高磷铁矿石含碳球团等温还原动力学

为了研究高磷铁矿石含碳球团等温还原动力学在温度为1 173、1 273、1 323、1 373、1 423和1 473K时,采用界面化学反应模型、Jander方程、Ginstling-Broushtein方程、G Valensi-R E Carter方程等固-固/气反应机理函数对反应过程进行拟合,并采用XRD、SEM、EDX等对样品的物相组成、微观形貌和元素分布进行表征分析。研究结果表明,随着还原程度提高,反应速率由0迅速增至最大值,随后逐渐减小并趋于平缓;当温度为1 173～1 373K时,反应过程符合界面化学反应,表观活化能为70.02kJ/mol,线性相关系数为0.948 1;当温度为1 373～1 473K时,反应过程符合Jander方程,限制步骤为铁离子固相扩散,表观活化能为215.36kJ/mol,线性相关系数为0.991 2。     

高磷鲕状铁矿直接还原?磁选提铁降磷扩大试验研究

为给回转窑工业试验提供参数,以小型试验最佳结果为基础,进行了高磷鲕状铁矿煤基直接还原?磁选提铁降磷扩大试验。结果表明,在最佳的条件下可获得铁品位94.17%、铁回收率77.47%以及磷质量分数0.08%的粉末还原铁,推荐的回转窑工业试验初始条件为:石灰石用量（质量分数）28%、无烟煤用量（质量分数）16%、还原温度1300 ℃,还原时间3 h。采用XRD以及SEM-EDS研究了无烟煤的作用机理,发现无烟煤用量增加,促进了浮氏体、镁铁尖晶石的还原以及铁颗粒长大,从而提高了铁的回收效果,但过多的无烟煤通过增强还原气氛及其带入的灰分消耗了石灰石,使铁矿物中的磷以及磷灰石还原成单质磷并与铁颗粒形成铁磷合金。      

高磷铁矿气基还原冶炼低磷铁

针对鄂西鲕状高磷铁矿难选、难冶的特点,从该矿矿相结构分析出发,在使用HSC计算化学软件的热力学模拟和具体实验的基础上,提出了气基还原+电炉熔分冶炼高磷铁矿的新型工艺.实验结果与HSC软件模拟结果吻合.实验室含P 1.28%的高磷铁矿通过CO还原后熔分,得到含P 0.27%的低磷铁;通过H₂还原后熔分,得到含P 0.33%的低磷铁.由熔分铁的SEM和EDS结果证实,P仍以夹杂物的形态存在,可以在熔分时通过去除铁水中夹杂物的方法进一步脱磷,以满足炼钢的要求.     

高磷铁矿脱磷工艺研究现状

我国铁矿资源长期紧缺已是不争的事实,合理开发利用鄂西巨型铁矿资源具有重大经济意义,对此本文论述了国内外高磷铁矿降磷的现状及其发展,总结了当前降磷存在的问题,着重阐述了选矿降磷工艺和铁水预处理脱磷工艺研究的现状及其相关设备和材质的研究现状.     

高磷铁矿选择性除磷工艺研究

研究了从高磷铁中选择性除磷。考察了不同除磷剂的除磷效果及反应时间、液固体积质量比、搅拌速度、反应温度、除磷剂浓度对除磷的影响。试验结果表明:在反应时间45 min、高磷铁矿粒度小于0.147 mm、液固体积质量比4∶1、搅拌速度200 r/min左右、常温、除磷剂盐酸浓度为2.5 mol/L的优化条件下,除磷效果最佳。铁矿磷质量分数由1.16%下降到0.05%以下,全铁质量分数由42.676%上升到54%以上。     

高磷铁矿含磷矿物与脉石相碳热还原机理

针对高磷铁矿矿物组成特点,对氟磷灰石与高磷铁矿中脉石相的反应进行了研究,阐明了高磷铁矿在直接还原过程中含磷矿物的碳热还原机理.研究发现：在不配加石墨的情况下,氟磷灰石与脉石之间相互独立,没有发生反应;在配加石墨的情况下,氟磷灰石发生不同程度的还原,脉石中 SiO2脱磷能力最强.当 SiO2、Al2 O3和 Fe2 O3同时加入氟磷灰石后,氟磷灰石碳热还原速率加快,并且在脉石相中形成了 CaAl2 Si2 O8.     

高磷铁矿处理及高磷铁水脱磷研究进展

介绍了高磷铁矿选矿脱磷和炼钢脱磷反应机理研究的最新进展,对生产低磷钢的各个环节如铁水预处理,转炉冶炼,钢水炉外脱磷尤其是炉外脱磷的渣系组成及脱磷工艺进行了详细的论述.探讨了高磷铁水炼钢的可行性.     

配加高磷铁矿的烧结杯实验

在固定碱度和MgO含量等条件下,进行了配加高磷铁矿的烧结杯实验,研究了烧结过程、烧结矿性能及适宜配碳量,为工业应用高磷铁矿提供参考;通过烧结前后磷的存在形式变化,分析了磷的转化机理,探讨了烧结脱磷的可行性。     

配加高磷铁矿的小型烧结试验研究

应用压块、焙烧方法,结合试样的显微结构及X射线衍射（XRD）分析,在固定的烧结温度与碱度的条件下,研究了不同高磷铁矿配比对烧结试样的显微结构和矿物组成的影响。结果表明：随着高磷铁矿配比的增加,试样的显微结构由非均相结构向均相结构过渡;赤铁矿由粒状转变为熔蚀结构,铁酸钙由板状转变为针状;赤铁矿含量逐渐减少,铁酸钙含量逐渐...     

高磷铁矿脱磷技术现状及磷资源化提取新方法

 为了提高磷铁矿作为炼铁原料的使用率,对高磷铁矿中磷元素的降低和脱除技术（选矿法、化学浸出法、生物浸出法、高温脱磷法）的特点及发展现状进行了综合评述,并从磷的资源化利用的角度探讨其提取与利用的可能性。介绍了一种基于湿法酸浸-生物吸附方法提取高磷铁矿或高温脱磷渣中磷资源新工艺技术,对其基本原理、工艺流程与技术特点进行了讨论。该提磷新方法的最大优势在于可以从pH值为1～2的酸浸溶液中直接选择性地吸附脱磷,使酸液得以循环使用,而磷也可解吸成高纯度的磷酸盐得以回收,吸附剂本身则可以多次循环使用。     

Intensifying Gaseous Reduction of High Phosphorus Iron Ore Fines by Microwave Pretreatment

 Gaseous reduction kinetics of the high phosphorus iron ore fines from Hubei in China and effect of microwave pretreatment on the gaseous reduction behavior were studied. Gaseous reduction kinetics were investigated by TG (Thermogravimetric) methods using LINSEIS STA PT 1600 thermal analysis equipment. Microwave pretreatments to the ore fines with four power levels were performed using a high temperature microwave reactor. Its effect was examined by TG methods and its mechanism was analyzed by SEM (scanning electron microscope) and EDS (energy dispersive spectrometer). Gaseous reduction tests were carried out using a tubular furnace. Results of kinetic study indicate that controlling step of the gaseous reduction of the ore fines is a mixing control of gas internal diffusion and interface chemical reaction when reduction fraction is less than 0. 8 and is solid state diffusion when reduction fraction is more than 0. 8. Microwave pretreatment of the ore fines could change the pore structure of the oolitic unit to generate cracks, fissures and loose zones, which promotes reduction in the early stage and delays the occurrence of sintering. Gaseous reduction tests show in the condition that the ore fines are pretreated with a microwave power of 450 W for 4 min and reduced under temperature of 1273 K, the gaseous reduction of the ore fines could be apparently intensified. Using CO or H2 as a reductant and ore fines being reduced for 1. 5 to 2 h , increase of metallization rate of the ore fines is 10% to 13%.     

Phosphorus Removal of High Phosphorus Iron Ore by Gas-Based Reduction and Melt Separation

A new method (gas-based separation plus melt separation) has been proposed to remove phosphorus of the high phosphorus iron ore which was 1.25% of phosphorus content and 50.0% of iron content.HSC chemistry package and the coexistence theory of slag structure were adopted for theoretical analysis.The gas-based reduction was carried out using a fixed bed reactor and the ore sample of 80 g with an average particle size of 2 mm were reduced using CO or H2 at temperature of 1073 K for 5 hours.50 g of the reduced...     

高磷鲕状赤铁矿深度还原过程中磷的迁移规律

 针对鄂西某地高磷鲕状赤铁矿进行了深度还原技术研究,考查了还原温度、还原时间、配碳系数和CaO添加量对磷迁移规律的影响。结果表明：进入铁粉中磷的品位和回收率随着还原温度的升高和还原时间的延长而升高,随着配碳系数的增大先升高后降低,并在配碳系数为2.0时达到最大;而受CaO添加量的影响较小。还原物料的XRD和SEM分析表明大部分磷被还原为单质迁移进入了铁粉中。对高磷鲕状赤铁矿深度还原过程中磷的迁移规律进行了初步探索,为进一步研究高磷鲕状赤铁矿提供了一定的理论基础。     

Study on Direct Reduction Characteristics of Iron Ore Coal Mixed Pellets

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富氧顶吹熔融还原冶炼高磷铁矿与钛铁矿配矿的试验研究

采用模拟HIsmelt的富氧顶吹熔融还原技术冶炼惠民高磷铁矿与勐桥钛铁矿配矿,在温度为1 500K,碱度为1.3,配碳比为1.0的条件下,恒温时间20min(在升温过程中,没有通入惰性气体),恒温过程中通入O2(流量250L/h、纯度为99%)10min。恒温时间结束后,调整氧气流量为5L/h,保持其氧化性气氛至冷却。研究了不同配矿比例对铁回收率、生铁中磷、硫含量以及磷、硫分配比的影响。研究结果表明,在惠民铁矿和勐桥精矿的比例为1∶1时,其冶炼结果比较理想:铁的回收率为95.1%,生铁中磷的质量分数约为0.32%,硫的质量分数为0.054%,钛的质量分数为0.031%。     

Direct Reduction of Mixtures of Manganese Ore and Iron Ore

This paper presents recent results of direct reduction investigation of different combination of blends of manganese ore, iron ore and coal at the Department of Ferrous Metallurgy (IEHK) of RWTH Aachen University. A mixture of iron and manganese ore in a ratio of 75/25 is a good raw material for steelmaking of high Mn‐alloyed grades. The experimental studies consisting of reduction of (a) fine material and (b) agglomerated material (briquettes) were carried out in the range of 1273 to 1673 K. The behaviour of combined reduction of manganese ore and iron ore and the employment in the direct reduction on a coal and gas basis for production of steels with high Mn content were investigated. It was found that a high metallization degree for Mn can be reached at 1273 K with the reduction of manganese ore by hydrogen‐containing gas. Addition of carbon monoxide to the reducing gas retarded the reduction process. The addition of coal to manganese ore and iron ore blends increased the degree of reduction. The results of carbothermic reduction of briquettes consisting of a mixture of manganese ore and iron ore combined with coal as reducing agent show that a high temperature, a low Mn/Fe ratio and a high Fe₂O₃ content have a favourable effect on the degree of reduction. In order to obtain a high degree of metallization, the temperature should be higher than 1473 K. The reduction of briquettes at higher temperatures (up 1573 K) has shown a molten phase and the separation of slag and metal.     

提高低品位铁矿球团直接还原金属化率研究

应用直接还原炼铁工艺技术有许多研究,直接还原炼铁金属化率偏低一直是阻碍该技术推广的一个重要难题.本文通过调整低品位矿球团粒度、配料比和焙烧温度等影响因素的直接还原实验,提高了DRI球团金属化率,最高为98.20％.通过经济评价可知:金属化率最高,不是最经济;要同时兼顾煤耗、料耗及CO2排放,寻求效益最大化;较好的控制为球团粒度8～12mm,焙烧温度1 320℃,焙烧时间31 min,球团中不含NCP和膨润土,DRI球团金属化率在91％以上,有利于节能减排、降本增效.     

高铁硫化矿选择性浸出铁的研究

将镍钴火法冶炼转炉渣进行还原硫化,制备成富含镍钴铜的高含铁硫化矿,并采用加压选择性浸出其中的铁。对铁的浸出行为进行了研究。结果表明,随着铜浸出率从98%降到-42%,铁浸出率从3%升到43%左右,选择性浸出后液含铁越来越高,而且以二价铁居多,这是造成高铁硫化矿难以进行加压选浸的主要原因。     

Kinetics of Nitrate Reduction by Iron at Near Neutral pH

Although considerable research has been conducted on nitrate reduction by zerovalent iron (ZVI), the process kinetics at near neutral pH has not been studied thoroughly. In this study, a kinetic model with a double-Langmuir-adsorption formulation was developed to represent site saturation effects of aqueous Fe2+ and NO3? on nitrate reduction in a ZVI system at near neutral pH. Both an analytical solution and a numerical solution of the proposed model were developed. The kinetic parameters were evaluated based on batch experiments with two types of ZVI. Sensitivity analysis indicates that it is rather difficult and unreliable to estimate the parameters of the proposed multivariable nonlinear kinetic model from a single test curve. A better strategy is to obtain reliable parameters by designing specific experiments to target one parameter each time. The results indicate that, although the values of the kinetic parameters might change with different types of iron powder, the kinetic model can fit the experimental data very well, and therefore is consistent with the proposed mechanism.