添加剂对低镍高铁红土镍矿选择性还原的影响

采用还原焙烧-磁选法处理低镍高铁型红土镍矿,研究了添加剂(Na2SO4,Na2CO3,CaCO3和CaSO4)对镍、铁矿物选择性还原的影响规律,并通过X射线衍射(XRD)、扫描电镜-能谱分析等方法,分析了添加剂作用下焙烧矿中矿物成分、相变转化、微观结构特征及元素赋存状态.结果表明:添加剂Na2CO3,CaCO3及CaSO4作用下选择性还原效果较差,而Na2SO4作用效果明显,在Na2SO4用量10%,烟煤用量2%,1 250℃焙烧50min条件下,获得镍铁产品中镍的品位为9.52%,镍回收率88.40%,镍铁回收率之差达60.50%,实现了镍铁矿物的选择性还原,其原因是Na2SO4作用下弱还原气氛抑制了浮氏体还原成金属铁,降低了铁的回收率,同时Na2SO4分解出的S降低了镍铁颗粒的表面能和熔点,而且焙烧矿呈熔融状态,促进了镍铁颗粒长大,有利于镍铁颗粒与脉石矿物充分分离.     

低品位红土镍矿的直接氢还原实验研究

在对单纯镍铁氧化物氢还原热力学分析的基础上,对低品位复杂红土镍矿进行了直接氢还原实验研究,考察了还原时间、还原温度、氮氢混合气体中氢含量对镍铁还原率的影响。对还原产物进行的物相分析表明,由于红土矿组成的复杂性,高温下共熔相产生的粘结和包覆作用使还原率降低。最佳实验条件为还原温度850℃,还原时间40 min,氮氢混合反应气体中氢含量65%,镍和铁的还原率分别达到43%和62%。铁氧化物的还原为分步还原过程。     

印尼红土镍矿粉成球机理及其利用

为探讨红土矿粉造球并直接入炉的可行性,通过对红土矿粉粒度、化学成分的分析,采用造球的方法使其成为具有一定形状的球团,实验研究不同粘接剂的成球性能,并模拟回转窑温度和还原性气氛对球团进行预还原实验和高温强度测试。结果表明:红土镍矿粉配入3%的新型粘接剂进行造球,成球率达到70%以上,球团干燥后落下强度达到30次以上。在还原性气氛、1 100℃预还原焙烧后球团都能保持颗粒的完整性,无破裂粘接现象,抗压强度为472 N个,完全可以作为冶炼原料进入电炉进行生产,达到了工业生产入炉要求。     

低品位镍红土矿直接氢原实验研究

在对单纯镍铁氧化物氢还原热力学分析的基础上,对低品位复杂红土镍矿进行了直接氢还原实验研究,考察了还原时间、还原温度、氮氢混合气体中氢含量对镍铁还原率的影响。对还原产物进行的物相分析表明,由于红土矿组成的复杂性,高温下共熔相产生的粘结和包覆作用使还原率降低。最佳实验条件为还原温度850℃,还原时间40 min,氮氢混合反应气体中氢含量65%,镍和铁的还原率分别达到43%和62%。铁氧化物的还原为分步还原过程。     

钠化还原焙烧-磁选法处理红土镍矿的研究

试验用红土镍矿属于褐铁矿型红土镍矿,其主要矿相为针铁矿.在煤粉做还原剂,硫酸钠做添加剂条件下,红土镍矿在一定温度下焙烧一定时间后得到的焙烧产物中Ni主要以Fe-Ni合金形式存在,通过磁选可以使其得到有效的富集.本文探究了各工艺参数对磁选后镍铁精矿中镍品位及镍回收率的影响.结果表明,当红土镍矿、硫酸钠和煤粉的质量比为100∶22∶9,焙烧温度为1 200℃,焙烧时间为80 min,磁选磁场强度为150 m T条件下,可以得到镍品位为11.36%,镍回收率为83.35%的镍铁精矿,该精矿可直接作为冶炼不锈钢的原料.     

焙烧法生产氧化铬工艺参数的优化研究

对重铬酸钾硫磺还原焙烧法生产氧化铬的焙烧工艺参数进行了优化研究，探讨了焙烧反应中配料、温度的时间等因素变化对氧化铬收率及色泽的影响。     

阎地拉图红铁矿选矿工艺研究

对阎地拉图红铁矿进行了焙烧磁选、强磁选、重选及重选－强磁选四种选矿工艺的试验研究，结果表明，用螺旋溜槽选别＋０．０７４ｍｍ粒级，用强磁选别－０．０７４ｍｍ粒级的重选－强磁选方案可得到品位为５１．００％、回收率为７２．３０％的综合铁精矿。该方案投资少，生产成本低，适合现厂的实际。     

明矾石脱水焙烧的研究

本文对吉林省长白县产出的明矾石进行了化学分析和差热分析。研究了焙烧时硫酸盐的实收率和挥发分的排出量。为了提高硫酸盐的实收率,焙烧温度应接近或略超过硫酸盐的分解温度。在挥发量为12～18%时,是得到较好硫酸盐实收率的焙烧条件。     

含铌铁矿粉氢气选择性还原实验研究

实验在自制底供气扩散床管式电阻炉内,研究不同还原时间（30～180 min）和温度（800～1 050℃）下,H2选择性还原含铌铁矿粉中铁氧化物的规律。得到950℃为最佳还原温度,还原2 h还原度达到90.98%,金属化率为86.47%,还原3 h还原度达到94.07%,金属化率为91.11%,而低于这一温度或高于这一温度时,还原度和金属化率在同样还原时间下都有所降低。     

Extraction of valuable metals from low-grade nickeliferous laterite ore by reduction roasting-ammonia leaching method

Nickel and cobalt were extracted from low-grade nickeliferous laterite ore using a reduction roasting-ammonia leaching method. The reduction roasting-ammonia leaching experimental tests were chiefly introduced, by which fine coal was used as a reductant. The results show that the optimum process conditions are confirmed as follows: in reduction roasting process, the mass fraction of reductant in the ore is 10%, roasting time is 120 min, roasting temperature is 1 023–1 073 K; in ammonia leaching process, the liquid-to-solid ratio is 4:1(mL/g), leaching temperature is 313 K, leaching time is 120 min, and concentration ratio of NH₃ to CO₂ is 90 g/L:60 g/L. Under the optimum conditions, leaching efficiencies of nickel and cobalt are 86.25% and 60.84%, respectively. Therefore, nickel and cobalt can be effectively reclaimed, and the leaching agent can be also recycled at room temperature and normal pressure.     

Magnetizing roasting mechanism and effective ore dressing process for oolitic hematite ore

Magnetizing roasting of oolitic hematite ore from western Hubei Province was investigated.The mechanism for reduction roasting of oolitic hematite ore was discussed and analyzed.It is found that flash magnetizing roasting-magnetic separation process is a promising approach for the processing of oolitic hematite ore from western Hubei Province.     

Thermodynamics of chromite ore oxidative roasting process

To explicate the thermodynamics of the chromite ore lime-free roasting process,the thermodynamics of reactions involved in this process was calculated and the phrases of sinter with different roasting times were studied.The thermodynamics calculation shows that all the standard Gibbs free energy changes of the reactions to form Na2CrO4,Na2O·Fe2O3,Na2O·Al2O3 and Na2O·SiO2 via chromite ore and Na2CO3 are negative,and the standard Gibbs free energy changes of the reactions between MgO,Fe2O3 and SiO2 released f...     

Kinetics study of leaching arsenic from Ni-Mo ore roasting in dust mixture of hydrochloric and sulfuric acids

The kinetics of leaching arsenic from Ni-Mo ore roasting dust was investigated. The effects including leaching temperature, particle size of the smelter dust, stirring speed, the coefficient β（the molar ratio of sodium chlorate to arsenic in the smelter dust） and the initial H＋ concentration on leaching arsenic were studied. The results indicate that the leaching of arsenic increases sharply with the decrease of particle size. The orders of reaction with respect to H＋ concentration and particle size are determinted to be 1.136 and 1.806, respectively. The leaching of arsenic reaches 99% under experimental conditions, the apparent activation energy is determined to be 11.157 kJ/mol, which is consistent with the values of activation energy for diffusion model The kinetics equation of leaching arsenic from the roasting dust could be expressed by a semi-empirical equation as 1-2/3η （1 -η）^2/3 = k0（c[H＋]）^1.136ro^-1.806 exp[（-11157 /RT）t].     

高磷铁矿碳热还原同步脱磷的实验研究

为探索高磷铁矿的有效利用途径,对高磷鲕状赤铁矿进行碳热还原同步脱磷实验研究,在含碳球团中添加CaO和Na2C O3作为脱磷剂,采用D T A-T G- M S综合热分析、X R D、SE M、E DS等方法分别对高磷鲕状赤铁矿的碳热还原过程以及还原产物进行分析. 结果表明,添加适量的CaO和Na2C O3可以显著提高脱磷率;在1 573 K、Na2C O3添加量为2 %、含碳球团碱度为1 .2的条件下,高磷鲕状赤铁矿能够被快速还原成含磷0 .09 %、含碳4 .6 %的碳饱和铁,脱磷率达到95 %;生铁中碳过饱和后以片状石墨的形态析出,生铁中的磷以夹杂物Ca3（P O4）2和Na2Ca4（P O4）2SiO4的形式存在     

Application of multi-stage dynamic magnetizing roasting technology on the utilization of cryptocrystalline oolitic hematite:A reviewOA

A large number of studies have shown that oolitic hematite is an iron ore that is extremely difficult to utilize because of its fine disseminated particle size, high harmful impurity content and oolitic structure.To recover iron from oolitic hematite, we developed a novel multistage dynamic magnetizing roasting technology. Compared with traditional magnetizing roasting technologies, this novel technology has the following advantages: firstly, the oolitic hematite is dynamically reduced in a mult...     

Effect of bastnaesite as reductant on hematite reduction during in-situ suspension magnetization roasting of refractory iron ore under neutral atmosphereOA

The iron tailings of Bayan Obo mines are solid waste,which occupies land area and also causes environmental pollution;however,this waste can be recycled.In this study,based on the characteristics of iron minerals and fluorocarbonate contained in Bayan Obo iron tailings,clean magnetization roasting of iron minerals by bastnaesite from iron tailings during in-situ suspension magnetization roasting in a neutral atmosphere was explored.The results show that for iron tailings with a mass of 12 g, a N...