Oxidation Potentials in Matte Smelting of Copper and Nickel

The oxidation potential, given as the base-ten logarithm of the oxygen partial pressure in bars and the temperature [log pO₂/T, °C], defines the state of oxidation of pyrometallurgical extraction and refining processes. This property varies from copper making, [?6/1150]; to lead/zinc smelting, [?10/1200]; to iron smelting, [?13/1600]. The current article extends the analysis to the smelting of copper and nickel/copper sulfide concentrates to produce mattes of the type Cu(Ni)FeS(O) and iron silicate slags, FeO_xSiO₂—with oxidation potentials of [?7.5/1250].     

SO2 abatement,energy conservation,and productivity at copper cliff

Inco pioneered the use of tonnage oxygen in nonferrous metallurgy when it commissioned the first industrial oxygen flash smelting process for the treatment of copper concentrates in the early 1950s. This was followed by other applications of oxygen such as the enrichment of reverberatory furnace and Peirce-Smith converter blasts; oxy-fuel smelting in reverb furnaces; and, very recently, flash conversion of chalcocite to copper. Inco is currently implementing a sulfur dioxide abatement project designed to reduce SO₂ emissions from the smelter by 60 percent (to 265 kt) in 1994. At that time, oxygen consumption at the smelter will reach about 1.7 t O₂/t Cu+Ni. Oxygen smelting and converting technology will lead toa substantial decrease in the use of fossil fuels and to the generation afhigh-strength SO₂ off-gases suitable for cost-effective fixation in a new acid plant.     

Flash smelting copper concentrates

Flash smelting is a comparatively new method of smelting copper and nickel sulfide concentrates. It takes place when the concentrate, with or without additional fuel, is suspended in gases containing oxygen whereby the heat of oxidation reactions bring the suspended particles to a smelting temperature. From the suspended state the hot particles are separated and molten slag and matte are deposited on the furnace hearth.     

闪速熔炼在中国的进展与研究--冷风技术及"非接触冶金"

从环境保护角度阐述了世界铜、镍闪速熔炼的发展与现状,讨论了"冷风节能"及其工业应用技术.介绍了中国在"闪速炉扩产"、"闪速冶金事故监控"、"水套新材料"、"闪速炉连续炼铜"等方面的研究成果.为根本解决强化冶金对炉衬的腐蚀,提出了"非接触冶金"的思路,描述了中心旋涡柱闪速熔炼方法,并介绍了旋涡喷嘴基本设计及计算机仿真实验.     

EFFECTS OF TEMPERATURE ON DISTRIBUTION BEHAVIORS OF MINOR ELEMENTS IN COPPER FLASH SMELTING──COMPUTER SIMULATION

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Oxidation Potentials in Iron and Steel Making

The state of oxidation of a pyrometallurgical process given by the partial pressure of oxygen and the temperature (the oxidation potential) is one of the important properties monitored and controlled in the smelting and refining of iron and the nonferrous metals. Solid electrolyte sensors based on ZrO₂ and a reference electrode such as Cr/Cr₂O₃ to measure the oxygen pressure found early application in the steel industry, followed soon after in copper, nickel, lead, and zinc smelting. Similar devices are installed in automobile postcombustion/exhaust trains as part of emission control systems. The current discussion reviews this technology as applied in the primary steps of iron and steel making and refining.     

基于数值模拟的闪速连续炼铜炉型结构研究

分析4种闪速连续炼铜炉型的本质特性,提出将闪速连续炼铜过程视为由相对独立的闪速造锍熔炼过程和连续吹炼造铜过程构成,分别建立闪速造锍熔炼多相平衡数学模型和连续吹炼造铜局域平衡数学模型,并通过中间物料的传递将两模型有机结合,从而构建完整的闪速连续炼铜过程热力学模型。运用此模型,考察炉型结构对闪速连续炼铜过程的粗铜生成条件、Fe3O4行为、铜在渣中损失以及铜直收率等因素的影响。结果表明：相对于其他3种炉型,甩渣吹炼双烟道D型炉是比较理想的连续炼铜炉体;对于闪速连续炼铜,造锍熔炼段和铜锍吹炼段宜在相对独立的分区进行,各自炉渣和烟气也应分开排出炉体。     

硫化铅矿闪速熔炼过程的热力学分析

基于最小吉布斯自由能原理,建立硫化铅矿闪速熔炼过程多相平衡热力学模型,考察熔炼温度(T)、吨矿氧量(VOVPTO)对粗铅含硫量、炉渣含铅量、烟气含铅量及铅在各平衡相中分配比的影响。结果表明:对一定用量和一定成分的硫化铅矿,随着T和VOVPTO的增大,粗铅含硫量可降至0.1%(质量分数)以下,但过高的VOVPTO会使渣含铅量升至60%(质量分数)以上,铅在粗铅中的分配比低于30%(质量分数);烟气中的铅主要以PbS形式存在,其含量随着T的升高及VOVPTO降低而增高。综合考虑铅的直收率及产物处理的难易程度,闪速炉直接炼铅应采取分区分步熔炼方式,先在氧化区制低硫铅,然后在还原区造低铅渣,且氧化区熔炼温度宜较低。     

Recovery of rhenium from molybdenum and copper concentrates during the Looping Sulfide Oxidation process

Rhenium is recovered during pyrometallurgical processing of molybdenum sulfide and copper sulfide ores; the traditional technology involves removing rhenium(VII) oxide, Re₂O₇, from the sulfurous gas phase generated during multiple hearth roasting (in molybdenum processing) and smelting (in copper processing). A new technology platform called Looping Sulfide Oxidation (LSO) has been proposed to produce molybdenum and copper using alternative process chemistries. A detailed thermodynamic study of the reaction conditions used in LSO process indicates that rhenium recovery is possible at higher rates than currently realized in the industry. Conditions at which Re₂O₇ is reduced to rhenium metal by S₂ have been identified and key process conditions are outlined to maximize performance of the LSO scheme and rhenium recovery.     

氧气底吹铜熔池熔炼过程的机理及产物的微观分析

对氧气底吹熔炼过程气体喷吹行为、造锍熔炼化学反应机理及熔炼炉内热工作状态进行理论分析及水模型实验和取样分析验证。结果表明,氧气底吹气流能使熔体形成均匀的扩散区,实现熔体的搅拌,在气体连续相区和液体连续相区,气液、液液之间的相互作用强烈,为炉内化学反应及传热传质提供了良好的动力学条件;氧气底吹熔炼过程在零配煤的情况下能达到自热熔炼,在节能减排方面,该工艺具有很强的优势;获得了铜渣、冰铜和蘑菇头中各组分的形貌,确定了铜渣、冰铜和蘑菇头的物相组成,渣样主要由冰铜相、磁铁矿相、铁橄榄石相和玻璃体相组成,熔炼内的氧势和硫势分布有利于反应的进行,能有效抑制Fe3O4的形成以及降低渣含铜。     

Energy requirements for the pressure oxidation of gold-bearing sulfides

A variety of feed materials may be subjected to pressure oxidation of their sulfide content to liberate gold contained therein for later recovery by cyanidation. Energy is required to pump the feed slurry into the pressurized reaction vessel, to heat the slurry to the reaction temperature, to supply oxygen, and to agitate the slurry and disperse the oxygen. At a certain grade of sulfide, depending on the mineralogy, the process becomes autothermal, obviating the need for heating during normal operation. The sulfide level required for autothermal operation can be reduced by providing one or more stages of heat recovery, wherein steam is flashed from the product and used to heat the feed. The production of oxygen required for the reaction is power intensive, and any steps improving oxygen utilization are beneficial.     

提高冶炼低硅含钛铁水转炉废钢比工艺攻关

废钢比是转炉生产的重要经济技术指标,其值大小直接影响转炉冶炼钢铁料消耗及热平衡,提高入炉废钢比是实现节铁增钢、降本增效的重要技术手段。然因冶炼低硅含钛铁水成渣难、脱磷难等问题,对应入炉废钢比持低不高,直接影响转炉生产成本。为此,基于低硅含钛铁水冶炼特点及难点分析,结合水钢生产实践,通过氧枪喷头优化、枪位优化、添加提温剂等工艺优化和技术开发,使入炉废钢比由优化前7.41%提高至13.48%,优化效果较为明显,为实现节铁增钢、降本增效奠定了一定基础。     

Influence Analysis of Air Flow Momentum on Concentrate Dispersion and Combustion in Copper Flash Smelting Furnace by CFD Simulation

The Outokumpu flash smelting process is a very successful technology for copper extraction from sulfide concentrate. Numerical simulation has been used for several decades in the analysis and evaluation of the smelting process. However, significant delay in the particle ignition was found in computations of flash furnaces that had great expansion in their productivity. A study was thereafter carried out to investigate how the gaseous flows influence the particle dispersion and combustion. A momentum ratio was defined to describe the effective portion of the pressure forces caused by the lateral and the vertical gaseous flows. Simulations were carried out with Fluent 6.3 (Fluent Inc. The software package is now known as Ansys Fluent of Ansys Inc.) for cases with different momentum ratios as well as of the same momentum value. A detailed analysis and discussion of influences of the gaseous momentum on the particle dispersion are presented. The result reveals that a large momentum ratio combined with large amount of distribution air is helpful for good particle dispersions and thus quicker combustions. Also the process air is found to perform a constraint influence on the particle dispersions, particularly for those of medium and small sizes.     

Mathematical modelling and numerical optimization of particle heating process in copper flash furnace

A mathematical model of the particle heating process in the reaction shaft of flash smelting furnace was established and the calculation was performed. The results indicate that radiation plays a significant role in the heat transfer process within the first 0.6 m in the upper part of the reaction shaft, whilst the convection is dominant in the area below 0.6 m for the particle heating. In order to accelerate the particle ignition, it is necessary to enhance the convection, thus to speed up the particle heating. A high-speed preheated oxygen jet technology was then suggested to replace the nature gas combustion in the flash furnace, aiming to create a lateral disturbance in the gaseous phase around the particles, so as to achieve a slip velocity between the two phases and a high convective heat transfer coefficient. Numerical simulation was carried out for the cases with the high-speed oxygen jet and the normal nature gas burners. The results show that with the high-speed jet technology, particles are heated up more rapidly and ignited much earlier, especially within the area of the radial range of R=0.3–0.6 m. As a result, a more efficient smelting process can be achieved under the same operational condition.     

Mass balance calculations in copper flash smelting by means of genetic algorithms

This paper presents mass balance calculations using genetic algorithms for copper smelting in an Outokumpu flash furnace. Based on the elemental composition of the copper concentrates being fed to the reactor, the mineralogical composition of the concentrate mixture is adjusted by means of genetic algorithms. The macroscopic mass balance equations for the species entering and leaving the furnace are solved and the compositions and flow rates of matte, slag, and the off-gas stream are computed. Good agreement between the predicted and plant data was obtained in terms of matte and slag flow rates, matte grade, and copper, iron, magnetite, and silica contents in the slag. Predictions are more suitable and faster to obtain with this method than a conventional method in which the mineralogical composition of the feed is not adjusted. Future applications of the formulation are discussed. For more information, contact V.M. Sanchez-Corrales, Universidad de Sonora, Departamento de Ingeniería Química y Metalurgia, Blvd. Luis Encinas y Rosales, Hermosillo, Sonora, 83000, Mexico; +662-259-2105; fax +662-259-2105; e-mail vsanchez@guaymas.uson.mx.     

Recovery of valuable metals from spent lithium ion batteries by smelting reduction process based on FeO–SiO2–Al2O3 slag system

A novel smelting reduction process based on FeO–SiO₂–Al₂O₃ slag system for spent lithium ion batteries with Al cans was developed, while using copper slag as the only slag former. The feasibility of the process and the mechanism of copper loss in slag were investigated. 98.83% Co, 98.39% Ni and 93.57% Cu were recovered under the optimum conditions of slag former/battery mass ratio of 4.0:1, smelting temperature of 1723 K, and smelting mass ratio of time of 30 min. The FeO–SiO₂–Al₂O₃ slag system for the smelting process is appropriate under the conditions of m(FeO):m(SiO₂)=0.58:1–1.03:1, and 17.19%–21.52% Al₂O₃ content. The obtained alloy was mainly composed of Fe–Co–Cu–Ni solid solution including small amounts of matte. The obtained slag mainly consisted of fayalite and hercynite. Meanwhile, the mechanism of copper loss is the mechanical entrainment from strip-like fayalite particles in the main form of copper sulfide and metallic copper.     

Thermodynamic Consideration for Oxygen Pressure in a Copper Flash Smelting Furnace at Toyo Smelter

JOM - Based on the emf measurements of the galvanic cell (Fe, MgO/O in slag or matte) and the equilibrium calculations, the oxygen pressure in a copper flash smelting furnace at Toyo smelter is...     

Role of alloyed copper on corrosion resistance of austenitic stainless steel in H2S–Cl− environment

Corrosion test, surface analysis and thermodynamic calculation were carried out in the H₂S–Cl⁻ environments to clarify the role of alloyed Cu on the corrosion resistance of austenitic alloys. The alloyed Cu improved pitting corrosion resistance in the H₂S–Cl⁻ environment. The surface film of Cu-containing alloy indicated double layer consists of copper sulfide and chromium oxide, and the copper sulfide was able to exist stably compared to iron sulfide and nickel sulfide. It is concluded that the copper sulfide would enhance the formation of chromium oxide film which improve the pitting corrosion resistance in the H₂S–Cl⁻ environment.     

Flash smelting and converting furnaces: A 50 year retrospect

1999 marked the 50th anniversary of the Outokumpu flash-smelting process. Originating during the post-World War II energy crisis, flash smelting is a high-intensity process developed to attain ever-increasing throughputs and intensities. Many innovations and continuous development ensued during the next 50 years before today’s state-of-the-art copper-making process chain and environmental benchmarking technology (e.g., Outokumpu flash smelting, Kennecott-Outokumpu flash converting, and flash technology) became possible. This article reviews how Outokumpu flash furnace design, especially cooling for higher heat loads, has improved over the years. For more information, contact I.V. Kojo, Outokumpu Engineering Contractors Oy, P.O. Box 862, FIN-02201 Espoo, Finland; telephone 358-9-4211; fax 358-9-421 3973; e-mail ilkka.kojo@outokumpu.com.     

Accelerating column leaching trial on copper sulfide ore

The main measures to accelerate leaching sulfide ore are large spraying intensity,manual oxygen supply,temperature control,and acclimated bacteria.The indoor experiment accelerating sulfide ore leaching detected the temperature during leaching process,dissolvability of oxygen,bacterial concentration,Cu concentration and slag grade.At the same time,this paper also analyzed the effect of four factors,which are bacterial diversity cultivation stage,spraying intensity,air supply,and whether to control temperature,on the leaching efficiency of copper.The results indicate that the oxygen content of leach solution has a close relationship with temperature but it is rarely affected by air supply.The bacterial concentration preserves from 106 to 107 mL^-1,and temperature has a great effect on the bacterial activity under the condition of proper temperature and oxygen supply,and the lack of nutrition prevents the bacterial concentration from rising in the late stage.The relationships of the copper leaching efficiency to temperature,air feed,and spraying intensity are directly proportional.The leaching efficiencies of the cultivated bacteria and acclimation bacteria are 1.2 and 1.4 times as large as that of the original bacteria.