Corrosion test data were measured using non-destructive electrochemical techniques and analysed for studying inhibition effectiveness by different concentrations of NazCr207 on the corrosion of concrete steel-rehar in...Corrosion test data were measured using non-destructive electrochemical techniques and analysed for studying inhibition effectiveness by different concentrations of NazCr207 on the corrosion of concrete steel-rehar in NaC1 and in H2SO4 media. For these, specifications of ASTM G16-95 R04 were combined with the normal and the Gumbel probability density functions as model analytical methods for addressing issues of conflicting reports of inhibitor effectiveness that had generated concerns. Results show that reinforced concrete samples admixed with concentrations having 4 g （0.012 7 tool）, 8 g （0.025 4 mol） and 6 g （0.019 l tool） NaaCr207 exhibited, in that order, high inhibition effectiveness, with respective efficiency, r/, of （90.46±1.30）%, （88.41＋2.24）% and （84.87±4.74）%, in the NaC1 medium. These exhibit good agreements within replicates and statistical methods for the samples. Also, optimal inhibition effectiveness model in the H2SO4 medium was exhibited by 8 g （0.025 4 mol） Na2Cr207 concentration having r/=（78.44±1.10）%. These bear implications for addressing conflicting test data in the study of effective inhibitors for mitigating steel-rebar corrosion in aggressive environments.展开更多
The dissolution of molybdenite concentrate in NaC1 electrolyte was investigated. The results show that the dissolution rate increases with the increase in liquid-to-solid ratio, stirring speed, NaCl concentration and ...The dissolution of molybdenite concentrate in NaC1 electrolyte was investigated. The results show that the dissolution rate increases with the increase in liquid-to-solid ratio, stirring speed, NaCl concentration and temperature. When the liquid-to-solid ratio is 30：1, stirring speed is 400 r/min, concentration of NaCI is 4 mol/L at pH=9 and room temperature, the leaching efficiency of molybdenite concentrate will reach 99.5% in 240 min. Molybdenite concentrate cannot be electro-oxidized directly on the anode. The kinetic studies show that the dissolution of molybdenite concentrate is represented by shrinking core model with diffusion through a porous product layer of element sulfur, and the apparent activation energy for the dissolution reaction is 8.56 kJ/mol.展开更多
Nucleation mechanism and technological process for Ni-Fe co-deposition with a relatively high Fe^(2+)concentration surrounded were described,and the effects of Fe^(2+) concentration,solution pH,temperature,and sodium ...Nucleation mechanism and technological process for Ni-Fe co-deposition with a relatively high Fe^(2+)concentration surrounded were described,and the effects of Fe^(2+) concentration,solution pH,temperature,and sodium dodecyl sulfonate concentration were investigated.Electrochemical experiments demonstrate that iron's electrodeposition plays a leading role in the Ni-Fe co-deposition process,and the co-deposition nucleation mechanism accords with a progressive nucleation.Temperature increase does favor in increasing nickel content in the ferronickel(Ni-Fe co-deposition products),while Fe^(2+) concentration increase does not.When solution pH is higher than 3.5,nickel content in the ferronickel decreases with pH because of the hydrolysis of Fe^(2+).With the current density of 180 A/m^2,Na_2SO_4 concentration of 100 g/L and Ni^(2+) concentration of 60 g/L,a smooth ferronickel deposit containing 96.21% Ni can be obtained under the conditions of temperature of 60 °C,Fe^(2+) concentration of 0.3 g/L,solution pH of 3 and sodium dodecyl sulfonate concentration of 40 mg/L.展开更多
文摘Corrosion test data were measured using non-destructive electrochemical techniques and analysed for studying inhibition effectiveness by different concentrations of NazCr207 on the corrosion of concrete steel-rehar in NaC1 and in H2SO4 media. For these, specifications of ASTM G16-95 R04 were combined with the normal and the Gumbel probability density functions as model analytical methods for addressing issues of conflicting reports of inhibitor effectiveness that had generated concerns. Results show that reinforced concrete samples admixed with concentrations having 4 g （0.012 7 tool）, 8 g （0.025 4 mol） and 6 g （0.019 l tool） NaaCr207 exhibited, in that order, high inhibition effectiveness, with respective efficiency, r/, of （90.46±1.30）%, （88.41＋2.24）% and （84.87±4.74）%, in the NaC1 medium. These exhibit good agreements within replicates and statistical methods for the samples. Also, optimal inhibition effectiveness model in the H2SO4 medium was exhibited by 8 g （0.025 4 mol） Na2Cr207 concentration having r/=（78.44±1.10）%. These bear implications for addressing conflicting test data in the study of effective inhibitors for mitigating steel-rebar corrosion in aggressive environments.
基金Project(2007BAB22B01) supported by the 11th Five-Year Plan of National Science and Technology of China Project(50704036) supported by the National Natural Science Foundation of China
文摘The dissolution of molybdenite concentrate in NaC1 electrolyte was investigated. The results show that the dissolution rate increases with the increase in liquid-to-solid ratio, stirring speed, NaCl concentration and temperature. When the liquid-to-solid ratio is 30：1, stirring speed is 400 r/min, concentration of NaCI is 4 mol/L at pH=9 and room temperature, the leaching efficiency of molybdenite concentrate will reach 99.5% in 240 min. Molybdenite concentrate cannot be electro-oxidized directly on the anode. The kinetic studies show that the dissolution of molybdenite concentrate is represented by shrinking core model with diffusion through a porous product layer of element sulfur, and the apparent activation energy for the dissolution reaction is 8.56 kJ/mol.
基金Project(51574135)supported by the National Natural Science Foundation of ChinaProject(KKPT201563022)supported by Collaborative Innovation Center of Kunming University of Science and Technology,China
文摘Nucleation mechanism and technological process for Ni-Fe co-deposition with a relatively high Fe^(2+)concentration surrounded were described,and the effects of Fe^(2+) concentration,solution pH,temperature,and sodium dodecyl sulfonate concentration were investigated.Electrochemical experiments demonstrate that iron's electrodeposition plays a leading role in the Ni-Fe co-deposition process,and the co-deposition nucleation mechanism accords with a progressive nucleation.Temperature increase does favor in increasing nickel content in the ferronickel(Ni-Fe co-deposition products),while Fe^(2+) concentration increase does not.When solution pH is higher than 3.5,nickel content in the ferronickel decreases with pH because of the hydrolysis of Fe^(2+).With the current density of 180 A/m^2,Na_2SO_4 concentration of 100 g/L and Ni^(2+) concentration of 60 g/L,a smooth ferronickel deposit containing 96.21% Ni can be obtained under the conditions of temperature of 60 °C,Fe^(2+) concentration of 0.3 g/L,solution pH of 3 and sodium dodecyl sulfonate concentration of 40 mg/L.
