冷却方式对焙烧鲕状赤铁矿磨矿性能影响

鲕状赤铁矿有用矿物嵌布粒度细,磨矿成本高,属于典型难选铁矿石。磁化焙烧-磁选工艺是分选此类难选铁矿石的有效方法,研究了不同冷却方式对磁化焙烧矿的磨矿性能产生的影响.鲕状赤铁矿进行磁化焙烧后分别隔绝空气密闭冷却、水淬及空气中自然冷却,进行粒度筛析和磨矿试验.发现焙烧后矿石粒径变粗,从原矿的平均粒径为0.069 9mm至密闭冷却、水冷和自然冷却焙烧矿的0.088 2mm、0.084 3mm、0.087 0mm.相同磨矿条件下,原矿、密闭冷却焙烧矿、水冷焙烧矿和自然冷却焙烧矿-0.045mm含量分别为84.89%、83.89%、76.51%、77.14%.表明磁化焙烧使鲕状赤铁矿变得更为难磨,密闭冷却时磨矿效果最佳,自然冷却次之,水冷最差.     

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...     

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...     

助磨剂对鄂西高磷鲕状赤铁矿磨矿的影响

鄂西高磷鲕状赤铁矿在微细粒磨矿时黏度非常高,严重影响磨矿效率,导致磨矿能耗大幅上升。用助磨剂六偏磷酸钠和三聚磷酸钠对鄂西高磷鲕状赤铁矿进行降黏度磨矿试验。结果表明,添加两种助磨剂均可降低矿浆的黏度,助磨剂添加量为0.2%时降黏和助磨效果最佳;助磨剂使球磨机的生产能力得到显著提高,其相对增量最高可达144%,磨矿时间为5min时助磨效果最佳。添加助磨剂后磨矿产品中粒度小于38μm的颗粒含量明显增加,两种助磨剂都能有效降低磨矿的能耗,最大能耗降幅为57.14%。     

某鲕状赤铁矿流化床燃煤还原焙烧-磁选研究

运用小型循环流化床锅炉,针对铁品位为49.20%、磷质量分数为1.16%的湖北某鲕状赤铁矿进行磁化焙烧-磁选试验研究.试验结果表明,将粒径为106～150 μm的鲕状赤铁矿在700 ℃下焙烧15 min,选取磨矿后粒径在74 μm以下的颗粒质量分数为85%的焙烧矿物,运用湿式磁选管在139.22 kA/m的磁场强度下对筛选后的焙烧矿物进行磁选抛尾,可以获得铁品位为55.12%、全铁回收率为70.11%、磷质量分数为0.67%的铁精矿.研究表明,运用循环流化床局部还原性气氛高速磁化焙烧铁矿石是可行的,运用该磁化焙烧-磁选工艺流程可以达到一定的提铁降磷效果.     

红土镍矿干燥焙烧工艺条件选择研究

以红土镍矿为原料,用热重分析(TG)和X射线衍射分析(XRD)等方法,对红土铁矿干燥焙烧条件进行研究.结果表明,在矿石粒度为0~3 mm且小于180目颗粒占25%,配焦粉量8%,焙烧温度850℃,焙烧时间90 min,干燥焙烧效果最佳.     

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...     

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].     

内蒙古阿拉善额日登基性岩体中超低品位铁矿石特征及选矿工艺研究

通过合适的选矿工艺,将超低品位铁矿石中的铁选出成为可利用的资源,为解决铁矿石资源紧张提供新的、广阔的来源.调查了内蒙古阿拉善地区基性岩中铁矿石铁的质量分数分布情况,并分析了额日登基性岩体磁性异常区中含铁辉长岩特征,对其中的超低品位铁矿石进行分选工艺试验,确定了可行的工艺流程.     

Mechanism for suspension magnetization roasting of iron ore using straw-type biomass reductant

As an alternative reductant for fossil fuel in the future, straw-type biomass contributes to emission reduction and green utilization in the suspension roasting process. In this study, the influences of the roasting time, roasting temperature and dose of straw-type biomass after suspension magnetization roasting (SMR) and separation were investigated. The optimal conditions were determined to be a roasting time of 7.5 min with a straw-type biomass dose of 20 wt% and a roasting temperature of 800 ℃, in which an iron grade of 71.07% and recovery of 94.17% were obtained for the iron concentrate. The maximum saturation magnetization under optimal conditions was 35.05 A·m²·g⁻¹, and the gaseous regulation of the biomass revealed that cumulative reducing gas volume was 293.93 mL at the optimal roasting time of 450 s. The transformation of hematite to magnetite was detected by X-ray diffraction (XRD). During microstructure evolution, the outer layer consisting of fissures and tiny holes continuously deepened toward the core.     

镁质低品位铁镍硫化矿的活化工艺及机理

细菌浸出是镁质低品位铁镍硫化矿的潜在处理方案之一。针对该矿石浸出活性较低的问题,研究了硫酸预浸出和硫酸铵焙烧预浸出2种活化方案,并与细菌直接浸出(空白试验)做了比较。结果表明,2种活化方案都有利于金属回收,但硫酸铵焙烧预浸出方案的活化效果更优:浸出时间为8 d时,Ni、Cu和Mg的浸出率分别为90.2%、89.56%和61.19%,分别高于硫酸预浸出方案2.08%、12.2%和8.95%。矿石中的Mg主要在硫酸铵焙烧预浸出阶段进入溶液,细菌对Mg浸出的影响不大。XRD和能谱分析表明:浸出渣中Ni和Cu的残留量很低,Mg主要存在于难浸出的蛇纹石之中。     

Magnetic and flotation studies of banded hematite quartzite （BHQ） ore for the production of pellet grade concentrate

To identify and establish beneficiation techniques for banded hematite quartzite (BHQ) iron ore, a comprehensive research on BHQ ore treatment was carried out. The BHQ ore was assayed as 38.9wt% Fe, 42.5wt% SiO2, and 1.0wt% Al2O3. In this ore, hematite and quartz are present as the major mineral phases where goethite, martite, and magnetite are present in small amounts. The liberation of hematite particles can be enhanced to about 82% by reducing the particle size to below 63 μm. The rejection of silica par...     

Recovery of valuable metals from a low-grade nickel ore using an ammonium sulfate roasting-leaching process

Metal leaching from a low-grade nickel ore was investigated using an ammonium sulfate roasting-water leaching process.The nickel ore was mixed with ammonium sulfate,followed by roasting and finally leaching with water.During the process the effects of the amount of ammonium sulfate,roasting temperature,and roasting time on the leaching recovery of metal elements were analyzed.The optimum technological parameters were determined as follows:ammonium sulfate/ore ratio,0.8 g/g;roasting temperature,400°C;and roasting time,2 h.Under the optimum condition the leaching recoveries of Ni,Cu,Fe,and Mg were 83.48%,76.24%,56.43%,and 62.15%,respectively.Furthermore,the dissolution kinetics of Ni and Mg from the nickel ore was studied.The apparent activation energies for the leaching reaction of Ni and Mg were 18.782 and 10.038 kJ·mol-1,which were consistent with the values of diffusion control reactions.Therefore,the results demonstrated that the leaching recoveries of Ni and Mg were controlled by diffusion.     

Thermodynamics and kinetics of alumina extraction from fly ash using an ammonium hydrogen sulfate roasting method

A novel method was developed for extracting alumina （Al2O3） from fly ash using an ammonium hydrogen sulfate （NH4HSO4） roasting process, and the thermodynamics and kinetics of this method were investigated. The thermodynamic results were verified experi-mentally. Thermodynamic calculations show that mullite present in the fly ash can react with NH4HSO4 in the 298-723 K range. Process op-timization reveals that the extraction rate can reach up to 90.95% when the fly ash reacts with NH4HSO4 at a 1：8 mole ratio of Al2O3/NH4HSO4 at 673 K for 60 min. Kinetic analysis indicates that the NH4HSO4 roasting process follows the shrinking unreacted core model, and inner diffusion through the product layer is the rate-controlling step. The activation energy is calculated to be 16.627 kJ/mol;and the kinetic equation can be expressed as 1-（2/3）α-（1-α）2/3=0.0374t exp[-16627/（RT）], whereαis the extraction rate and t is the roasting temperature.     

我国钢铁发展对铁矿石选矿科技发展的影响

分析了我国钢铁快速增长情况下国产铁矿石生产和进口铁矿石的比例增长情况。对我国磁铁矿石提铁降硅选矿工艺和阴离子反浮选、强磁选———细筛、磁化焙烧等难选红铁矿选矿关键技术应用现状进行了分析,对选矿设备的发展动态进行了探讨,并展望了闪速磁化焙烧等复杂难选铁矿选矿技术发展前景,提出了急待解决的高效细磨设备、耐磨防堵的细筛网、磁化焙烧新装备、反浮选浮选柱、新型磁化率计、磁铁矿阳离子反浮选药剂的研究等重要问题。     

Adsorption of sodium oleate at the microfine hematite/aqueous solution interface and its consequences for flotation

The adsorption of sodium oleate(NaOL) at the microfine hematite/aqueous solution interface was investigated in this paper. Experimental research indicated that negative effects stemmed from the dissolution of the microfine hematite(D50=19.21 μm) could be effectively eliminated via the appropriate dosage of NaOL at alkali pH conditions. Solution chemistry calculation and adsorption test results indicated that RCOO^- and(RCOO)₂^2- ions were responsible for microfine ...     

Acting mechanism of F, K, and Na in the solid phase sintering reaction of the Baiyunebo iron ore

The effect of F,K,and Na on the solid phase reaction of the Baiyunebo iron ore was investigated by differential thermal analysis (DTA) and X-ray diffraction(XRD).It has been identified that alkaline elements K and Na in the Baiyunebo ore instigate the formation of low melting point compounds Na_2SiO_3 and Na_2O·Fe_2O_3 and the generation of molten state in the solid phase sintering.Element F in the Baiyunebo ore facilitates the formation of cuspidine compound 3CaO·2SiO_2·CaF_2 in the solid phase reaction...