Silicon oxynitride was added in shaped Al_2O_3-SiC-C refractory material to improve the slag resistance in this paper.Optimum adding quantity of silicon oxynitride powder was also studied. The results show that the sl...Silicon oxynitride was added in shaped Al_2O_3-SiC-C refractory material to improve the slag resistance in this paper.Optimum adding quantity of silicon oxynitride powder was also studied. The results show that the slag resistance of Al_2O_3-SiC-C shaped refractory is improved when 2% or 3% Si_2N_2O is added. A reasonable amount of Si_2N_2O added into Al_2O_3-Si C-C shaped refractory can produce silicon oxide into the slag, which can improve the viscosity of slag and prevent the slag erosion and penetration.展开更多
To resolve the difficulty in slag formation during steelmaking with low silicon hot metal and to increase productivity, a new 5-hole lance was developed by increasing oxygen flow from 50 000 m^3/h to 60 000 m^3/h. Syn...To resolve the difficulty in slag formation during steelmaking with low silicon hot metal and to increase productivity, a new 5-hole lance was developed by increasing oxygen flow from 50 000 m^3/h to 60 000 m^3/h. Synthetic slag was added to adjust the slag composition. The problems such as difficulty in dephosphorization and slag adhesion to oxygen lance and hood were settled. Steel production and metal yield were increased and the nozzle life was prolonged through these techniques.展开更多
On the basis of the practical production of non-oriented silicon steel, the formation of Mg O·Al2O3 inclusions was analyzed in the process of ＂basic oxygen furnace（BOF） → RH → compact strip production（CSP）...On the basis of the practical production of non-oriented silicon steel, the formation of Mg O·Al2O3 inclusions was analyzed in the process of ＂basic oxygen furnace（BOF） → RH → compact strip production（CSP）＂. The thermodynamic and kinetic conditions of the formation of Mg O·Al2O3 inclusions were discussed, and the behavior of slag entrapment in molten steel during RH refining was simulated by computational fluid dynamics（CFD） software. The results showed that the Mg O/Al2O3 mass ratio was in the range from 0.005 to 0.017 and that Mg O·Al2O3 inclusions were not observed before the RH refining process. In contrast, the Mg O/Al2O3 mass ratio was in the range from 0.30 to 0.50, and the percentage of Mg O·Al2O3 spinel inclusions reached 58.4% of the total inclusions after the RH refining process. The compositions of the slag were similar to those of the inclusions; furthermore, the critical velocity of slag entrapment was calculated to be 0.45 m·s^-1 at an argon flow rate of 698 L·min^-1, as simulated using CFD software. When the test steel was in equilibrium with the slag, [Mg] was 0.00024wt%–0.00028wt% and [Al]s was 0.31wt%–0.37wt%; these concentrations were theoretically calculated to fall within the Mg O·Al2O3formation zone, thereby leading to the formation of Mg O·Al2O3 inclusions in the steel. Thus, the formation of Mg O·Al2O3 inclusions would be inhibited by reducing the quantity of slag entrapment, controlling the roughing slag during casting, and controlling the composition of the slag and the Mg O content in the ladle refractory.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
There are some problems in steelmaking with hot metal containing low silicon content such as difficulty in slag formation, less slag for dephosphorization and slag adhesion on oxygen lance and hood. To overcome these ...There are some problems in steelmaking with hot metal containing low silicon content such as difficulty in slag formation, less slag for dephosphorization and slag adhesion on oxygen lance and hood. To overcome these problems, experiments wcrc conducted and some improvements were obtained, such as adding appropriate flux, increasing the lance position slightly during steelmaking and using effective multi-outlet nozzle. Moreover, to keep normal heating rate, the ore and scrap charge should be reduced due to less chemical heat input in steelmaking.展开更多
Powder iron monosilicide with certain structure exhibits magnetic properties and can be used as an alloying additive in the production of electrical steels and silicon alloys with special physical and chemical propert...Powder iron monosilicide with certain structure exhibits magnetic properties and can be used as an alloying additive in the production of electrical steels and silicon alloys with special physical and chemical properties. From this point of view, development of the energy-saving technology for receiving such a valuable alloying agent with the disposal of secondary waste is an urgent task. For this purpose, the method of joint aluminothermic reduction of preliminary mechanically activated metallurgical waste is offered. Recently, a method for combining the self-propagating high-temperature synthesis and preliminary mechanical activation for obtaining metal powders with certain phase composition and structure is considered as one of the efficient ones. As the initial materials for obtaining iron monosilicide, the waste (or converter) slags of the Alaverdi copper-smelting plant and molybdenum slags of the Yerevan Pure Iron Plant are used. Besides the mentioned slags, NaNO<sub>3</sub> and CaO are added. Properties and structure of the received silicide depend on the contents, quantity of components, and the mass relation of two wastes in the burden. Therefore, the processes of structure formation of the iron monosilicide received from metallurgical waste are investigated. Studies have shown that the best results are obtained in case of waste and molybdenum slag relation of 4:1, when the 60-minute grinding in the vibromill leads to a significant increase in the mechanical activation of the burden. At this relation of FeO and SiO2, a condition is created for receiving iron monosilicide showing magnetic properties. On the whole, those transformations lead to a decrease in the reaction activation power of the interacting substances, an increase of the reactivity capacities, as well as to a new original course of reactions and new modified materials.展开更多
Low cement Al2O3 - SiO2 castables was prepared using super grade bauxite （ w（ Al2O3 ） 〉85% ） as aggregate, brown fused corundum, silicon carbide, Secar 71 CA cement, α-Al2O3 micropowder and microsilica as fine p...Low cement Al2O3 - SiO2 castables was prepared using super grade bauxite （ w（ Al2O3 ） 〉85% ） as aggregate, brown fused corundum, silicon carbide, Secar 71 CA cement, α-Al2O3 micropowder and microsilica as fine powders. The influence of SiC （0, 5 wt%, 10 wt%, and 15 wt% ）on resistance to PbO- rich slag was investigated by static crucible slag test （1 300℃ for 5 h, in air）. The slag corrosion mechanism of the castables was analyzed by means of SEM, EDS and XRD. The results show that the resistance of Al2O3 -SiO2 castables to PbO-rich slag is improved obviously by the addition of SiC. The corrosion mechanism of the PbO-rich slag can be discribed as that PbO in the slag reacts with SiO2 and CaO in Al2O3 - SiO2 castables, forming low-melting compounds （such as PbO · SiO2 and 2PbO · SiO2 ）.展开更多
文摘Silicon oxynitride was added in shaped Al_2O_3-SiC-C refractory material to improve the slag resistance in this paper.Optimum adding quantity of silicon oxynitride powder was also studied. The results show that the slag resistance of Al_2O_3-SiC-C shaped refractory is improved when 2% or 3% Si_2N_2O is added. A reasonable amount of Si_2N_2O added into Al_2O_3-Si C-C shaped refractory can produce silicon oxide into the slag, which can improve the viscosity of slag and prevent the slag erosion and penetration.
文摘To resolve the difficulty in slag formation during steelmaking with low silicon hot metal and to increase productivity, a new 5-hole lance was developed by increasing oxygen flow from 50 000 m^3/h to 60 000 m^3/h. Synthetic slag was added to adjust the slag composition. The problems such as difficulty in dephosphorization and slag adhesion to oxygen lance and hood were settled. Steel production and metal yield were increased and the nozzle life was prolonged through these techniques.
文摘On the basis of the practical production of non-oriented silicon steel, the formation of Mg O·Al2O3 inclusions was analyzed in the process of ＂basic oxygen furnace（BOF） → RH → compact strip production（CSP）＂. The thermodynamic and kinetic conditions of the formation of Mg O·Al2O3 inclusions were discussed, and the behavior of slag entrapment in molten steel during RH refining was simulated by computational fluid dynamics（CFD） software. The results showed that the Mg O/Al2O3 mass ratio was in the range from 0.005 to 0.017 and that Mg O·Al2O3 inclusions were not observed before the RH refining process. In contrast, the Mg O/Al2O3 mass ratio was in the range from 0.30 to 0.50, and the percentage of Mg O·Al2O3 spinel inclusions reached 58.4% of the total inclusions after the RH refining process. The compositions of the slag were similar to those of the inclusions; furthermore, the critical velocity of slag entrapment was calculated to be 0.45 m·s^-1 at an argon flow rate of 698 L·min^-1, as simulated using CFD software. When the test steel was in equilibrium with the slag, [Mg] was 0.00024wt%–0.00028wt% and [Al]s was 0.31wt%–0.37wt%; these concentrations were theoretically calculated to fall within the Mg O·Al2O3formation zone, thereby leading to the formation of Mg O·Al2O3 inclusions in the steel. Thus, the formation of Mg O·Al2O3 inclusions would be inhibited by reducing the quantity of slag entrapment, controlling the roughing slag during casting, and controlling the composition of the slag and the Mg O content in the ladle refractory.
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.
文摘There are some problems in steelmaking with hot metal containing low silicon content such as difficulty in slag formation, less slag for dephosphorization and slag adhesion on oxygen lance and hood. To overcome these problems, experiments wcrc conducted and some improvements were obtained, such as adding appropriate flux, increasing the lance position slightly during steelmaking and using effective multi-outlet nozzle. Moreover, to keep normal heating rate, the ore and scrap charge should be reduced due to less chemical heat input in steelmaking.
文摘Powder iron monosilicide with certain structure exhibits magnetic properties and can be used as an alloying additive in the production of electrical steels and silicon alloys with special physical and chemical properties. From this point of view, development of the energy-saving technology for receiving such a valuable alloying agent with the disposal of secondary waste is an urgent task. For this purpose, the method of joint aluminothermic reduction of preliminary mechanically activated metallurgical waste is offered. Recently, a method for combining the self-propagating high-temperature synthesis and preliminary mechanical activation for obtaining metal powders with certain phase composition and structure is considered as one of the efficient ones. As the initial materials for obtaining iron monosilicide, the waste (or converter) slags of the Alaverdi copper-smelting plant and molybdenum slags of the Yerevan Pure Iron Plant are used. Besides the mentioned slags, NaNO<sub>3</sub> and CaO are added. Properties and structure of the received silicide depend on the contents, quantity of components, and the mass relation of two wastes in the burden. Therefore, the processes of structure formation of the iron monosilicide received from metallurgical waste are investigated. Studies have shown that the best results are obtained in case of waste and molybdenum slag relation of 4:1, when the 60-minute grinding in the vibromill leads to a significant increase in the mechanical activation of the burden. At this relation of FeO and SiO2, a condition is created for receiving iron monosilicide showing magnetic properties. On the whole, those transformations lead to a decrease in the reaction activation power of the interacting substances, an increase of the reactivity capacities, as well as to a new original course of reactions and new modified materials.
文摘Low cement Al2O3 - SiO2 castables was prepared using super grade bauxite （ w（ Al2O3 ） 〉85% ） as aggregate, brown fused corundum, silicon carbide, Secar 71 CA cement, α-Al2O3 micropowder and microsilica as fine powders. The influence of SiC （0, 5 wt%, 10 wt%, and 15 wt% ）on resistance to PbO- rich slag was investigated by static crucible slag test （1 300℃ for 5 h, in air）. The slag corrosion mechanism of the castables was analyzed by means of SEM, EDS and XRD. The results show that the resistance of Al2O3 -SiO2 castables to PbO-rich slag is improved obviously by the addition of SiC. The corrosion mechanism of the PbO-rich slag can be discribed as that PbO in the slag reacts with SiO2 and CaO in Al2O3 - SiO2 castables, forming low-melting compounds （such as PbO · SiO2 and 2PbO · SiO2 ）.
