To elucidate the effects of Cl^(-)and Ca^(2+) on the corrosion and scale formation of 3Cr steel in CO_(2) floodingproduced fluid,corrosion weight loss experiments,and titration experiments were conducted.The resulting...To elucidate the effects of Cl^(-)and Ca^(2+) on the corrosion and scale formation of 3Cr steel in CO_(2) floodingproduced fluid,corrosion weight loss experiments,and titration experiments were conducted.The resulting products were characterized using scanning electron microscopy(SEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).This study examined the corrosion and scaling behavior of 3Cr steel under the influence of Cl^(-)and Ca^(2+).The results indicate that both Cl^(-)and Ca^(2+)promote the corro sion of 3Cr steel.Notably,Cl^(-)diminishes the promoting effect of Ca^(2+)on corro sion and inhibits scaling,revealing a mutual enhancement between corrosion and scaling.The mechanisms of localized corrosion under varying concentrations of Cl^(-)and Ca^(2+)differ;under-scale corrosion occurs in environments with 5000 mg·L^(-1) Cl^(-),while Cl^(-)induced corrosion is observed in 20000 mg·L^(-1) Cl^(-)environments.This study highlights that under the synergistic effects of Cl^(-),Ca^(2+),and scaling processes,the protective product film dissolves,thereby influencing both corrosion and scaling processes.展开更多
The high-carbon ferrochrome is an essential raw material for producing stainless steel,and the demand of it increases with the increase of stainless steel.So increasing Cr recovery rate from chromite is essential for ...The high-carbon ferrochrome is an essential raw material for producing stainless steel,and the demand of it increases with the increase of stainless steel.So increasing Cr recovery rate from chromite is essential for lower costs and higher economic benefits in high-carbon ferrochrome production process.This study calculated the activity of CrO_(x)in slag and investigated the distribution behavior of Cr between slag and alloy.Theω(MgO)/ω(Al_(2)O_(3))was 1.0,and the w(CaO)/w(SiO_(2))was from 0.2 to 0.6 in this study.The calculation and experimental results showed that the main phases of the slag were chrome-containing spinel,magnesium-aluminum spinel,olivine and melilite.The content of spinel in slag decreased with the increasing w(CaO)/w(SiO_(2)),and the w(CrO_(x))in spinel also reduced,but the content of melilite increased.The distribution ratio of Cr between slag and alloy decreased with the increase of slag basicity at 1600℃,meansning that increasing the w(CaO)/w(SiO_(2))of slag can improve the recovery of Cr in chromite smelting process.展开更多
The crystallization behavior and kinetics of CaO-MgO-Al2O3 SiO2（CMAS） glass with the Fe2O3 content ranging from zero to 5%were investigated by differential scanning calorimetry（DSC）.The structure and phase analyse...The crystallization behavior and kinetics of CaO-MgO-Al2O3 SiO2（CMAS） glass with the Fe2O3 content ranging from zero to 5%were investigated by differential scanning calorimetry（DSC）.The structure and phase analyses were made by Fourier transform infrared spectroscopy（FT-IR） and X-ray diffraction（XRD）.The experiment results show that the endothermic peak temperature about 760℃ is associated with transition and the exothermic peak temperature about 1000℃ is associated with crystallization.The crystallization peak temperature decreases with increasing the Fe203 content.The crystallization mechanism is changed from two-dimensional crystallization to one-dimensional growth,and the intensity of diopside peaks becomes stronger gradually.There is a saltation for the crystallization temperature with the addition of 0.5%Fe2O3 due to the decomposition of Fe2O3.Si-O-Si,O-Si-O and T-O-T（T=Si,Fe,Al） linkages are observed in Fe2O3-CaO-MgO-Al2O3-SiO2 glass.展开更多
Lutetium oxide nanocrystals codoped with Tm3+and Yb3+were synthesized by the reverse-like co-precipitation method,using ammonium hydrogen carbonate as precipitant.Effects of the Tm3+,Yb3+molar fractions and calcinatio...Lutetium oxide nanocrystals codoped with Tm3+and Yb3+were synthesized by the reverse-like co-precipitation method,using ammonium hydrogen carbonate as precipitant.Effects of the Tm3+,Yb3+molar fractions and calcination temperature on the structural and upconversion luminescent properties of the Lu2O3 nanocrystals were investigated.The XRD results show that all the prepared nanocrystals can be readily indexed to pure cubic phase of Lu2O3 and indicate good crystallinity.The experimental results show that concentration quenching occurs when the mole fraction of Tm3+is above 0.2%.The optimal Tm3+and Yb3+doped molar fractions are 0.2%and 2%,respectively.The strong blue(490 nm)and the weak red(653 nm)emissions from the prepared nanocrystals were observed under 980 nm laser excitation,and attributed to the 1G4→3H6 and IG4→3F4 transitions of Tm3+,respectively.Power-dependent study reveals that the 1G4 levels of Tm3+can be populated by three-step energy transfer process.The upconversion emission intensities of 490 nm and 653 nm increase gradually with the increase of calcination temperature.The enhancement of the upconversion luminescence is suggested to be the consequence of reducing number of OH-groups and the enlarged nanoerystal size.展开更多
基金the support from the National Natural Science Foundation of China (51774249)the Sichuan Science and Technology Program (21JCQN0066)。
文摘To elucidate the effects of Cl^(-)and Ca^(2+) on the corrosion and scale formation of 3Cr steel in CO_(2) floodingproduced fluid,corrosion weight loss experiments,and titration experiments were conducted.The resulting products were characterized using scanning electron microscopy(SEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).This study examined the corrosion and scaling behavior of 3Cr steel under the influence of Cl^(-)and Ca^(2+).The results indicate that both Cl^(-)and Ca^(2+)promote the corro sion of 3Cr steel.Notably,Cl^(-)diminishes the promoting effect of Ca^(2+)on corro sion and inhibits scaling,revealing a mutual enhancement between corrosion and scaling.The mechanisms of localized corrosion under varying concentrations of Cl^(-)and Ca^(2+)differ;under-scale corrosion occurs in environments with 5000 mg·L^(-1) Cl^(-),while Cl^(-)induced corrosion is observed in 20000 mg·L^(-1) Cl^(-)environments.This study highlights that under the synergistic effects of Cl^(-),Ca^(2+),and scaling processes,the protective product film dissolves,thereby influencing both corrosion and scaling processes.
基金Project(2023XQLH055)supported by Central South University Graduate Research Innovation Project(University-Enterprise Joint Project),China。
文摘The high-carbon ferrochrome is an essential raw material for producing stainless steel,and the demand of it increases with the increase of stainless steel.So increasing Cr recovery rate from chromite is essential for lower costs and higher economic benefits in high-carbon ferrochrome production process.This study calculated the activity of CrO_(x)in slag and investigated the distribution behavior of Cr between slag and alloy.Theω(MgO)/ω(Al_(2)O_(3))was 1.0,and the w(CaO)/w(SiO_(2))was from 0.2 to 0.6 in this study.The calculation and experimental results showed that the main phases of the slag were chrome-containing spinel,magnesium-aluminum spinel,olivine and melilite.The content of spinel in slag decreased with the increasing w(CaO)/w(SiO_(2)),and the w(CrO_(x))in spinel also reduced,but the content of melilite increased.The distribution ratio of Cr between slag and alloy decreased with the increase of slag basicity at 1600℃,meansning that increasing the w(CaO)/w(SiO_(2))of slag can improve the recovery of Cr in chromite smelting process.
基金Projects(51264023,51364020,U1202271)supported by the National Natural Science Foundation of ChinaProject(IRT1250)supported by the Program for Innovative Research Team in University of Ministry of Education of ChinaProject(2014HA003)supported by the Science and Technology Leading Talent of Yunnan Province,China
文摘The crystallization behavior and kinetics of CaO-MgO-Al2O3 SiO2（CMAS） glass with the Fe2O3 content ranging from zero to 5%were investigated by differential scanning calorimetry（DSC）.The structure and phase analyses were made by Fourier transform infrared spectroscopy（FT-IR） and X-ray diffraction（XRD）.The experiment results show that the endothermic peak temperature about 760℃ is associated with transition and the exothermic peak temperature about 1000℃ is associated with crystallization.The crystallization peak temperature decreases with increasing the Fe203 content.The crystallization mechanism is changed from two-dimensional crystallization to one-dimensional growth,and the intensity of diopside peaks becomes stronger gradually.There is a saltation for the crystallization temperature with the addition of 0.5%Fe2O3 due to the decomposition of Fe2O3.Si-O-Si,O-Si-O and T-O-T（T=Si,Fe,Al） linkages are observed in Fe2O3-CaO-MgO-Al2O3-SiO2 glass.
基金Foundation item:Projects(10704090,10774140,11047147)supported by the National Natural Science Foundation of ChinaProjects(KJ090514,KJTD201016)supported by the Natural Science Foundation of Chongqing Municipal Education Commission,China
文摘Lutetium oxide nanocrystals codoped with Tm3+and Yb3+were synthesized by the reverse-like co-precipitation method,using ammonium hydrogen carbonate as precipitant.Effects of the Tm3+,Yb3+molar fractions and calcination temperature on the structural and upconversion luminescent properties of the Lu2O3 nanocrystals were investigated.The XRD results show that all the prepared nanocrystals can be readily indexed to pure cubic phase of Lu2O3 and indicate good crystallinity.The experimental results show that concentration quenching occurs when the mole fraction of Tm3+is above 0.2%.The optimal Tm3+and Yb3+doped molar fractions are 0.2%and 2%,respectively.The strong blue(490 nm)and the weak red(653 nm)emissions from the prepared nanocrystals were observed under 980 nm laser excitation,and attributed to the 1G4→3H6 and IG4→3F4 transitions of Tm3+,respectively.Power-dependent study reveals that the 1G4 levels of Tm3+can be populated by three-step energy transfer process.The upconversion emission intensities of 490 nm and 653 nm increase gradually with the increase of calcination temperature.The enhancement of the upconversion luminescence is suggested to be the consequence of reducing number of OH-groups and the enlarged nanoerystal size.
