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By R. J. Batterham

This paper sets the scene for the Australian-Asian Pacific Course and Conference on Pyrometallurgy for complex materials and wastes. The relentless presence of competitiveness is rehearsed as the source of the current trends towards continuous improvement and benchmarking. While this might be expected to lead to more spending on pyrometallurgy, the opposite appears to be the case. The paper examines the reasons and suggests that we face an increasing challenge for selective developments that can lead to sustainable competitive advantage - both in mineral and in waste processing.

Jan 1, 1994

By Fujio Ishii

The deoxidation of liquid nickel and nickel binary alloys with silicon has been determined at temperatures between 1500°C and 1650°C using quartz crucibles in order to investigate the deoxidation of nickel based alloys. The equilibrium constant of the deoxidation reaction in liquid nickel and the effects of the different alloying elements such as chromium, molybdenum, tungsten, iron, cobalt and coppcr on the activity coefficient of oxygen in liquid nickel have been established.

Jan 1, 1993

By Alan P. Prosser

The heap leaching of gold ores by cyanide solution was simulated by computer program. The program uses only basic m1neralogical and chemical data; no process testwork data, such as column leach results, are required. The simulation can be used to forecast the consequences of various changes before and during the testwork, design and operation stages of a particular ore-process system. Also, data about the state of different parts of the heap at various times help create an understanding of what is happening. The effects of mineralogical and process variables on the overall performance of the ?heap leaching process are illustrated. Comparisons are made to column leach tests and production data. The potential of the simulation strategy is discussed for making better use of operating experience and for suggesting specific research objectives. It has become clear that more attention should be paid to other metals that dissolve in the solution.

Jan 1, 1989

By Behrouz Abedian, Livia M. Racz

"We address dynamic interactions between high-energy, reactive surfaces of polymer-matrix composites and solid surfaces. A common characteristic of these interfaces is that bonding occurs readily upon contact. In many industrial and biomedical applications, it is desirable to suppress this bonding phenomenon. This interfacial effect is discussed in light of the development of our new method of handling polymer-matrix composites in dental applications. This method involves vibration of the solid-polymer interface at different frequencies. For each material, there is a critical frequency at which the sum of the viscoelastic and inertial energies of the fluid at the surface exceeds the energy available for bonding. When the polymer is vibrated at or beyond this frequency, it does not adhere to solid surfaces. An important aspect of the developed process is that it can be used to characterize surface and interfacial properties of polymers under dynamic conditions, whereas existing techniques are restricted to the study of bulk dynamic properties.IntroductionThe purpose of this paper is to report on the development of a new method for manipulating polymer-matrix composite materials used in dental applications, and the potential of this process for use in materials characterization. The materials under discussion have polymer matrices of a combination of bisphenol A-glycidyl methacrylate (BIS-GMA) and triethylene glycol dimethacrylate (TEGDMA), and contain filler particles of silica and/or zirconia glasses. These materials are called direct aesthetic restorative materials, and are used for filling of cavities, repairing chipped teeth, and for other restorations in which appearance is of importance. They have the appearance of natural tooth material, and are therefore in great demand for use in the anterior portion of the mouth(l,2)."

Jan 1, 1998

By L. M. Abrantes, A. P. Paiva

"A brief review of some innovative methods for the direct recovery of metals from loaded organic phases is presented; emphasis is given to electroreductive stripping and cementation, which are described and illustrated by examples: of current research. The recovery of silver using a two-phase electrolysis - by direct application of an electrical potential to a mixture of a metal loaded organic phase· containing Cyanex 471X, obtained by solvent extraction, and a stabilized sodium thiosulfate solution - is more extensively discussed. The overall efficiencies are analyzed and compared with data obtained by conventional stripping procedures. Some preliminary results achieved for the recovery of the precious metal using galvanic stripping, applied directly to similar organic solutions and involving zinc and iron powders as reducing agents, are also evaluated.Introductory ReviewThe application of hydrometallurgical methods to the recovery of metal values from ores and concentrates has been receiving a growing interest, either from researchers or from the mining industry [1].For the concentration / purification of the relatively low concentrated metallic solutions resulting from the leaching of those raw materials, solvent extraction (SX) is a well established technique [2]; the loaded organic solvent is then conventionally contacted with a suitable aqueous solution, the metal in its final form being usually recovered from this solution by electrowinning.As an efficient and / or selective stripping is sometimes difficult to achieve, depending on the specific characteristics of the system under consideration, some alternative procedures have been analyzed in order to overcome this problem. One of the chosen routes, mainly developed by Hirai and Komasawa, is to promote the reduction of the desired metal species in the organic phase, in such a way that the stripping stage becomes feasible; for the selective stripping of vanadium from a solvent containing a mixture of vanadium and molybdenum, the authors successfully used reductive [3], electro-reductive [4,5] and photo-reductive [6] techniques. The two latter methodologies have also been applied to the recovery of europium from a solvent containing europium, samarium and gadolinium [7,8].However, further processing is necessary to recover the metal in its solid state; therefore, methods causing the direct reduction of the metal species in the organic phase to their fmal metallic form would be of interest, as an intermediate step would be avoided"

Jan 1, 1997

By Adriana de Aquino Soeiro da Silva, Joao Alves Sampaioa, Luiz Carlos Bertolino, Francisco Manoel Garrido, Marta Eloisa Medeiros

"Brazil has a large agricultural potential and its production success is related to the chemicaland physical soil characteristics. Therefore, the demand in the use of a great quantity offertilizers to compensate the low amount of nutrients in the soil includes about 40% of foodproduction costs. In order to develop economical alternatives to traditional fertilizers, rockswith potential use in agriculture will be studied. In this work the potassium rock, a greensandslate, will be chemically and structurally characterized for the development of a potassiumthermophosphate. This alternative fertilizer will be obtained based on a fusion of a ponderedmixture of potassium, magnesium and phosphate rocks to be applied in the Brazilianagriculture. Preliminary characterization results indicate that the greensand slate presents ahigh percentage of glauconite, quartz and micas.Keywords: Potassium thermophosphate, alternative fertilizers, greensand slate.IntroductionBrazil has a great agricultural potential and its production success is closely related to thesoil's chemical and physical characteristics. However, the country's soils present lownutrients content and high acidity due to weather conditions. Thus, the use of a high amountof fertilizers makes up for the soils' lack of nutrients and accounts for 40% of food productioncosts. Therefore, research on obtaining new alternative fertilizers is a constant worry due tothe increase on food demand [ 1].The lack of raw material for the preparation of NPK fertilizers in Brazil is a concern and theissue of potassium fertilizers a priority. Such a fact is because in 2008 only 608.000 tons ofKCl were produced, corresponding to just 10% of the Brazilian necessity. Thus, the use ofrocks as agricultural nutrients can contribute to reduce the need for industrial fertilizers.This way, the development of a new agricultural raw material originated from a rock thatalready exists in the country's soil is of great importance for the mineral and agriculturalsectors."

Jan 1, 2011

By J. Avraamides

Some operational difficulties have been encountered in the transfer of carbon-in-pulp technology to Australian conditions. Many gold mines? are located in remote and arid areas where the available ground water is highly saline. There is a gradual depletion of free milling oxidised gold ore reserves resulting in the necessity to treat deeper primary sulphide .deposits which can be refractory. Some near-surface ore-bodies and tailing dumps are contaminated by natural vegetative matter which can interfere with the adsorption of gold from the cyanided pulp,. Advances which have been? made include potable water conservation in elution, a new type of regeneration kiln, inter-stage screens, alternative leaching systems transportable carbon-in-pulp plants and efficient open-cut mining methods. Academic and applied research is well supported by government and industry and the results are normally rapidly disseminated and put into practice by the gold mining industry.

Jan 1, 1989

By Hao Rang

The article Is specially to Introduce the recovery process of Nb, Mn, P from slags and reutilization techniques of the remaining slags. Nb-Mn-Fe alloys which contain 14-16% Nb, 40-60% Mn can be obtained after using fire refining process of " Blast Furnace-Revolving Furnace-Electric Furnace -Electric Furnace, "meanwhile, phosphorous slags which the content of phosphorus pentoxide Is 29.21%. Further going through wet metallurgical processing and electrowinning technics to recover grading 99°o metallic manganese. Finally, phosphorous slags are grinded finely to be as phosporous fertilizers to be directly used for farmlands. Small particle size (0-8mm) rich slags are mixed with slight solid additions for balling directly, and taken Into blast furnace with blocky slags all together. The remaining tall slags are fully used as constructional materials, slags cement as well as a serial of wall materials, road materials, ground ornamental materials without burning operation and steam curing. The compressive strength range of those materials is up to 15-30 MPa. There is no more solid waste slags effluent In the full technical process.

Jan 1, 1994

By A. Kar

A mathematical model is presented for pure titaqium deposition from titanium tetrabromide on a stainless-steel (SS 304) substrate. Five three-dimensional, transient, and nonlinear partial differential equations are used to account for the diffusion of various species inside the deposition chamber and the thermal decomposition of titanium tetrabromide, titanium dibromide, and titanium monobromide at the surface of the substrate in order to determine the thickness of the titanium film deposited on the substrate. The effects of various process parameters on the deposition and shape of titanium films are examined, and under certain conditions, the deposited titanium films are found to have volcanic profiles.

Jan 1, 1992

By Masao Suzuki

Over 5 million cars are scrapped yearly in Japan. After dismantling. scrapped automobiles, they are put into a shredder for differential recovery of ferrous and nonferrous metals. The residue, which is called shredder dust, runs over 1.2 million tons per year. This paper reports a entire sequence of scrapping. cars. in Japan with the following sections: (1) production and scrapped car management, (2) material composition, (3) dismantling, (4) shredder plant, (5) differential recovery of metals including specific gravity separation and newly developed color separation.

Jan 1, 1995

By Kun Wang, Xinhui Li, Huaqing Xie, Qingbo Yu, Qin Qin

"Three typical model compounds of bio-oil (ethanol, acetone and phenol) were studied in the steam reforming process for hydrogen production. In the thermodynamic analysis, the three componds showed the similar trends. The hydrogen yields increased with the increase of steam/carbon (S/C) ratios, and the temperatures of the maximum hydrogen yields moved afterward to low temperature zone. However, the hydrogen contents were just about 70%. For improving hydrogen yield, a new system for steam reforming of bio-oil with site CO2 capture was put forward. This system required the catalst with the larger granularity having greater mechanical strength and higher abrasion resistance. So, six Ni-base catalysts loaded on Al2O3 particles prepared were used and among them, Mg-Ni/Co catalyst showed the best catalytic performance. For the simulated bio-oil (the mixture of the compounds), the hydrogen yield can attain 63% with Mg-Ni/Co catalyst with the good stability and regeneration ability.IntroductionCurrently the interest in the use of hydrogen as a clean energy carrier is increasing, and the main way for producing hydrogen is steam reforming of fossil fuels, containing steam reforming of nature gas, naphtha and coal. But this way caused substantial amounts of CO2 emitted, and these sources of hydrogen which are non-renewable energy will eventually be used up [1, 2]. As a kind of renewable energy, biomass is recognized as an attractive alternative to fossil fuels, because of its neutral CO2 emissions [3]. There are mainly two thermochemical processes using biomass to produce hydrogen, gasification and flash pyrolysis followed by steam reforming (SR) of the biooil produced in the flash pryolysis process [4]. The latter was known as one of the most promising and economically viable methods for hydrogen production [5]. In the last decades, the biomass flash pyrolysis technology was adequately developed and fairly mature [6]. But the steam reforming of bio-oil is still at the research stage and yet has been leading to more and more concerns by the researchers. In their research, the catalysts were widely studied and yet mainly were powdery[7-10], and the reactors manily were fixed bed reactors[11-13], readly causing the carbon deposition and the catalyst deactivation, against the continuous running. In this paper, a new systerm was put forward and could realize continuous production of hydrogen, yet needed catalysts with the larger granularity having greater mechanical strength and higher abrasion resistance, as well as powdery CO2 sorbents which mainly calcium oxide based ones.In this paper, the thermodynamic analysis of the steam reforming processes of three typical bio-oil model compounds (ethanol, acetone, phenol) was performed, and the effect of S/C ratio and temperature on the hydrogen yield and the compositions of gaseous products were investigated. Then, a new systerm for steam reforming of bio-oil with site CO2 capture was put forward, and the catalysts with a certain granularity were prepared and studied."

Jan 1, 2014

By V. D. Tathavadkar

Chromite ore is of immense importance for the extraction of metallic chromium and chromium chemicals. The mineralogy and crystal structure of chromite phase are therefore important part of our investigation on the extraction chemistry of chromium species. In this investigation, we have studied the effect of the processing parameters, i.e., the temperature and the oxygen potential on the microstructure and composition of mineral phases formed in the Cr2O3 ?Al2O3 -FexOy -MgO system. In particular the importance of the spinodal decomposition reaction is emphasized in the extraction of chromium as sodium chromite and sodium chromate. Experiments were carried out in order to study the differences in the crystallography of different chromite minerals. Phase equilibria in natural chromite minerals were investigated by calcining chromite mineral in air, argon, and 5% hydrogen + argon atmospheres over a temperature range from 200 to 1200 °C. The effect of the oxygen partial pressure and temperature on the phase constituents of the calcined product has been discussed. The microstructural changes were examined using scanning electron microscope (SEM) and the changes in elemental composition in different phases were analysed by electron probe micro analyser (EPMA). The results obtained from EPMA studies were used to calculate lattice parameter of the spinel lattice, and these values were compared with the values obtained from X-Ray powder diffraction data. On the basis of the experimental data, the mechanism of the spinodal decomposition of complex spinel phases is described under the influence of oxygen partial pressure and temperature.

Jan 1, 2000

By Yotamu Stephen Rainford Hara, Animesh Jha

The investigation focuses on a low temperature recovery of Cu and Co from a 40 wt% SiO2-(30 wt%Fe,6 wt%Al)2O3-10wt% CaO-7wt%CuO-7wt%CoO slag over a temperature range of 1173K to 1323K. The alloy phases containing Cu-Co and Fe-Co alloy formed via the carbothermic reduction of oxides: MO + C = M + CO(g), where M represents metallic copper, cobalt or iron. In the direct reduction of oxides, the recovery of metallic phase was well below 90% at 1323K, due to the kinetic barrier which was analysed and attributed to oxygen and metal-ion transport in the slag. This barrier was overcome by adding CaSO4 and carbon, which yields a matte (MS) phase via MO + CaSO4 + 4C = MS + CaO + 4CO reaction. Lime thus produced in situ participates in metal oxide/metal sulphide reduction reactions, which are analysed with the help of X-ray powder diffraction, scanning electron microscopy, and thermogravimetric analysis.

Jan 1, 2014

By B. C. Jena

Activities of carbon, cobalt and nickel were evaluated in the ternary systems iron-carbon-cobalt and iron-carbon-nickel for the temperature range 1300-1600°C for cobalt and 1300-1700°C for nickel. The carbon activities were determined from the knowledge of activities (1) in the binary system iron-carbon, (2) in the dilute ternary systems and (3) from the knowledge of carbon saturation data. The activities were mathematically expressed with the Taylor series expansion of Wagner's interaction parameter formalism modified to suit concentrated solutions. The cobalt and nickel activities were determined from the knowledge of carbon activities by applying the Gibbs-Schuhmann integration and from cobalt and nickel activities in the binary systems iron-cobalt and iron-nickel. Partial molar enthalpies of mixing were determined based on the temperature behaviour of the activity coefficients.

Jan 1, 1992

By Ernest D. Mast

Noranda's Altonorte custom smelter, located in the 2nd region of Chile, 20 kilometres southeast of the city of Antofagasta, started operations in 1993. Presently, 1150 tonnes per day of new feed are smelted with an 85% sulphur capture. An oxy-fuel reverberatory furnace produces a 48%-55% copper matte that is treated in 13 ft. x 36 ft. (3..96m x 10.97m) Peirce-Smith converters (two hot and one blowing). Up to thirty percent of the new concentrate is smelted via dry concentrate injection into the converters. This paper reviews the development of the concentrate drying and injection system, and oxygen enrichment at Altonorte from start-up in 1995 to the present time. The relationship between oxygen enrichment and concentrate injection is reviewed from a theoretical and practical standpoint. Concentrate injection has improved the smelter's productivity and added flexibility to the operations. Due to the relatively high matte grades and the subsequent short converting times, maintaining consistent operations was difficult at times and the smelter has gone through a learning curve. Plant operating results and experiences are presented on the impact of concentrate injection in relation to: feed treatment, blowing times, revert generation, slag quality and refractory wear.

Jan 1, 1999

By Katia Vutova, Vania Vassileva

Investigations and results on the refining of tungsten scrap applying electron beam melting (EBM) in vacuum are presented and discussed. In this work EB melting experiments were performed in single or double-melt operations with different power inputs and refining times for tungsten purification and recovery of multiple metals (including refractory and other metals such as Mo, Nb, Cu, Zn, etc.), which are alloyed elements or impurities with high concentrations in the initial materials. Evaluations for extraction of some valuable metals, generated in the condensate at their removal from the liquid metal during the refining process are provided. Efficient technological regimes for e-beam melting and refining that enable the simultaneous production of pure metal ingots and condensates that can be used directly or can be used for subsequent extraction of expensive and valuable metals are presented.

Jan 1, 2016

By Yasuhiro Konishi, Yoshiyuki Noda

"This paper describes a new processing of rare-earth oxide precursor, in which rare-earth carbonate powders are precipitated directly from emulsions of rare-earth loaded carboxylate solutions, using CO2 gas and water. This synthetic route of rare earth carbonate is a combined process of the stripping and precipitation stages in a conventional solvent extraction. Using this technique, lanthanum carbonate and yttrium carbonate were prepared at temperatures of 10 to 80°C and CO2 pressures of 0.1 to 3.0 MPa for 120 min. The rates of carbonate precipitation in a batch autoclave were sensitive to processing parameters such as CO2 pressure, temperature, and organic-phase composition. The particle size distributions of the carbonate powders were markedly dependent on temperature and C02 pressure.IntroductionSolvent extraction is the most appropriate commercial technology for separation and purification of rare earths. In typical commercial processes, the rare earths are stripped from loaded solvent extractants using aqueous solutions of mineral acid. After adjusting the pH of the aqueous strip solution, the rare earths are precipitated as insoluble powders of oxalates or carbonates, from which oxides can be produced by calcination. Such conventional processing can be simplified when the stripping and precipitation stages are combined by emulsifying rare-earth loaded solvent extractant with aqueous oxalic acid solution. It is likely that the single-stage precipitation stripping results in a marked decline in the consumed amounts of precipitating and neutralizing agents, thereby saving on both running and capital costs.Yoon and Doyle1) first demonstrated that oxalate powders of lanthanum and yttrium are directly precipitated from rare-earth loaded carboxylic acid solvent extractant when contacted with aqueous oxalic acid solution at ambient temperature and atmospheric pressure. Yttrium oxalate pow4ers were also prepared by precipitation stripping of di-(2 ethylhexyl) phosphoric acid. (D2EHPA) extractant using oxalic acid-hydrochloric acid solutions. 2) Moreover, neodymium oxalates were directly precipitated from organic solutions of tertiary aliphatic monocarboxylic acid and 2-ethylhexyl phosphonic acid mono-2- ethylhexyl ester using aqueous oxalic acid solutions, and powder characteristics of the resulting oxalates were compared with those of powders by the conventional solvent extraction routes. 3 • 4) Recently, attention has been directed towards the influence of processing parameters on the particle size distributions of yttrium oxalate precipitates. 5)"

Jan 1, 2000

By W. K. Collins

Engineered Scavenger Compounds (ESCs), developed by the U.S. Bureau of Mines, are a novel class of compounds that can selectively recover a desired element from a solid or molten alloy. Lithium titanate (Li2Ti3O7 or L'20-3T'02) is being used as an ESC to recover lithium (Li) from Aluminum-Lithium (Al-Li) alloys. X-ray diffraction measurements have shown that lithium titanate undergoes a phase change from an orthorhombic structure to a hexagonal structure. This change is due to the incorporation of Li in the matrix of the material and the effect of temperature. Although both are metastable, the hexagonal phase that forms during the scavenging of Li from Al-Li alloys appears to be the more stable phase. Recovering Li from the ESC by electrodeposition does not cause the structure to revert to the orthorhombic phase. Both the orthorhombic and the hexagonal structures of Li2Ti3O7 have similar scavenging capacities for Li. This paper proposes a new mechanism for the phase transformation.

Jan 1, 1993

By Milton Manrique, Edgar E. Vidal, Patrick R. Taylor

"Ultrafine zirconium carbide powder has been synthesized using zircon concentrate and methane in a thermal plasma reactor. The effect of several experimental variables, such as power used and zircon particle size, on the conversion has been studied. A thermodynamic analysis of the possible reactions and stable compounds was performed. A mathematical model that describes the in-flight decomposition of zircon particles was developed based on a description of the temperature and velocity profiles calculated in the reactor. It was shown that the formation of zirconium carbide from zircon and methane is thermodynamically possible. Complete 'vaporization of zircon in the reactor is predicted when the particle size is below 45flm and the effective power entering the reactor is 15 kW. The powders were collected and characterized by XRD, SEM, TEM and chemical analysis using ICP. Results of the product analysis indicated the presence of zirconium carbide, zirconium oxide, silicon carbide and silicon oxide.IntroductionIn recent years there has been an increased interest in the production of nanometric sized powders of ceramic materials for use in advanced materials applications. One possible method to produce these powders is with a thermal plasma reactor, which offers high temperatures and fast quenching rates. This technology has been called - Thermal Plasma Synthesis - [1].Zirconium Carbide (ZrCx) has typical properties of transition metal carbides: elevated hardness - between alumina and diamond - a high melting temperature of 3420°C and high chemical stability at room temperature [2]. ZrCx has a Bl crystal structure with deficiencies in the number of carbon atoms in the cell with x between 0.6 and 1 [3]. Different methods have been used to produce ZrC, one method is by direct reaction of zirconium hydride or halide with carbon. Other methods used are direct reduction and carburization of zirconium oxide (Zr02) and reaction of metallic zirconium with a caburizing gas such as acetylene [3]. Recently small films of ZrC have been obtained using a sputtering device [4,5]. ZrC has been used in nuclear plants as a low neutron absorbing and high mechanical resistant refractory material and also as a constituent in cathodes made of UC-ZrC [6]. It is also used in the form of tubes, boats and crucibles to handle molten metals and as part of electronic devices used for thermoionic transducers. Recently ZrC has been used along with zirconium diboride (ZrB2) to produce composite materials [7,8]."

Jan 1, 1996

By Gordon Lewis

A complex mixture of hydrated reaction products is obtained from hydrothermally treated refractory cements and castable concretes. TGA can be used both to identify the product phases in the mixture and to determine a quantitative relationship among the phases. When reacted mixtures contain compounds that decompose simultaneously, or nearly so, additional assumptions must be introduced in order to develop a quantitative phase analysis. It is the purpose of this paper to examine some of these assumptions and to demonstrate their application, particularly to refractory cement systems.

Jan 1, 1982