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By M. H. Staia

A Venezuelan ilmenite concentrate has been chlorinated at a temperature of 700" C by carbon tetrachloride. In the experimental rig, built at laboratory level, the direct chlorination process yielded a TiCI, recovery of approximately 85% after 280 minutes processing. The partial pressure of carbon tetrachloride was nearly atmospheric (0.94 atm). Product vapors from the reactor were fractionally condensed in a condenser which was maintained at a temperature of 250°C meanwhile TiCl, vapors were condensed in refrigerated coils at a temperature of -20°C. The concentrate used in this investigation was obtained by applying gravitational and magnetic concentration methods to the black sands. The experimental results have shown the need to asses the influence of the weight ratio of ilmenite to carbon tetrachloride on the resultant products. The equilibrium of the heterogeneous system has been calculated taking into account the initial experimental conditions.

Jan 1, 1995

By Hideyuki Itou

Municipal wastes are mainly incinerated in Japan. Both bottom ash and fly ash from the incineration treatment are smelted recently to decrease the volume. Direct smelting of municipal wastes is also becoming popular. The smelting treatment generates fly ash which contains concentrated heavy metals such as Zn, Pb and Cu, and the harmfulness is causing concern. The smelter fly ash is mainly landfilled after stabilization. An effective treatment process of the smelter fly ash is required to recover the metals. For the treatment process, an application of chloridizing volatilization technique is considered. Chloridizing volatilization experiments were carried out to determine the effects of various factors on the volatilization behaviors in this study. A pretreated ash was mixed with a main raw material which mainly consists of hematite. Calcium chloride water solution was added into the mixture. The mixture was pelletized, dried and used as samples for the volatilization experiments. The sample was placed in the reaction tube heated in an electric resistance furnace. 5%02-95%N2 gas with controlled humidity was introduced into the reaction tube. Effects of humidity in the carrier gas, addition of calcium chloride and mixed ratio of the ash to the main raw material were investigated on the volatilization of Zn, Cu and Pb. To determine the volatilization behavior, samples were taken from the furnace at specified temperatures on the heating stage. In addition, experiments at specified holding temperatures for 15 minutes with shortened heating time were conducted. The two series of experiments revealed the effect of heating temperature on the volatilization behavior of Zn, Cu, Pb and Cl.

Jan 1, 2006

By Edwin de Jesús Deveaux

After 32 years of operations beneficiating lateritic nickel ore in a fully integrated pyrometallurgical complex, Falconbridge Dominicana (FALCONDO), situated at Bonao and La Vega Provinces, Dominican Republic, has become profitable with one of the lowest nickel grade content processing plants in the world, and literally without any by-product (granulated slag, will be utilized in the future as a post-processing subproduct). To December 2002, mineral reserves were 64.1 million tonnes containing laterite grading as low as 1.15 % Ni when full dilution is applied. At a cut-off grade of 1.20% Ni, the reserves will provide 15-20 years of production. The mineralized thickness over the seven active deposits averages 6 m. Development of very selective and unique mining practices, together with improvements in the process plant, are key to achieving the production goal (30 kt Ni/yr) and to meet the quality standards for the ferronickel produced. Keywords: Laterites, grade control, mining methods, environment

Jan 1, 2004

By E. V. Redin, B. A. Dubrovsky, E. V. Knyazev, A. I. Starikov

"Ti-V magnetite is one of the most abundant composite ore resources in the world. This ore cannot be fully processed via blast furnace technology because of high content of Ti02. According to the investigations carried out in the USA and Japan ITmk3 RHF (Rotary Hearth Furnace) technology is a breakthrough in Ironmaking. Reduction, melting and slag removal can be achieved in just 10 min. The main objective of the investigation is to establish optimum operation conditions for the production of iron nuggets from Ti-V magnetite ore via the ITmk3 by means of the lab scale testing. Samples of ore from the Maly Kuybas deposit (Southern Ural), carbon reductant and fluxes were chemically analyzed. Green pellets were processed via a lab chamber furnace to simulate RHF conditions. The nuggets and slag were chemically analyzed. This preliminary test work provides valuable information which may be used for large-scale testing in a commercially sized RHF.IntroductionThe ITmk3 process upon which this paper focuses was developed by Kobe Steel in its research facilities [l]. After pilot testing at Kobe Steel's Kakogava Works in 1999-2004 the pilot demonstration plant was built and operations were successfully carried out by Mesabi Nugget joint venture in 2002-2004. Steel Dynamics put into operation the commercial plant at the Mesabi Nugget site in Hoyt Lakes (Minnesota) in 2010. Results were consistent with nugget characteristics confirming ITmk3' s flexibility with respect to raw material inputs. At the same time, no research in the field of nugget from the Ti-V magnetite bearing ore with high content of Ti02 and Alz03 has been done. It is well known, if a lot of Ti02 and Alz03 enter the blast furnace, slag becomes viscous. The viscous slag is obstacle for stable operation of the blast furnace. Besides, high content of Alz03 raises the melting temperature of gangue minerals disturbing the coalescence of reduced iron to the nuggets."

Jan 1, 2013

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 P. E. Donaldson

Since 1992, Falconbridge has made available to the international copper industry, Kidd Creek's licensed refinery process technology under the name of the Kidd Process. This has resulted in the supply and installation of permanent cathodes and associated product handling equipment to refineries in Canada, the United States, South Korea, Chile and Mexico. These installations accommodate both electrorefining and electrowinning processes. The growth and industrial acceptance of the Kidd Process has generated technical advancements in the areas of product random sampling, corrugation, marking, labeling, product tracking and data acquisition. In a different area, the expanded development of custom materials processing at Kidd created a need to advance technologically. The process-related problem of high nickel concentrations in refinery electrolyte compromised an increase in current density to >300 A/m2. The need for nickel removal resulted in Kidd Creek's newly developed Nickel Recovery System. The effective and economical extraction of nickel, along with reduced antimony and bismuth levels, reduces bleed stream volumes and/or neutralization costs and simultaneously produces a marketable nickel carbonate product.

Jan 1, 1999

By Claassen J. O.

The Zinc Corporation of South Africa Ltd. (Zincor) operates an integrated roast ? leach ? electrowinning circuit. The efficient removal and control of iron forms an integral part of the process. Zincor developed its own iron removal process (Zincor Process), which was recently shown to be unique with some similarities to the para-goethite iron removal process. Newly developed operating parameters for iron removal are in the process of being implemented. These include a change in the pH-profile and operating temperature, the recycling of seed material and the utilisation of an alternative neutralising agent to aid iron removal. Some of these actions, together with the implementation of a pre-neutralisation step, new filtration equipment and control systems in Zincor?s Residue Treatment Plant have significantly reduced zinc losses associated with iron in calcine and the iron residue produced. This enabled Zincor to take a step closer to world-class zinc recovery levels of around 96% for a similar type of operation.

Jan 1, 2003

By John Sakala, Jeyapandian Sasikumar, Sydney Kwalela

The Isasmelt Furnace was commissioned in September 2006 with a concentrates treatment capacity of 850,000 tonnes per annum. However, the converter section became a bottleneck to the high throughput. Over 25% of the Isasmelt Furnace down time was attributed to lack of converter space. Factors that affected converter operations were low tuyere line campaign life (an average of 150 blows), high reverts generation, low conversion rates, and high converter cycle time. As a result of efforts carried out to improve converter operation, the average campaign life has increased to over 250 blows and reverts generation has been reduced from 22% of concentrate treated to 15%. Blister copper conversion rate has increased from 15 tonnes per hour to 19 tonnes per hour and blowing time per cycle has been reduced from 5.7 hours to 4.7 hours.

Jan 1, 2012

By Kazuteru Tozcwa

The oxidation of several sulfide minerals in aqueous ammoniacal solution is discussed thermodynamically. The region in which Cu(NH3)2 4+ is stable has been estimated as a function of pH and concentration of total ammonia, {[NH3) + [NH4)}. In ammonia leaching when copper in sulfides is assumed to be extracted in the form of Cu(NH3)2 which will be rapidly converted to cupric ammine, thermodynamic data predict that such minerals are oxidized readily in the following order, CuS, Cu2S, CuFeS2, ZnS, NiS, Ag2S. This agrees with investigations on ammonia leaching of sulfide minerals, reported previously. The leaching of copper sulfide concentrate has been examined experimentally. Copper in a copper sulfide concentrate, in which the main constituents were chalcopyrite and pyrite, was effective¬ly extracted. The copper extraction was affected by factors such as (1) agitation intensity, (2) oxygen partial pressure, (3) NH3/Cu molar ratio, (4) leaching temperature and (5) addition of ammonium sulfate. From the results obtained in this work, it is concluded that mass transfer of oxygen plays the most important role in ammonia leaching of copper sulfide minerals.

Jan 1, 1976

By Junji Shibata

Zeolite synthesized from coal fly ash has many intelligent properties such as cation exchange, adsorption, catalyst and so on. The suitable use of the zeolite, however, is not established in an actual commercial scale yet. From the viewpoints of an effective usage of coal fly ash and the zeolite obtained from coal fly ash, we propose the new concept for environmentally friendly usage of zeolite, in which coal fly ash safely returns to the soil with growing plants and purifying wastewater. This method can make great contribution to recycle of coal fly ash, to purification of high nutritious water and to tree planting.

Jan 1, 2002

By Toshiyuki Kozuka

CdTe metal composite semi-conducting material has high potential in good performance of energy conversion efficiency for solar cell and there is much room for improvement of the performance by developing a process of making a thin CdTe film. In this paper, the imposition of intense magnetic field on CdTe electro-depositing surface is proposed, which is one of the possibilities for improving the energy conversion efficiency. In the experiment, cryogen-free super-conducting magnet up to 5T was used and CdTe film was deposited electrically in -o.nv vs. SHE The electrolyte was Cd and Te ammonia alkali solution with controlled temperature in the acrylic cell of 70mm diameter. Electro-deposition behavior of CdTe has affected by the imposition of the intense magnetic field due to microscopic convection in the vicinity of the depositing surface. Electro-deposited surface of CdTe becomes smooth due to microscopic convection around the surface, and the crystallization behavior is also affected, where crystallization temperature and the grain size is changed by the imposition of intense magnetic field.

Jan 1, 2003

By Jackson Jenkins

The second survey of world copper SXEW plants has been completed. Solvent extraction and electrowinning data published in 1996 has been updated and leach data from seventeen plants is now included. The following pages list the results of the thirty- two plants that responded to the survey. Selected information is summarized in graphical form.

Jan 1, 1999

By A. Vahed

The Goro Nickel Project is situated in the Southern Province of New Caledonia. Inco Limited and Goro Nickel S.A. have developed a process that features the use of pyrohydrolysis to produce nickel oxide. The process treats a blend of laterites by Pressure Acid Leaching followed by solvent extraction of nickel and cobalt using Cyanex 301®. Purified nickel chloride solution is converted to high purity NiO product and 6M hydrochloric acid, which is recycled back to the SX circuit. In co-operation with Andritz AG, spray roaster and fluid-bed pyrohydrolysis technologies were examined for this purpose. Tests were conducted at the Andritz AG pilot plant in Vienna, Austria, and at Goro in larger scale installations. The latter served to establish process engineering design parameters for scale-up. Several process variables were investigated in both technologies and the off-gas characteristics were established. Fluid-bed pyrohydrolysis was selected for the Goro commercial plant, primarily because it produced a granular nickel oxide. The main focus of this paper is to outline the results obtained in pilot plant studies of liquid fueled fluid bed pyrohydrolysis for the Goro Project. Keywords: lnco Goro Nickel, Fluid Bed Pyrohydrolysis, Pilot Plant Tests

Jan 1, 2004

By Mark William Kennedy

"Electric furnaces containing high quantities of slag are applied in many areas of pyrometallurgy, often for smelting or slag cleaning. A variety of ratios or rules of thumb have been employed in the industry for the dimensioning of these vessels, in most cases with no clear technical basis.In this paper, several design guidelines are presented (electrode size, spacing, vessel dimensions, energy intensity, etc.) as an attempt to provide some technical basis for optimal dimensioning.Furnace heat generation is related to side wall copper cooler heat losses, in an attempt to establish a methodical design strategy particularly for minimum electrode to wall spacing for modern furnaces with cooled linings.Issues regarding the true nature of heat production in a slag furnace are discussed with regards to the possible impact on accurate modeling and design.IntroductionSlag furnaces have passed through a number of design 'generations' characterized by increasing energy intensities, improved electrode technologies and advancing development in their physical structure or 'furnace integrity' as shown in Table I f 1]. A 3rd generation furnace using ultra-high-power (UHP) graphite electrodes is shown in Figure 1, as a generic example of the types of physical structures present in modern slag furnace designs [1]."

Jan 1, 2012

By K. A. Lewandowski

Agglomeration of ore can be used to immobilize fine particles during heap leaching by agglomerating them into granules. Without agglomeration, the fine ore particles can migrate within the heap, clogging flow channels and producing large areas where access of solution to the ore is very poor. The benefits of agglomeration are well-known in gold heap leaching operations, which can be effectively agglomerated using binders such as Portland cement due to the alkaline leaching solutions used. However, agglomeration has not been very effective in the heap leaching of copper ores, because these ores require an acidic leaching solution. Acid destroys the effectiveness of most binders, causing the agglomerates to disintegrate as soon as the leaching solution is applied. In order to gain the benefits of agglomeration in copper heap leaching, an economical, acid-resistant binder is needed. The two issues that needed to be addressed were: 1) Lack of effective methods for evaluating binder acid resistance before performing expensive, time-consuming, full-scale heap leaching tests, and 2) The vast majority of known binders react poorly to acid conditions, and so a basis was needed for determining which binders are most likely to be acid-resistant. In this paper, the development of two new tests for evaluating binder acid resistance in the laboratory are described. The ?soak test? determines the degree to which agglomerates disintegrate and release fines on contact with acidic solution, measuring the relative quantities of fines released by agglomerates made with different binders under controlled conditions, and serves as a rapid means for comparing large numbers of binders. The ?percolation test? measures several different parameters to determine how a binder is likely to perform in heap leaching: 1) the degree of ?slump? and compaction of agglomerates as they are wetted by acidic solutions; 2) the hydraulic conductivity of the agglomerate bed; 3) the migration of fines through the bed as the solution flows through it; and 4) the quantity of liquid retained in the agglomerates after they are drained. Using these tests, a broad spectrum of binders were examined. Soak testing determined that the most acid-resistant binders were nonionic polymers. Five of these binders were further evaluated using percolation testing.

Jan 1, 2006

By Ko-ichiro Ohno

It is recently recognized that the iron reduction and melting as well as the slag separation of a composite of granular iron ore and coal are completed in a very short period of about 10 minutes when the composite is rapidly heated up to approximately 1673K. These phenomena are expected to be applied to a new iron-making process. The mechanism of iron ore reduction and iron-slag separation during rapid heating has not yet been revealed and the fundamental research has just started. Carburization of the reduced iron is regarded as one of the most important steps in this process. In the present work, the composite was prepared from four kinds of coal or graphite as a carbon source and electrolytic iron powder as a completely reduced iron ore. The temperature at which the liquid formation and iron carburization occurred was monitored. Direct observation of smelting reduction behavior was made by a confocal laser-scanning microscope combined with the infrared image-heating furnace to clarify the effect of molten ash on iron carburization. It was found that the meltdown temperature of composite became lower as the melting temperature of coal ash decreased. From the observed result, it was presumed that the liquid slag would act as an important media for the carbon transfer from coal to iron. The carburization mechanism during the smelting reduction was estimated as follows. When slag containing iron oxide melted down and contacted carbon, iron oxide in the slag was reduced and the formation of the metallic iron particle as well as the its carburization occurred simultaneously at the slag-carbon interface. Carburized iron particle was carried from slag-carbon to slag-iron interfaces due to the slag convection flow caused by the difference of the interfacial tension between the carbon-slag and iron-slag interfaces. Carburization of reduced iron could proceed with a repeat of the above-mentioned process.

Jan 1, 2003

By Xianzhong Hu, Qingbo Yu, Qin Qin

"Oxy-fuel combustion is one promising option among different CO2 capture technologies. The object of this work is to show the effect of CO2 dilution on the laminar flame speed, flame structure and reaction pathway for methane oxidation at O2/CO2 atmosphere. In this paper, kinetic simulations were made using CHEMKIN with GRI-Mech 3.0 mechanism, which was validated by experimental data of laminar flame speeds. The reaction pathway of CH4/O2/CO2 mixture was derived from reaction flow analysis. Results showed that CO2 decreased the flame speeds, lowed concentration of major intermediates and increased flame thickness. The major chemical pathways of CH4 to CO2 have not changed at O2/CO2 atmosphere comparing with O2/N2 atmosphere, but contributions to major intermediates formation from each related elementary reaction have changed a lot. In addition, the secondary chemical pathways of CH3 oxidation became different at O2/CO2 atmosphere.IntroductionNowadays, as the global economy is developing fast and the pollutant levels (especially global warming gases) are increasing, a lot of researches are focusing on new technologies which can cut greenhouse gas emissions [1]. New technologies have been developed, such as high Mild combustion, flameless combustion and Integrated Gasification Combined Cycle (IGCC) technology. Oxy-fuel combustion using carbon dioxide as dilution of oxygen is considered as a promising approach for reducing CO2 emission. The properties of CO2 in flue gas are different from N2 in air. On one side, the transport, thermal and radiative properties of CO2 are different from N2 in air. On the other side, CO2 is not inert but directly participates in chemical reactions and recent researches [2-5] also present the chemical effects of CO2 on oxy-combustion. For these differences above, the characteristics of oxy-combustion are not alike with traditional combustion. It is necessary to develop the investigation of oxy-combustion.In all combustion processes, laminar flame speed is an important parameter, which links to combustion behavior. Analysis of this parameter can provide a better understanding of the effect of CO2 dilution in the process of oxy-combustion. Several investigations of laminar flame speeds of oxy-fuel flame have been improved, including experimental measurements and numerical computations. A.A.Konnov et al. measured the flame speeds of oxy-methane and oxy-ethane mixture using the heat flux method with a flat burner [6-8]. V. Ratna Kishore et al. used heat flux method to measure the adiabatic laminar flame speeds of hydrogen [9] and H2/CO mixture [10]. Adiabatic laminar flame speeds of hydrogen in O2/CO2 atmosphere are much smaller than in O2/N2 or in O2/Ar. The burning velocity of H2/CO mixture decreased with increase in CO2 content in mixture. Jeongseog Oh et al. [11] used Bunsen flame to measure the laminar flame speeds of premixed oxy-methane mixture with angle methods in atmospheric condition (300k, 1atm). The results were SL=29.1cm/s and SL=29.5cm/s respectively derived from oxy-methane from CH* images and Schlieren photos."

Jan 1, 2014

By Sylwia Zymankowska-Kumon, Rafal Danko, Józef Danko, Mariusz Holtzer

"Burning of ceramic materials is carried out at temperatures 900+ 1300°C, in dependence of the required functional properties. The Faculty of Foundry Engineering together with the Faculty of Material Engineering and Ceramics developed the technology of production of burned ceramic materials with using spent moulding and core sands. The mentioned above waste materials of the foundry industry fulfilled -in plastic masses intended for obtaining ceramic materials -the role of the addition weakening clay raw materials. The laboratory investigations were fully verified by the results of industrial tests. It should be pointed out that none negative effects were observed at the stage of mixing raw materials and preparation of plastic masses. The measurements of exhaust gases emissions performed during burning the products containing spent moulding sands as well as during the normal production did not exhibit any significant differences, which could have indicated the harmful impact on the natural environment.IntroductionSands are used by the foundry industry to make metal casting molds and are a mixture of silica sand, bentonite clay and carbonaceous additives or resins. During the casting process, the molten metal cause thermal decomposition of carbonaceous additives or resins, which results in the formation of potentially hazardous organics, that are emitted to the atmosphere and condense in the molding sand. Each year the U.S. foundry industry landfills about 10 million tones of sand because it is no longer suitable to make metal casting molds. A large high-silica sand content in spent foundry sands (SFSs) generates rational premises for their reuse in other than foundry practice fields. Efforts to divert the SFSs from landfills and encourage their beneficial use in manufactured soils, geotechnical applications, the construction industry (road construction, highway construction), the building materials industry (cement, bricks, limestone manufacture), in the filling of mining cavities or in landfill construction (roads on landfills, permanent covers) are make [1-7]."

Jan 1, 2013

By Per Anders Eidem, Merete Tangstad, Jens Davidsen

"During excavations of submerged arc furnaces producing silicomanganese, silicon carbide (SiC) has been found. Contributing to the size of the inactive area of the furnace, the active area of the furnace where reactions occur will decrease, thus reducing the potential for pre-reduction in the furnace.This work studied the formation of SiC from the liquid-solid reaction between slag, metal, and metallurgical coke. Slags and metals with different levels of silica (S1O2) and silicon (Si) have been studied. The slag and metal has been heated together with coke, and the samples investigated by microprobe. The results show that SiC was formed on the coke particle through reactions with both slag and metal. For the metal, the carbon most likely diffused through the SiC to react with Si in the alloy. SiC formation with slag is likely to go through the reduction of Si02 to Si.IntroductionToday, Silicomanganese (SiMn) is produced in submerged arc furnaces (SAF) by reduction of S1O2 and manganese oxides, mainly with metallurgical cokes. Typically, the tapped metal has a silicon content of 17 - 20 wt.%. To achieve higher levels of Si, the metal can be refined by adding off-grade silicon metal, yielding low carbon SiMn. [1]. What is believed to be SiC that has been found during dig-outs of SiMn furnaces producing high silicon alloy. It is possible that excess amounts of SiC in the furnace cause operational problems, since SiC will occupy furnace volume. As SiC accumulates, the active volume of the furnace will decrease, increasing the flow of material and gas in the active areas of the furnace. Formation of SiC is inevitable, so it is desired to keep the formation as low as possible. To be able to control the formation of SiC, one has to understand the basic mechanisms."

Jan 1, 2012

By Dilek Kirgöz, Onuralp Yücel, Murat Alkan

"In this study, Mo containing Fe-based alloys, such as Fe-Ni-Cr-Mo, were synthesized using a mixture of Fe203-NiO-Cr203-Mo03 powders reducing with Al powders by metallothermic process which is a high energy efficient, fast and low-cost production technique for synthesis of cast alloys and advanced ceramics. Detailed thermochemical studies were simulated by using FactSage 6.2 Thermochemical software in order to calculate adiabatic temperature of the reactions and effects of initial molar composition on the final products. In the metallothermic processes, effects of stoichiometric Al addition and addition of the oxide powders (Alz03, Si02, CaO, MgO) on the metal recovery and compositions of final alloys were carried out. Final products were characterized by using chemical analysis (AAS), XRD, XRF and SEM/EDS techniques.IntroductionSelf Propagating High Temperature Synthesis (SHS) has significant advantages compared to the high technology furnace applications, such as very short processing time, simple operation, low energy requirement and low cost [l, 2]. In a SHS process, the ignition starts the combustion and propagates throughout the reactant mixture yielding the desired product. However, the disadvantages of the process such as inhomogeneous or unreacted products due to undesirable reaction rates needs to be overcome by changing some parameters such as ignition temperature, particle size, additive, atmosphere etc. [3, 4]. This work aims to establish a scientific and engineering background in the production of some cast Fe based alloys (Fe-Ni-Cr-Mo) which are used as surface coatings, wear-corrosion-oxidation resistive applications via SHS (Self Propagating High Temperature Synthesis) metallurgy which is attractive process technique regarding fast and low-cost production ability of cast alloys."

Jan 1, 2013