Understanding the phase equilibria of the Fe3O4-Cr2O3-CaO system is essential for the efficient recycling of stainless steel pickling sludge.The isothermal section of this system at 1473 K under oxygen par...Understanding the phase equilibria of the Fe3O4-Cr2O3-CaO system is essential for the efficient recycling of stainless steel pickling sludge.The isothermal section of this system at 1473 K under oxygen partial pressure of 0.15 Pa was investigated.Key experiments on the relevant binary systems were conducted using a combination of equilibrium-quenching techniques,X-ray diffraction,high-resolution transmission electron microscope,and electron probe microanalysis.These systems were rigorously assessed using the CALPHAD(CALculation of Phase Diagram)method,incorporating the present experimental data.The liquid phase was modeled using the ionic two-sublattice model,represented as(Ca2+,Cr3+,Fe2+)P(O2-,Va,FeO1.5)Q,where Va represents vacancy,and P and Q denote the number of sites on the cation and anion sublattices,respectively.To ensure electroneutrality,the values of P and Q adjust according to the composition of the mixture.From this,the isothermal section of the Fe3O4-Cr2O3-CaO system at 1473 K under the specified oxygen partial pressure was obtained based on the thermodynamic parameters of the binary systems.The present experimental data and calculation results hold significant implications for the comprehensive recycling of stainless steel pickling sludge.展开更多
Reduction smelting of the bismuth oxide residue from pressure leaching of bismuth sulfide was investigated in the FeO-SiO_2-CaO ternary slag system.The results show that all the recovery ratios of Bi,Ag,Cu and Pb incr...Reduction smelting of the bismuth oxide residue from pressure leaching of bismuth sulfide was investigated in the FeO-SiO_2-CaO ternary slag system.The results show that all the recovery ratios of Bi,Ag,Cu and Pb increase with the increase of reductive coal proportion,reaction temperature and time,while too much reductive coal would help Fe enter metal phase;CaO/SiO_2and Fe O/SiO_2 of the chosen slag system should be 0.5-0.75 and 1.25-1.75,respectively,for the reason that the slag system has the optimum mobility and is beneficial for the recovery of metals.The corresponding optimum conditions are determined as follows:the added coal proportion is 7%of the leaching residue,CaO/SiO_2 mass ratio in the chosen slag system is 0.5 and FeO-SiO_2 is 1.5,the reaction temperature is 1300°C and the reaction time is 40 min.Under the above conditions,the recovery ratios of Bi,Ag,Cu and Pb are 99.6%,99.8%,97.0%and 97.3%,respectively.展开更多
The desulfurization experiment of an Al2O3-CaO base pre-molten refining slag containing SrO was carried out. Experimental samples were made from industrial materials. In order to predict the slag's desulfurization...The desulfurization experiment of an Al2O3-CaO base pre-molten refining slag containing SrO was carried out. Experimental samples were made from industrial materials. In order to predict the slag's desulfurization ability, sulphur capacity was calculated by means of optical basicity, and there is consistency between calculated results and experimental data. A mathematical model between components and sulphur partition ratio was established with the experimental data. Based on the regression equation, the effects of single and interactive components on sulphur partition ratio were discussed. The results show that the sulphur capacity and distribution ratio decrease with the increment of Al2O3/CaO. SrO and MgO can increase the sulphur partition ratio. The best content of SrO in the slag should not be more than 10%, and the MgO content should be about 8%. The effect of CaF2 on sulphur partition ratio is not obvious, therefore the addition should be limited for environmental protection.展开更多
The O2-CaO jet with shrouding combustion flame demonstrates some advantages in quick melting and effective slag foaming by delivering lime powder deeply into the molten bath.Combining the discrete particle model an...The O2-CaO jet with shrouding combustion flame demonstrates some advantages in quick melting and effective slag foaming by delivering lime powder deeply into the molten bath.Combining the discrete particle model and the eddy dissipation concept model with the detailed chemical kinetic mechanisms(GRI-Mech 3.0),computational fluid dynamics models of the O2-CaO jet with different shrouding fuel mediums injection were developed.Firstly,the results of the numerical simulation were validated by the measured data of cold test for O2-CaO injection.Then,the interaction between the particles and the gas jet of the O2-CaO jet and the effect of shrouding fuel medium species on the fluid flow characteristics of the O2-CaO jet were analyzed.Results show that the CaO particles can be effectively heated by the shrouding high-temperature combustion flame and compared with the O2-CaO jet without shrouding gas,the potential core length was increased about 2.5,3.3 and 4.3 times by the shrouding flame generated from CO,CH4 and C3H8.And with shrouding CH4 and C3H8 injection,the CaO particles can be clustered together in a long distance,which would be helpful to improve the utilization efficiency of CaO particles.展开更多
基金supports on the Project 52274306 from the National Natural Science Foundation of China are gratefully acknowledged.
摘要Understanding the phase equilibria of the Fe3O4-Cr2O3-CaO system is essential for the efficient recycling of stainless steel pickling sludge.The isothermal section of this system at 1473 K under oxygen partial pressure of 0.15 Pa was investigated.Key experiments on the relevant binary systems were conducted using a combination of equilibrium-quenching techniques,X-ray diffraction,high-resolution transmission electron microscope,and electron probe microanalysis.These systems were rigorously assessed using the CALPHAD(CALculation of Phase Diagram)method,incorporating the present experimental data.The liquid phase was modeled using the ionic two-sublattice model,represented as(Ca2+,Cr3+,Fe2+)P(O2-,Va,FeO1.5)Q,where Va represents vacancy,and P and Q denote the number of sites on the cation and anion sublattices,respectively.To ensure electroneutrality,the values of P and Q adjust according to the composition of the mixture.From this,the isothermal section of the Fe3O4-Cr2O3-CaO system at 1473 K under the specified oxygen partial pressure was obtained based on the thermodynamic parameters of the binary systems.The present experimental data and calculation results hold significant implications for the comprehensive recycling of stainless steel pickling sludge.
基金Project(134414) supported by the Postdoctoral Funded Program of Central South University,China
摘要Reduction smelting of the bismuth oxide residue from pressure leaching of bismuth sulfide was investigated in the FeO-SiO_2-CaO ternary slag system.The results show that all the recovery ratios of Bi,Ag,Cu and Pb increase with the increase of reductive coal proportion,reaction temperature and time,while too much reductive coal would help Fe enter metal phase;CaO/SiO_2and Fe O/SiO_2 of the chosen slag system should be 0.5-0.75 and 1.25-1.75,respectively,for the reason that the slag system has the optimum mobility and is beneficial for the recovery of metals.The corresponding optimum conditions are determined as follows:the added coal proportion is 7%of the leaching residue,CaO/SiO_2 mass ratio in the chosen slag system is 0.5 and FeO-SiO_2 is 1.5,the reaction temperature is 1300°C and the reaction time is 40 min.Under the above conditions,the recovery ratios of Bi,Ag,Cu and Pb are 99.6%,99.8%,97.0%and 97.3%,respectively.
摘要The desulfurization experiment of an Al2O3-CaO base pre-molten refining slag containing SrO was carried out. Experimental samples were made from industrial materials. In order to predict the slag's desulfurization ability, sulphur capacity was calculated by means of optical basicity, and there is consistency between calculated results and experimental data. A mathematical model between components and sulphur partition ratio was established with the experimental data. Based on the regression equation, the effects of single and interactive components on sulphur partition ratio were discussed. The results show that the sulphur capacity and distribution ratio decrease with the increment of Al2O3/CaO. SrO and MgO can increase the sulphur partition ratio. The best content of SrO in the slag should not be more than 10%, and the MgO content should be about 8%. The effect of CaF2 on sulphur partition ratio is not obvious, therefore the addition should be limited for environmental protection.
基金the Fundamental Research Funds for the Central Universities(FRF-TP-19-031A1)the China Post Postdoctoral Science Foundation(2020T130053,2019M660459)the National Natural Science Foundation of China(No.51734003).
摘要The O2-CaO jet with shrouding combustion flame demonstrates some advantages in quick melting and effective slag foaming by delivering lime powder deeply into the molten bath.Combining the discrete particle model and the eddy dissipation concept model with the detailed chemical kinetic mechanisms(GRI-Mech 3.0),computational fluid dynamics models of the O2-CaO jet with different shrouding fuel mediums injection were developed.Firstly,the results of the numerical simulation were validated by the measured data of cold test for O2-CaO injection.Then,the interaction between the particles and the gas jet of the O2-CaO jet and the effect of shrouding fuel medium species on the fluid flow characteristics of the O2-CaO jet were analyzed.Results show that the CaO particles can be effectively heated by the shrouding high-temperature combustion flame and compared with the O2-CaO jet without shrouding gas,the potential core length was increased about 2.5,3.3 and 4.3 times by the shrouding flame generated from CO,CH4 and C3H8.And with shrouding CH4 and C3H8 injection,the CaO particles can be clustered together in a long distance,which would be helpful to improve the utilization efficiency of CaO particles.