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By T. Nakamura

TiO2 and Ti/TiO2 thin films were deposited on a quartz substrate by laser ablation of TiO2 and Ti targets using Nd:YAG pulsed laser. After sulfurization of the TiO2 film in H2S or CS2 gas at 1273 K for I hour, the surface atomic structure was changed. Furthermore, the Tirri02 film was successfully prepared by the subsequent ablation of Ti and Ti02 targets. The morphology and structure of the films were characterized by XRD, XPS and AFM analyses.

Jan 1, 2003

TiO2 and Ti/TiO2 thin films were deposited on a quartz substrate by laser ablation of Ti02 and Ti targets using Nd:YAG pulsed laser. After sulfurization of the Ti02 film in H2S or CS2 gas at 1273 K for 1 hour, the surface atomic structure was changed. Furthermore, the Ti/TiO2 film was successfully prepared by the subsequent ablation of Ti and TiO2 targets. The morphology and structure of the films were characterized by XRD, XPS and AFM analyses.

Jan 1, 2003

By C. Lupi

The electrorefining of primary copper is a well known technology: in this work copper scrap was directly processed in the same way. he copper and copper alloy scrap was previously pressed by means of a 20 tons apparatus in order to avoid pyrometallurgical operations. The samples obtained in this manner showed a good compactness so that they were used as anodes in the electrorefining tests. The tests were carried out on anodes made by copper scrap, copper alloy scrap and a mixture of the two. The electrorefining tests were performed at both 303 and 333 K, in a perspex cell having a volume of 500 ml using a current density of 250 A/m2. The cathode used was always a sheet of pure copper and the electrolyte composition was 40-50 g/l Cu as CuS04 and 150-200 g/l H2SO4. Current efficiency in the range of 92-97% and specific energy consumption ranging from 0.14- 0.20 kWg of copper were reached in all the tests. The refined copper deposits were analyzed by AAS to verify their purity and observed by SEM to highlight their morphology.

Jan 1, 1998

By Tatsuo Itou

Both sales volume of Aluminum Can and its recycling rate are remarkably increasing here in Japan. In 1993, recycled can volume was 11.78 billion cans ( 116,258 metric tons ) and its recycling rate 57.8 percent. We, MITSUBISHI MATERIALS CORPORATION. the leading manufacturer of aluminum can in Japan and our affiliated companies are very deeply involved in recycling used beverage cans ( U.B.C ) and recycling them back to can stock. In this paper. I would like to present the following; 1. Recent trend of beverage can consumption in Japan. 2. Trend of aluminum can and its recycling rate in Japan. 3. Future of aluminum can business in Japan.

Jan 1, 1995

By L. R. Verney

A number of interrelated factors influence the economics of the sulphide smelting of copper, lead, zinc and nickel. This paper discusses these factors, mainly from a US point of view, and shows how they affect the cost of construction and operation of new and existing plants. The paper shows how metallurgical plant construction costs and the consumer price index have increased at a much faster rate than metal prices thereby making some metal mining and production operations within the USA, Canada and the EEC less profitable than operations elsewhere. This in turn inhibits new "grass roots" metallurgical developments. It is explained how retrofit of existing pyrometallurgical plants can be a more viable development than the construction of "green field" plants, especially if such retrofit improves, energy efficiencies, overall operating costs and reduces emissions of sulphur and other toxic wastes. Some aspects of metallurgical plant operation are examined, especially for copper and nickel, to show how changes in operating practices may develop in order to improve overall smelting economies, especially when developed in conjunction with objective retrofit. The paper also examines some financial aspects, especially insofar as the disparity between terms for loans offered to third world countries and the USA and the EEC are concerned and also comments upon the need, especially within the USA, for legislation to permit rapid depreciation of capital. Specific comments are made about environmental aspects, including the lack of uniformity of pollution control legislation and how environmental considerations may have some bearing of the location of future smelting operations.

Jan 1, 1983

By Etsuro Shibata

The saturated solubility of chromium oxide and the valence of chromium in the slag are important matters when considering how to effectively utilize chromium-containing slags. The experimental data of various types of slags cited in the literature were arranged according to the optical basicity in order to evaluate the effects of the oxygen potential and the slag composition. The saturated solubility of chromium oxide and the Cr2+/ Cr3+ ratio tend to decrease with the increase of the optical basicity of the slag at an oxygen potential below 10.5 atm. However, at an oxygen potential of 0.21 atm, the saturated solubility and the Cr6+/Cr3+ ratio tend to increase with an increase of the optical basicity. A practical approach was suggested to reduce chromium in the stainless steel slag and simultaneously recover it as a ferroalloy by the direct smelting reduction of chromium oxide in the molten slag using some reductant in a small furnace.

Jan 1, 2003

By Yotamu Stephen Rainford Hara

"The study focuses on the reduction mechanisms of copper, cobalt and iron during carbothermic reduction of copper-cobalt mineral sulphide concentrates in the presence of lime, in the temperature range of 1073K and 1273K. We have used three types of mineral concentrates which were derived from froth flotation from the Copperbelt region in Zambia. The reduction mechanisms were studied using thermogravimetric analysis in which selected reactions were stopped at different times for characterising the reaction mechanism using optical microscopy, XRD and SEM-EDX analyses. Using SEM-EDX analysis, we have analysed in details the stages of metallic phase formation during reduction process. Metallic cobalt and iron were embedded into copper, thereby permitting magnetic separation of the reduced metals even though copper is diamagnetic. Methods of preferential reduction of metal values were investigated by analysing the metallic phase formation.IntroductionIn conventional smelting or converting of copper sulphide minerals, metallic copper forms by giving off S02 gas on. Although in terms of overall energy balance the selective oxidation for metal production has major advantages, the process suffers from drawbacks in smelting complex concentrates containing copper, cobalt and iron sulphides minerals and these are: (i) cobalt and iron are oxidised, and consequently cobalt is lost into the slag phase. (ii) The volume of S02 gas produced is in low concentrations, which is insufficient for extracting sulphur or manufacturing sulphuric acid. The release of dilute S02 causes serious environmental pollution. The major cause for the loss of cobalt and iron into the slag, is due to that fact that the oxides of these metals are more stable than their sulphides. Since cobalt and copper are more valuable than iron, reducing conditions are required in a separate slag treatment reactor using electric arc melting for recovering the lost metal oxides from slag. This energy-intensive step makes metal making expensive.During chemical beneficiation of mineral sulphides (Cu2S, CoS, FeS) in the presence oflime (CaO), two types of equilibrium conditions may be set up either by forming CaS under reducing conditions, or by stabilizing CaS04 under oxidising conditions [l]. By comparison in the presence of carbon, CaS and metallic phases form, enabling the recovery of metals from sulphide minerals, which have been investigated by a number of authors [2-9]. During reduction of metal sulphide in the presence of lime and with carbon, it has been proven that the overall reaction le proceeds via two main steps: [5, 8, 9] (i) the anion exchange reaction between metal sulphides (MS) and CaO as shown in equation la, followed by (ii) the reduction of metal oxide (MO) via reaction lb."

Jan 1, 2013

By Shengli Wu, Fengjie Zhang, Feng Chang, Hua Lu, Kaiping Du

In order to make a complete understanding of steel plant metallurgical dusts and to realize the goal of zero-waste, a study of their properties was undertaken. For these purposes, samples of two sintering dusts (SD), two blast furnace dusts (BFD), and one electric arc furnace dust (EAFD) taken from the regular production process were subjected to a series of tests. The tests were carried out by using granulometry analysis, chemical analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy via SEM (EDS), and Fourier transform infrared spectroscopy (FTIR). The dominant elements having an advantage of reuse are Fe, K, Cl, Zn, C. The dominant mineralogical phases identified in sintering dust are KCl, Fe2O3, CaCO3, CaMg(CO3)2, NaCl, SiO2. Mineralogical phases exist in blast furnace dust are Fe2O3, Fe3O4, with small amount of KCl and kaolinite coexist. While in electric arc furnace dust, Fe3O4, ZnFe2O4, CaCO3, CaO, Ca(OH)2 are detected.

Jan 1, 2015

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 John R. Turney

The success of the Mclaughlin acid pressure oxidatiun process has proved that a complex hydrometallurgical process can be an economically viable means of treating refractory gold ores. Homestake's Mclaughin acid pressure oxidation process was commissioned in August 1985 and ts currently operating at design tonnage of 3,000 tons per day. Mineralogical and process studies on the operating plant are discussed to show the improved understanding: of the process and its future applications. These studies are also compared with the initial process development work, thus illustrating the success of the initial scale up considerations.

Jan 1, 1989

By Adam J. Gesing

Eddy current separators are increasingly used by the auto shredder operators to produce higher grade of nonferrous metal concentrate for recycling. While this increases the unit price of the concentrate, metal losses through inefficient metal recovery quickly offset the price differential. We show how to optimize the eddy current separation system at the shredder to maximize mate- rial throughput, nonferrous metal recovery and grade of the nonferrous metal concentrate.

Jan 1, 1998

By Yanhui Liu, Xuewei Lv, Chenguang Bai

A thermodynamic model for determining the surface tension of molten slag by considering the surface tension and molar volume of the pure oxide component, and their ionic radii was extended to the slag bearing high TiO2 (varying from 80 to 67%) at 1973 K. The iso-surface tension curves for the FeO-TiO2-Ti2O3 ternary system at 1973 K are almost parallel to the FeOTi2O3 line. TiO2 plays a role of surface-active solute, and its surface-active effect is attenuating with increasing the TiO2 content. The iso-surface tension curve shifts away from the TiO2 corner, indicating that the surface tension of the ternary slag decreases along with the addition of SiO2. The reasons include the addition of SiO2 with lower surface tension and the decrease of the total ion moment at the surface. Both CaO and MgO can bring about that the iso-surface tension curve shifts towards the TiO2 corner, indicating that the surface tension of the ternary slag increases along with the addition of CaO or MgO. CaO has a more pronounced effect on increasing the surface tension of the ternary slag than MgO at an equimolar amount addition. The increase of the surface tension results from both the compositional change and the variation of the slag structure.

Jan 1, 2015

By Li Yuhai

Kinetics of non-isothermal precipitate process and crystal growth of perovskite (CaO ? Ti02) phase in CaO-TiOz-Si02-AlP3-MgO system were studied. The experimental results show that the relative volume fraction can be described by the equation given by K. Matusita et at. and the experiential expression of average crystal radius was obtained. The particle coarsening in non-isothermal process has important effects on the crystal growth of perovskite phase.

Jan 1, 2000

By Larry M. Southwick

Considerable process and equipment development and analysis were conducted during design of Freeport Sulfur's laterite nickel facilities in the late 1950's. These covered ore concentration at Moa Bay, Cuba, and concentrate refining at Port Nickel, Louisiana. Both facilities utilized acid pressure leaching and product refining steps that were similar to those later used elsewhere in the laterite processing industry. Unfortunately, developments in Cuba removed the Moa Bay facilities from Freeport control. This deprived the project of a start-up that would have allowed thorough resolution of difficulties and a quicker attainment of production capacity. This meant lost opportunity to positively prove and complete the technology when optimum resources and staff were available. This paper reviews the original rationale of how design was developed via laboratory, bench scale and pilot studies by Freeport Sulfur. Some later operating problems will also be discussed. This case is unusual, but the lessons learned may be instructive in the application of difficult and complicated technologies, as well as the need to understand and retain access to the original development and design activities Keywords: Moa Bay, Freeport Sulfur, Port Nickel, acid pressure leaching, pilot plant, pachuca, Chemical Construction, pressure letdown, cobalt, titanium

Jan 1, 2004

By Melvin H. Miles

"Considerable research has been conducted on the anodic oxidation of methanol in fuel cells. The electrochemical reduction of carbon dioxide in aqueous solutions to form methanol is the same reaction in reverse, i.e. CO2 + 6 H+ + 6 e- ? CH3OH + H2O. The same catalysts and conditions may operate for both reaction directions. This carbon dioxide reduction reaction, however, must be able to compete with the electrochemical reduction of water to form hydrogen gas. Thermodynamically, the reduction of CO2 to form CH3OH is slightly more favorable than the reduction of water. The use of nearly neutral electrolytes rather than acidic electrolytes makes the reduction of CO2 kinetically more favorable. The thermodynamics of various reaction steps are presented. Similarities exist with the electrochemical reduction of CO2 and the green-plant photosynthesis process that converts CO2 to carbohydrates.IntroductionVirtually all of the oxygen in the earth’s atmosphere is of biological origin having been generated by green-plant photosynthesis from water and carbon dioxide [1]. The net reaction can be represented byCO2 + H2O ? O2 + [CH2O] (carbohydrates, etc.) (1)Chlorophyll and enzymes promote this reaction, and the energy required comes from sunlight. The actual photosynthesis process is a complex multistage reaction and requires 469 kJ mol-1 of energy supplied by the sun. Isotope tracer experiments using 18O have shown that both the oxygen atoms in the O2 molecule originate from H2O, whereas oxygen atoms in the carbohydrates come from CO2 [1]. The total amount of water on the earth is split by photosynthesis and reconstituted by respiration and combustion once every 2 million years or so. The photosynthetically generated oxygen gas temporarily enters the atmosphere and is recycled about once every 2000 years [1]. The carbon dioxide is partly recycled in the atmosphere and oceans after an average residence time of 300 years and is partly fixed by precipitation of CaCO3 and other carbonate minerals [1]."

Jan 1, 2008

By S. Bagchi

The LaNi5-xMnx-hydrides have potential applications in cryocooling devices for non-mechanical method to compress hydrogen gas. Thermal aging behavior of LaNi5-xMnx-hydrides of compositions x=0.4 and x=1.5 has been investigated. The hydriding properties of the La1.02Ni4.6Mno.4 alloy do not change significantly after thermal aging at 453K for 260 hours. X-ray diffraction analyses of this aged alloy do not reveal the presence of any new phases but the Bragg peaks become broader. Line profile analyses show anisotropic microstrains with an average <e2>1/2 value of -5x103. Thermal aging of the other hydride, LaNi3.5Mn1.5 hydride, at 623K for 280 hours, showed significant disproportionation; the hydrogen capacity reduced significantly from an H/M value of 0.75 in the activated condition to -0.15 after aging. X-ray diffraction analyses showed disproportionated lanthanum dihydride, metallic Ni, and Mn phases. The Bragg peaks were very broad indicative of microstrains or small crystalline domains.

Jan 1, 1997

By Rick Honaker

Rare earth elements (REEs) contained in coal and associated mineral matter exist in several forms including micro-dispersed minerals, ion adsorption onto clay surfaces, and chemically bound. Tests found that REEs can be effectively recovered from certain components of three coal sources by leaching under mild conditions followed by solvent extraction. A range of pH values were evaluated at solution temperatures of 25 and 75 °C. When using 1.2 M of sulfuric acid, nearly 85% recovery of the REEs was extracted from the middlings material collected from an operating plant. Acid leaching of a second middling source from another plant resulted in 60% of the total REEs being recovered under the same leaching conditions. Solvent extraction treatment of the leachate produced from six different coal sources resulted in products containing up to 50% total REEs from feedstocks starting with around 300 ppm.

By Noel A. Warner

Modern steelmaking is based on direct use of oxygen in high intensity batch reactors. A totally new approach is proposed in this paper, based on the view that pursuit of high intensity is unlikely to lead to successful coal-based continuous steelmaking. By substituting carbon dioxide and water vapor as the oxidants rather than using oxygen directly, the intensity is greatly reduced. Accordingly. subsurface formation of carbon monoxide bubbles can be avoided by careful manipulation of the three participating rate processes, gaseous diffusion, interfacial chemical kinetics and liquid phase mass transfer. Steelmaking can then be carried out without explosive ejection of molten droplets and the generation of micro-spray but rather in a controlled and fumeless fashion. The vital component is the introduction of generic melt circulation technology. Three melt circulation loops in series are envisaged. Starting with a composite feed of iron ore fines, pulverized coal and lime flux, a metallized solid raft floating on molten iron is propelled out of the ironmaking loop onto the first of two downstream steelmaking loops. In the first, a liquid slag is formed, primary decarburization is undertaken not with oxygen but rather with CO2 and H2O and the melt is desulfurized. The semi-product stream enters the third melt circulation loop, where open-channel decarburization is effected along with dephosphorization to yield a low carbon steel product. Alternatively, the melt leaves the last loop to irrigate a packed tower countercurrent to argon at around 100 mbar to continuously produce ultra-low carbon (ULC) steel.

Jan 1, 2003

By T. Shoji

"The human history is characterized by social development based on mineral and energy resources, and many conflicts to take the resources by power. This is shown by not only world wars but also many local conflicts as well as international supremacy.IntroductionThe world population after B. C. 10000, which is summarized in several papers, is approximated by four straight lines on a semilogarithmic diagram as shown in Figure 1 [l]. The annual rates of increasing are 0.0041, 0.071, 0.53, and 1.85 % from the old and young periods. The boundaries among four periods are approximately B. C. 4600, AD. 1670, and 1930. The start of the second period seems to correspond to the beginning of agriculture and cattle breeding. Precisely speaking, the usage of natural energy resources such as woods and domestic animals already began, but is inferred to have become common after the age. The third and fourth periods are characterized by the common usage of coal and oil, respectivety. Not only energy resources but also mineral resources including gold, copper, iron and others are also important for the human history.Mineral and energy resources have supported the development of the .human civilization, and have caused many conflicts because of this reason. Every day newspapers report conflicts, such as Chechnya, East Timor and Ache. We can easily point out the facts that the conflicts closely relate to mineral and energy resources. Groznyj, Capital of Chechnya, is located on the western margin of Caspian oil field. Many mineral deposits occur in Kavkaz Mountains running south of Chechnya. Subsea oil fields occur in Timor Gap located between East Timor and Australia. Ache is also one of oil fields in Indonesia. It is very difficult to state present conflicts independently of a political view of point. For this reason let us try to historically review the relation between mineral and energy resources and international domination and conflicts [2] based on many papers [3]."

Jan 1, 2000

By Yasuo Ojima

A new copper continuous converting process was investigated to evaluate the possibility of its application in the commercial operation. The tests were performed both in the laboratory and in pilot plant scale. Bath smelting process with the use of the top submerged lance technology was applied in these tests. Furnace shape was modified to a lengthwise eylindrical one with a settling area. The furnace monitor was put in the settling area to check the furnace from inside, FeOx-Si02, FeOx-CaO and FeOx-CaO-Si02 based slag systems were used to check their efficiency, The optimum slag chemistry to have good metallurgical results was discussed and FeOx-CaO system with some Si02 content turned out to be preferable although it has not been practically used, In this pilot plant test feeding rate of I tIH of solid grain matte was charged consecutively for two weeks and continuous converting could be done successively. This process is expected to overcome the problems of existing processes and be easily applied in existing plants.

Jan 1, 2003