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By Oleg I. Platonov

The process for desulfurizing coke oven gas in a regenerative system ?scrubber-stripper?, with sour gas being fed to Sulfur Recovery Unit (SRU) and tail gas being recycled to raw coke gas scrubber, has been developed. A key problem of this process is the presence of elemental sulfur in the SRU off-gas, which may deposit on gas-blowing equipment, thus disrupting its operation. A new treatment technology for SRU off-gas that has been worked out for a Claus unit operated by «Russian Metallurgical Company» (RMC) in Magnitogorsk (Russia) is presented. It incorporates a catalytic hydrolysis/hydrogenation stage, where all sulfur-bearing species such as sulfur dioxide, carbonyl sulfide and elemental sulfur are converted to hydrogen sulfide. The SRU in Magnitogorsk comprises three main units: gas re-heater; catalytic hydrolysis reactor and waste gas cooler. Re-heater is required to increase temperature of the process gas up to a level of catalytic conversion (beyond 330-3500C). Oxygen utilized as an oxidizing agent reduces the volume of waste gas to a minimal possible value. The operational data garnered since 16.07.2004 clearly shows that the new technology allows high-level purification of Claus tail gas from elemental sulfur. Unlike SCOT ? process, this technology does not require separate stages for H2S removal and enrichment that tangibly simplifies its implementation at lower capital and operation expenditures.

Jan 1, 2006

By David E. Jones

In any manufacturing process, the generation of secondary, associated or waste products along with the primary product is inevitable. Today there is great emphasis on the concept of waste minimisation. As part of that overall strategy, the search .for markets for these materials formally regarded as wastes, can mean the development of whole new industries. This paper examines some of the work necessary to develop recycling and markets for associated products with particular reference to iron and steelmaking slags.

Jan 1, 1994

By R. Rajiv Srivastava

Brine leaching of a TSL processed zinc-plant residue (ZPR), containing 83.3% anglesite, has been investigated for lead recovery. A prior treatment of ZPR in acid solution did not show any significant effect of acid concentration in zinc dissolution. The study reveals that the solubility limits of PbCl2 is as an important factor with respect to the brine concentration and pulp density in lixiviant. The dissociated sulfate ions hinder the formation of PbCl2 on prolong leaching (above 60 min), while exhibiting the reverse solubility of lead as PbSO4. A 3-step leaching process could yield >92% leaching efficiency when the parameters were maintained as: 10% pulp density in a 250 g/L NaCl solution, 80 °C temperature, and 60 min time. This leaves the insoluble ferrite, sulfides and oxy-sulfates of zinc and lead in the final residue as revealed by the XRD characterization.

By Alan DonaldsoN

Plasma Quench production of titanium is the thermal dissociation of titanium tetrachloride into gaseous titanium and chlorine followed by rapid quenching to prevent back reactions. Titanium tetrachloride dissociates into titanium and chlorine atoms at 5000 K. Expansion through a Delaval nozzle accelerates the gas to supersonic speed cooling it very rapidly. Cooling rates are as high as 7exp 1 0 Kelvins per second. Injected hydrogen reacts with condensed titanium particles to form titanium hydride and with the chlorine to form hydrogen chloride. We have produced titanium powder at 20 kglh in a continuous reactor. Costs are projected to be lower than the Kroll Process at large enough scale. Most of the cost reduction would result from elimination of magnesium as a reducing agent and much lower capital costs.

Jan 1, 2001

By Art Johnston

Gas handling at Magma Copper company's, San Manuel smelter receives process gas from a flash .smelting furnace and four copper converters. The major gas handling equip11lent consists of four electrostatic precipitators and a sulfuric acid plant. Process ,vessels in gas handling are, typically confined, spaces. Lethal gases, mechanical and chemical hazards, and the difficulty of rescue, should an accident occur, makes this area a must in the safety plan. The presence': of hazardous chemicals and explosive gases in process' vessels and piping are of major concern when repairs' are required. Proper job procedures are critical to prevent injury during repairs. This includes plant employees and contractors who are likely to be unfamiliar with the hazards ,involved. The safe operation of a gas handling operation must include the functions of operations employees on a daily basis. This includes a safe working environment and involvement of all employees in the safety program. If an injury does occur quick medical response is critical to prevent serious injury. Medical responders must be adequately trained and prepared to treat the injured person without becoming victims' themselves. The methods used at Magma Copper Company to deal with these safety problems are the focus of this presentation.

Jan 1, 1992

By Gus Van Weert

This paper describes the results of autoclave testwork where ferric nitrate was hydrolysed in the presence of certain cations and anions and the resulting hematite analyzed for foreign constituents. For the cations Zn++, Ni++, Cu++, and AI+++, selectivity factors of over 107 were found. Magnesium gave 3.106. These factors are calculated as Me/Fe in solution over Me/Fe in the hematite; Me representing the metal in ion added. As-a result of the testwork at Delft University of Technology, BUDELCO (the Netherlands electrolytic zinc producer) ran a series of ferric nitrate hydrolysis tests in the presence of 10 additional trace elements. Impurity levels were prejudiced on Me2 EPHA extraction of iron from their zinc circuit, followed by HNO3 stripping. Good selectivity against base metals was confirmed, but trace elements forming anions (As. Sb) and sulphate were incorporated in the hematite. These BUDELCO results are also presented.

Jan 1, 1995

By Jin Liu

To improve value metals recovery, a new operating concept for the Inco flash furnace was investigated, in which the flash furnace coke addition practice would aim at establishing a reducing barrier on the surface of the molten bath. The descending partially oxidized sulfide mineral particles would reach the supernatant coke layer prior to the formation of slag. The key for success depends on the effectiveness of the coke layer to produce a sulfur deficient matte while maintaining furnace production capacity. The mechanism and rate of carbon reduction of the phases formed in the flash flame, i.e. sulfide (matte) and oxysulfide was investigated by means of crucible graphite reduction test work. The objective of these tests was to measure the rate of solid graphite reduction of matte, oxysulfide, slag, and matte+slag mixture at different temperatures. These tests were expected to permit understanding and explaining the reduction mechanism of each material by comparing the respective reaction rates, product reaction gas compositions, reduced material assays, and other relevant parameters. Direct visual inspection of the test crucibles would provide additional information.

Jan 1, 2006

By Tullio Corsini

Scrap battery recovery process, developed by Engitec Impianti S.p.A., is improved transforming batches operations in continuous. Benefits expected: constant and better quality of the products; easier and more reliable control of the operating parameters, reduction of manpower requirements. Paste will content less sulfate, particularly in soluble form. Sodium sulphate is obtained with higher and constant purity.

Jan 1, 1993

By James D. Navratil

The mineral magnetite, or synthetically prepared iron ferrite (FeO?Fe2O3), has been used to separate a wide variety of substances, such as dissolved metal species and particulate matter, from wastewater. In the absence of an external magnetic field, activated magnetite readily adsorbs numerous metal species including actinide elements. In the presence of the external magnetic field, enhanced capacity was observed in using supported magnetite for removal of actinides and heavy metals from wastewater. The enhanced capacity is primarily due to magnetic filtration of colloidal and submicron particles along with some complex and ion exchange sorption mechanisms. The removal of the magnetic field and use of a regenerating solution can easily regenerate the loaded magnetite. The process has recently been tested for the removal of other metal ions including cobalt and iron. This paper will review previous work on the use of iron oxides for wastewater treatment and discuss the development and potential of the magnetic filtration/sorption process for wastewater treatment applications in hydrometallurgy.

Jan 1, 2003

By Carole Read

Hydrogen is under consideration by several countries for its potential as an energy carrier for transportation applications. In order to compete with vehicles in use today, hydrogen-powered vehicles will require a driving range of greater than 300-miles in order to meet customer needs and expectations. For the overall vehicular light-duty fleet, this dictates that a range of 5 to 13 kg of hydrogen be stored on-board (assuming a fuel cell power plant) within stringent system weight, volume, and cost constraints. Vehicular hydrogen storage thus constitutes a major scientific and technological challenge. To meet this challenge, the U.S. Department of Energy (DOE) initiated a ?National Hydrogen Storage Project? with roughly 40 universities, 15 companies and 10 federal laboratories, actively engaged in hydrogen storage research. Centers of Excellence in metal hydrides, chemical hydrides, and carbon-based materials have been established, as well as independent university and industry projects in the areas of new concepts/materials, hydrogen storage testing, and storage system analysis. Recent technical progress in each of these areas is discussed, as well as collaborative hydrogen storage activities under the recently established International Partnership for the Hydrogen Economy (IPHE).

Jan 1, 2006

By Qixing Yang, Björn Haase, Fredrik Engström, Anita Wedholm

"MiMeR, the Minerals and Metals Recycling Research Centre at Luleå University of Technology, Sweden, started industry-related research work to stabilize an EAF slag from Höganäs AB with of CaO/SiO2 values near to 3.2. The intention was to determine the suitability of the EAF slag as construction material after stabilization. Some of the stabilizers effective for preventing disintegration of AOD slag were examined in laboratory tests for stabilization of the EAF slag. The EAF slag samples were mixed together with stabilizers for melting at 1600ºC and then cooling in a crucible system. With a laboratory granulation system, the liquid EAF slag was cooled rapidly using air. Samples from the tests were characterized by different techniques, including XRD and SEM. Some of the results from the work may be useful for preventing slag disintegration and, thus, enhancing utilization of the EAF slag as construction material, thereby saving valuable natural resources.IntroductionAt steel plants of some MiMeR member companies, steel grades with low carbon contents were produced in Electric Arc Furnaces (EAF). EAF slag was tapped out of the furnace to slag pots for transport to slag yards, where the slag was poured on the ground. Very often, the EAF slag disintegrated during cooling on the ground. Fines from the slag disintegration were often difficult to handle and use as material for road construction [1, 2]. The EAF slag disintegration was rather similar to the disintegration occurring in the slag tapped from some AOD (Argon Oxygen Decarburization) converter heats.Literature studies show that formation of dicalcium silicate (C2S) is the main reason for the disintegration or dusting of AOD slag from production of stainless steel [1-4]. The C2S can form while the content ratio of CaO to SiO2 of the slag, CaO/SiO2, exceeds 1.4 [1]. Values of CaO/SiO2 for the AOD slag are often near to 2.0, making the C2S a predominant slag component. The ß phase of C2S, ß-C2S, transforms into its low temperature ? form in the temperature range of 400-500°C, inducing a volume expansion of nearly 12% [1-4]. The volume expansion disintegrates the AOD slag."

Jan 1, 2008

By Daniel Kim, Justin McAllister, Shijie Wang

"At the Kennecott Utah Copper Refinery, impurities in the electrolyte are being precipitated in the circulation system and form a hard scale in the piping. This scale must be removed periodically for proper electrolyte flow. Distinct layers of differing composition form as the operating conditions of the tank house change. Scale samples from the inlet and outlet pipes were analyzed to discover the nature of the precipitates. Each sample was sectioned and examined under optical microscopy and SEM. The composition of the scale was analyzed using ICP, XRD, and SEM/EDX mapping. The rate of deposition was determined by measuring the amount deposited on new pipes after elapsed time intervals. In order to determine how to minimize the formation of the scale, the mechanism was studied and the results are presented in this paper.IntroductionIn copper electrorefining, impure copper anodes are refined into pure copper cathodes. The impurities from the anodes are either insoluble and report to the slimes or soluble and dissolve concentrating in the electrolyte. These impurities are controlled by bleeding electrolyte from the system. Over time, the impurities combine to precipitate a hard scale on the surfaces contacted by the electrolyte. The scale causes problems with tank house circulation systems. In order for the refinery to operate properly, the scale must be removed periodically from the walls of the pipes. The first step to control the buildup of scale on the pipes is to understand the composition and the phases that are present in the scale."

Jan 1, 2012

By Zachery Zanetell

Flotation circuit performance has become increasingly more challenging due to the complexity of available ore sources. To optimize value mineral recovery, the mineralogical composition of the ore should be evaluated and understood. Utilizing a variety of mineralogical and analytical tools, flotation processing challenges can be overcome and potential limitations understood. In this paper, several case studies will be discussed in terms of the value that has been provided through the use of mineralogical analysis to optimize flotation performance.

By S. B. Breyner, A. Ressler, D. Gregurek, A. Spanring

"The changes in process conditions that frequently decrease the service life of refractory products provided incentive for RHI AG to develop high performance bricks, especially for non-ferrous metal applications. Innovative product development was required to determine suitable refractory products for improving lining life. At the Technology Center in Leoben, Austria, practical corrosion testing methods and facilities, including an induction furnace and rotary kiln, enable detailed comparative analysis of brick wear on a pilot scale. In tests that were carried out using a fayalite type slag, the newly developed RADEX VFG magnesia-chromite grade showed very promising results compared to the standard grades. Based on the test results, optimal refractory solutions can be recommended for this challenging industrial application and field trials can be performed directly at the customer's site.IntroductionThe complexity of metallurgical processes in the non-ferrous metal industry, and especially changes to the process conditions in combination with the diversity of metal processing furnaces ''', requires a precise understanding of each individual system for appropriate refractory product selection l2'. In addition, particular importance is focused on the specific refractory consumption being as low as possible.Another important aspect results from the global shortage of resources, which forces companies to invest in recycling processes. In the base metal industry, recycling operations have resulted in significant changes; for example, operating with two slag chemistries and process temperatures will influence the performance of previously suitable linings. The raw material mix for primary smelters has also changed, including higher levels of secondary raw materials in the smelter feed."

Jan 1, 2012

By Jun Li

Several metal sulfides were examined in-situ by Raman spectroscopy before and after anodic oxidation. Results obtained for chalcocite, chalcopyrite, covellite, galena, pyrrhotite and pyrite electrodes are presented. Under appropriate conditions, sulfur was detected after a potential was applied to the mineral electrodes for a threshold period of time. For all the minerals, application of a negative potential on the oxidized mineral reduced the surface product and the sulfur peaks disappeared from the observed spectra. For those minerals containing sulfur as S< in the crystal lattice, polysulfides were identified as oxidation intennediates.

Jan 1, 1993

By J. Partinen

Drying is a unit process which has numerous applications in metallurgical process industry. Kumera Technology Center, being a worldwide equipment and process supplier, has developed sophisticated solutions for both direct and indirect drying. In conventional direct drum drying, the energy is taken from combustion of fossil fuels, requiring energy input and emitting considerable amount of off gases. In modem copper smelters, thermal energy from the off gases is recovered in waste heat boilers making the steam available. Using that steam as the energy source for concentrate drying, the total volume of off gases can be considerably reduced and releasing of harmful combustion gases into the atmosphere can be avoided. Kumera Technology Center has recently developed and promotes a new steam drying process for drying of copper concentrates. In the development of the new dryer, Kumera&apos;s approach has been to combine the best properties of both the steam dryers and the drum dryers. In the design special attention has been paid to overcome problems of excessive wear and clogging and to reduce the required maintenance operations. In this paper the environmental issues and energy consumption related to both direct and indirect drying processes are discussed. The estimated operation costs and emission levels are compared, based on calculations and the data collected from industry. Finally, the development project of the Kumera Steam Dryer is briefly reviewed

Jan 1, 1999

By Fumito Tanaka

The Converting Furnace (C-furnace) of the Mitsubishi process has solely provided opportunities for producing blister copper continuously from molten matte. Continuous converting originates from the proven technology for controlling the behavior of magnetite in lime-ferrite slag of the CaO-FeOX-Cu2O system. Recent improvements in the C-furnace operation have included the slag controls reflecting the impact of minor oxides on magnetite behavior. Although previous investigations focused on magnetite behavior, sulfur has also affected the C-furnace operation because it is of practical importance to avoid the precipitation of gypsum from lime-ferrite slag and the separation of matte from blister copper. This paper will quantify the behavior of sulfur in C-furnace with respect to the gypsum formation and matte separation, and discuss better controls for C-furnace operation.

Jan 1, 2006

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

The microstructure evolution during solution treatment plays an important role in mechanical properties of heat-treated aluminum alloys. In this paper, models were reviewed that can predict the microstructure evolution during the solutionizing process of the aging heat treatment of aluminum alloys. The dissolution ofMg2Si particles has been modeled as a diffusion process of Mg in the a-Al matrix. The evolution of volumetric fraction of fragmented silicon as a function of time and temperature was also considered. The growth and coarsening of silicon particles during the heat treatment was considered. It was found that constitutive equations and required property data for most of the phenomena that need to be considered are available. Several model parameters that need to be obtained from material characterization were identified. Pending the availability of these model parameters, this comprehensive model can be used to describe the microstructure evolution of aluminum alloys in order to optimize the solutionizing heat treatment for energy savings.

Jan 1, 2013

By F. Mucciardi

While flash smelting and converting are capturing a greater share of the market, injection through circular injectors will remain with us for the foreseeable future. The use of top lances for injection is a key feature in several processes (e.g. Mitsubishi, Ausmelt). Tuyeres, on the other hand, are incorporated into a number of processes (e.g. Noranda, Peirce-Smith). To date no lances or tuyeres are cooled by an external source. The reagent provides the bulk of the cooling. With limited cooling, it is normal to have substantial wear on the nozzles - especially in the case of lances. To overcome the issue of wear, a new patented injector (lance or tuyere) has been developed by Noranda and McGill University. This novel unit is based on heat pipe technology. It can operate for an extended period of time without wearing. Enhanced lance/tuyere life is achieved by operating the injector at a low enough temperature that promotes the formation of a thin frozen layer on the outer body of the unit. The vaporizing and condensing substance within the unit acts to cool&apos; the high heat flux portions and dissipate the heat to areas of low heat flux outside the vessel. A fairly large number of tests have been conducted with a prototype unit. The tests have shown that the heat pipe lance is a viable unit. In this paper is detailed a test which illustrates how the lance functions when pure oxygen is injected into copper matte. In addition, the findings from a basic study of a heat pipe in high heat flux environments are also presented.

Jan 1, 1999

By Eltefat Ahmadi

Iron-free titanium oxycarbonitride (TiOxCyNz) is a promising feedstock for production of titanium tetrachloride (TiCl4) at low temperatures. In this study, the effects of leaching variables such as temperature, time, particle size of staring material and concentration of the leaching solutions were evaluated on iron removal from nitrided Malaysian ilmenite by Becher process. The nitrided ilmenite was prepared by isothermal reduction with graphite at 1200 °C for 3 h in H2-N2 atmosphere. The aerated leaching experiments were conducted at 50–90 °C with addition of 0.3–2.0 wt% of NH4Cl catalyst. The highest extent of iron removal (XFe) was obtained at about 96.2% for the sample leached at 90 °C for 7 h with 2.0 wt% NH4Cl. The iron concentrate and titanium oxycarbonitride product were characterized by ICP-OES, XRD, XRF and SEM-EDX analyses. The results indicated that the aeration leaching process was a successful route to prepare low-iron titanium oxycarbonitride.