硫磺还原高铁赤泥提铁

为提高高铁赤泥的综合利用率,响应国家“碳达峰”与“碳中和”的号召,提出了利用硫磺还原高铁赤泥、固相还原—磁选提铁的新方法,研究了不同的焙烧温度、配料比、焙烧时间对硫磺还原赤泥中Fe₂O₃效果的影响.利用XRD分析了焙烧产物的物相组成,采用湿法磁选机磁选分离出精矿和尾矿,并计算出精矿中铁的回收率.结果表明：在硫磺与高铁赤泥的配料比(即S与赤泥中Fe₂O₃的摩尔比)为1∶6、焙烧温度为800℃、焙烧时间为0.5 h的条件下,还原效果最佳,铁回收率高达90%.     

含铌尾矿中铁与铌的分离与回收

在热力学分析的基础上,通过碳热还原和磁选分离对白云鄂博含铌尾矿中铁的回收与铌的富集进行探索性研究。结果表明,在1 000~1 100℃下,以碳为还原剂进行焙烧可以对含铌尾矿中的铁氧化物进行选择性还原。1 100℃焙烧0.5h并经湿磨后在50mT的磁场强度下磁选,可实现铁精粉与含铌矿物的分离。磁选所得铁精粉中铁品位为84.82%,铁收得率为81.95%,磁选尾矿中铌品位为1.98%,铌回收率达到95%以上。     

双鸭山含镓铁矿固相还原法提镓

实验表明,通过制团、固相还原焙烧和磁选方法可将铁精粉中铁的氧化物和镓的氧化物同时还原.在固相还原法最佳条件下,铁的还原率达81.57%,镓的含量为0.007 38%,是原料中镓含量的1.54倍.磁选试验优化结果,产物中镓的含量达0.016%,是原料中镓含量的3.31倍.采用固相还原法处理铁精粉提镓可取得较好的实验效果.     

赤泥中铁资源的回收利用研究

系统概述了目前国内外赤泥中铁回收利用技术和应用。对澳大利亚赤泥进行了还原焙烧—磁选、熔炼生铁工艺试验。分析了赤泥及还原焙烧样微观显微镜下铁元素的赋存状态和分布情况。阐明了还原焙烧时赤泥中绝大部分赤铁矿或磁赤铁矿等各类氧化铁已完成向金属铁的转变,但各类铁矿物与非晶态的铁尖晶石关系过于密切且嵌布特征十分复杂,焙烧后细磨无法使二者充分解离,因此不易获得高品位铁精矿。在焦比20%、熔炼时间90min、钙铝比2.0、1 500℃进行赤泥还原熔炼,可实现渣铁的有效分离,金属铁回收率可达到99.4%以上,所得铁水质量符合炼钢生铁标准。在碳酸钠100g/L、液固比10∶1、温度80℃、时间1.5h下进行自粉化熔渣中铝的浸出,Al2O3浸出率达到91.12%。     

从赤泥中回收铁的试验研究

赤泥是氧化铝生产过程中的副产品,其中铁在赤泥中的含量为30％左右。通过还原焙烧试验,可以回收赤泥中的铁。得到的最佳试验条件为：赤泥、碳酸钠和焦炭的质量比为5：5：1;还原焙烧温度为1000℃;焙烧时间为60min。     

铜渣与高炉灰共还原—磁选回收铁试验

以铁品位35.59%的山东某地的铜渣和山东、甘肃两地的四种高炉灰为原料,进行共还原—磁选回收铁工艺试验,研究了高炉灰作为共还原—磁选工艺还原剂的可行性。结果表明,焙烧体系中仅加入高炉灰时,铜渣与高炉灰共还原—磁选所得还原铁指标均较差;当加入氟化钙时,还原铁中铁品位和铁回收率均大于90%,指标较好,实现了铜渣与高炉灰中铁资源的高效回收。高炉灰种类及用量、氟化钙用量、还原温度、还原时间及磨选条件均对还原铁指标有影响,在铜渣∶G1∶氟化钙质量比为100∶30∶15、共还原温度1250℃、共还原时间60 min的条件下焙烧,然后在磨矿细度-74μm占51.87%、磁场强度80 kA/m条件下磁选,可获得铁品位和铁回收率分别为92.06%和92.65%的直接还原铁。该工艺可以为铜渣和高炉灰的综合利用提供参考。     

牙买加赤泥提铁实验研究

通过实验室试验,对牙买加赤泥分别进行了直接还原-磁选和磁化焙烧-磁选两种工艺方案的提铁实验研究。试验结果表明:采用磁化焙烧-磁选工艺方案,最终得到的铁精矿品位最高为31.84%,铁回收率最高57.46%;采用直接还原-磁选工艺方案,最终得到的金属化铁粉的铁品位最高34.62%,金属化率42.20%,铁回收率最高65.04%。     

混合稀土精矿还原焙烧磁选工艺研究

利用还原焙烧技术将内蒙古某混合稀土精矿中铁矿物还原为金属单质,经过磁选分离实现了铁与稀土、铌等元素的高效分离及富集。通过单因素实验考察了还原温度、焙烧时间、配碳量条件对还原焙烧效果的影响,以及不同焙烧温度下稀土和铌富集、回收的情况。在焙烧温度1 175℃,焙烧时间90 min,配碳量C/O为1.5的优化条件下,铁金属化率达到92.52%,磁性物中铁品位为89.71%,铁回收率为92.12%,而非磁性物中铌品位及回收率为3.85%和87.92%;稀土品位及回收率达到7.15%和88.23%。     

赤泥提铁研究进展

我国赤泥堆存量已超过10亿t,主要类型为拜耳法赤泥,该赤泥中含铁量高达30%以上,是经济价值较高的铁资源。目前回收赤泥中铁资源的方法主要是高温还原焙烧-磁选,还原剂以固态碳基还原剂和气基还原剂为主,需大量能耗和成本。我国是农业大国,主要农作物秸秆年产量在7亿t以上,这些生物质具有碳中性、反应活性高、灰分含量低、储量高、可再生等优点,而且热解温度远远低于固态碳质还原剂,其还原三价铁的温度仅为300～800℃,属于低温热解,采用生物质还原焙烧赤泥可大幅降低能耗和成本。本文重点对固态碳质还原剂、气基还原剂和生物质还原剂还原三价铁的参数进行对比,并详细阐述了生物质热解过程及还原赤泥中Fe₂O₃的机理,认为生物质还原焙烧-磁选技术可以实现赤泥和农业秸秆等固体废弃物的减量化和高值化利用,具有极高的经济价值和环境效益。最后对未来研究赤泥中铁资源回收提出以下建议：加强探究技术耦合实现赤泥产业化处置;回收利用生物质热解产气及热量;探究尾渣综合利用途径;增强对铁铝矿物的分离研究,以实现铁精矿的连续动态化生产。     

转底炉处理赤泥工艺技术

为了综合利用氧化铝冶炼产生的赤泥,探索在转底炉中直接还原赤泥、磨矿磁选获得高品位直接还原铁。通过实验室试验摸索了转底炉还原工艺参数,并在转底炉工业试验线进行了工业试验。实验室结果表明,赤泥还原后的直接还原铁(DRI)金属化率可达88.6%,磁选后的铁品位可达82.1%,磁选后的铁回收率可达88.9%。工业试验中,转底炉还原后,产品金属化率平均为69.2%,将还原后的DRI磁选获得高品位的DRI产品,磁选后DRI的铁品位为72.8%,磁选后铁回收率达到了85.2%,初步打通了在转底炉中还原赤泥、磁选的工艺路径。     

拜耳法赤泥制备海绵铁影响因素分析

采用煤基直接还原烧成—渣铁磁选分离—母液溶出的方法处理拜尔法赤泥,配入自制复合助剂,进行了生产优质海绵铁的试验探讨。通过SEM-EDS、X射线等手段研究了煤基直接还原过程中金属铁晶粒长大特性,着重讨论了添加剂种类、焙烧条件及磁选参数等对金属铁晶粒长大特性的影响,自制添加剂A为优选添加剂,最佳焙烧温度为1 200℃,焙烧时间2 h,磁场强度以2 000 A/m为宜,所得产品的金属化率为92.9%,含铁品位为93.7%,铁回收率为94.42%。     

Recovery of Iron From High-Iron Red Mud by Reduction Roasting With Adding Sodium Salt

 Red mud is the waste generated during aluminum production from bauxite, containing lots of iron and other valuable metals. In order to recover iron from red mud, the technology of adding sodium carbonate—reduction roasting—magnetic separation to treat high-iron red mud was developed. The effects of sodium carbonate dosage, reduction temperature and reduction time on the qualities of final product and the phase transformations in reduction process were discussed in detail. The results showed that the final product (mass percent), assaying Fe of 90.87% and Al2O3 of 0.95% and metallization degree of 94.28% was obtained at an overall iron recovery of 95.76% under the following conditions of adding 8% sodium carbonate, reduction roasting at 1050 ℃ for 80 min and finally magnetic separation of the reduced pellets by grinding up to 90% passing 0.074 mm at magnetic field intensity of 0.08 T. The XRD (X-ray diffraction) results indicated that the iron oxides were transformed into metallic iron. Most of aluminum mineral and silica mineral reacted with sodium carbonate during the reduction roasting and formed nonmagnetic materials.     

添加剂对低品位菱铁矿制备高品位碳化铁的影响

低品位菱铁矿作为一种典型的难处理铁矿目前难以应用于钢铁行业.为了促进低品位菱铁矿的利用,提出了渗碳-磁选-酸浸制备优质电炉原料(碳化铁)的新工艺,并探究了添加剂对菱铁矿球团渗碳产物中碳化铁和脉石分离的作用机制以及对酸浸过程中碳化铁提纯效果的影响规律.结果 表明,添加剂能显著促进碳化铁颗粒长大、改善碳化铁与脉石的嵌布关系...     

高磷鲕状赤铁矿铁磷分离试验研究

对高磷鲕状赤铁矿进行了显微结构研究,采用添加脱磷剂直接还原焙烧-磁选工艺进行了铁和磷分离试验,研究了焙烧温度、内配碳量、添加剂配比对铁、磷分离主要技术指标的影响。结果表明:磷主要以磷灰石的形态嵌布在鲕状结构中,部分与赤铁矿形成环状间层,层间的厚度变化范围在3~15μm之间;在焙烧温度1 000℃、内配碳量6%、添加剂配比10%的优化工艺条件下,通过球磨-磁选试验可得到含铁品位大于85%、含磷量在0.15%~0.20%之间的优质还原铁粉和含磷为3.5%~4%的富磷渣。     

Recovery of iron and copper from copper tailings by coal-based direct reduction and magnetic separation

A technique comprising coal-based direct reduction followed by magnetic separation was presented to recover iron and copper from copper slag flotation tailings. Optimal process parameters, such as reductant and additive ratios, reduction temperature, and reduction time, were experimentally determined and found to be as follows: a limestone ratio of 25%, a bitumite ratio of 30%, and reduction roasting at 1473 K for 90 min. Under these conditions, copper-bearing iron powders (CIP) with an iron content of 90.11% and copper content of 0.86%, indicating iron and copper recoveries of 87.25% and 83.44% respectively, were effectively obtained. Scanning electron microscopy and energy dispersive spectroscopy of the CIP revealed that some tiny copper particles were embedded in metal iron and some copper formed alloy with iron, which was difficult to achieve the separation of these two metals. Thus, the copper went into magnetic products by magnetic separation. Adding copper into the steel can produce weathering steel. Therefore, the CIP can be used as an inexpensive raw material for weathering steel.     

Preparation of metallic iron powder from copper slag by carbothermic reduction and magnetic separation

Copper slag is a solid waste that has to be treated for metals recovery. In order to recover iron from copper slag, the technology of carbothermic reduction and magnetic separation was developed. During the reduction roasting, additive CaO reacted with Fe₂SiO₄ of copper slag, forming CaO·SiO₂ and 2CaO·SiO₂, which ameliorates the separation between iron and other minerals during magnetic separation. Meanwhile, additive CaF₂ improved the growth of iron grains, increasing the iron grade and iron recovery. The metallic iron powder obtained contained 90.95?wt-% TFe at 91.87?wt-% iron recovery under the optimum conditions, which can be briquetted as a burden material for steel making by electric arc furnace to replace part of scrap.     

含铌铁精矿煤基直接还原过程中铌的行为研究

以含铌铁精矿为研究对象,采用固态煤作还原剂还原焙烧,再经磁选得到还原铁产品.在不同焙烧温度、还原剂用量、助熔剂用量条件下,分别以褐煤和无烟煤为还原剂,研究了各因素对直接还原焙烧-磁选结果的影响,考察焙烧过程中铌分别在渣相和金属相中的分布.试验结果表明,1200℃时80％的铌矿物进入尾矿中;而1300℃时添加助熔剂TS2用量10％条件下,90％铌矿物在直接还原焙烧-磁选得到还原铁产品中富集.     

红土镍矿选择性还原焙烧过程中的相变转化

针对传统选矿方法难以回收低品位红七镍矿中有价金属镍的问题,采用选择性还原焙烧法研究了不同焙烧温度以及不同焙烧时间条件下红土镍矿(Ni品化为1.49%)中发生的微观结构变化以及相变转化.通过X射线衍射、扫描电镜及X射线能谱分析等测试手段分析表明,在不同焙烧温度及不同时间条件下经选择性还原后的红土镍矿中,镍氧化物逐渐被还原成镍铁合金相,铁氧化物主要转变成浮氏体相,硅酸盐主要以橄榄石形式存在.最后通过还原焙烧磁选试验证实,还原剂为烟煤,添加剂为NCS,两者用量分别为原矿质量的2%和7%,在1200℃条件下焙烧50min,磁选分离得到镍铁产品中镍品位为9.78%,镍的回收率为92.06%,镍铁回收率差为62.51%,实现了红土镍矿中镍铁的选择性还原.      

Separation of aluminium and preparation of powdered DRI from lateritic iron ore based on direct reduction process

Lateritic iron ore has not been used effectively due to excess content of multiple metals. In this work, separation of aluminium from a high-aluminium lateritic iron ore was achieved by the process of ‘direct reduction with sodium sulfate-magnetic separation’, with a powdered direct reduced iron (DRI) produced. It is found that the presence of 12% sodium sulphate during reductive roasting significantly improves separation of iron and aluminium in magnetic separation: the total iron grade (TFe) of powdered DRI increases from 80.6 to 92.0% and the Al₂O₃ content decreases from 9.8 to 1.3% correspondingly. The presence of sodium sulphate results in formation of sodium aluminosilicates instead of FeAlO₂. Moreover, sodium sulphate significantly promotes growth of metallic iron grains which is beneficial to sufficient liberation and separation of metallic iron grains from gangue minerals in grinding and magnetic separation.     

红土镍矿还原焙烧-磁选试验研究

论述了采用还原焙烧-磁选工艺处理含镍1.66%、全铁13.0%的红土矿。考察了配煤量、焙烧温度和焙烧时间对焙烧球团铁、镍品位及铁金属化率的影响;当焙烧温度达到1 350℃时出现粒铁。磁选结果表明,粒铁的生成有利于磁选精矿中铁、镍品位的提高,磨矿粒度越细,磁选效果越好。试验结果达到镍质量分数(含量)6.56%、全铁51.60%。