Boron removal from metallurgical grade silicon （MG-Si） using a calcium silicate slag was studied. The results show that it is impossible basically to remove boron using a pure SiO2 refining. The oxidizing ability of...Boron removal from metallurgical grade silicon （MG-Si） using a calcium silicate slag was studied. The results show that it is impossible basically to remove boron using a pure SiO2 refining. The oxidizing ability of CaO-SiO2 slag for boron removal was characterized by establishing the thermodynamic relationship between the distribution coefficient of boron （LB） and the activities of SiO2 and CaO. The experimental results show that the distribution coefficient and the removal efficiency of boron are greatly improved with the increase of CaO proportion in the slag. The maximal value of LB reaches 1.57 with a slag composition of 60%CaO-40%SiO2 （mass fraction）. The boron content in the refined silicon is reduced from 18×10^-6 to 1.8×10^-6 using slag refining at 1600 ℃ for 3 h with a CaO-SiO2/MG-Si ratio of 2.5, and the removal efficiency of boron reaches 90%.展开更多
In view of the present problem of sulfur enrichment in the metallurgical recycling process of ladle furnace （LF） refining slag, a simple and efficient method of removing sulfur from this slag was proposed. The propo...In view of the present problem of sulfur enrichment in the metallurgical recycling process of ladle furnace （LF） refining slag, a simple and efficient method of removing sulfur from this slag was proposed. The proposed method is compatible with current steelmaking processes. Sulfur removal from LF refining slag for SPHC steel （manufactured at a certain steel plant in China） by blowing air in the hot state was studied by using hot-state experiments in a laboratory. The FactSage software, a carbon/sulfur analyzer, and scanning electron micros- copy in conjunction with energy-dispersive X-ray spectroscopy were used to test and analyze the sulfur removal effect and to investigate factors influencing sulfur removal rate. The results show that sulfur ions in LF refining slag can be oxidized into SO2 by O2 at high tempera- ture by blowing air into molten slag; SO2 production was observed to reach a maximum with a small amount of blown O2 when the tem- perature exceeded 1350℃. At 1370℃ and 1400℃, experimental LF refining slag is in the liquid state and exhibits good fluidity; under these conditions, the sulfur removal effect by blowing air is greater than 90wt% after 60 min. High temperature and large air flow rate are benefi- cial for removing sulfur from LF refining slag; compared with air flow rate, temperature has a greater strongly influences on the sulfur re- moval.展开更多
The prevention and treatment of mercury in coal-fired power plants has always been the focus and difficulty.How to control the pollution of mercury to human body and ecological environment quickly and effectively is a...The prevention and treatment of mercury in coal-fired power plants has always been the focus and difficulty.How to control the pollution of mercury to human body and ecological environment quickly and effectively is a hot research topic nowadays.As a low cost and potential adsorbent,there is a huge space for the development of coal dry powder gasification coarse slag.In this paper,Mercury osmotic tubes are heated by water bath tank as mercury source,and the scavenging effect of adsorbent on Mercury monomer under different influence conditions is explored.The adsorbent plays an important role in adsorption of mercury monomer because of its special active sites on the surface.The reason is that the adsorbent surface is rich in carboxyl group,hydroxyl functional group,combined with mercury to form complexes.This shows that chemical adsorption facilitates the adsorption process.展开更多
This study investigates a purification process for metallurgical-grade silicon(MG-Si) in which Si is alloyed with tin(Sn) and Ca O–Si O_2–Ca Cl_2 slag is used to remove boron(B) impurity. Acid leaching was performed...This study investigates a purification process for metallurgical-grade silicon(MG-Si) in which Si is alloyed with tin(Sn) and Ca O–Si O_2–Ca Cl_2 slag is used to remove boron(B) impurity. Acid leaching was performed to remove the Sn phase after slag refining to recover high-purity Si from the Si–Sn alloy. The effect of refining time was investigated, and acceptable refining results were realized within 15 min. The effects of slag composition and Sn content on the removal of B were also studied. The results indicate that increasing Sn content favors B removal. With the increase of Sn to 50% of the alloy, the final B content decreased to 1.1 × 10^(-4) wt%, 93.9% removal efficiency.展开更多
The formation of slag eye in a gas stirred ladle was studied through cold models and industrial trials. In the cold model,water and sodium tungstate solution were employed to simulate liquid steel,and silicon oil was ...The formation of slag eye in a gas stirred ladle was studied through cold models and industrial trials. In the cold model,water and sodium tungstate solution were employed to simulate liquid steel,and silicon oil was employed to simulate slag. The simulation results revealed that the gas flow rate and bath height had strong effects on the slag eye size. In particular,the thickness of slag layer played a strong role in the slag eye size. In addition,the slag eye could not be formed when the thickness of the top layer was more than 4 cm in water-silicone oil model.Besides,the section area of vessel had a great impact on the slag eye size. Industrial trials results showed a similar trend that the gas flow rate was very significant on the slag eye size. The predictions of the existing models showed larger predictions deviations compared with the experimental data. Moreover,a new model without fitting parameters was developed based on force balance and mathematical derivation,and verified by the experimental data. The new model provides the prediction with small deviations by comparing with the data acquired from cold models and industrial trials.展开更多
Slag refining,as an important option for boron removal to produce solar grade silicon（SOG-Si） from metallurgical grade silicon（MG-Si）,has attracted increasing attention.In this paper,Na_2CO_3-SiO_2 systems were ch...Slag refining,as an important option for boron removal to produce solar grade silicon（SOG-Si） from metallurgical grade silicon（MG-Si）,has attracted increasing attention.In this paper,Na_2CO_3-SiO_2 systems were chosen as the sodium-based refining slag materials for boron removal from molten silicon.Furthermore,the effect of Al_2O_3 addition for boron removal was studied in detail,which showed that an appropriate amount of Al_2O_3 can help retention of the basicity of the slags,hence improving the boron removal rate.展开更多
The transport of inclusion particles through the liquid metal/molten slag interface and their dissolution in the slag are two key processes of inclusion removal.Based on the latest version of inclusion transport model...The transport of inclusion particles through the liquid metal/molten slag interface and their dissolution in the slag are two key processes of inclusion removal.Based on the latest version of inclusion transport model that takes into account full Reynolds number range and a dissolution kinetics model,a coupled model was developed to simulate the whole process of inclusion removal,from floating in the liquid steel to crossing the interface and further to entering and dissolving in the molten slag.The interaction between the inclusion motion and dissolution was discussed.Even though the inclusion velocity is a key parameter for dissolution,the simulation results show no obvious dissolution during moving state because the process is too short and most of the inclusions dissolve during its static stay in the slag side above the interface.The rate-controlling step of inclusion removal is the transport through the steel-slag interface for the small-size inclusion and static dissolution above the interface for the large-size inclusion,respectively.展开更多
基金Projects (51104080,u1137601) supported by the National Natural Science Foundation of ChinaProject (14118557) supported by the Personnel Training Foundation of Kunming University of Science and Technology in China
文摘Boron removal from metallurgical grade silicon （MG-Si） using a calcium silicate slag was studied. The results show that it is impossible basically to remove boron using a pure SiO2 refining. The oxidizing ability of CaO-SiO2 slag for boron removal was characterized by establishing the thermodynamic relationship between the distribution coefficient of boron （LB） and the activities of SiO2 and CaO. The experimental results show that the distribution coefficient and the removal efficiency of boron are greatly improved with the increase of CaO proportion in the slag. The maximal value of LB reaches 1.57 with a slag composition of 60%CaO-40%SiO2 （mass fraction）. The boron content in the refined silicon is reduced from 18×10^-6 to 1.8×10^-6 using slag refining at 1600 ℃ for 3 h with a CaO-SiO2/MG-Si ratio of 2.5, and the removal efficiency of boron reaches 90%.
基金supported by China Postdoctoral Science Foundation (Nos. 2014M560890 and 2015T80039)the National Natural Science Foundation of China (No. 51404022)
文摘In view of the present problem of sulfur enrichment in the metallurgical recycling process of ladle furnace （LF） refining slag, a simple and efficient method of removing sulfur from this slag was proposed. The proposed method is compatible with current steelmaking processes. Sulfur removal from LF refining slag for SPHC steel （manufactured at a certain steel plant in China） by blowing air in the hot state was studied by using hot-state experiments in a laboratory. The FactSage software, a carbon/sulfur analyzer, and scanning electron micros- copy in conjunction with energy-dispersive X-ray spectroscopy were used to test and analyze the sulfur removal effect and to investigate factors influencing sulfur removal rate. The results show that sulfur ions in LF refining slag can be oxidized into SO2 by O2 at high tempera- ture by blowing air into molten slag; SO2 production was observed to reach a maximum with a small amount of blown O2 when the tem- perature exceeded 1350℃. At 1370℃ and 1400℃, experimental LF refining slag is in the liquid state and exhibits good fluidity; under these conditions, the sulfur removal effect by blowing air is greater than 90wt% after 60 min. High temperature and large air flow rate are benefi- cial for removing sulfur from LF refining slag; compared with air flow rate, temperature has a greater strongly influences on the sulfur re- moval.
文摘The prevention and treatment of mercury in coal-fired power plants has always been the focus and difficulty.How to control the pollution of mercury to human body and ecological environment quickly and effectively is a hot research topic nowadays.As a low cost and potential adsorbent,there is a huge space for the development of coal dry powder gasification coarse slag.In this paper,Mercury osmotic tubes are heated by water bath tank as mercury source,and the scavenging effect of adsorbent on Mercury monomer under different influence conditions is explored.The adsorbent plays an important role in adsorption of mercury monomer because of its special active sites on the surface.The reason is that the adsorbent surface is rich in carboxyl group,hydroxyl functional group,combined with mercury to form complexes.This shows that chemical adsorption facilitates the adsorption process.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 51334002 and 51604023)
文摘This study investigates a purification process for metallurgical-grade silicon(MG-Si) in which Si is alloyed with tin(Sn) and Ca O–Si O_2–Ca Cl_2 slag is used to remove boron(B) impurity. Acid leaching was performed to remove the Sn phase after slag refining to recover high-purity Si from the Si–Sn alloy. The effect of refining time was investigated, and acceptable refining results were realized within 15 min. The effects of slag composition and Sn content on the removal of B were also studied. The results indicate that increasing Sn content favors B removal. With the increase of Sn to 50% of the alloy, the final B content decreased to 1.1 × 10^(-4) wt%, 93.9% removal efficiency.
基金financially supported by National Natural Science Foundation of China(51534001,51604003)Natural Science Research Project of Anhui Province Universities(KJ2016A089)Youth Foundation of Anhui University and Technology(QZ201502)
文摘The formation of slag eye in a gas stirred ladle was studied through cold models and industrial trials. In the cold model,water and sodium tungstate solution were employed to simulate liquid steel,and silicon oil was employed to simulate slag. The simulation results revealed that the gas flow rate and bath height had strong effects on the slag eye size. In particular,the thickness of slag layer played a strong role in the slag eye size. In addition,the slag eye could not be formed when the thickness of the top layer was more than 4 cm in water-silicone oil model.Besides,the section area of vessel had a great impact on the slag eye size. Industrial trials results showed a similar trend that the gas flow rate was very significant on the slag eye size. The predictions of the existing models showed larger predictions deviations compared with the experimental data. Moreover,a new model without fitting parameters was developed based on force balance and mathematical derivation,and verified by the experimental data. The new model provides the prediction with small deviations by comparing with the data acquired from cold models and industrial trials.
文摘Slag refining,as an important option for boron removal to produce solar grade silicon（SOG-Si） from metallurgical grade silicon（MG-Si）,has attracted increasing attention.In this paper,Na_2CO_3-SiO_2 systems were chosen as the sodium-based refining slag materials for boron removal from molten silicon.Furthermore,the effect of Al_2O_3 addition for boron removal was studied in detail,which showed that an appropriate amount of Al_2O_3 can help retention of the basicity of the slags,hence improving the boron removal rate.
基金The authors gratefully acknowledge the support from the National Natural Science Foundation of China(Nos.51574020 and 51674023)。
文摘The transport of inclusion particles through the liquid metal/molten slag interface and their dissolution in the slag are two key processes of inclusion removal.Based on the latest version of inclusion transport model that takes into account full Reynolds number range and a dissolution kinetics model,a coupled model was developed to simulate the whole process of inclusion removal,from floating in the liquid steel to crossing the interface and further to entering and dissolving in the molten slag.The interaction between the inclusion motion and dissolution was discussed.Even though the inclusion velocity is a key parameter for dissolution,the simulation results show no obvious dissolution during moving state because the process is too short and most of the inclusions dissolve during its static stay in the slag side above the interface.The rate-controlling step of inclusion removal is the transport through the steel-slag interface for the small-size inclusion and static dissolution above the interface for the large-size inclusion,respectively.
