Smelting separations of Hongge vanadium-bearing titanomagnetite metallized pellets（HVTMP）prepared by gas-based direct reduction were investigated,and the effects of smelting parameters on the slag/metal separation b...Smelting separations of Hongge vanadium-bearing titanomagnetite metallized pellets（HVTMP）prepared by gas-based direct reduction were investigated,and the effects of smelting parameters on the slag/metal separation behaviors were analyzed.Relevant mechanisms were elucidated using X-ray diffraction analysis,FACTSAGE 7.0 calculations,and scanning electron microscopy observations.The results show that,when the smelting temperature,time,and C/O ratio are increased,the recoveries of V and Cr of HVTMP in pig iron are improved,the recovery of Fe initially increases and subsequently decreases,and the recovery of Ti O_2 in slag decreases.When the smelting Ca O/Si O_2 ratio is increased,the recoveries of Fe,V,and Cr in pig iron increase and the recovery of Ti O_2 in slag initially increases and subsequently decreases.The appropriate smelting separation parameters for HVTMP are as follows：smelting temperature of 1873 K;smelting time of 30–50 min;C/O ratio of 1.25;and Ca O/Si O_2 ratio of 0.50.With these optimized parameters（smelting time：30 min）,the recoveries of Fe,V,Cr,and Ti O_2 are 99.5%,91.24%,92.41%,and 94.86%,respectively.展开更多
The leaching of chromium from stainless steel dust （SSD） is deleterious to the environment. To address this issue, the reduction of SSD briquettes can be employed to effectively extract chromium. The recovery rates ...The leaching of chromium from stainless steel dust （SSD） is deleterious to the environment. To address this issue, the reduction of SSD briquettes can be employed to effectively extract chromium. The recovery rates of iron, chromium, and nickel via ironbath reduction of SSD briquettes were determined using X-ray fluorescence spectroscopy, X-ray diffraction, and scanning electron microscopy measurements. First, the effects of basicity and contents of silicon, iron, CaF2, and carbon on the recovery rates of the three metals were analyzed using the slag amount prediction model, which was originally established from the A1203 balance of corundum crucible erosion behavior. Second, the effect of feeding mode, i.e., whether steel scrap and SSD briquettes were simultaneously added, on the recovery rates was discussed in detail. Third, the iron-bath reduction of SSD briquettes was thermodynamically analyzed. The results indicated that the recovery rates of the three metals are greater than 95% those of using a basicity of 1.5 and 6.0% CaF2, 15% carbon, and 7% ferrosilicon. The recovery rate of chromium increases twofold with the addition of ferrosilicon. The feeding mode of adding briquettes and steel scrap simultaneously is better for recovery of metals and separation of the metal and slag than the feeding mode of adding steel scrap firstly and then briquettes.展开更多
The resource recovery of heavy metals from effluent has significant environmental implications and potential commercial value.Chromium phosphide nanoparticles embedded in a nitrogen-/phosphorus-doped porous carbon mat...The resource recovery of heavy metals from effluent has significant environmental implications and potential commercial value.Chromium phosphide nanoparticles embedded in a nitrogen-/phosphorus-doped porous carbon matrix(CrP/NPC)are synthesized via a consecutive Cr^(6+)leachate treatment and resource recovery process.Electrochemical testing shows that CrP/NPC shows excellent nitrogen reduction reaction(NRR)performance,which yields the highest NH_(3) production rate of 22.56μg h^(−1) mg^(−1)_(cat).and Faradaic efficiency(16.37%)at−0.5 V versus the reversible hydrogen electrode in a 0.05M Na_(2)SO_(4) aqueous solution,as well as robust catalytic stability.The isotopic experiments using ^(15)N^(2) as a nitrogen source confirm that the detected NH_(3) is derived from the NRR process.Finally,density functional theory(DFT)calculations show that the electron deficiency environment of the Cr site can significantly reduce the barrier of the NRR process and promote the formation of intermediate species.展开更多
基金financially supported by the National Natural Science Foundation of China (No.51574067)
文摘Smelting separations of Hongge vanadium-bearing titanomagnetite metallized pellets（HVTMP）prepared by gas-based direct reduction were investigated,and the effects of smelting parameters on the slag/metal separation behaviors were analyzed.Relevant mechanisms were elucidated using X-ray diffraction analysis,FACTSAGE 7.0 calculations,and scanning electron microscopy observations.The results show that,when the smelting temperature,time,and C/O ratio are increased,the recoveries of V and Cr of HVTMP in pig iron are improved,the recovery of Fe initially increases and subsequently decreases,and the recovery of Ti O_2 in slag decreases.When the smelting Ca O/Si O_2 ratio is increased,the recoveries of Fe,V,and Cr in pig iron increase and the recovery of Ti O_2 in slag initially increases and subsequently decreases.The appropriate smelting separation parameters for HVTMP are as follows：smelting temperature of 1873 K;smelting time of 30–50 min;C/O ratio of 1.25;and Ca O/Si O_2 ratio of 0.50.With these optimized parameters（smelting time：30 min）,the recoveries of Fe,V,Cr,and Ti O_2 are 99.5%,91.24%,92.41%,and 94.86%,respectively.
基金This research was supported by the National Natural Science Foundation of China （Grant No. 51304053）, Jiangxi University of Science and Technology Doctoral Start-up Fund （No. 3401223181）.
文摘The leaching of chromium from stainless steel dust （SSD） is deleterious to the environment. To address this issue, the reduction of SSD briquettes can be employed to effectively extract chromium. The recovery rates of iron, chromium, and nickel via ironbath reduction of SSD briquettes were determined using X-ray fluorescence spectroscopy, X-ray diffraction, and scanning electron microscopy measurements. First, the effects of basicity and contents of silicon, iron, CaF2, and carbon on the recovery rates of the three metals were analyzed using the slag amount prediction model, which was originally established from the A1203 balance of corundum crucible erosion behavior. Second, the effect of feeding mode, i.e., whether steel scrap and SSD briquettes were simultaneously added, on the recovery rates was discussed in detail. Third, the iron-bath reduction of SSD briquettes was thermodynamically analyzed. The results indicated that the recovery rates of the three metals are greater than 95% those of using a basicity of 1.5 and 6.0% CaF2, 15% carbon, and 7% ferrosilicon. The recovery rate of chromium increases twofold with the addition of ferrosilicon. The feeding mode of adding briquettes and steel scrap simultaneously is better for recovery of metals and separation of the metal and slag than the feeding mode of adding steel scrap firstly and then briquettes.
基金This study was supported by Taishan Scholars Project Special Funds(tsqn201812083)the Natural Science Foundation of Shandong Province(ZR2019YQ20 and 2019JMRH0410)the National Natural Science Foundation of China(51972147,52022037 and 52002145).
文摘The resource recovery of heavy metals from effluent has significant environmental implications and potential commercial value.Chromium phosphide nanoparticles embedded in a nitrogen-/phosphorus-doped porous carbon matrix(CrP/NPC)are synthesized via a consecutive Cr^(6+)leachate treatment and resource recovery process.Electrochemical testing shows that CrP/NPC shows excellent nitrogen reduction reaction(NRR)performance,which yields the highest NH_(3) production rate of 22.56μg h^(−1) mg^(−1)_(cat).and Faradaic efficiency(16.37%)at−0.5 V versus the reversible hydrogen electrode in a 0.05M Na_(2)SO_(4) aqueous solution,as well as robust catalytic stability.The isotopic experiments using ^(15)N^(2) as a nitrogen source confirm that the detected NH_(3) is derived from the NRR process.Finally,density functional theory(DFT)calculations show that the electron deficiency environment of the Cr site can significantly reduce the barrier of the NRR process and promote the formation of intermediate species.
