[ Objective] The research aimed to study Cr wastewater treatment by steel slag. [ Method] Steel slag was used as adsorbent to remove Cr from wastewater, and influence factors of the Cr wastewater treatment by steel sl...[ Objective] The research aimed to study Cr wastewater treatment by steel slag. [ Method] Steel slag was used as adsorbent to remove Cr from wastewater, and influence factors of the Cr wastewater treatment by steel slag were studied. [ Result] Removal rate of Cr（VI） by steel slag was quite low, and the highest removal rate only reached 8.9%. Cr （III） removal by steel slag was quite effective. For 50 ml of Cr（VI） solution （100 mg/L）, after reduction, 0.30 g of steel slag （100 meshes） was added to oscillate for 35 min, and total Cr removal rate was up to 90%. Cr adsorption by steel slag was an exothermal process, and physical adsorption was dominant. Steel slag was suitable for treating acidic Cr wastewater, and its adsorption process on Cr followed Frenndlich isothermal adsorption model. [ Conduslon] It could reach the aim of ＂waste treat- ment by waste＂ bv usin~ steel slaq to treat Cr wastewater.展开更多
以砂样钢渣作为吸附剂,研究了去除废水中Cr6＋的工艺条件和机理。结果表明,最佳工艺条件分别为：p H值0.8--1.5,温度为20℃--25℃,钢渣投放量为5 g,废水初始体积以150--200 m L为宜。铬去除量与钢渣水溶液静置时间呈线性关系,且颗粒内...以砂样钢渣作为吸附剂,研究了去除废水中Cr6＋的工艺条件和机理。结果表明,最佳工艺条件分别为：p H值0.8--1.5,温度为20℃--25℃,钢渣投放量为5 g,废水初始体积以150--200 m L为宜。铬去除量与钢渣水溶液静置时间呈线性关系,且颗粒内扩散模型、准一级和二级速率方程、Langmuir和Freundlich吸附等温模型拟合曲线的相关系数较大,属于单分子层的吸附方式并具有较好的吸附性。通过机理分析可知,砂样钢渣对Cr6＋的吸附过程分为还原（降毒）、水化、沉淀、吸附等4个阶段,钢渣最大吸附量为45.872 mg/g,占砂样钢渣的比例较小。钢渣完成吸附铬后,仍可用来配制砂浆、混凝土等。展开更多
The by-product of wet flue gas desulfurization,desulfurized steel slag(DS),had chemical characteristics like natural gypsum that can be used to improve saline-sodic soil.However,contamination risk of heavy metals for ...The by-product of wet flue gas desulfurization,desulfurized steel slag(DS),had chemical characteristics like natural gypsum that can be used to improve saline-sodic soil.However,contamination risk of heavy metals for cycling utilization of DS in agriculturewas concerned mostly.Both pot and field experiments were conducted for evaluating the potential pollution risk of DS as the amendment of saline-sodic soil.Results showed that application of DS decreased the contents of Cd,Cu,Zn,and Pb,while significantly increasing chromium(Cr)content in DS-amended soils.The field experiment demonstrated that the migration of heavy metals(Cd,Zn,Cu,and Pb)in the soil profile was negligible.The application of DS at the dosage of 22.5–225 tons/ha significantly increased the Cr content in alfalfa(Medicago sativa L.)but lower than the national standard for feed in China(GB 13078-2017).DS altered the chemical fraction of heavy metals(Zn,Cu,and Pb),transferred exchangeable,reducible into oxidizable and residual forms in DS-amended soil.Application of DS combined with fulvic acid(FA)could effectively reduce the movement of heavy metals in soil and the accumulation of Cr in alfalfa.Based on our results,DS was a safe and feasible material for agricultural use and presented relatively little pollution risk of heavy metals.However,the results also showed that DS to a certain extent had a potential environmental risk of Cr if larger dosages of DS were used.展开更多
The optimal composition of a CaO-SiO_(2)-Al_(2)O_(3)-MgO slag in the ladle furnace refining process was investigated to precisely control the contents of[0]and[Si]and improve the cleanliness of 30Cr2Ni4MoV steel.The i...The optimal composition of a CaO-SiO_(2)-Al_(2)O_(3)-MgO slag in the ladle furnace refining process was investigated to precisely control the contents of[0]and[Si]and improve the cleanliness of 30Cr2Ni4MoV steel.The iso-[O]lines and iso-[Si] lines of the equilibrium between the CaO-SiO_(2)-Al_(2)O_(3)-MgO refining slag and 30Cr2Ni4MoV steel at 1873 K were calculated by the thermodynamic software FactSage 7.3,and the activities of SiO_(2),Al_(2)O_(3)and CaO in the refining slag were discussed to achieve the optimal composition range of the refining slag.Finally,combined with high-temperature"slag-steel"equilibrium experiments,the effects of different refining slags on the oxygen contents,chemical composi-tions,quantities and sizes of inclusions in steels were studied,and then the thermody namic formation mechanism of MgAl_(2)O_(4) inclusions in 30Cr2Ni4MoV steel was discussed.The results showed that the contents of dissolved[O]nd[Si]in steel can be controlled below 10 × 10^(-6)and 0.05%.respectively;when the slag basicity is above 7.the CaO/Al_(2)O_(3)ratio is above I.and the mass fraction of SiO_(2)in the slag docs not cxcced 7%.The chemical composition of the slag has a great influence on the removal and composition of inclusions.The assessed stability phase diagrams of MgO.Al_(2)O_(3)and MgOAl_(2)O_(3) inclusion formation in the Fe-Al-Mg-O system calculated by FactSage 7.3 show good agreement with the experimental results.展开更多
The influence of CaF2 content on the formation behavior of spinel inclusions in the Ni-Cr-V-alloyed special steel was presented. The spinel was not formed at CaF2 content lower than 10 wt%. However, it was formed at e...The influence of CaF2 content on the formation behavior of spinel inclusions in the Ni-Cr-V-alloyed special steel was presented. The spinel was not formed at CaF2 content lower than 10 wt%. However, it was formed at early stage when the CaF2 content was greater than 30 wt%, followed by a modification to the aluminosilicate-type inclusions. Because the slag was saturated by MgO, the activity of MgO was unity irrespective of CaF2 content in the slag. Thus, Mg was transferred from slag to metal phase. Mg transferred to molten steel reacted with Al2O3-rich inclusions to form MgO.Al2O3 spinel. However, the spinel inclusion was modified to aluminosilicate-type inclusions by the reaction with Si and Ca transferred from slag to molten steel about 2-3 h later.展开更多
文摘[ Objective] The research aimed to study Cr wastewater treatment by steel slag. [ Method] Steel slag was used as adsorbent to remove Cr from wastewater, and influence factors of the Cr wastewater treatment by steel slag were studied. [ Result] Removal rate of Cr（VI） by steel slag was quite low, and the highest removal rate only reached 8.9%. Cr （III） removal by steel slag was quite effective. For 50 ml of Cr（VI） solution （100 mg/L）, after reduction, 0.30 g of steel slag （100 meshes） was added to oscillate for 35 min, and total Cr removal rate was up to 90%. Cr adsorption by steel slag was an exothermal process, and physical adsorption was dominant. Steel slag was suitable for treating acidic Cr wastewater, and its adsorption process on Cr followed Frenndlich isothermal adsorption model. [ Conduslon] It could reach the aim of ＂waste treat- ment by waste＂ bv usin~ steel slaq to treat Cr wastewater.
基金supported by the Science and Technology Innovation 2025 Major Project of Ningbo City,China(No.2018B10091)Ningbo Taiji Environmental Protection Equipment Co.,Ltd.(NTEPEC)provided experimental materials(desulfurized steel slag)。
文摘The by-product of wet flue gas desulfurization,desulfurized steel slag(DS),had chemical characteristics like natural gypsum that can be used to improve saline-sodic soil.However,contamination risk of heavy metals for cycling utilization of DS in agriculturewas concerned mostly.Both pot and field experiments were conducted for evaluating the potential pollution risk of DS as the amendment of saline-sodic soil.Results showed that application of DS decreased the contents of Cd,Cu,Zn,and Pb,while significantly increasing chromium(Cr)content in DS-amended soils.The field experiment demonstrated that the migration of heavy metals(Cd,Zn,Cu,and Pb)in the soil profile was negligible.The application of DS at the dosage of 22.5–225 tons/ha significantly increased the Cr content in alfalfa(Medicago sativa L.)but lower than the national standard for feed in China(GB 13078-2017).DS altered the chemical fraction of heavy metals(Zn,Cu,and Pb),transferred exchangeable,reducible into oxidizable and residual forms in DS-amended soil.Application of DS combined with fulvic acid(FA)could effectively reduce the movement of heavy metals in soil and the accumulation of Cr in alfalfa.Based on our results,DS was a safe and feasible material for agricultural use and presented relatively little pollution risk of heavy metals.However,the results also showed that DS to a certain extent had a potential environmental risk of Cr if larger dosages of DS were used.
基金supported by the National Natural ScienceFoundation of China(Grant Nos.51774217,52074198 and51604201).
文摘The optimal composition of a CaO-SiO_(2)-Al_(2)O_(3)-MgO slag in the ladle furnace refining process was investigated to precisely control the contents of[0]and[Si]and improve the cleanliness of 30Cr2Ni4MoV steel.The iso-[O]lines and iso-[Si] lines of the equilibrium between the CaO-SiO_(2)-Al_(2)O_(3)-MgO refining slag and 30Cr2Ni4MoV steel at 1873 K were calculated by the thermodynamic software FactSage 7.3,and the activities of SiO_(2),Al_(2)O_(3)and CaO in the refining slag were discussed to achieve the optimal composition range of the refining slag.Finally,combined with high-temperature"slag-steel"equilibrium experiments,the effects of different refining slags on the oxygen contents,chemical composi-tions,quantities and sizes of inclusions in steels were studied,and then the thermody namic formation mechanism of MgAl_(2)O_(4) inclusions in 30Cr2Ni4MoV steel was discussed.The results showed that the contents of dissolved[O]nd[Si]in steel can be controlled below 10 × 10^(-6)and 0.05%.respectively;when the slag basicity is above 7.the CaO/Al_(2)O_(3)ratio is above I.and the mass fraction of SiO_(2)in the slag docs not cxcced 7%.The chemical composition of the slag has a great influence on the removal and composition of inclusions.The assessed stability phase diagrams of MgO.Al_(2)O_(3)and MgOAl_(2)O_(3) inclusion formation in the Fe-Al-Mg-O system calculated by FactSage 7.3 show good agreement with the experimental results.
文摘The influence of CaF2 content on the formation behavior of spinel inclusions in the Ni-Cr-V-alloyed special steel was presented. The spinel was not formed at CaF2 content lower than 10 wt%. However, it was formed at early stage when the CaF2 content was greater than 30 wt%, followed by a modification to the aluminosilicate-type inclusions. Because the slag was saturated by MgO, the activity of MgO was unity irrespective of CaF2 content in the slag. Thus, Mg was transferred from slag to metal phase. Mg transferred to molten steel reacted with Al2O3-rich inclusions to form MgO.Al2O3 spinel. However, the spinel inclusion was modified to aluminosilicate-type inclusions by the reaction with Si and Ca transferred from slag to molten steel about 2-3 h later.
