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By J. Miernik, D. Krupka, B. Ochab

The electrolytic zinc plant, with a capacity 75,000 tonnes per year, is part of Zaklady Gorniczo-Hutnicze BOLESLAW. It is the biggest zinc producer in Poland. The electrolytic zinc plant started up in 1955 with a capacity 15,000 tonnes per year, and multiplied its production by 5 till nowadays. At the beginning, the plant processed only calcine from zinc oxides (60% Zn, 3-4% Pb, 0,03 % Cd) which were produced from Waeltz fumes by calcination in a rotary kiln. Participation of calcine from zinc sulfide concentrates in the feed grew during the BOLESLAW plant expansion. Currently, only roasted sulphide concentrates, calcine from fluid-bed roasters, is processed. This paper presents a general description of the ZGH BOLESLAW plant and discusses the processes of roasting, leaching, purification and electrolysis. Also shown are the chemical analyses of the various process materials.

Jan 1, 2000

By Dmitri Nassyrov, In-ho Jung

"All relevant thermodynamic and phase diagram data in the CaO-Fe10-CaF2 system were critically reviewed. One set of model parameters describing the Gibbs energy of all phases has been obtained as a result of critical evaluation of the available data and optimization of the model parameters. The Modified Quasichemical Model was used to describe the interactions in the liquid phase. All calculations were performed using the FactSage thermochemical software.IntroductionSlags contaimng CaF2 are of significant interest to the steelmaking community. Notable examples of slags containing significant amounts of CaF2 include Electro-slag Remelting (ESR) slags [1] and mould flux for continuous casting [2]. The role of these slags is, among other things, to refine steel by absorbing inclusions and dissolved impurities. During slag-steel interaction, some iron from the steel will inevitably get oxidized and form iron oxides which will dissolve into the slag. With this in mind, it is important to understand the interaction between CaF2 and Fe,0 for accurate prediction of slag composition and process optimization. A thermodynamic optimization of the CaO-FetO-CaF2 was thus undertaken."

Jan 1, 2013

By James R. Craig

Petroleum coke is becoming an increasingly important source of light hydrocarbon products as product crudes become heavier and of poorer quality. The use of petroleum coke to generate synthesis gas results in the formation of residual slags that are enriched in silica, alumina, sulfides, oxides, and free metals. The characterization of these slags and their con? stituent phases is an essential step in considering the ultimate use or disposal of such slags and in understanding how to alter the properties of the slags to optimize the efficiency of gasifiers. Depending upon temperatures and bulk compositions, quenched slags typically consist of silicate glasses, calcium silicates, iron-nickel oxide-sulfide masses, aluminate spinels and free metals. Whereas the glasses contain relatively uniformly dispersed metals and sulfur, the iron-nickel oxide-sulfide masses highly concentrate nickel and sulfur. The aluminate spinels very effectively concentrate vanadium and chromium, thus depleting glasses or other adjacent phases. The abundance as well as the make up of the slags strongly affects the physical behavior of the slags within the gasifiers

Jan 1, 1989

By J. W. Evans

Mathematical modeling has now become a standard technique in the development of new technology and the improvement of existing technology in the processing industries. Physical modeling has a longer history but a smaller following at present. The paper reviews some examples of the application of both types of modeling in non-ferrous metal extraction, particularly within the copper and aluminum industries. The objective is to show that well founded models can lead to results that have practical consequence in scaleup, design and operation.

Jan 1, 1993

By Luciano E. Ramírez, Jesús L. Valenzuela, José R. Parga

"An innovative process for removing copper cyanide complexes including silver and zinc from cyanidation circuits has been developed. The technology was based on the inducing the nucleated precipitation of copper and silver in a tube serpentine reactor, using sodium sulfide as the precipitate and sulfuric acid as pH control. The results showed that pH had a great effect on copper cyanide removal efficiency and the optimum pH was about 3 to 3.5. At this pH value copper cyanide removal efficiency could be achieved above 97 and 99 % ,when influent copper concentration ions were 650 and 900 ppm respectively. In this process (sulphidizaton-acidification-recycle-thickening), the cyanide associated with the copper cyanide complexes is released as HCN gas under weakly acidic conditions, allowing it to be recycled back to the cyanidation process as free cyanide. This system was successfully commercial applied at Minera William in Mexico.IntroductionThe recovery of gold and silver from minerals and concentrates with cyanide is an important hydrometallurgical process, which has been studied for more than 124 years. Patented by MacArthur in 1888 [1], the process relies on the fact that gold dissolves in aerated cyanide solutions to produce the gold cyanide complex. The stoichiometry by wich this reaction occurs is known as the Elsner equation as shown here. Silver is accomplished in the same fashion."

Jan 1, 2012

By G. S. Victorovich

Technical progress in primary smelting has changed the face of the copper industry in the years since the Second World War. Much of this change has resulted from a wide acceptance of flash smelting technology. In addition, research has been directed toward devising converting processes to replace conventional Peirce-Smith converting technology. One major thrust has involved a revival of the old " ", idea of oxygen flash converting of comminuted mattes. This paper reviews the 60-year history of flash converting. Particular attention is paid to Inco's investigations into the processing of white metal containing significant amounts of nickel and, in some cases, iron. Thermodynamic analysis and laboratory experimental results are presented which throw light on the behaviour of nickel and other salient features of flash converting. The possible role of oxygen flash converting in the copper pyrometallurgy of the future is briefly discussed vis-a-vis direct production of copper.

Jan 1, 1993

By Shoji Taniguchi, Lifeng Zhang, Kaike Cai

"In the present paper, based on the two-phase (Eulerian-Eulerian) model, the 3D fluid flows in gas-stirred systems, i.e., air-stirred water vessel and argon-stirred liquid steel ladle, are simulated. In the Eulerian-Eulerian two-phase model, gas and liquid are considered to be two different continuous fields. The phases are assumed to share space in proportion to their volume fractions. The exchange between the phases is represented by source terms in conversation equations. Turbulence simulated by the k- e model is assumed to be the property of the liquid phase. The following effects of mathematical treatments and operational factors on the fluid flow are discussed, such as interphase drag force, turbulent model, the size of bubble, and gas injection mode.Some interesting results are derived. Except the interphase drag force, the interphase lift force should be taken into accounted in order to exactly simulate the fluid flow in gas-stirred systems. Suitable turbulent model and drag coefficient have effect on the mathematical simulation. Injecting small bubbles can realize a well mixing flow condition. The distance between the two gas-injection nozzles has effect on the fluid flow."

Jan 1, 2000

By N. E. Ablesimov

Electron probe X-ray microanalyser of a coating deposited with "Elitron¬22A" electrospark alloying (ESA) set (anode - Cr, base-catode - chrome vanadium steel) has shown that the zone of phase forming can be divided into three parts: the coating itself, diffusion zone and a thermal affection zone in the base material. Waves of iron and chrome concentrations have been found in the diffusion zone. The authors interprete them as a phenomenon of substance self-organizing in the 30 pill deep diffusion zone, characterized by a change of compositions during the transfer of material from the coating to the base: coating - 20 µm (FeCr2), diffusion zone - 30 µm (Fe3Cr, FeCr, Fe4Cr, Fe2Cr), base - steel (Fe - 87 %, Cr - 12 %, V - I %). This ESA phenomen has been noted for the first time. It may be relative to the phenomenon of periodic formation of secondary products during the mutual diffusion of reacting substances in the case of a one-way reaction. Similar regular structures may appear in the diffusion zone during ESA of vanadium steels with vanadium, manganese steels with manganese and so on.

Jan 1, 1999

By Joseph Gambogi

In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of futile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium. In this paper, we discuss all aspects of the titanium industry from ore deposits through extraction to present and future applications. The methods of both primary (mining of ore, extraction, and purification) and secondary (forming and machining) operations will be analyzed. The chemical and physical properties of titanium metal will be briefly examined. Present and future applications for titanium will be discussed. Finally, the economics of titanium metal production also are analyzed as well as the advantages and disadvantages of various alternative extraction methods.

Nov 26, 1999

By S. Eckert, G. Gerbeth, K. Timmel, B. Willers, T. Wondrak, N. Shevchenko, M. Röder

The quality of the produced steel in the continuous casting process is significantly governed by the melt flow in the mold. However, direct flow measurements in liquid metals are still rather scarce. In order to investigate these flow phenomena, three experimental facilities operating with low melting liquid metals were installed at Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The melt flow in the models is measured by the Ultrasonic Doppler Velocimetry (UDV) or the Contactless Inductive Flow Tomography (CIFT), multi-phase flows can be visualized by X-ray imaging. The obtained measurement results are primarily used for validation of numerical models. In this paper we will investigate the fluid flow in the mold and the behavior of the surface of the liquid metal using flow measurements by UDV and surface profile measurement by a laser scanner, respectively. Strong fluctuations and deviations of the free surface were observed in case of a static magnetic field

Jan 1, 2016

By Timothy W. Skszek, Adrian S. Sabau, Hebi Yin, Gerard M. Ludtka, Xiaoping Niu

"A constitutive model has been developed to predict the yield strength aging curves for aluminum casting alloys during non-isothermal age-hardening processes. The model provides the specific relationship between the process variables and yield strength. Several aging heat treatment scenarios have been investigated using the proposed model, including two-step aging recipes. Two-step aging heat treatments involve a low temperature regime to promote nucleation of secondary phases and a second step at higher temperature for the growth of the secondary phases. The predicted results show that a yield strength of approximately 300MPa might be obtained in a shorter aging time, of approximately 30 minutes. As a result, better mechanical properties can be obtained by optimizing the time-temperature schedules for the precipitation hardening process of heat treatable aluminum alloys.IntroductionA356 is one of the commercially heat treatable aluminum casting alloys, and T6 is one of the heat-treated conditions to improve mechanical properties. The first stage of a T6 temper is solution treatment at an elevated temperature, generally in the range of 480 - 540°C. After solution treatment, the cast part is typically quenched in water/air to retain the solute-rich homogeneous matrix chemistry at room temperature. Subsequent ageing treatment stages capitalize on this super-saturated solid solution to generate controlled dispersions of very small strengthening precipitates within the matrix of Al grains [l]."

Jan 1, 2013

By P. Tim Johnson

Relentless increases in demand for nickel and vanadium for uses such as steelmaking, catalysts and battery materials, plus the growing financial and environmental costs of their primary extraction, have led to much interest in potential secondary sources of these metals. The presence of such metals in heavy fuel oils, bitumen and related materials offers both opportunities and challenges for potential extraction methods, especially with the growing production and importance of metal-rich fossil fuels around the world. For several decades, Tetronics’ DC plasma smelting technology has been used for the recovery of metals such as nickel and chromium from stainless steel melt dusts and other wastes in compact, environmentally-friendly and efficient plants. This paper explores the suitability of DC plasma smelting as part of a wider flowsheet with feed preparation and aluminothermic reduction techniques for smaller-scale extraction operations based on this important niche secondary source of these key metals.

By Heric Henrique Souza e Silva, Johne Jesus Mol Peixoto, Natalia Barros Barony, Itavahn Alves da Silva, Weslei Viana Gabriel, Carlos Antonio da Silva, Varadarajan Seshadri

In this work the circulation rates have been determined in a 1:7.5 scale physical model of RH reactor (Ruhrstal Heraeus) and using oil/water and oil/zinc chloride solution to simulate steel melt/slag in the prototype with the objective of evaluating the influence of density and viscosity on the entrainment of oil simulating slag. A technique based on strain gage bridge and particle image velocimetry was developed to assess the circulation rate, as the usual tracer method is not feasible due to the presence of chloride ions in ZnCl2. The critical velocity and critical diameter of oil drops for slag (oil) entrainment in water/oil and ZnCl2/oil systems were estimated using equations from the literature. Due to the difference in density, the ZnCl2/oil system, showed a critical velocity that is 28% higher than the silicone oil/water system while the maximum size of the entrained droplets was about 65% lower than that for water/oil system.

Mar 1, 2017

By M. Kawakami

In the blast furnace, the reduction of iron oxide and gasification of coke occur simultaneously. It is well accepted that the gasification reaction controls the simultaneous reaction. Therefore, it is important to develop highly reactive carbonaceous materials. It is also known that the reaction is accelerated catalytically with the addition of some materials. In the present work, the catalytic effect of iron, nickel and CaO on the gasification of graphite and coke was examined. The catalytic effect of iron, nickel and CaO on the reaction rate of graphite was noticed The effect was larger at lower temperature. At 1373 K, the effect almost vanished. The effect was larger in the order of CaO, iron and nickel. The reaction rate of de-ashed coke increased by the addition of iron and nickel. The effect of iron was larger than that of nickel. The effect was larger at higher temperature, which was contrary to the case of graphite. The reactive surface area increased also by the addition. Therefore, the catalytic effect on reaction rate might be attributable to the increase in the reactive surface area.

Jan 1, 2006

By Henry Hu

In high pressure die casting processes, proper control of temperature die yields a high casting production rate and superior quality components, Die temperature is usually influenced by various die design and process parameters such as size and location of intemal water cooling lines, flow rates of cooling lines, and pouring temperature of molten metal. Among them, the cooling water flow rate plays a major role in controlling thermal pattern of the die_ In order to develop an effective control strategy, data of local die temperature must be collected and analyzed, In this study, a PC-based data acquisition and control system (DACS) for die temperature control has been designed, and established, The developed DACS has three input channels for temperature signals and one input channel for water flow rate signals, as well as one output channel for a water pump, and is capable of displaying data in both curve format and value format. Implementation of the DACS in a laboratory setup has also been attempted, It should be pointed out that more advanced control mechanisms can be potentially integrated into this system in future,

Jan 1, 2003

By Wei Lv, Gangqiang Fan, Xuewei Lv, Kai Tang, Yingyi Zhang

The EAF smelting process of ilmenite concentrate consumes large amounts of energy. Semi-melting reduction can lower the reaction temperature and separate the iron and slag more thoroughly. However, this needs additives and pre-oxidation to promote the reaction. In this paper, the pre-oxidized ilmenite powders were reduced isothermally with graphite and Na2SO4. The influence of reduction conditions on the metallization ratio of samples, such as reaction temperature, and sodium sulfate additive were investigated. The results show that additive such as Na2SO4 can significantly decrease the melting point of pre-oxidized ilmenite concentrate.

Mar 1, 2017

By W. Kunda

A laboratory study was carried out on the treatment of sulphidic copper concentrates in aqueous chloride systems under elevated temperatures and oxygen overpressure. Exploratory tests showed that chalcopyriteoxidizes with various chloride salts to form, depending upon the pH of the system, soluble copper chloride or insoluble copper oxychloride salts; the copper can then readily be recovered from the solution or residues respectively. During the leaching, iron was oxidized to iron oxide and remained in the leach residue while the bulk of the sulphide sulphur was oxidized to the elemental form with a minor portion oxidized further to sulphate. The presence of metal chloride salts in the system increased the oxidation rates of chalcopyrite and depressed the solubilization of iron in the system. A systematic oxidation leach study carried out in (1) ammonium chloride and (2) sodium chloride systems showed that the former system required little or no HC1 addition while the latter required 2 mol of HC1 per mol of dissolved copper (plus zinc). The copper was recovered from the cuprous or cupric chloride leach solutions by cementation with iron. Extractions of 99% copper and zinc, 97% silver, and negligible iron were obtained. Sulphur was oxidized to the elemental or sulphate form; the relative proportions of the total sulphur were 60 and 30% for system (1) and 80 and 10% for system (2). A flowsheet for a conceptual process with minimal reagent requirements was proposed.

Jan 1, 1976

By Gregor Kücher

Lack of basic knowledge on the semi-direct recycling methods for hard metals hinders the application on an industrial scale. However, advantages like reduced expenses and lower environmental impact draw interest at future potentials. Consequently, this report aims to offer insight into the influence of varying bulky hard metal substrates during their lixiviation in acidic media with an oxidant. The statistical software Modde 11 assisted in the development of a design of experiments (DOE) for evaluation of the impact of average grain size, binder and tantalum carbide (TaC) content on the leaching characteristics. The other experimental parameters were constant. Among them were temperature, solution concentration and quantity, duration and substrate surface exposed to liquid volume. Eventually, prediction plots and factors of the computed model equation describe the effects of varying substrate qualities on leached binder metal and selectivity.

By J. Daniel Bryant

Deformation processing of rapidly solidified powder alloys presents a technical challenge different in several ways from the processing of ingot based alloys. The metastable phases formed during planar flow casting of aluminum alloy 8009 (FVS0812) must be safe-guarded from high temperature excursions during processing to avoid decomposition; this restriction prohibits liquid phase sintering of particles during consolidation. The development of strong particle-particle adhesion, therefore, relies on the imposition of very large strains during forming operations to insure sufficient mechanical meshing of the aluminum particles and break-up of prior particle oxide boundaries. These strains are generally much greater than those required for metallurgical transformations in ingot based alloys. In an attempt to quantify the deformation required to improve interparticle bonding, the finite element method (FEM) was employed. Preliminary results which predict the metal flow and strain distribution in several workpiece configurations are discussed. These predictions are then correlated to measurements made on experimental subscale forgings. Lastly, experimentally measured quantities which reflect the degree of interparticle bondingg are related back to FEM model predictions.

Jan 1, 1992

By V. Blet

Rare earth elements (REE) are regarded today as highly critical raw materials but currently lack suitable recycling processes. A combined hydro- and pyrometallurgical process aimed at REE recovery from used NdFeB permanent magnets was recently developed by the CEA. The process integrates the physico-chemical treatment of magnets, followed by a solvent extraction step for the recovery and intra-REE separation using a selective extractant. A subsequent pyrometallurgical treatment via molten chloride salt electrolysis allowed the isolation of pure Dy metal. Technical-economic assessment and life-cycle analysis were also conducted. Following this first successful demonstration, a new project aimed at the recovery of REE from end-of-life nickel-metal-hydride batteries is currently being developed in association with industrial and academic partners. The project aims at evaluating from an experimental and economic perspective different processes converging at the production of value-added products such as cermet materials for catalytic applications, purified REO concentrates, or metallic alloys.