褐铁矿微波还原焙烧-磁选单因素实验研究
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摘要
针对褐铁矿铁品位难提高的问题,采用"微波还原焙烧-磁选"工艺,将褐铁矿还原成磁铁矿,弱磁选后获得高品位磁铁精矿。采用SEM和XRD检测方法,研究了褐铁矿微波焙烧过程中的矿相演变规律,同时采用单因素实验方法,重点考察了保温时间、焙烧温度、配碳量以及磁选电流和磨矿细度对焙烧矿磁选结果的影响。结果表明:随着温度升高,褐铁矿逐渐还原为磁铁矿,加热到570~650℃时,生成大量磁铁矿,750℃下焙烧矿烧结严重,并产生大量弱磁性的硅酸亚铁,不利于后续磁选。单因素实验结果及分析表明,褐铁矿微波还原焙烧-磁选最佳工艺条件为:保温时间7.5 min,焙烧温度650℃,配碳量1.40%,磁选电流0.6 A,磨矿细度-0.044 mm。最终获得的铁精矿品位、回收率及产率分别为61.33%、75.11%和40.17%,达到了炼铁生产入炉要求。
In view of the difficulty in upgrading iron grade of limonite,the technique of reduction roasting-magnetic separation by microwave heating was proposed to make limonite firstly reduced into magnetite,which was subjected to low-intensity magnetic separation,resulting in the high-grade magnetite concentrate. The mineral phase variation during the process of reduction roasting of limonite by microwave heating was investigated by SEM and XRD analysis. And the effects of heat holding time,roasting temperature,carbon content,magnetic current and grinding fineness on the results of magnetic separation were investigated through single-factor test. Results showed that limonite was gradually reduced into magnetite with the rising temperature,and a large amount of magnetite were produced at the temperature ranges of570 ~ 650 ℃. However,serious sintering of roasted ore would be occurred at 750 ℃,resulting in the generation of ferrous silicate with weak magnetism,being unfavorable for the following magnetic separation. The single-factor test results showed that the process of reduction roasting-magnetic separation of limonite by microwave heating,with the optimum condition including heat holding time of 7. 5 min,at the temperature of 650 ℃,carbon content of 1. 40%,magnetic current of 0. 6 A,and grinding fineness at- 0. 044 mm,can result in the final iron concentrate grading 61. 33% Fe at the recovery of 75. 11%,with the yield of 40. 17%,which can meet the feed requirement for ironmaking production.
In view of the difficulty in upgrading iron grade of limonite,the technique of reduction roasting-magnetic separation by microwave heating was proposed to make limonite firstly reduced into magnetite,which was subjected to low-intensity magnetic separation,resulting in the high-grade magnetite concentrate. The mineral phase variation during the process of reduction roasting of limonite by microwave heating was investigated by SEM and XRD analysis. And the effects of heat holding time,roasting temperature,carbon content,magnetic current and grinding fineness on the results of magnetic separation were investigated through single-factor test. Results showed that limonite was gradually reduced into magnetite with the rising temperature,and a large amount of magnetite were produced at the temperature ranges of570 ~ 650 ℃. However,serious sintering of roasted ore would be occurred at 750 ℃,resulting in the generation of ferrous silicate with weak magnetism,being unfavorable for the following magnetic separation. The single-factor test results showed that the process of reduction roasting-magnetic separation of limonite by microwave heating,with the optimum condition including heat holding time of 7. 5 min,at the temperature of 650 ℃,carbon content of 1. 40%,magnetic current of 0. 6 A,and grinding fineness at- 0. 044 mm,can result in the final iron concentrate grading 61. 33% Fe at the recovery of 75. 11%,with the yield of 40. 17%,which can meet the feed requirement for ironmaking production.
引文
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[12]李解,张邦文,李保卫.白云鄂博中贫氧化矿微波磁化焙烧-磁选试验研究[J].金属矿山,2010,407(5):89-91.
[13]Ying LEI,Yu LI,Jinhui PENG,et al.Carbothermic reduction of panzhihua oxidized ilmenite in a microwave field[J].ISIJ International,2011,51(3):337-343.
[14]JIE LI,BAOWEI LI,JICHENG HAN,et al.A comparative study on the reduction mechanism of Fe2O3under different heating methods[J].JOM,2014,66(8):1529-1536.
[15]韩磊,李解,李保卫,等.微波加热褐铁矿的脱水反应动力学[J].过程工程学报,2014,14(2):28-33.
[2]Satoshi MACHIDA,Takahide HIGUCHI,Nobuyuki OYAMA,et al.Optimization of coke breeze segregation in sintering bed under high pisolite ore ratio[J].ISIJ International,2009,49(5):650-658.
[3]刘东辉,吕庆,邹雷雷,等.褐铁矿配比对钒钛磁铁矿烧结基础特性的影响[J].钢铁,2014,49(4):13-17.
[4]刘兴华,罗良飞,刘卫,等.某低品位褐铁矿的选矿工艺研究[J].矿冶工程,2013,33(4):70-73.
[5]谢兴中,王毓华.褐铁矿浮选的有效捕收剂及其机理研究[J].矿冶工程,2011,31(2):49-52.
[6]裴元东,赵志星,马泽军,等.高比例褐铁矿烧结机理分析及试验研究[J].烧结球团,2011,36(5):1-7.
[7]张红新,李洪潮,张成强,等.某易泥化褐铁矿选矿试验研究[J].矿产保护与利用,2011(3):19-21.
[8]高照国,曹耀华,刘红召,等.某难选褐铁矿直接还原焙烧-磁选工艺研究[J].矿冶工程,2013,33(4):49-51.
[9]王秋林,陈雯,余永富,等.复杂难选褐铁矿的闪速磁化焙烧试验研究[J].矿产保护与利用,2010(3):27-30.
[10]王在谦,唐云,舒聪伟,等.难选褐铁矿氯化离析焙烧-磁选研究[J].矿冶工程,2013,33(2):81-83.
[11]陈津,刘浏,曾加庆,等.微波加热还原含碳铁矿粉试验研究[J].钢铁,2004,39(6):1-5.
[12]李解,张邦文,李保卫.白云鄂博中贫氧化矿微波磁化焙烧-磁选试验研究[J].金属矿山,2010,407(5):89-91.
[13]Ying LEI,Yu LI,Jinhui PENG,et al.Carbothermic reduction of panzhihua oxidized ilmenite in a microwave field[J].ISIJ International,2011,51(3):337-343.
[14]JIE LI,BAOWEI LI,JICHENG HAN,et al.A comparative study on the reduction mechanism of Fe2O3under different heating methods[J].JOM,2014,66(8):1529-1536.
[15]韩磊,李解,李保卫,等.微波加热褐铁矿的脱水反应动力学[J].过程工程学报,2014,14(2):28-33.