Spinel phase is considered to be the optimal phase for stabilization of chromium in stainless steel slag.In order to restrain chromium leaching from slag for the effective environmental protection,Al2O3 was utilized f...Spinel phase is considered to be the optimal phase for stabilization of chromium in stainless steel slag.In order to restrain chromium leaching from slag for the effective environmental protection,Al2O3 was utilized for the modification treatment,and the effects on the enrichment and stabilization of chromium were investigated. The mineral phases and the existence state of chromium in slag with various Al2O3 contents at different basicities（ w（CaO）/w（SiO2） were analyzed by scanning electron microscopy-energy dispersive spectroscopy（ SEM-EDS） and X-ray diffraction（ XRD）. The results showed that chromium mainly existed in the glass and spinel phases at basicity of 1. 0 and 1. 5. As the slag basicity increased to 2. 0,chromium was also found in periclase phase. Al2O3 in the stainless steel slag reacted with MgO and Cr2O3,which could generate the Al-rich Mg（CrxAl（1- x））2O4 solid solution. Moreover,the addition of Al2O3 was favorable to reduce the solubility of chromium oxide in liquid phase and suppress the precipitation of periclase phase. The experimental results demonstrated that Al2O3 modification has a positive influence on the enrichment and the stabilization of chromium in the stainless steel slag.展开更多
A new solution called component modification in-process was introduced to the difficult grinding of air quenching steel slag by a series of experiments. The results show that the fly ash added into the molten steel sl...A new solution called component modification in-process was introduced to the difficult grinding of air quenching steel slag by a series of experiments. The results show that the fly ash added into the molten steel slag before air quenching can more effectively improve the slag's grindability than milltailings, which is the other modification agent tested under the same conditions. The role of fly ash is strengthened as its proportion increases, although the degree of promotion is gradually reduced. As a result of the reaction between fly ash and steel slag at high temperature, some new mineral phases and vitreous bodies with fine grindability promote the slag grinding easily. This work is helpful to making a comprehensive utilization of steel slag and maximize its economic efficiency in China.展开更多
To improve the efficiency of melting modification for stainless steel(SS) slag, a shear force was introduced in this work and its effects on the spinel and silicate melt were experimentally investigated. The results i...To improve the efficiency of melting modification for stainless steel(SS) slag, a shear force was introduced in this work and its effects on the spinel and silicate melt were experimentally investigated. The results indicated that the use of shear force changed the nucleation and growth behaviors of spinel and that the effects of shear force varied with its intensity. The aggregation behavior of spinel under different shear-force conditions was studied, revealing that large spinel clusters could be formed when the stirring speed was controlled. However, no notable change in the melt structure of the silicate was detected in this study. The optimal stirring speed for the melting modification treatment was 50 r·min^(-1), which substantially promoted spinel growth and aggregation, resulting in modified SS slag with excellent chromium sequestration capability.展开更多
运用均匀设计结合BP神经网络算法,在磷酸、硅烷环境下将超细粉磨后的800目钢渣微粉进行优化改性后,部分代替炭黑同橡胶按比例复合制备高性能生态橡胶材料。建立制备工艺参数与力学性能的BP神经网络优化模型,优化设计生态橡胶的工艺参数...运用均匀设计结合BP神经网络算法,在磷酸、硅烷环境下将超细粉磨后的800目钢渣微粉进行优化改性后,部分代替炭黑同橡胶按比例复合制备高性能生态橡胶材料。建立制备工艺参数与力学性能的BP神经网络优化模型,优化设计生态橡胶的工艺参数。利用BET、FTIR、XRD和SEM对优化后的生态橡胶进行表征。结果表明,优化后生态橡胶制备工艺参数:磷酸与橡胶的质量比为0.013、硅烷K550与橡胶的质量比为0.003、促进剂与橡胶的质量比为0.007、硫磺与橡胶的质量比为0.011以及硬脂酸与橡胶的质量比为0.009。优化生态橡胶的力学性能:拉伸强度为18.6 MPa、邵尔A硬度为69.7和撕裂强度为45.6 k N/m。模型预测结果与实测结果具有较高的吻合度,误差范围为-1.59%^-0.85%。展开更多
This study was performed to investigate the removal of phosphate from domestic wastewater using a modified steel slag as the adsorbent. The adsorption effects of alkalinity, salt, water,and thermal modification were i...This study was performed to investigate the removal of phosphate from domestic wastewater using a modified steel slag as the adsorbent. The adsorption effects of alkalinity, salt, water,and thermal modification were investigated. The results showed that thermal activation at 800℃ for 1 hr was the optimum operation to improve the adsorption capacity. The adsorption process of the thermally modified slag was well described by the Elovich kinetic model and the Langmuir isotherm model. The maximum adsorption capacity calculated from the Langmuir model reached 13.62 mg/g. Scanning electron microscopy indicated that the surface of the modified slag was cracked and that the texture became loose after heating. The surface area and pore volume did not change after thermal modification. In the treatment of domestic wastewater, the modified slag bed（35.5 kg） removed phosphate effectively and operated for 158 days until the effluent P rose above the limit concentration of 0.5 mg/L. The phosphate fractionation method, which is often applied in soil research, was used to analyze the phosphate adsorption behavior in the slag bed. The analysis revealed that the total contents of various Ca-P forms accounted for 81.4%-91.1%, i.e., Ca10-P 50.6%-65.1%, Ca8-P 17.8%-25.0%,and Ca2-P 4.66%-9.20%. The forms of Al-P, Fe-P, and O-P accounted for only 8.9%-18.6%. The formation of Ca10-P precipitates was considered to be the main mechanism of phosphate removal in the thermally modified slag bed.展开更多
During the cooling process of AOD（argon-oxygen decarburization）stainless steel slag,the serious disintegrating problem happened,which will cause serious environmental pollution.The disintegrating mechanism of the AO...During the cooling process of AOD（argon-oxygen decarburization）stainless steel slag,the serious disintegrating problem happened,which will cause serious environmental pollution.The disintegrating mechanism of the AOD slag was analyzed in detail,and experimental research on prevention of disintegrating of AOD stainless steel slag was developed by adjusting the basicity of the slag and adding the quartz sand and borax.The disintegrating problem during the cooling process of AOD stainless steel slag is caused by the 2CaO·SiO2phase transformation fromα＇-C2S toγ-C2S.By means of adjusting the basicity of the AOD stainless steel slag from 2to 1.5by adding quartz sand,disintegrating of slag was prevented.But the adding amount must arrive at 15% which increases the difficulty of industrialization.Disintegration of AOD stainless steel slag can be effectively controlled by adding borax,and the adding amount is only 0.5%-0.8%.This method can be easily industrialized.展开更多
基金financial support by the National Natural Science Foundation of China(Project No.51374059 and 51304042)
文摘Spinel phase is considered to be the optimal phase for stabilization of chromium in stainless steel slag.In order to restrain chromium leaching from slag for the effective environmental protection,Al2O3 was utilized for the modification treatment,and the effects on the enrichment and stabilization of chromium were investigated. The mineral phases and the existence state of chromium in slag with various Al2O3 contents at different basicities（ w（CaO）/w（SiO2） were analyzed by scanning electron microscopy-energy dispersive spectroscopy（ SEM-EDS） and X-ray diffraction（ XRD）. The results showed that chromium mainly existed in the glass and spinel phases at basicity of 1. 0 and 1. 5. As the slag basicity increased to 2. 0,chromium was also found in periclase phase. Al2O3 in the stainless steel slag reacted with MgO and Cr2O3,which could generate the Al-rich Mg（CrxAl（1- x））2O4 solid solution. Moreover,the addition of Al2O3 was favorable to reduce the solubility of chromium oxide in liquid phase and suppress the precipitation of periclase phase. The experimental results demonstrated that Al2O3 modification has a positive influence on the enrichment and the stabilization of chromium in the stainless steel slag.
基金Project(IRT0708) supported by Program for Changjiang Scholars and Innovative Research Team in University of China ("PCSIRT")Project(20070008031) supported by the Research Fund for the Dectoral Program of Higher Education of China
文摘A new solution called component modification in-process was introduced to the difficult grinding of air quenching steel slag by a series of experiments. The results show that the fly ash added into the molten steel slag before air quenching can more effectively improve the slag's grindability than milltailings, which is the other modification agent tested under the same conditions. The role of fly ash is strengthened as its proportion increases, although the degree of promotion is gradually reduced. As a result of the reaction between fly ash and steel slag at high temperature, some new mineral phases and vitreous bodies with fine grindability promote the slag grinding easily. This work is helpful to making a comprehensive utilization of steel slag and maximize its economic efficiency in China.
基金financially supported by the National Natural Science Foundation of China(No.51704068)the National Key Technologies R&D Program of China(No.2017YFC0805100)the Fundamental Research Funds for the Central Universities(No.N172504020)
文摘To improve the efficiency of melting modification for stainless steel(SS) slag, a shear force was introduced in this work and its effects on the spinel and silicate melt were experimentally investigated. The results indicated that the use of shear force changed the nucleation and growth behaviors of spinel and that the effects of shear force varied with its intensity. The aggregation behavior of spinel under different shear-force conditions was studied, revealing that large spinel clusters could be formed when the stirring speed was controlled. However, no notable change in the melt structure of the silicate was detected in this study. The optimal stirring speed for the melting modification treatment was 50 r·min^(-1), which substantially promoted spinel growth and aggregation, resulting in modified SS slag with excellent chromium sequestration capability.
文摘运用均匀设计结合BP神经网络算法,在磷酸、硅烷环境下将超细粉磨后的800目钢渣微粉进行优化改性后,部分代替炭黑同橡胶按比例复合制备高性能生态橡胶材料。建立制备工艺参数与力学性能的BP神经网络优化模型,优化设计生态橡胶的工艺参数。利用BET、FTIR、XRD和SEM对优化后的生态橡胶进行表征。结果表明,优化后生态橡胶制备工艺参数:磷酸与橡胶的质量比为0.013、硅烷K550与橡胶的质量比为0.003、促进剂与橡胶的质量比为0.007、硫磺与橡胶的质量比为0.011以及硬脂酸与橡胶的质量比为0.009。优化生态橡胶的力学性能:拉伸强度为18.6 MPa、邵尔A硬度为69.7和撕裂强度为45.6 k N/m。模型预测结果与实测结果具有较高的吻合度,误差范围为-1.59%^-0.85%。
基金supported by the Mega-projects of Science Research for Water Environment Improvement of China (Nos. 2013ZX07209-001-003, 2012ZX07307-001-006)
文摘This study was performed to investigate the removal of phosphate from domestic wastewater using a modified steel slag as the adsorbent. The adsorption effects of alkalinity, salt, water,and thermal modification were investigated. The results showed that thermal activation at 800℃ for 1 hr was the optimum operation to improve the adsorption capacity. The adsorption process of the thermally modified slag was well described by the Elovich kinetic model and the Langmuir isotherm model. The maximum adsorption capacity calculated from the Langmuir model reached 13.62 mg/g. Scanning electron microscopy indicated that the surface of the modified slag was cracked and that the texture became loose after heating. The surface area and pore volume did not change after thermal modification. In the treatment of domestic wastewater, the modified slag bed（35.5 kg） removed phosphate effectively and operated for 158 days until the effluent P rose above the limit concentration of 0.5 mg/L. The phosphate fractionation method, which is often applied in soil research, was used to analyze the phosphate adsorption behavior in the slag bed. The analysis revealed that the total contents of various Ca-P forms accounted for 81.4%-91.1%, i.e., Ca10-P 50.6%-65.1%, Ca8-P 17.8%-25.0%,and Ca2-P 4.66%-9.20%. The forms of Al-P, Fe-P, and O-P accounted for only 8.9%-18.6%. The formation of Ca10-P precipitates was considered to be the main mechanism of phosphate removal in the thermally modified slag bed.
基金Sponsored by National Science and Technology Support Plan of China(2009AA064003)
文摘During the cooling process of AOD（argon-oxygen decarburization）stainless steel slag,the serious disintegrating problem happened,which will cause serious environmental pollution.The disintegrating mechanism of the AOD slag was analyzed in detail,and experimental research on prevention of disintegrating of AOD stainless steel slag was developed by adjusting the basicity of the slag and adding the quartz sand and borax.The disintegrating problem during the cooling process of AOD stainless steel slag is caused by the 2CaO·SiO2phase transformation fromα＇-C2S toγ-C2S.By means of adjusting the basicity of the AOD stainless steel slag from 2to 1.5by adding quartz sand,disintegrating of slag was prevented.But the adding amount must arrive at 15% which increases the difficulty of industrialization.Disintegration of AOD stainless steel slag can be effectively controlled by adding borax,and the adding amount is only 0.5%-0.8%.This method can be easily industrialized.
