高硫碳酸锰矿与软锰矿直接浸出实验

传统电解锰生产中,软锰矿需要经过还原焙烧将其中的Mn4+还原为Mn2+才能被稀硫酸浸出制得MnSO4溶液。利用高硫碳酸锰矿中的硫铁矿成份和浸出时产生的具有还原性的H2S和溶液中的Fe2+,可以直接浸出软锰矿中的Mn4+。经过多次实验对比,总结出了较理想的高硫碳酸锰矿与软锰矿的配矿比,既有利于高硫碳酸锰矿在浸出时产生的H2S的利用吸收,减少尾气中的H2S,给尾气处理减轻负担,又有利于保持较高的浸出率,可为高硫碳酸锰矿和软锰矿的直接浸出提供参考。     

高铝铁矿和高锰铁矿共还原行为的研究

高铝铁矿和高锰铁矿是两种储量丰富但又极难分选的铁矿资源,实现铁、锰、铝的高效综合利用具有重要意义.本文研究了这两种铁矿石工艺矿物学,考查了单矿种及两者的混合矿种的直接还原行为及还原过程中的矿物组成演变,揭示了相应的还原机理.结果表明:高铝铁矿难还原,其机理为经还原后仅部分铁氧化物转化为金属铁,其余的铁与铝、硅矿物形成难还原的铁橄榄石和铁尖晶石;高锰铁矿易还原,其中的铁氧化物大部分被还原成金属铁,锰氧化物与铝、硅矿物结合形成锰尖晶石和锰橄榄石,促进了铁氧化物的还原.而且在相同还原条件下,高锰铁矿球团金属化率比高铝铁矿高30个百分点,前者还原性明显优于后者.两种矿进行共还原,当高锰铁矿配比达到60%时,球团金属化率就可大于90%.锰氧化物的存在对高铝铁矿石中铁氧化物的还原具有显著的促进作用.     

氢气还原1～3mm铁矿粉的动力学研究

在自制的kg级高温流化床中研究了氢气还原1～3 mm矿粉的动力学试验。随着时间的增加,气体利用率下降,表明还原前期反应速度快,后期反应慢;温度越高,气体利用率越高,但随着还原时间的增加,差距在逐步缩小;对于750℃,前20 min的气体利用率为9%,金属化率达到84%,说明氢气还原矿粉反应是非常迅速的。随着气速的增加,金属化率在增加,并且几乎成线性关系,因此使用氢气作为还原剂,可以允许更高的气速,从而提高设备的生产效率。随着料高的增加,金属化率不断下降,然而气体利用率却在不断升高。使用氢气作为还原剂,可以将还原温度降低到700～750℃,避免流化床过程中的粘结难题;试验中氢气还原1～3 mm铁矿粉时的表观活化能为58.4kJ/mol。     

Novelty on reduction of raw and pre-oxidised titaniferous magnetite ore with boiler grade coal

Pre-oxidation of fines of magnetite containing materials is usually carried out to get better yield of metals. Titaniferous magnetite ore (TMO) is one kind of low-grade iron ore (around 45–50% of total Fe) with a significant amount of TiO₂ (23.23%) and V₂O₅ (0.403%). TMO fines have been pre-oxidised at 973?K (700°C) for 9?h under air atmosphere. The effect of reduction of raw TMO fines as well as the pre-oxidised TMO fines using boiler grade coal in the form of cylindrical briquettes has been studied in the temperature range of 1273?K (1000°C) to 1473?K (1200°C) for periods of 10, 20, 30, 40 and 60?min to estimate the relative yield of iron. The influence of temperature and time on reduction experiments has also been investigated with XRD, FESEM analyses along with chemical analysis of the reduced samples. The most novel result is that the yield of Fe by direct reduction of raw TMO (92.42%) is even marginally better than that of reduction of pre-oxidised TMO (90.89%) at 1473?K (1200°C) for 60?min. Thus the single-step reduction of raw TMO is techno-economically more viable than the pre-oxidation followed by reduction technique.     

Effect of Microwave Treatment Upon Processing Oolitic High Phosphorus Iron Ore for Phosphorus Removal

Influence of microwave treatment on the previously proposed phosphorus removal process of oolitic high phosphorus iron ore (gaseous reduction followed by melting separation) has been studied. Microwave treatment was carried out using a high-temperature microwave reactor (Model: MS-WH). Untreated ore fines and microwaved ore fines were then characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thermogravimetric analysis (TGA). Thereafter, experiments on the proposed phosphorus removal process were conducted to examine the effect of microwave treatment. Results show that microwave treatment could change the microstructure of the ore fines and has an intensification effect on its gaseous reduction by reducing gas internal resistance, increasing chemical reaction rate and postponing the occurrence of sintering. Results of gaseous reduction tests using tubular furnace indicate both microwave treatment and high reduction temperature high as 1273 K (1000 °C) are needed to totally break down the dense oolite and metallization rate of the ore fines treated using microwave power of 450 W could reach 90 pct under 1273 K (1000 °C) and for 2 hours. Results of melting separation tests of the reduced ore fines with a metallization rate of 90 pct show that, in addition to the melting conditions in our previous studies, introducing 3 pct Na₂CO₃ to the highly reduced ore fines is necessary, and metal recovery rate and phosphorus content of metal could reach 83 pct and 0.31 mass pct, respectively.     

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%.     

锰矿直接还原合金化模型与实验研究

依据锰矿直接还原热力学理论,并基于转炉冶炼的基本条件,建立锰收得率和经济效益预测模型。通过实验验证模型的可靠性,分析提高锰收得率的途径和转炉常规冶炼条件下采用锰矿直接还原合金化工艺的经济效益。     

Effect of Coating MgO on Sticking Behavior during Reduction of Iron Ore Concentrate Fines in Fluidized Bed

The effect of coating MgO with different methods on sticking behavior during the reduction of iron ore fines was investigated, at 1073 K with 70%CO–30%H₂ gas mixture in a visualization fluidized bed. It was found that coating MgO on particle surface could extend fluidization time from 12 min to more than 80 min, and improve the degree of metallization from 22% to more than 80%. The expansion level of bed after defluidization could also be obviously decreased. To achieve a similar effect, the initial coating content with solution method was less than that with powder method. The reason was that coating MgO could effectively insulate the contact of metallic iron on particle, which provided the reaction time for carbon deposition and the production of Fe₃C with low stickiness. Therefore, the decrease of metallic iron on particle surface led to the decrease of particle stickiness at high temperature.     

Direct Reduction of High-phosphorus Oolitic Hematite Ore Based on Biomass Pyrolysis

Direct reduction of high-phosphorus oolitic hematite ore based on biomass pyrolysis gases(CO,H_2,and CH_4),tar,and char was conducted to investigate the effects of reduction temperature,iron ore-biomass mass ratio,and reduction time on the metallization rate.In addition,the effect of particle size on the dephosphorization and iron recovery rate was studied by magnetic separation.It was determined that the metallization rate of the hematite ore could reach 99.35% at iron ore-biomass mass ratio of 1∶0.6,reduction temperature of 1 100℃,and reduction time of 55 min.The metallization rate and the aggregation degree of iron particles increase with the increase of reduction temperature.The particle size of direct reduced iron(DRI) has a great influence on the quality of the iron concentrate during magnetic separation.The separation degree of slag and iron was improved by the addition of 15 mass% sodium carbonate.DRI with iron grade of 89.11%,iron recovery rate of 83.47%,and phosphorus content of 0.28% can be obtained when ore fines with particle size of-10 μm account for 78.15%.     

Study on Direct Reduction Characteristics of Iron Ore Coal Mixed Pellets

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Consolidation Behavior of High-Fe Manganese Ore Sinters with Natural Basicity

High-iron content manganese ore resources are becoming the mainstream raw ores for manganese extraction due to the depletion of high-grade manganese ores. Our previous research has reported the optimization parameters for the sintering of high-Fe manganese ore (abbr. high-Fe Mn-ore) fines. This study further investigated the consolidation behavior of high-Fe Mn-ore sinters with natural basicity. Sintering pot tests showed that the high-Fe Mn-ore sintering required high coke breeze dosage (about 9.9 wt.%). The CO content of the outlet flue gas (7.5 vol.%~8.0 vol.%) in the high-Fe Mn-ore sintering was higher than that in the ordinary iron ore sintering (1.0 vol.%~2.2 vol.%). XRD and SEM-EDS analyses indicated that the major mineral phases in the sinters included Fe-Mn oxides (Fe_xMn_3-xO₄), ferrotephroite ((Fe,Mn)₂SiO₄), Ca-,Al-,Mn-,Fe- bearing silicate melts, and a small quantity of hausmannite (Mn₃O₄) and free quartz (SiO₂). Optical microstructure and SEM images showed that the Fe-Mn oxides, Ca-, Al-, Mn-, Fe- bearing silicate melts and ferrotephroite particles are closely interconnected with one another. The formation of Fe-Mn oxides and ferrotephroite were beneficial to the sinter strength. Thermodynamic and phase diagram analyses further demonstrated that the major bonding phases of Fe-Mn oxides and ferrotephroite were easily formed under the strong reductive sintering atmosphere of high-Fe Mn-ores.     

高炉瓦斯灰制含碳球团直接还原试验研究

通过试验对高炉瓦斯灰和氧化铁皮制得含碳球团的直接还原进行了研究,考察了不同还原气氛、球团中不同C/O、还原时间、还原温度对还原结果的影响。结果表明:高温下含碳球团在空气中直接还原就能获得很高的金属化率。当球团中C/O在1.2以上时,球团的金属化率在还原过程中一直增加,在1 350℃下还原30 min,球团的金属化率达到96.94%。球团金属化率的变化趋势表明球团在反应开始是由化学反应控速环节控制,而后逐渐向扩散控速环节过渡。在1 400℃下空气中还原30 min,球团中还原出的铁与渣完全分离。     

煤的性质对铁矿—煤压块反应过程的影响

在升温条件下进行了不同性质的煤制成的铁矿－煤压块反应实验。结果表明：反应初期主要是挥发分的析出,在还原过程中,铁矿－无烟煤压块中挥发分先将铁氧化物还原至FeO,然后硕将FeO还原到Fe。铁矿－烟煤压块中挥发分和碳能够边疆将铁氧化物还原至Fe,无烟煤和烟煤混合制成的铁矿－混合煤压块中先是烟煤中的碳将铁氧化物部分还原至Fe,然后无烟煤中的碳将剩余的FeO还原到Fe。     

基于低温快速预还原的熔融还原炼铁流程

提出了基于低温快速预还原的熔融还原炼铁流程。由三部分组成:熔融气化炉,主要功能是熔化海绵铁和产生预还原所需的还原煤气;预还原部分,由两级快速循环床和一级矿粉预热床组成,主要功能是将矿粉转变成高金属化率的铁粉,金属化率大于85%;煤气处理,包括尾气换热、煤气洗涤、煤气增压、脱除CO2等工序,功能是调节预还原所需的煤气成分、煤气量与温度。新工艺采用精矿粉或粒度小于1 mm的矿粉,具有还原温度低、反应接近平衡态、金属化率高等特点,吨铁燃料比有望在600 kg左右,实现炼铁工艺的高效、节能与减排。     

Low Temperature Reduction Degradation Characteristics of Sinter, Pellet and Lump Ore

 The reduction degradation characteristics of typical sinter, pellet and lump ore were tested with the reducing gas conditions simulating two kinds of iron-making processes. The results show that, in the same condition of gas composition and temperature, the reduction degradation degree (RDI＜3.15 mm) of sinter is high, RDI＜3.15 mm of lump ore is low and RDI＜3.15 mm of pellet is in the middle level. With two kinds of gas composition simulating different iron-making processes, the reduction degradation indices (RDI) of three kinds of iron ores all present the tendency of “inverted V-shape” in the temperature range from 450 to 650 ℃, and the RDI reach the maximum value at 550 ℃. The reduction degradation degrees of iron ores are extended when mixing the gas with hydrogen to increase the reduction potential, and the influence extent is discrepant for different iron ores. Colligating the increase amplitude of grains in small size fraction, the influence of reducing gas on lump ore is the greatest, the influence on sinter is the second, and the sensitivity of pellet on the reducing gas properties change is relatively small. As for the degradation form, lump ore and sinter both present the degradation of cracking, and the distribution of small grains generated from the cracking is in the range from 0.5 to 6.3 mm uniformly. The lump ore presents surface cracking, while sinter presents integral cracking. The pellet presents the degradation of surface stripping, and the proportion of grains smaller than 0.5 mm is the highest, which is up to 90% in the grains smaller than 3.15 mm.     

Technical analysis on ironmaking process of rotary kiln pre- reduction and smelting by coal and oxygen

The traditional blast furnace ironmaking process has many problems such as long process flow, high dependence on coke and large environmental pollution. In order to solve these problems, the new ironmaking process of rotary kiln pre- reduction and smelting by coal and oxygen was developed. This new process has advantages of wide raw material adaptability, no coke consumption, less pollutant emissions and suitable for special iron ore resources. The mathematical model of the new process was established. Numerical simulation results show that the metallization rate of pre- reduction iron, smelting furnace gas oxidation degree and blast air oxygen content have great influence on coal and oxygen consumption. The coal and oxygen consumption reduces with the increase of pre- reduction iron metallization rate, the rise of oxygen degree of coal gas or the decrease of oxygen content of blast air. This process has a significant advantage in smelting special iron ore resources, which can make up the shortage of blast furnace ironmaking. It is also of great significance to reduce fuel consumption and CO2 emissions.     

Continuous Reduction of Iron Ore with Coal in an Electrically Heated Furnace

Abstract

This paper presents the results of a fundamental study for the development of a new ironmaking process based on coal and iron ore concentrates [1]. The coal/iron ore mixture is fed mechanically and continuously through a reaction tube in a tubular, electrically heated furnace. Investigations have been made on the effect of several of the most important operating variables, i.e. temperature, linear velocity of solids, coal particle size and coal/iron ore ratio, on the degree of metallization and on the smoothness of the operation. The gases generated during reactions have also been analysed. The rapid rate of metallization obtained and the composition of gases generated indicate that development of a new and economical ironmaking process is encouraging.     

铁矿石还原气-固还原行为研究现状

系统分析了铁矿石还原性的影响因素以及铁矿石的气固还原动力学特征,铁矿石的化学成分、孔隙率和矿 物组成对其还原性都有影响,总体来看,铁矿石中的碱性氧化物对铁矿石的还原有促进作用,而酸性氧化物对其还 原有阻碍作用。提高铁矿石中微气孔的比例以及提高还原性好的矿物,如铁酸钙的含量可改善铁矿石的还原性; 对于铁氧化物气固还原动力学的研究大多采用未反应核模型,在还原的不同阶段具有不同的限制性环节,比如在 浮士体还原到金属铁阶段,前期还原反应由气体内扩散与界面化学反应混合控制,后期界面化学反应为还原反应 的控制环节。总结前期的研究结果,结合当前资源现状提出了今后铁矿石还原行为的2个研究方向:①加强 Al 2 O 3 、K 2 O、Na 2 O、ZnO等杂质元素和有害元素对铁矿石还原性影响研究;②加强高炉实际含铁原料,如烧结矿、 球团矿和块矿的气固还原动力学研究。     

低锰高铁矿直接还原-熔分制备富锰渣试验研究

摘要：试验以锰品位27.7%,铁品位18.1%的低锰高铁矿为研究对象还原制备富锰渣,生产得到的富锰渣可用于冶炼硅锰合金,以达到高效利用低品位锰矿的目的。根据该矿的成分分析、XRD分析和粒度检测分析结果,采用还原 熔分法对低锰矿进行还原制备富锰渣试验,试验结果表明：单因素试验下各参数对低锰高铁矿的还原-熔分后渣中Mn、Fe元素的含量和Mn元素的回收率均有较大影响,同时结合Box-Behnke原理设计方案,选取温度、碱度以及配碳量3个试验因素,通过响应曲面法研究各因素交互作用下对Mn元素回收率的影响规律,对试验因素进行优化分析,建立相应的多项式模型。模拟优化得到最优的工艺条件为：还原温度1402℃,碱度0.10,配碳量10.04%,Mn元素回收率为97%。在最佳条件下做验证试验得出Mn元素回收率为95.80%,误差1.24%,证明响应曲面法预测模型具有可靠性,同时对低锰高铁矿的应用有重要指导意义。     

Experimental study on preparation of manganese rich slag by direct reduction melting separation of low manganese high iron ore

In this experiment, low manganese high iron ore with manganese grade of 27.7% and iron grade of 18.1% was used as the research object to reduce and prepare manganese rich slag. The obtained manganese rich slag can be used for smelting silicon manganese alloy to achieve the purpose of efficient utilization of low grade manganese ore. According to the results of composition analysis, XRD analysis and particle size analysis of the ore, the reduction melting separation method was used to prepare manganese rich slag from low manganese ore. The experimental results show that each parameter has a greater impact on the mass fraction of manganese and iron in the reduction melting separation slag of low manganese high iron ore and the recovery rate of manganese under the single factor test. At the same time, combined with the Box Behnke principle design scheme, three experimental factors including temperature, alkalinity and carbon content were selected. The influence of each factor on the recovery rate of manganese was studied by response surface method. The experimental results were analyzed to establish the corresponding polynomial model, and the optimal process conditions were as follows: reduction temperature of 1402℃, alkalinity of 0.10, carbon content of 10.04%, and the recovery rate of manganese was 97%. A verification test was conducted under the optimal conditions; the recovery rate of manganese was 95.80%, and the error was 1.24%, which proved that the response surface method was a reliable and accurate prediction model. At the same time, the results are instructive for the application of low manganese and high iron ore.