The oxidation induration and reduction swelling behavior of chromium-bearing vanadium titanomagnetite pellets(CVTP)with Cr2O3 addition were studied,and the reduction swelling index(RSI)and compressive strength(CS)of t...The oxidation induration and reduction swelling behavior of chromium-bearing vanadium titanomagnetite pellets(CVTP)with Cr2O3 addition were studied,and the reduction swelling index(RSI)and compressive strength(CS)of the reduced CVTP with simulated coke oven gas(COG)injection were investigated.The results showed that the CS of the CVTP decreases and the porosity of the CVTP increases with increasing amount of Cr2O3 added.The Cr2O3 mainly exists in the form of(Cr,Fe)2O3 solid solution in the CVTP and as Fe-Cr in the reduced CVTP.The CS of the reduced CVTP increases and the RSI of the reduced CVTP decreases with increasing amount of Cr2O3 added.The limited aggregation and diffusion of metallic iron contribute to the formation of dense lamellar crystals,which leads to the slight decrease for reduction swelling behavior of reduced CVTP.This work provides a theoretical and technical basis for the utilization of CVTP and other Cr-bearing ores such as chromite with COG recycling technology.展开更多
The oxidation induration and reduction swelling behavior of the chromium-bearing vanadium titanomagnetite pellets (CVTP) with B2O3 addition were investigated. Besides, the reduction swelling index (RSI) and compressiv...The oxidation induration and reduction swelling behavior of the chromium-bearing vanadium titanomagnetite pellets (CVTP) with B2O3 addition were investigated. Besides, the reduction swelling index (RSI) and compressive strength (CS) of the reduced CVTP were also examined using the simulated coke oven gas (COG). The results suggested that the CS of CVTP was increased from 2448 to 3819.2 N, while the porosity of CVTP was decreased from 14.86% to 10.03% with the increase in B2O3 addition amounts. Moreover, the B2O3 mainly existed in the forms of TiB0.024O2 and Fe3BO5 in both CVTP and the reduced CVTP. Specifically, the CS of the reduced CVTP was elevated from 901 to 956.2 N, while the RSI was reduced from 5.87% to 3.81% as the B2O3 addition amounts were increased. Taken together, B2O3 addition would facilitate the aggregation and diffusion of metallic iron particles, which contributed to reducing the formation of metal iron whiskers and weakening the reduction swelling behavior.展开更多
A safe,economical treatment of hazardous chromium-bearing vanadate residue(CVR)will significantly benefit the clean production of chromate-bearing salts.This study investigated recovery of sodium vanadate and sodium c...A safe,economical treatment of hazardous chromium-bearing vanadate residue(CVR)will significantly benefit the clean production of chromate-bearing salts.This study investigated recovery of sodium vanadate and sodium chromate from CVR in sodium bicarbonate solution.Results indicate that the stability of calcium vanadate and calcium chromate depends on pH and[HCO3?].CaV2O6?4H2O transforms into CaV2O6?4H2O,CaV2O6?2H2O,CaV2O6,Ca2V2O7?2H2O,and Ca5(VO4)3(OH)when pH increases from 7.51 to 12.32.Increasing pH and reducing CVR dosage improve the vanadate extraction rate,and high V2O5 and Na2Cr2O7?2H2O extraction rates are achieved in dilute NaHCO3 solution.Moreover,addition of NaOH positively contributes to the recovery of vanadate and chromate from CVR.Over 95%V2O5 and Na2Cr2O7?2H2O in CVR can be extracted from 60 g/L NaHCO3 and 30 g/L NaOH solutions at 90°C for 2 h.In order to reduce the hazardous residue containing chromate after recovery of CVR,calcium circulation is presented.Results show that more than 60%lime can be saved with fresh residue addition to remove vanadate from sodium chromate solution due to the active CaCO3.Moreover,no lime is required in removal of vanadate when the roasting residue is added.Therefore,a novel process is developed for utilization of CVR.展开更多
The effect of nickel oxide additive on the smelting behaviors of chromium-bearing vanadium titanomagnetite pellets(CVTP)was investigated while analyzing the transfer behavior of nickel in iron and slag.The results sho...The effect of nickel oxide additive on the smelting behaviors of chromium-bearing vanadium titanomagnetite pellets(CVTP)was investigated while analyzing the transfer behavior of nickel in iron and slag.The results show that when NiO added to CVTP increases from 0 to 6 wt.%,softening start temperature increases from 1148 to 1212℃,and the softening end temperature increases from 1280 to 1334℃;the melting start temperature increases from 1318 to 1377℃,and the dripping temperature decreases from 1558 to 1521℃.The pig iron comprises a compound of Fe-Ni-C.The slag structure depolymerizes with increasing nickel addition.The softening-melting behaviors of CVTP,the reduction of nickel into pig iron,and the depolymerization of slag structure indicate the feasibility of producing nickel-iron alloy through the blast furnace process.展开更多
采用常压下空气氧化-碱浸工艺,对钒冶炼的钒铬还原渣进行提钒.通过正交实验考察了碱浓度、浸出温度、液固比对钒浸出率的影响,研究了钒的浸出动力学.结果表明,最佳条件为碱浓度100 g/L、浸出温度100℃、液固比4 m L/g、浸出时间1 h.该...采用常压下空气氧化-碱浸工艺,对钒冶炼的钒铬还原渣进行提钒.通过正交实验考察了碱浓度、浸出温度、液固比对钒浸出率的影响,研究了钒的浸出动力学.结果表明,最佳条件为碱浓度100 g/L、浸出温度100℃、液固比4 m L/g、浸出时间1 h.该条件下钒浸出率最高达98%.钒的浸出过程符合核收缩模型,受扩散步骤控制,表观活化能为11.04 k J/mol.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.51674084, 51174051, and 51574082)
文摘The oxidation induration and reduction swelling behavior of chromium-bearing vanadium titanomagnetite pellets(CVTP)with Cr2O3 addition were studied,and the reduction swelling index(RSI)and compressive strength(CS)of the reduced CVTP with simulated coke oven gas(COG)injection were investigated.The results showed that the CS of the CVTP decreases and the porosity of the CVTP increases with increasing amount of Cr2O3 added.The Cr2O3 mainly exists in the form of(Cr,Fe)2O3 solid solution in the CVTP and as Fe-Cr in the reduced CVTP.The CS of the reduced CVTP increases and the RSI of the reduced CVTP decreases with increasing amount of Cr2O3 added.The limited aggregation and diffusion of metallic iron contribute to the formation of dense lamellar crystals,which leads to the slight decrease for reduction swelling behavior of reduced CVTP.This work provides a theoretical and technical basis for the utilization of CVTP and other Cr-bearing ores such as chromite with COG recycling technology.
基金Projects(51674084,51174051,51574082)supported by the National Natural Science Foundation of China
文摘The oxidation induration and reduction swelling behavior of the chromium-bearing vanadium titanomagnetite pellets (CVTP) with B2O3 addition were investigated. Besides, the reduction swelling index (RSI) and compressive strength (CS) of the reduced CVTP were also examined using the simulated coke oven gas (COG). The results suggested that the CS of CVTP was increased from 2448 to 3819.2 N, while the porosity of CVTP was decreased from 14.86% to 10.03% with the increase in B2O3 addition amounts. Moreover, the B2O3 mainly existed in the forms of TiB0.024O2 and Fe3BO5 in both CVTP and the reduced CVTP. Specifically, the CS of the reduced CVTP was elevated from 901 to 956.2 N, while the RSI was reduced from 5.87% to 3.81% as the B2O3 addition amounts were increased. Taken together, B2O3 addition would facilitate the aggregation and diffusion of metallic iron particles, which contributed to reducing the formation of metal iron whiskers and weakening the reduction swelling behavior.
基金Project(51274242)supported by the National Natural Science Foundation of ChinaProject(2015CX001)supported by the Innovation-driven Plan of Central South University,China
文摘A safe,economical treatment of hazardous chromium-bearing vanadate residue(CVR)will significantly benefit the clean production of chromate-bearing salts.This study investigated recovery of sodium vanadate and sodium chromate from CVR in sodium bicarbonate solution.Results indicate that the stability of calcium vanadate and calcium chromate depends on pH and[HCO3?].CaV2O6?4H2O transforms into CaV2O6?4H2O,CaV2O6?2H2O,CaV2O6,Ca2V2O7?2H2O,and Ca5(VO4)3(OH)when pH increases from 7.51 to 12.32.Increasing pH and reducing CVR dosage improve the vanadate extraction rate,and high V2O5 and Na2Cr2O7?2H2O extraction rates are achieved in dilute NaHCO3 solution.Moreover,addition of NaOH positively contributes to the recovery of vanadate and chromate from CVR.Over 95%V2O5 and Na2Cr2O7?2H2O in CVR can be extracted from 60 g/L NaHCO3 and 30 g/L NaOH solutions at 90°C for 2 h.In order to reduce the hazardous residue containing chromate after recovery of CVR,calcium circulation is presented.Results show that more than 60%lime can be saved with fresh residue addition to remove vanadate from sodium chromate solution due to the active CaCO3.Moreover,no lime is required in removal of vanadate when the roasting residue is added.Therefore,a novel process is developed for utilization of CVR.
基金financial supports from the National Natural Science Foundation of China(Nos.21908020,U1908226)。
文摘The effect of nickel oxide additive on the smelting behaviors of chromium-bearing vanadium titanomagnetite pellets(CVTP)was investigated while analyzing the transfer behavior of nickel in iron and slag.The results show that when NiO added to CVTP increases from 0 to 6 wt.%,softening start temperature increases from 1148 to 1212℃,and the softening end temperature increases from 1280 to 1334℃;the melting start temperature increases from 1318 to 1377℃,and the dripping temperature decreases from 1558 to 1521℃.The pig iron comprises a compound of Fe-Ni-C.The slag structure depolymerizes with increasing nickel addition.The softening-melting behaviors of CVTP,the reduction of nickel into pig iron,and the depolymerization of slag structure indicate the feasibility of producing nickel-iron alloy through the blast furnace process.
文摘采用常压下空气氧化-碱浸工艺,对钒冶炼的钒铬还原渣进行提钒.通过正交实验考察了碱浓度、浸出温度、液固比对钒浸出率的影响,研究了钒的浸出动力学.结果表明,最佳条件为碱浓度100 g/L、浸出温度100℃、液固比4 m L/g、浸出时间1 h.该条件下钒浸出率最高达98%.钒的浸出过程符合核收缩模型,受扩散步骤控制,表观活化能为11.04 k J/mol.
