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By Nobumasa Kemori

Six kinds of copper '90ncentrates. were treated individually in a ,pilot scale. Outokumpu flsah smelting furnace ~n order to study their ?flash smelting behavior with respect to oxygen efficiency and dust generation. The copper concentrates tested were selected from the more than twenty sources which are treated at the Sumitomo Toyo copper smelter, so as to provide a wide range of chemical composition in terms .of Cu, S,Fe, Pb + Zn + As, and Si~ content. Oxygen efficiency 'and dust generation rates obtained in 'the experiments ranged from 80% ,to 108% and 11% to 20%, respectively. Relationships between these results and experhnental conditions such as chemical and mineral composition of the copper concentrates, flux ratio, fuel consumption and so on are also discussed quantitatively in this paper.

Jan 1, 1998

By Liu Wei

In order to make clear the dissolving characteristic of the chrysocolla (CuSiO3?H2O) in the ammonia-ammonium chloride solution, a thermodynamic model of the chrysocolla (CuSiO3?H2O)-ammonia- ammonium chloride-water system is established using the exponential computation method based on both mass balance and charge balance equations. The equation group of the thermodynamic model is solved by the MATLAB Soft on PC. The condition which is favorable for dissolving high concentration of copper in solution is making out. The stable area of chrysocolla (CuSiO3?H2O) and the condition of chrysocolla (CuSiO3?H2O) converting to atacamite (Cu(OH)1.5Cl0.5) is also studied. A group of experiments are designed to validate the veracity of the results of the thermodynamic calculation.

Jan 1, 2010

By C. Kathryn Sole

The close proximity of cobalt and nickel on the Periodic Table and their frequent occurrence together in nature means that their separation in primary hydrometallurgical flowsheets is not only often necessary, but requires the use of innovative chemistry to achieve high selectivity. Today, increasingly stringent demands for the high-purity cobalt and nickel salts required for battery applications in consumer electronics, electric vehicles, and solar applications are again challenging the state of the art. The evolution of cobalt–nickel separations is traced from the basic precipitation technologies employed in 1960s, through commissioning of the first cobalt solvent-extraction plant in South Africa in 1974, to the commercialisation of organophosphinic-acid extractants (which provided a step-change improvement in selectivity) and their eventual widespread use in the 1980s and ’90s. This was followed later by their sulphur analogue, which enabled different possibilities for laterite processing in the new millennium. Separations in chloride media, which take advantage of the different speciation chemistries, and nickel extraction by oximes in ammoniacal systems are also discussed. More recently, chelating and solvent-impregnated resins have added further dimensions to the possibilities for flowsheet design and enabled higher purity products to be attained from both primary and secondary sources. Selected case studies and flowsheets are described.

By Eulogio Velasco, Jose Nino, Marcos Cardoso

"Recycling of aluminum scrap for production of secondary alloys used for automotive applications is increasing continuously. Automotive alloys require a strict control to remove alloy impurities, inclusions and excess of magnesium. The advantage of aluminum is its recyclability with large energy and emission savings with minimal loss in material properties. The aim of this work is to study the magnesium removal from recycled aluminum by chlorine injection in a reverberatory furnace, and removal by an oxidation process at high temperature in an industrial rotary furnace.The magnesium removal by gas injection is carried out by the reaction between chlorine and magnesium, with its efficiency associated to kinetic factors. In the rotary rapid oxidation of aluminum and magnesium elements at high temperature is characterized by the formation of surface films composed of magnesium oxide. Additionally this work reviews the benefits of an efficient demagging process.IntroductionThe advantages of using light alloys for automotive applications include fuel economy improvement, greenhouse gas reductions and polluting emissions. These characteristics makes the aluminum alloys an attractive option for automotive components such as powertrain products and other critical parts like cylinder heads and blocks. [1]Aluminum alloys coming from recycled automotive components, used beverage cans (UBC) and wrought alloys have positive effects in the energy savings and current environmental trends. Producing a scrap recycled aluminum ingot consumes approximately 5% of the energy required to produce a primary aluminum ingot from bauxite ore. [2]"

Jan 1, 2011

By Qingwei Wang

Heavy metal-containing wastewater from hydrometallurgical processes of lead-zinc was treated by biologics in a 200 m3/h industrial scale experiment. The result shows that Zn concentration declined from 50.28 mg/L~240.81 mg/L to 0.21 mg/L~1.98 mg/L, Pb from 1.00 mg/L~13.47 mg/L to 0.083 mg/L~0.71 mg/L, Cu from 0.24 mg/L~2.38 mg/L to 0.059 mg/L~0.40 mg/L, Cd from 2.12 mg/L~23.47 mg/L to 0.011 mg/L~0.071 mg/L and As from 0.50 mg/L~6.00 mg/L to 0.005 mg/L~0.10 mg/L. The concentrations of the above heavy metals in the treated water were lower than that in Integrated Wastewater Discharge Standard (GB8978~1996) in China. Furthermore, the treated wastewater was recycled and reused in smelter plant. Zinc content in hydrolytic sludge reached up to 34.04%, which indicates that this sludge can be used to recover valuable metals.

Jan 1, 2010

By Jewel A. G. Gomes

Green rust (GR) are layered Fe(II)-Fe(III) double hydroxides, having a pyroaurite-type structure consisting of positively charged hydroxide layers and hydrated ions in interlayers. This special feature of GR is very efficient for wastewater treatment as the pollutants are easily taken in or exchanged with the anions in the interlayers. It can be simply and cost-effectively produced by electrocoagulation (EC). Chicken processing plant (CPP) produces large amount of wastewater containing variety of readily biodegradable organic compounds, fats, and proteins. The possible re-use of properly treated CPP wastewater would be economic and environment friendly. In this study, we present our work on treatment of CPP wastewater using EC, specifically for the removal of COD. Analysis of the EC-treated water for reuse in the same plant is discussed considering the U.S.EPA regulations. Two types of EC-reactors were used for this purpose. To better understand the treatment mechanism, EC-floc was also characterized using XRD and SEM-EDS.

Jan 1, 2010

By Ho-Sang Sohn

The kinetic study on desulfurization of copper matte by gas bubbling was designed under the presumptions of lower FeO activity and of no slag formation, Copper matte with 59% Cu and 22.6% S in weight was oxidized at 1523K by bubbling of Ar + O2 gas through a submerged nozzle. The effects of oxygen partial pressure and flow rate of gas on the oxidation rate of matte were discussed. The desulfurization rate and the evolution rate of SO2 gas of copper matte were significantly influenced by the oxygen partial pressure, but the dependence on gas flow rate was rather complicated. The desulfurization rate and evolution rate of SO2 gas of copper matte were described by the mass transfer rate through the gas film around the rising gas bubbles. Thermodynamic correlation equations between the partial pressure of gaseous species and matte composition were incorporated to the kinetic calculation, The present model shows that the reaction path starts to transiently cross over an isobar line of PSO2 to asymptotically approach to the particular isobar line drawn in a matte composition plane of %S and %O.

Jan 1, 2003

By Rodney Hundermark, July Ndlovu, Lloyd Nelson, Phillimon Mukumbe, Paul van Manen, Whitey Seyanund, Bart Pieterse, Bertus de Villiers, Diale Mokwena

The 2003 redoubling in power to 68MW on the Polokwane Smelter furnace represented a significant intensification in platinum group metal (PGM) smelting. Combined with onerous ‘green’ PGM concentrate smelting requirements, this yielded conditions unusually corrosive to copper coolers and refractories. This presented unexpected operational and design challenges to reliable crucible operation and maintenance. Combined with specific operational control intervention, development of protective coatings has led to the life of water-cooled copper components improving from 9 to 40 months. The furnace matte endwall was extended in 2010 to address accelerated wear of refractories and the potential risk for contact of copper components by superheated matte. An 18 month planned endwall rebuild cycle has been demonstrated (versus catastrophic failure within 9 months). Finally, benefits including lower energy consumption, improved metal recoveries and higher productivity resulting from operational and in-house design developments will be described, that justify “Celebrating the Mega-scale” in PGM smelting.

Jan 1, 2014

By Carlos Maurício Fontes Vieira

In the present work a ceramic body, fabricated using a mixture of clays and sand, for roofing tiles, produced in Campos dos Goytacazes, north of the State of Rio de Janeiro in Brazil, was characterized. Characterization was performed by X-ray diffraction, thermo analysis, chemical analysis, particle size distribution determination and plasticity. In addition, technological properties related to water absorption, linear shrinkage and flexural rupture strength were determined in samples fired at 700, 900 and 1100oC. The results showed that the investigated ceramic body has satisfactory plasticity and presents a refractory behavior during firing due to the predominantly kaolinitic nature of the clays.

Jan 1, 2006

By Patricia Martínez Nicolás

Nickel and ferronickel are some of the major components in the production of special alloys; however, the energy consumption for their production greatly increases their price. A cheaper option could be to use NiO and a reducing agent. This work presents experimental and theoretical analysis to estimate the effect of slag basicity and amount of reducing agents on the NiO reduction from the slag which interacted with molten steel at 1600 °C in an EAF. The slag system contained CaO, SiO2, CaF2 and NiO together with a reducing agent, ferrosilicon or carbon. The NiO content in the slag was 25 mass%. The amounts of the reducing agents (Si and C) were 1 to 4 times the stoichiometric mass to reduce NiO. The CaO/SiO2 ratio was 1.5 and 2.5. The kinetics of the process was very fast since after few minutes the maximum nickel yield was obtained. The slag basicity had a negligible effect on the reduction of NiO.

Jan 1, 2006

By V. I. Lakshmanan

The demand for elements such as nickel, cobalt, titanium and gold in various applications has increased significantly. Innovation to recover these elements now plays a major role in metallurgical processes as established technologies have challenges in treating the types of ores that are available while meeting the increasingly stricter environmental regulations. Alternative chloride based processes have been developed that can be used to recover the value elements from the available feed stocks with potentially lower environmental impact. Chloride-based hydrometallurgical processes have several advantages, including higher leachability of complex ores/tailings and relative stability of chloro-complexes of the metals. Process Research ORTECH Inc. (PRO) has developed mixed-chloride process flowsheets, where innovative solvent extraction process steps are used for the separation of nickel, cobalt, titanium and gold from their respective chloride solutions. This paper will discuss the potential aqueous chloro-chemistry of these metals and separation reaction mechanisms involved in the solvent extraction process.

By C. E. M. Meskers

End-of-life Electronic and Electrical Equipment, o_cially called WEEE, is unjustly regarded as mainly a waste management problem. What is structurally overlooked is the enormous resource impact of these devices. EEE rep- resents a tremendous metal resource, which should be uti- lized through e_ective recycling, which has a much lower environmental footprint than primary production. The actual amount of end-of-life EEE recycled today is embar- rassingly low since insu_cient EEE is collected and part of the collected EEE is exported to developing countries, where it is largely not entering o_cial recycling systems. To achieve a global recycling society issues like technol- ogy, economics, life cycle structure, stakeholder aware- ness and legislation have to be addressed in a global, co-operative manner so that sustainable closed product cycles can be obtained. Requirements for a "global re- cycling society" are de_ned to address today's reality of global ows of used consumer products, taking into ac- count the likely needs of the future.

Jan 1, 2009

By Jürgen Antrekowitsch, Thomas Griessacher

"Heavy metal containing residues are typically hazardous wastes because on the one hand, a deposition gets more and more complicated and on the other hand, the large amounts of metals like Zn, Cu, Fe and Pb represent a significant value. Thus, a post-treatment of these materials with the recovery/recycling of the metals and stabilization of the waste is not only ecological but often also economical. The therefore typically applied recycling processes utilize pyrometallurgical steps, where carbon or carbon monoxide from fossil coal and coke is used as a reducing agent, which results in large amounts of CO2 emissions. An alternative option is the application of a hydrogen-rich gas emitted in biomass utilization processes as a carbon-neutral reducing agent. Investigations in a retort process which were done at different temperatures and times showed excellent results concerning the achievable reduction rates and final contents of the heavy metals for various residues.IntroductionNowadays heavy metal containing residues like electric arc furnace dust (EAFD), dust from cupola furnaces, waelz slag, etc. are declared as hazardous wastes in a growing number of countries due to the leachability of the heavy metals in these residues. For that reason it is no longer possible to landfill these materials or use them for road construction or disposal works. Some land filling activities, carried out until now, have only been realizable because of some process modifications or cost intensive post-treatment steps of these residues. But the disposal capacities for such materials are decreasing, therefore increasing the prices. The second point for the growing disposal limitations is the stringent environmental legislations and regulations, which restrict the number and amounts of materials which can be dumped [1 – 5].From the other point of view these heavy metal containing residues usually have high contents of zinc, lead, iron, etc., which represent a significant value and therefore a big potential to recover these metals. This is why in recent years the number of recycling processes and the amount of recycled heavy metal containing residues have continuously increased. These recycling processes have the target to recover the valuable metals from the residual materials in the form of a saleable product as well as the stabilization of the slag produced in these processes [5, 6]."

Jan 1, 2011

By Frederick T. Wallenberger

"Laser assisted chemical vapor deposition (LCVD) is a new containerless fiber process whereby growth of small diameter fibers or microstructures (microsprings, microsolenoids) occurs directly from the vapor phase. The laser beam has a focal point adjusted to coincide with the tip of the growing fiber inside the reaction chamber. Since the growing fiber is not in contact with reactor walls or foreign materials, it is chemically pure, and suitable for optical uses and uses requiring high structural uniformity. Continuous fibers and multifilament yams are possible. The use -of high reaction chamber pressures (1-10 bar) and a small wavelength Nd-YAG laser made it possible to fabricate small diameter fibers at growth rates >1 mm/s. This paper describes the synthesis of single crystal, polycrystalline and amorphous fibers by LCVD, and provides a comprehensive analysis of phase transformations occurring during their fabrication.IntroductionLaser assisted chemical vapor deposition (LCVD) is a new containerless fiber process [1-10] whereby growth of small diameter fibers or microstructures occurs directly from the vapor phase. The laser beam has a focal point adjusted to coincide with the tip of the growing fiber in the reaction chamber (Figure 1). The diameter of the growing fiber corresponds to that of the laser focus. Depending primarily on the laser energy (Le., the temperature at the growing fiber tip), it is possible to obtain single crystal, poly crystalline or amorphous fibers by this method.Since the growing fiber is not in contact with reactor walls or foreign materials, it is chemically pure, and suitable for optical uses and uses requiring high structural uniformity. Laser assisted CVD is a potentially continuous process; continuous fibers and multifilament yams are possible."

Jan 1, 1994

By K. Morsi

The interest in spark plasma sintering has been growing considerable over the past few years. This has been brought about by the unique advantages of the process, which include reduced sintering temperatures and times and the production of materials with unique microstructures and properties. Despite its current reputation as an outstanding process that has solved major problems such as nano-powder consolidation, it has so far been largely limited to the manufacture of simple shapes, due to its inherent geometric configuration. In this paper we present preliminary results on spark plasma "extrusion" that can allow the production of extended geometries via electric-current processing. Preliminary results on the processing and microstructure of spark plasma extruded aluminum are discussed.

Jan 1, 2009

By Zhang Chuanfu

Keywords: modified coprecipitation method, Ni-Co alloy powders, solid-solution oxalate, growth mechanism Homogeneous solid-solution oxalates of Ni2+ and Co2+ ions were synthesized by modified coprecipitation method and the composition and morphology of the fibrous solid-solution oxalates precursor were characterized by XRD, IR, DTA/TG and SEM analysis. The effects of feeding methods, pH values, precipitation temperature, reactant concentration, addition surfactant, alcohol washing and drying process on the morphology and dispersion of the precursor were investigated in detail. The experimental results showed that the coprecipitated powders have characteristics that are different from those of the mechanical mixtures with the same stoichiometry. Based on the observations of precursors growth and SEM morphology of the precursor, the oriented attachment was proposed for the well-aligned growth of the fibrous Ni-Co alloy precursor particles.

Jan 1, 2005

By Ramona Prillhofer

Salt slag is a waste product produced by the recycling of aluminum. In most European countries (e.g. Austria, Germany) the landfill disposal of this waste is forbidden because the slag contains soluble salts and these represent a potential source of pollution to the surface and groundwater. Additionally, consisting metal and some compounds in the salt slag can react with water and resulting from this, noxious gases are generated. The recovery of useful materials from these wastes is accordingly both environmentally necessary and economically feasible. This study describes a complete recycling-process for the salt slag, which includes a leaching-cristallization-process to obtain the oxidic residue, a pyrometallurgical-step to clear the oxidic residue and finally an extensive characterization of the achieved products. Due to the increasing price of raw materials, the utilization of the oxidic residue into commercial products has been investigated and application possibilities will be discussed.

Jan 1, 2009

By Clara María Lamus Molina

The following minerals found in the residual black sands from gold mining in El Bagre Antioquia (Colombia) were identified as having major economic interest: Ilmenite (FeTiO3), with an average of 49% of TiO2, frequently altered presenting crowns; lamellaes of rutile and alteration textures; titanomagnetite with up to 25% of TiO2; magnetite (Fe3O4) in individual grains or associated with others minerals as hematite and ferromagnesian silicates rutile (TiO2) with considerable quantities of Nb2O5(0.1-3.7%Wt); zircon (ZrSiO4) with 66%Wt of ZrO2 and monazite with an average of 63.43%Wt of REE, this frequently associated to xenotime and thorite forming textures as little drops. Analysis in EPMA and SEM/EDS showed percentages of minor elements and traces, thereby clearly establishing the applications of these minerals in diverse industries. Furthermore, a detailed granumetric study of the different minerals and textural relationships among them also allowed for establishing the basis for possible processing and exploitation.

Jan 1, 2006

By S. Fitzel

The Betts process for electrorefining of lead has been in operation since 1902 in the Trail Operations Metallurgical complex. The Betts process allows production of high purity lead in a single electrochemical step. Process improvements and plant expansions have taken place over the many decades of operation of this process which has proven to be robust, flexible, and capable of successfully treating a large range of anode bullion compositions. This paper reviews the history of the Betts lead electrorefining process, the innovations and quick industrial adoption of new discoveries that took place at the end of the nineteenth century. The process was first implemented in Trail Operations and integrated very well with metallurgical needs then and now.

By Huang Kai

By adding the solid oxalate acid powder into the solution of nickel chloride or its ammonia coordinated solution, the uniform compound particles were prepared and the precipitated particles were transferred to the mono-dispersed NiO particles by calcination. In this study, the various experimental conditions were investigated, the characteristics of the corresponding obtained particles were analyzed, and the formation mechanism of the particles was elucidated. It was found that the solid oxalate acid provided the solid-solution interface for the precipitation and induced the nucleation and growth of the product particles.

Jan 1, 2005