Resource utilization of metallurgical solid waste is vital for the sustainable development of the steel industry in the context of“dual carbon.”The calcification-carbothermal reduction method was employed to extract...Resource utilization of metallurgical solid waste is vital for the sustainable development of the steel industry in the context of“dual carbon.”The calcification-carbothermal reduction method was employed to extract zinc and iron from electric furnace dust effectively.In this process,calcium oxide reacts with zinc ferrite to form dicalcium ferrite and zinc oxide,which further promotes the effective separation of zinc and iron.However,the addition of pure calcium oxide increases production costs for steel companies.Herein,a new process for dust removal and zinc recovery in electric furnaces has been developed,using electric furnace slag as a calcium agent and mineral trough ash as a reducing agent.Large amounts of dicalcium ferrate phases were detected in the carbothermal reduction products by steel slag synergistic calcification.The reaction mechanism was determined as ZnFe_(2)O_(4)+CaO→Ca_(2)Fe_(2)O_(5)+ZnO→Ca_(2)Fe_(2)O_(5)+Zn(g).Such a two-step reaction path indicated that steel slag can effectively promote the reduction and volatilization of zinc.The experimental optimal roasting parameters were determined as roasting temperature of 1150℃,roasting time of 45 min,calcium to zinc molar ratio of 1.1,and carbon to oxygen molar ratio of 0.8.The mass percentage of added steel slag was recorded as 21.83%,while that of mineral trough ash was 21.85%.Under these conditions,the zinc removal rate above 99%and the metallization rate of pellets of about 75.31%were achieved.Overall,the proposed method looks promising for future efficient separation of zinc and iron in industrial steel slag.展开更多
Zinc diffusion kinetics of double phase brass as they were corroded in seawater was investigated by means of metallography microscope and mathematics regression analysis. The results showed that, the dezincification c...Zinc diffusion kinetics of double phase brass as they were corroded in seawater was investigated by means of metallography microscope and mathematics regression analysis. The results showed that, the dezincification corrosion of β phase continuous HMn58 2 brass is characterized by β phase volume diffusion, while that of α phase continuous HSn62 1 brass is controlled by α phase grain boundary diffusion. Apparent diffusion coefficients of zinc in both types alloys were calculated out by founding diffusion equation and boundary conditions. It was found that the value of theoretical calculation is close to that of experimentally measured, and it confirmed that Sn element inhibits dezincification of brass. The relativity between the dezincification depth and corrosion rate of different double phase brasses immersed in seawater was revealed. : Zinc diffusion kinetics of double phase brass as they were corroded in seawater was investigated by means of metallography microscope and mathematics regression analysis. The results showed that, the dezincification corrosion of β phase continuous HMn58 2 brass is characterized by β phase volume diffusion, while that of α phase continuous HSn62 1 brass is controlled by α phase grain boundary diffusion. Apparent diffusion coefficients of zinc in both types alloys were calculated out by founding diffusion equation and boundary conditions. It was found that the value of theoretical calculation is close to that of experimentally measured, and it confirmed that Sn element inhibits dezincification of brass. The relativity between the dezincification depth and corrosion rate of different double phase brasses immersed in seawater was revealed.展开更多
The effect of hydrogen on the dezincification layer-induced stress and the susceptibility to SCC was investigated. Experimental results showed that the dezincification layer-induced stress increased with increasing hy...The effect of hydrogen on the dezincification layer-induced stress and the susceptibility to SCC was investigated. Experimental results showed that the dezincification layer-induced stress increased with increasing hydrogen concentration, and 3x10-6 hydrogen could increase the susceptibility to SCC of brass in ammonia solution by 10%.展开更多
This work demonstrated quantitatively that DSA （dansylamide） and apo CA （dezincified carbon anhydrase） interacted with each other in the presence of Zn2＋ （zinc ion）. The fluorescence emission of DSA in the pres...This work demonstrated quantitatively that DSA （dansylamide） and apo CA （dezincified carbon anhydrase） interacted with each other in the presence of Zn2＋ （zinc ion）. The fluorescence emission of DSA in the presence of Zn2＋ and the intensity of fluorescence, which was proportional to the concentration of Zn2＋, could be used in the measurement of Zn2＋ concentration. Considering that Zn2＋ was the active center of enzymes like CA （carbon anhydrase）, two dezincification reagents were compared to ensure the validity of our method. A certain range concentration of Zn2＋ could be measured by the reaction product of apo CA, DSA and Zn2＋, where the measurement limitation was about 60 nmol/L. Interaction of CA with DSA was also studied with infrared spectrometry.展开更多
The Characteristic and mechanism of corrosion of brass exposed to seawater for several years, including alloys with single alpha-phase and alpha + beta phase, were investigated by means of metallograph, SEM, EDS and s...The Characteristic and mechanism of corrosion of brass exposed to seawater for several years, including alloys with single alpha-phase and alpha + beta phase, were investigated by means of metallograph, SEM, EDS and so on. It shows that severe corrosion with intergranular and dezincification characteristics occurred on the specimens of H-68A, which was single alpha-phase brass with As element addition. For the brass of HSn70-1A, which was single-phase alloy with ils and Sn additions, much better corrosion resistance could be exhibited due to the formation of Sn enrichment corrosion product film. Sn element is much easier to enrich at phase and grain boundaries than towards surface film. This would inhibit dezincification of the alpha + beta phase brass to some extent. However, it is not enough for the Sn element addition in the brass HSn62-1 with alpha + beta phase to resist dezincification corrosion getting through phase and grain boundaries of the brass. The alleging elements boundary diffusion plays an important role in the corrosion behavior of both alpha-phase and alpha + beta phase brass.展开更多
Dezincification layer formed during corrosion or stress corrosion cracking (SCC) of brass in an ammonia solution could induce an additive stress. The effect of hydrogen on the dezincification layer induced stress and ...Dezincification layer formed during corrosion or stress corrosion cracking (SCC) of brass in an ammonia solution could induce an additive stress. The effect of hydrogen on the dezincification layer induced stress and the susceptibility to SCC were studied. The dezincification layer induced stress was measured using the deflection method and the flowing stress differential method, respectively. The latter measures the difference between the flowing stress of a specimen before unloading and the yield stress of the same specimen after unloading and forming a dezincification layer. The susceptibility to SCC was measured using slow strain rate test. Results show that both the dezincification layer induced stress and the susceptibility to SCC increase with increasing hydrogen concentration in a specimen. This implies that hydrogen enhanced dezincification layer induced stress is consistence with the hydrogen increased susceptibility to SCC of brass in the ammonia solution.展开更多
基金the support from Graduate Student Scientific Research Innovation Projects in Jiangsu Province(KYCX22_3804)Natural Science Foundation of Jiangsu Province(No.BK20210888).
文摘Resource utilization of metallurgical solid waste is vital for the sustainable development of the steel industry in the context of“dual carbon.”The calcification-carbothermal reduction method was employed to extract zinc and iron from electric furnace dust effectively.In this process,calcium oxide reacts with zinc ferrite to form dicalcium ferrite and zinc oxide,which further promotes the effective separation of zinc and iron.However,the addition of pure calcium oxide increases production costs for steel companies.Herein,a new process for dust removal and zinc recovery in electric furnaces has been developed,using electric furnace slag as a calcium agent and mineral trough ash as a reducing agent.Large amounts of dicalcium ferrate phases were detected in the carbothermal reduction products by steel slag synergistic calcification.The reaction mechanism was determined as ZnFe_(2)O_(4)+CaO→Ca_(2)Fe_(2)O_(5)+ZnO→Ca_(2)Fe_(2)O_(5)+Zn(g).Such a two-step reaction path indicated that steel slag can effectively promote the reduction and volatilization of zinc.The experimental optimal roasting parameters were determined as roasting temperature of 1150℃,roasting time of 45 min,calcium to zinc molar ratio of 1.1,and carbon to oxygen molar ratio of 0.8.The mass percentage of added steel slag was recorded as 21.83%,while that of mineral trough ash was 21.85%.Under these conditions,the zinc removal rate above 99%and the metallization rate of pellets of about 75.31%were achieved.Overall,the proposed method looks promising for future efficient separation of zinc and iron in industrial steel slag.
文摘Zinc diffusion kinetics of double phase brass as they were corroded in seawater was investigated by means of metallography microscope and mathematics regression analysis. The results showed that, the dezincification corrosion of β phase continuous HMn58 2 brass is characterized by β phase volume diffusion, while that of α phase continuous HSn62 1 brass is controlled by α phase grain boundary diffusion. Apparent diffusion coefficients of zinc in both types alloys were calculated out by founding diffusion equation and boundary conditions. It was found that the value of theoretical calculation is close to that of experimentally measured, and it confirmed that Sn element inhibits dezincification of brass. The relativity between the dezincification depth and corrosion rate of different double phase brasses immersed in seawater was revealed. : Zinc diffusion kinetics of double phase brass as they were corroded in seawater was investigated by means of metallography microscope and mathematics regression analysis. The results showed that, the dezincification corrosion of β phase continuous HMn58 2 brass is characterized by β phase volume diffusion, while that of α phase continuous HSn62 1 brass is controlled by α phase grain boundary diffusion. Apparent diffusion coefficients of zinc in both types alloys were calculated out by founding diffusion equation and boundary conditions. It was found that the value of theoretical calculation is close to that of experimentally measured, and it confirmed that Sn element inhibits dezincification of brass. The relativity between the dezincification depth and corrosion rate of different double phase brasses immersed in seawater was revealed.
基金This project was supported by the Special Fund for the Major State Basic Research Project(G19990650)the NSFC(No.50071010)
文摘The effect of hydrogen on the dezincification layer-induced stress and the susceptibility to SCC was investigated. Experimental results showed that the dezincification layer-induced stress increased with increasing hydrogen concentration, and 3x10-6 hydrogen could increase the susceptibility to SCC of brass in ammonia solution by 10%.
基金Supported by National Natural Science Foundation of China(NSFC)(No.61177076)the Fundamental Research Funds for the Central Universities of WUT(Nos.2012-Ia-020 and 2013-Ia-038)
文摘This work demonstrated quantitatively that DSA （dansylamide） and apo CA （dezincified carbon anhydrase） interacted with each other in the presence of Zn2＋ （zinc ion）. The fluorescence emission of DSA in the presence of Zn2＋ and the intensity of fluorescence, which was proportional to the concentration of Zn2＋, could be used in the measurement of Zn2＋ concentration. Considering that Zn2＋ was the active center of enzymes like CA （carbon anhydrase）, two dezincification reagents were compared to ensure the validity of our method. A certain range concentration of Zn2＋ could be measured by the reaction product of apo CA, DSA and Zn2＋, where the measurement limitation was about 60 nmol/L. Interaction of CA with DSA was also studied with infrared spectrometry.
文摘The Characteristic and mechanism of corrosion of brass exposed to seawater for several years, including alloys with single alpha-phase and alpha + beta phase, were investigated by means of metallograph, SEM, EDS and so on. It shows that severe corrosion with intergranular and dezincification characteristics occurred on the specimens of H-68A, which was single alpha-phase brass with As element addition. For the brass of HSn70-1A, which was single-phase alloy with ils and Sn additions, much better corrosion resistance could be exhibited due to the formation of Sn enrichment corrosion product film. Sn element is much easier to enrich at phase and grain boundaries than towards surface film. This would inhibit dezincification of the alpha + beta phase brass to some extent. However, it is not enough for the Sn element addition in the brass HSn62-1 with alpha + beta phase to resist dezincification corrosion getting through phase and grain boundaries of the brass. The alleging elements boundary diffusion plays an important role in the corrosion behavior of both alpha-phase and alpha + beta phase brass.
文摘Dezincification layer formed during corrosion or stress corrosion cracking (SCC) of brass in an ammonia solution could induce an additive stress. The effect of hydrogen on the dezincification layer induced stress and the susceptibility to SCC were studied. The dezincification layer induced stress was measured using the deflection method and the flowing stress differential method, respectively. The latter measures the difference between the flowing stress of a specimen before unloading and the yield stress of the same specimen after unloading and forming a dezincification layer. The susceptibility to SCC was measured using slow strain rate test. Results show that both the dezincification layer induced stress and the susceptibility to SCC increase with increasing hydrogen concentration in a specimen. This implies that hydrogen enhanced dezincification layer induced stress is consistence with the hydrogen increased susceptibility to SCC of brass in the ammonia solution.
