUSION Percutaneous CT-guided HRFA is safe and efficacious in treating large HCC in the caudate lobe.
文摘The effect of hydrochloric acid concentration on stainless steel (Fe6956) at temperature range 303 - 333 ± 1 K has been studied using weight loss, thermometric and electrochemical polarization techniques. The corrosion rate of the stainless steel was found to be dependent on both temperature variation and acid concentration. The potentiostatic study showed that the active passive transition depends strongly on acid concentration while the weight loss measurements revealed that 2 M HCl at temperature 333 K had an appreciable corrosion rate which corresponds to 14.04 × 10﹣3 reaction number (RN) got from thermometric monitoring. Arrhenius equation and transition state theory were used to calculate kinetic and thermodynamic parameter such as Ea, ΔH* and ΔS*. Results obtained showed that corrosion reaction of Fe6956 in HCl is spontaneous and there is good agreement between the data got from the techniques employed.
文摘The effects of La 3+ ion and chelate reagent 8 hydroxyquinoline on the corrosion rate of zinc in hydrochloric acid were investigated by using weight loss method and electrochemical method. It is found that in a specific concentration range of La 3+ ion and 8 hydroxyquinoline, the obvious corrosion inhibition synergism is obtained. The mechanism of corrosion inhibition synergism was discussed on basis of adsorption theory.
文摘This article reports the extraction of zirconium(IV) from aqueous HCl solution by tri-octyl amine(TOA),Cyanex 921,and their binary mixture using kerosene as the diluent.The efect of some parameters on the extraction of Zr(IV) was investigated such as equilibration time,aqueous phase acidity,extractant molarity,chloride ion concentration,nature of diluents,and temperature.The extraction of Zr(IV) was found to be 99% from 7.5 M HCl using the mixture of extractants containing 0.1 M TOA and 0.02 M Cyanex 921 in kerosene.Kerosene was found to be the efective diluent for the extraction of Zr(IV) with the binary mixture of TOA and Cyanex 921.The positive enthalpy change and positive entropy change in the binary extraction system show the endothermic process with an increase in entropy.Stripping of Zr(IV) from the loaded organic phase containing the mixture of TOA(0.1 M) and Cyanex 921(0.02 M) indicates that HNO3and Na2CO3are the best stripping agents.
文摘The possibility of the recovery of hydrochloric acid from rare earth (RE) chloride solutions was first experimen-tally studied by batch vacuum membrane distillation (VMD). The recovery by continuous VMD was also studied to devise methods that enabled the operation of VMD setup in a stable condition as well as to increase the membrane-operating life The results indicated that HCl separation with RE by VMD was possible, and the recovery ratio of 80% could be achieved by batch VMD. In continuous VMD, when the temperature of circular solutions, circular rate, and downstream pressure was 62-63°C, 5.4 cm/s, and 9.33 kPa, respectively, the HCl concentration in circular solutions and the processing capacity per membrane area were obtained. The mathematical results were in accordance with the experimental ones.
文摘Vapor-liquid equilibria for water+hydrochloric acid+magnesium chloride and water+hydrochloric acid+calcium chloride systems at atmospheric pressure were measured using a Othmer-type equilibrium still. The experimental data are correlated using a modified Meissner’s method. Satisfactory agreements are obtained between the experimental and the calculated results.
基金supported by the National Natural Science Foundation of China(Nos.21077044,21171069)
文摘A novel,unsymmetrical diglycolamide,N,N'-dibutyl-N,N'-di(1-methylheptyl)-diglycolamide(DBD1MHDGA),was synthesized.The extraction of rare earth elements(REEs) from a hydrochloric acid medium with DBD1 MHDGA was investigated.The results of the extraction experiments indicated that the distribution ratios of RE(Ⅲ) ions increase with an increase in HC1 concentration,atomic number,and extractant concentration.The calculated thermodynamic data show that the extraction process is an exothermic reaction.The organic phase loaded rare earth ions were characterized by infrared spectroscopy.The composition of the extracted complex was determined.
文摘The hydrochloric acid recovery from rare earth chloride solutions by continuous vacuum membrane distillation was first experimentally studied, then material balance of the process was calculated, and the equations which mathematically stimulate the process were lastly achieved. The results indicate a given RE concentration in circular solutions means its constant HCl concentration during the continuous VMD process, furthermore, increasing RE concentration in feed solutions increases the processing capacity per membrane of the experimental set-up. When keeping constant RE concentration in feed solutions, increasing RE concentration in circular solutions decreases its HCl concentration, and HCl recovery ratio increases accordingly, however, processing capacity per membrane of the experimental set-up decreases at the same time. The mathematical results are in accordance with experimental results.
基金Project(10200202002) supported by the National Tobacco Monopolistic Bureau of China project(40473006) supportedby the National Natural Science Foundation of China project(2006KJ010A) supported by the Natural Science Key Research Foundation ofAnhui Province
文摘In order to amend the superficial performance of palygorskite and improve its application, the natural palygorskite(NP) was treated in the dipping and ionic exchanging experiments using 6mol/L hydrochloric acid treatment. The performance and pore structure of the treated palygorskite(TP) were investigated by means of microscope analyses, FT-IR, XRF, BET-SSA and full hole distribution analytical techniques. The results show that the hydrochloric acid treatment can make the gracile and aggregating compact crystal bundles inside palygorskite clay broken and dispersed, the roughness of microcrystalline surface increases, which not only can dissolve or remove dolomite but vary the superficial performance of palygorskite to some degree. The specific surface area and pore volume increase a lot, while the mean pore size decreases. The pore structure of TP changes remarkably compared with that of NP after 6mol/L hydrochloric acid treatment, and the relevant physicochemical performance can be improved.
文摘Response surface methodology (RSM) and Artificial neural network (ANN) were used for the simulation and optimization of galena dissolution in hydrochloric acid. The galena ore was characterized for structure elucidation using FTIR, SEM and X-ray diffraction spectroscopic techniques and the results indicate that the galena ore exists mainly as lead sulphide (PbS). A feed-forward neural network model with Leverberg-Marquardt back propagating training algorithm was used to predict the response (lead yield). The leaching temperature, acid concentration, solid/liquid ratio, stirring rate and leaching time were defined as input variables, while the percentage yield of lead was labelled as output variable. The multilayer perceptron with architecture of 5-9-1 provided the best performance. All the process variables were found to have significant impact on the response with p-values of 2 of 0.991 and 1.00, respectively. A non-dominated optimal response of 85.25% yield of lead at 343.96 K leaching temperature, 3.11 M hydrochloric acid concentration, 0.021 g/ml solid/liquid ratio, 362.27 rpm stirring speed and 87.37 min leaching time was established as a viable route for reduced material and operating cost using RSM.
文摘Corrosion of metal components constitutes a major challenge in many engineering systems, with appropriate design, proper material selection, and heat treatment as commonly used control strategies. In this study, the corrosion behaviour of heat-treated (annealed, normalised, hardened, and tempered) NST 37-2 steel in three concentrations (1.0, 1.5 and 2.0 M) of hydrochloric acid solution was investigated using weight loss and electrode-potential methods. Results showed that corrosion rate increased with increase in acid concentration. The decreasing order of corrosion resistance was Tempered > Annealed > Normalised > Hardened > Untreated. The surface pictures of the heat-treated and untreated samples showed uniform and pitting corrosion with the latter becoming more pronounced as concentration increased.
文摘ASTM A182 F51 duplex stainless steel with a 50:50 ratio of austenite to ferrite microstructure is a material used in mechanical engineering.Its uses include the manufacturing of equipment and components subject to acidification or acid stimulation for oil and gas industries.During acid stimulation or acidification,hydrochloric acid(HCl)solution with concentrations ranging from 5%to 28%(by volume)is injected into the limestone(CaCO3)and dolomite(CaCO3·MgCO3)reservoir rock to restore permeability and consequently increase oil well productivity.Therefore,it is important to use a corrosion inhibitor,such as propargyl alcohol,to prevent or inhibit the aggressive attack of HCl on duplex stainless steel.The present study evaluates the corrosion resistance of ASTM A182 F51 stainless steel using gravimetric(mass loss)and electrochemical(polarization)tests.Studies were completed with and without the addition of 500 and 1,000 mg/L propargyl alcohol in HCl solutions with concentrations of 10%and 15%(by volume)at temperatures of 25,40 and 55°C.The good protection by propargyl alcohol of duplex steel immersed in HCl is observed.
文摘This study was carried out to investigate the interaction of oxalic acid with hydrochloric acid to attain the better performance for iron dissolution in comparison to absence of oxalic acid. The effects of oxalic acid on ratio of hydrochloric acid, acid concentration, ratio of liquid to solid, temperature and dissolution time are investigated for the dissolution of Fe and Ti from ilmenite to produce synthetic rutile. The DX7 software basing on an experimental design method with the central composite of response surface design is applied to specify the effects of the parameters and to optimize the leaching process. The optimum condition was determined by analysis of variance (ANOVA), indicating that the ratio of oxalic acid to hydrochloric acid for Fe dissolution and acid concentration for Ti dissolution were the most effective parameters. The results showed that the dissolution of Fe and Ti in 30% (w/w) hydrochloric acid solution was only 48.65% and 5.14%, respectively, while at the same condition and in the presence of oxalic acid with twice the ratio, these values are increased to 78.65% and 12.06%, respectively. The optimum values of parameters were as follows: oxalic acid to hydrochloric acid ratio (2:1), acid concentration (30%), ratio of liquid to solid (10), temperature (160 °C), and dissolution time (3 h). By applying the optimized parameters, Fe and Ti dissolution of 97.15% and 2.8% were predicted by the software with a desirability of 0.745. The results of leaching tests indicated that the Fe and Ti dissolution of 97.58% and 2.43%, were achieved, respectively, which are very close to the predicted value.
文摘The influence of hydrochloric or sulphuric acid treatment on the electro-physical properties of superthin basalt fiber (STBF) made from Armenian basalt rocks was studied. Specific electric resistance for direct and alternating currents, dielectric parameters of ε, and ε,, were measured. It is shown that specific resistance and dielectric parameters of super-thin basalt fiber change essentially after hydrochloric or sulphuric acid treatment. The temperature dependences of these parameters were studied, too, and their non–monotonic behavior was observed. The probable variation of mentioned STBF parameters is explained by different water absorption capacity of pores as a result of acid treatment.
