直接还原处理钒钛矿资源的几种典型工艺评述

对新西兰钢铁公司、南非海威尔德钢钒公司、中国攀钢资源综合利用中试线分别采用的钒钛矿处理工艺进行了详细阐述。新西兰钢铁公司和海威尔德采用回转窑直接还原—电炉熔炼—含钒铁水提钒工艺,只能提取钒钛矿中的铁和钒,钛进入熔分渣,TiO2品位低,提取困难。攀钢采用转底炉直接还原—熔分电炉深还原—提钒工艺,熔分过程不调渣,含钛炉渣品位较高,稳定在45%以上,可利用传统的硫酸法提钛,实现了钒钛磁铁矿铁、钒、钛的回收利用。介绍直接还原处理钒钛矿的工艺方法,对钒钛矿资源以及类似的多金属共生矿的开发利用有借鉴作用。     

Thermodynamic modelling of the multiphase pyrometallurgical processing of electric arc furnace dust

Electric arc furnace (EAF) dust is produced when automobile scrap is remelted in an electric arc furnace and about 10–20 kilograms are generated per ton of steel. The major elements present in the dust are usually zinc, iron and calcium with smaller amounts of numerous other elements such as lead, copper and nickel. Typically, in the pyrometallurgical EAF dust treatment processes, the lead and zinc are separated as a crude zinc oxide while the iron is generally not worth recovering. Copper and nickel are usually not recovered as they report either to the oxide residue or to any metallic iron that is produced. In the present research, the recovery of the non-ferrous metals in a multiphase system consisting of gas, slag, matte, metal and solid carbon phases was investigated. The equilibrium compositions of the various phases, resulting from the smelting of the dust, were calculated using the SOLGASMIX module of Outokumpu HSC Chemistry. The effects of the following operating variables were investigated; carbon additions, sulphur additions, nitrogen and oxygen additions, temperature and dust composition. The thermodynamic modelling results show that the majority of the non-ferrous metals can be recovered, with the zinc and lead concentrating in the gas phase and the nickel and copper concentrating in the matte phase.     

Reduction of dioxin/furan emissions in the waste gas from electric arc furnaces

The iron and steel industry is under considerable pressure to continuously reduce the levels of generated dioxins and other harmful emissions from process offgas. In the early 1990s this industry commenced with the investigation of new offgas cleaning systems for sinter plants and electric arc furnaces (EAF) which resulted in a considerably improved offgas cleaning efficiency. The global tendency in the steel industry towards an increased application of the electric arc furnace for the production of steel and especially the introduction of scrap-pre-heating technologies in the late 1980s resulted in increased demands for VOC and dioxin reduction technologies. This paper presents an overview of the state-of-the-art of EAF offgas systems and its components with a special focus on the organic components of the offgas.     

DRI钛渣制备高钛渣新工艺研究

传统高炉工艺流程处理钒钛磁铁矿,钛资源回收率低。针对气基竖炉还原—电炉熔分的非高炉冶炼工艺得到熔分钛渣,开展DRI钛渣提质生产高钛渣的方案探索和尝试,成功开发了HCl加压浸出—碱浸工艺和NaOH/Na_2CO_3活化焙烧—浸出分离工艺,均可获得满足氯化钛白要求的高钛渣。     

Sustainable Electric Arc Furnace Steel Production: GREENEAF

In the modern electric arc furnace (EAF), more than 40 % of energy comes from chemical sources by fossil fuels: natural gas is used in dedicated burners during the melting of the scrap, while lump coal (mainly anthracite) is added to the basket and pulverized coal is injected as a foaming agent. Within the frame of the European Research Fund for Coal and Steel (RFCS), the ongoing project GREENEAF (RFSR-CT-2009-004) is studying the possibility to replace coal and natural gas in EAF with char and syngas produced by biomass pyrolysis. The best pyrolysis conditions to obtain the proper syngas and char quality have been defined by laboratory tests using biomass available in the surrounding of the partners steel shops. Industrial trials have been performed in three different EAF plants. The results demonstrated the technical feasibility of the approaches, while the economical evaluation has showed the sustainability of replacing the coal with char from biomass in addition to environmental benefits due to CO₂ reduction.     

Use of oxidation roasting to control NiO reduction in Ni-bearing limonitic laterite

Use of limonitic laterite as an iron source in conventional ironmaking is restricted due to its gangue composition and small particle size. Even direct reduction cannot effectively produce direct reduced iron (DRI) because NiO would be reduced together with iron oxide to form Fe–Ni. A small amount of Ni (about 2 wt.%) in DRI degrades the physical properties of final steel products. The current study investigated how oxidation roasting of limonitic laterite ores affected NiO reduction, with the goal of producing Ni-free DRI and Ni-bearing slag. Ni-bearing slag can be a good secondary Ni resource. Oxidation roasting made NiO inert under H₂ reduction at 900 °C by forming Ni-olivine. Optimum roasting temperature was proposed by examining phase transformation of limonitic laterite ores during heating and by FactSage calculation of the equilibrium Ni fraction in Ni-bearing phases. Furthermore, the effect of Mg–silicate forming additives on the control of NiO reducibility was clarified to maximize the suppression of NiO reduction. Among various additives such as MgSiO₃, Mg₂SiO₄ and Fe–Ni smelting slag, Ni-free olivine-typed flux was found to be the most effective form of Ni-olivine because Ni–Mg ion exchange between Ni-bearing phase and Ni-free olivine occurs more readily than other Ni-olivine formation schemes. Finally, the mechanism of Ni-olivine formation during roasting was studied using a diffusion couple test. Calculated diffusivity values of Ni in Mg₂SiO₄ indicated that the two major routes of Ni-olivine formation while roasting limonitic laterite ore are (1) Ni partitioning within Mg–Ni silicate before crystallization and (2) Ni diffusion from spinel to Ni free olivine after crystallization.     

A new process for comprehensive utilization of complex titania ore

Ilmenite concentrate is the second most abundant resource from the vanadium-bearing titaniferous magnetite in Panzhihua, comprising about 90% of the titanium resources in China. In order to fully utilize Panzhihua titanium resources, a new process was proposed in this work. In the process, Panzhihua ilmenite concentrate was first reduced in a rotated hearth furnace to produce iron and titanium-enriched material, then the latter was chloridized in a new combined fluidized bed to produce TiCl₄. The combined fluidized bed consisted of two fast fluidized beds and a turbulent fluidized bed, producing effective anti-agglomeration during the chloridizing of materials with high-level CaO and MgO.     

我国镍冶金的发展与工艺技术进步

我国的镍冶金生产近３０年来取得了巨大的发展，工艺技术的进步尤为突出。本文重点论述了我国镍冶金现有的电炉、闪速炉熔炼低冰镍－转炉吹炼高冰镍－铜镍磨浮分离－硫化镍阳极电解；高冰镍两段逆流硫酸选择性浸出－黑镍沉钴－电积；二次镍精矿制粒－沸腾焙烧生产氧化镍等工艺流程。同时，介绍了我国自行研究开发的高冰镍氯化精炼；焙烧－氨浸－氢还原；镍精矿微波脱硫－热等离子体熔炼高冰镍；大洋多金属结核常压氨浸和硫酸选择性浸出回收镍等有价金属的新工艺新技术。     

Die Direktreduktion von Feineisenerzen in Druckwirbelschichtreaktoren: Experimentelle Untersuchungen und morphologische Betrachtung zur Übertragung auf industrielle Prozesse

In industrial plants it was observed that the operating conditions in the prereduction stage have a significant effect on the final reduction degree. A laboratory scale, pressurized fluidized bed reactor was developed according to the concept of chemical similarity to perform experiments similar to industrial operating conditions. With this set-up, temperatures up to 900°C and operating pressures up to 10⁵ Pa absolute can be realized. Numerous experiments with H₂-rich reduction gas according to the FINMET^®-process and CO-rich reduction gas according to the FINEX^®-process were carried out. Temperature, residence time and gas composition were varied. The samples were analyzed and morphologically evaluated. The influence of the operating conditions in the prereduction stage on the final reduction degree was reproduced, studied and confirmed by morphological investigations.     

某海滨铁砂矿流态化气基还原—高温熔分试验

为了确定印度尼西亚某海滨铁砂矿的合理开发利用方案,在模拟流化床的竖直管式炉内,以CO与H2的混合气体为还原剂,对该海滨铁砂矿进行了直接还原试验,并对最佳条件下的还原产物进行了熔分条件试验。结果表明:1反应温度和还原气氛对还原效果影响显著,在还原温度为900℃、还原气体H2和CO的体积比为7∶3、还原时间为80 min情况下,还原产物中铁的还原度为96.11%、铁的金属化率为93.40%。2确定条件下的还原产物适宜的熔分温度为1 570℃、碱度为1.2、熔分时间为15 min,对应的铁回收率为92.99%。因此,流态化气基还原—高温熔分工艺是该海滨铁砂矿开发利用的有效工艺。     

高炉灰与高磷鲕状赤铁矿共还原回收铁的研究

为考察高炉灰作为还原剂用于高磷鲕状赤铁矿石还原焙烧的可能性,以鄂西某铁品位为42.72%的鲕状赤铁矿石和河北某铁品位为23.96%、固定碳含量为32.83%的高炉灰为原料,进行了共还原焙烧回收铁试验。结果表明：在高炉灰用量为30%、共还原焙烧温度为1 150 ℃、焙烧时间为60 min、还原产品磨矿细度为-0.043 mm占96%、磁选磁场强度为87.58 kA/m条件下,可获得铁品位为91.88%、回收率为88.38%、磷含量为0.072%的还原铁。不同高炉灰用量下焙烧产品的XRD分析结果表明：随高炉灰用量的增加,铁的衍射峰逐渐增强,增加高炉灰用量有利于含铁矿物被还原成金属铁,但还原铁产品磷含量也升高。高炉灰作为还原剂用于高磷鲕状赤铁矿共还原焙烧,为高效利用高炉灰和难选铁矿石提供了一种新思路,又可以降低鲕状赤铁矿石直接还原焙烧的成本,同时减轻高炉灰对环境的污染,具有较高的经济和环境效益。     

高铁闪锌矿还原浸出液直接萃取法分离回收铟

针对高铁闪锌矿湿法炼锌过程中产出的还原浸出液提出了预还原Fe3+,P204直接萃取回收铟的工艺。还原浸出液中铁达到50g/L以上,Fe3+占到10%左右,经预还原后Fe3+降低到0.5g/L左右,还原过后的浸出液进行直接萃取分离回收铟。考察了原液pH、相比、有机相浓度、搅拌转速等条件对整个萃取过程的影响。铟的萃取率主要受P204浓度和溶液pH的影响,萃取过程平衡时间为1~2min。三级逆流萃取综合验证试验表明,铟的萃取过程稳定,萃取率在98%以上,铟铁分离效果良好,分离系数达到10000以上,整个过程无乳化现象产生。直接萃取法回收铟具有操作简单、流程短、直收率高等特点。     

Use of mesalime and electric arc furnace (EAF) dust as neutralising agents in biooxidation and their effects on gold recovery in subsequent cyanidation

The cost of lime/limestone for neutralisation is the second largest operating cost in bioleaching. Therefore, these studies have been conducted with the aim to investigate the possibilities for use of by-products such as mesalime and electric arc furnace (EAF) dust for neutralisation during biooxidation of a refractory gold concentrate. Experiments were carried out using a retention time of 57 h in a one-stage reactor and the influence of two industrial by-products on the biooxidation performance was evaluated. The neutralising capacity of EAF dust was lower, while the mesalime was similar to the Ca(OH)₂ reference. The arsenopyrite oxidation in experiments ranged from 85% to 90%, whereas the pyrite oxidation was 63–74%. In subsequent cyanidation, final gold recoveries of 90% were achieved in bioresidues from mesalime and Ca(OH)₂, while the EAF dust bioresidue had a recovery of 85%. A comparatively high elemental sulphur content in EAF dust probably encapsulates part of the gold, which explains the lower recovery for the EAF dust bioresidue despite a longer residence time. Cyanide consumption was relatively high and ranged from 8.1 to 9.2 kg/ton feed after 24 h of cyanidation. Overall, the by-products tested here have proved to be feasible options as neutralising agents in bioleaching operations.     

用硫酸渣生产铁金属化团块的研究

本文叙述了硫酸渣的一种应用途径，即用硫酸渣加添加剂造球，然后进行球团矿的直接还原焙烧（焙烧温度为１１５０—１２００℃，焙烧时间为３ｈ），再将焙烧产物进行渣铁分离。用这一新工艺处理硫酸渣可得到含ＴＦｅ＝９０．４３％，铁金属化率达９４．５０％和铁回收率为９０．９４％的优质电炉炼钢用直接还原铁（ＤＲＩ）。     

钒钛海砂矿转底炉直接还原研究

针对印尼钒钛海砂选矿后的精矿,采用转底炉直接还原—电炉熔分工艺,先后完成了小型基础试验研究和中试试验。得到最佳的条件是,m（海砂精矿）:m（兰炭）:m（膨润土）:m（有机粘结剂）=100:25:3:1,含碳球团3层（54 mm）,还原温度1 260℃,还原时间30 min,中试得到球团平均金属化率88.63%,球团中剩碳4.81%。将金属化球团热装入300 kVA的直流电炉进行冶炼,得到含钒铁水,铁水中铁品位96.25%,钒品位0.443%,铁与钒回收率分别为99.64%和88.96%,炉渣中TiO₂品位38.86%,钛回收率为98.95%。结果表明,转底炉直接还原—电炉熔分处理海砂精矿技术上可行。      

经改性的电炉贫化铜渣的酸浸—弱磁选试验

某铜冶炼厂的电炉贫化渣铜、铁含量分别为1.24%和31.80%,主要可见铁橄榄石相和磁铁矿相。为了确定该电炉贫化渣的开发利用工艺,进行了工艺条件研究。结果表明,铜渣在磨矿细度为D90=52.6μm,硫酸的浓度为150 g/L,过氧化氢添加量为150 m L/kg,液固比为5 m L/g,浸出温度为60℃,浸出时间为60 min,弱磁选磁场强度为160 k A/m情况下,可获得铜浸出率为67.15%,铁精矿铁品位为56.01%、铁回收率为62.38%的试验指标,可较好地实现该资源中铜、铁的回收。     

电炉还原熔炼铜钴氧化矿生产白合金的工艺实践

通过M冶炼厂的实践运营,本文介绍了铜钴白合金的生产工艺流程,矿热电炉的工作原理及铜钴氧化矿的还原熔炼原理。讨论了生产过程中对冶炼温度、渣型、渣含钴及加料方式的控制。实践表明,矿热电炉处理铜钴氧化矿能生产合格的白合金。     

电炉钛渣制备高品位人造金红石的试验研究

以云南某地两种不同性状电炉冶炼钛渣为原料, 对氧化还原-流态化酸浸和活化焙烧-洗硅-流态化酸浸两种高钛渣制备人造金红石的工艺路线进行了试验研究, 并通过XRD、SEM分析等手段探讨了氧化还原和活化焙烧对高钛渣改性的机理。试验结果表明, 低硅含量的电炉钛渣采用氧化还原-流态化酸浸工艺可获得符合沸腾氯化钛白原料要求的人造金红石;采用活化焙烧-洗硅-酸浸工艺可得到TiO₂品位97%的细粒级人造金红石。     

某高品位磁铁精矿球团预热-煤基直接还原研究

为了了解高品位铁精矿球团的预热及煤基直接还原特性,以某高品位磁铁精矿为原料,对添加有机添加剂的球团进行了预热及直接还原工艺条件研究,并对确定条件下的DRI球团进行了性能表征。结果表明：①预热球团的抗压强度随预热时间的延长和预热温度的升高而增大,要获得抗压强度为1 000 N/个的预热球团,1 100 ℃下需预热14 min。②1 100 ℃预热14 min的抗压强度为1 000 N/个的预热球团在C、Fe质量比为1.5,温度为1 100 ℃,时间120 min的条件下进行还原,可获得铁品位为94.12%、金属化率为98.64%的DRI球团。③DRI球团中仅呈现金属铁的衍射峰,中心金属铁互连紧密,金属键桥发育充分,铁晶粒粗大,球团边缘更明显,该有害元素含量极低的特极DRI是冶炼特殊钢、制备粉末冶金铁粉及高纯铁的优质原料。④预热球团具有足够的抗压强度不仅是回转窑安全运行的重要保证,而且对直接还原速率有明显影响,适宜采用1 100 ℃预热14 min抗压强度为1 000 N/个左右的预热球团。     

The pros and cons of reductive matte smelting for PGMs

Platinum group metals (PGMs) are traditionally smelted in electric furnaces where the valuable metals are collected in a base-metal sulphide matte. An alternative to this process is the ConRoast process that uses reductive alloy smelting in a DC arc furnace to collect the valuable metals in an iron-rich alloy. Reductive smelting of feed materials containing PGMs, using carbon as a reducing agent, can be used to obtain high PGM and base-metal recoveries and to ensure the solubility of chromium in slags.Based on work carried out in Mintek’s 3 MW DC arc furnace at throughputs of over 1000 tons per month, it was found that PGMs could be collected effectively, and that the chromium problem could be managed. However, if matte is present in the furnace, there remains a significant risk of furnace failure. Furthermore, the PGM ‘lockup’ (inventory inside the furnace) in a process that used reductive matte smelting of UG2 concentrates was much greater than that of reductive alloy smelting. Further differences exist in the better working environment and lower emissions of SO₂ in the case of the ConRoast process.