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By Hong N. Vu, Jitka Jandova

"Gypsum and limestone methods were examined in this study to process zinnwaldite wastes originating from dressing Sn-W ores mined in the Czech Republic. These wastes containing 0.20-0.30% Li and 0.10-0.20% Rb were subjected to magnetic separation to obtain a zinnwaldite concentrate with 1.36% Li and 0.94% Rb. It was observed that processing of the zinnwaldite concentrate with gypsum resulted in almost 96% recovery of Li into aqueous liquors, whilst rubidium extraction was only 25%. At the same time, it is possible to extract almost 92% Li and Rb from the identical zinnwaldite concentrate if the concentrate is processed by limestone method. Lithium carbonate, a final product of both methods was recovered from the refined sulphate solution using K2CO3 as a precipitation agent and/or from unrefined hydroxide solution using gaseous CO2. In the continuation of this study, rubidium will be separated from carbonate solutions after Li2CO3 precipitation as RbAl(SO4)2, an intermediate for Rb2CO3 production. IntroductionLithium is used as an alloying constituent in lightweight alloys, as a heat transfer medium in nuclear reactors and as a component in primary and secondary batteries. With the development of a new generation of electric vehicles, the lithium demand will dramatically grow. Lithium chemicals find extensive application in many industrial branches such as metallurgical, glass, ceramic and pharmaceutical industries. Rubidium compounds are predominantly used in psychiatry and medicine, in magneto-optic modulators, solid-state lasers, phosphors and components of electrolytes for fuel cells. The four most important lithium minerals are amblygonite, spodumene, petalite, and lepidolite. Spodumene LiAlSi2O6 (6.0-7.5% Li2O) and petalite LiAlSi4O10 (3.5-4.5% Li2O) belong to aluminosilcate minerals. Lepidolite (Li.Al)3(Al.Si)4O10(F.OH)2 (3.30-7.74% Li2O), lithium mica, is the most important representative of the mica minerals, a subgroup of the aluminosilicates. It frequently contains 3–5% Rb2O and eventually caesium. Zinnwaldite, which has the general formula K(Li.Al.Fe)3(Al.Si)4O10(F.OH)2 (2-5% Li2O), is regarded as a variety of lepidolite with a high iron content. Commercial amblygonite is a complex phosphate (Li.Na)Al(F.OH)PO4 (up to 9.88% Li2O), however, its deposits have not been commercially exploited because of their small size. Natural brines with a high lithium chloride content are important in the industrial production of lithium [l]"

Jan 1, 2008

By H. U. R. Kattentidt, W. L. Dalmijn, T. P. R. de Jong

Sensor controlled sorting is a promising technique for the upgrading of scrap aluminium alloys. In a universal detection system of Delft University characteristic features are extracted · from the material particles by means of cameras. Examples are size, texture, edge-structure, homogeneity, and colour pattern. Additional sensors are added for higher selectivity: electromagnetic detection, light transmission, spectral reflection and more. Signal processing theory learns that a classification of particles fundamentally improves as the number of independent features increases. At the laboratories of the Delft University a test bench is available for the development of advanced multi-sensor quality control and sorting systems. It is based on a software system for detection, segmentation and classification of particles, which was especially developed for this application. Work is now in progress for high-speed detection and sorting of non-ferrous alloys, including aluminium casting and wrought alloys. A recently developed actuator design enables positive sorting into more than 3 fractions of particles that are randomly orientated on a flat conveyor belt.

Jan 1, 2000

By P. W. Godbehere

Over the past three years the Horne Smelter has successfully introduced concentrate smelting by injection in Peirce-Smith converters, allowing definitive closure of its last operating reverberatory furnace, while commissioning a large acid plant treating off gases from its Noranda reactor. Future strategies include a major revision to present converter practices to permit further significant reductions in sulphur and dust emissions. This paper gives an overview of the status of these and other technical and operating developments which will further contribute to ensuring the Horne's position as an efficient custom smelter of primary and secondary feeds.

Jan 1, 1993

By D. Maurice, W. D. Riley, J. A. Hawk

"The increased penetration of wrought aluminum into the automotive market is stimulating a need to separate wrought aluminum from cast aluminum because of: a) the additional value of scrap wrought alloys and b) the increase in the total amount of aluminum automotive scrap will outstrip the demands of secondary aluminum foundry industry. The availability of clean fractions of wrought and cast aluminum and incidentally, a clean cast magnesium fraction will allow increased recycling of aluminum used in the automotive industry.Hot crushing has been tested previously and proposed as a means to separate cast from wrought alunrinum product. The underlying concept is that when a mixture of cast and wrought aluminum is thermally processed and then subjected to crushing action, differences in toughness between wrought and cast aluminum alloys will become more pronounced. Hence, it should be possible for conditions can be established such that the cast material fragments, while the wrought material, having lost much less of its toughness, merely deforms. The two types of product could then be separated by simple sizing methods.In this paper we report on the testing of this concept. We were unable to replicate the results which originally demonstrated proof of concept. Possible reasons for this are discussed, as well as the possibility that the original results may not be as desirable as the current results for subsequent sorting."

Jan 1, 2000

By H. Kurama

In this paper, utilization of fly ash as a value added product in areas such as novel materials, waste management, fillers and agriculture is reviewed with the aim of helping the expand of the usage of fly ash and reduce the environmental and economic impacts of disposal. The used unburned carbon benefication/treatment methods such as low temperature combustion, froth flotation, partical size classification and electrostatic separations to remove unburned carbon particles from fly ash are also discussed.

Jan 1, 2006

By Qian Fu

Although chlorine fluxing to remove magnesium has been widely practiced in the aluminum industry for many years, there appear to have been few fundamental studies of the kinetics and transport phenomena involved. The paper describes such a study in which the rates of reaction of individual argon/chlorine bubbles with aluminum/magnesium melts were measured. The detachment of bubbles from a submerged nozzle, at variable depth in the melt, was detected by a microphone and the arrival of the bubble at the top surface by conductivity probes. Analysis of exit gases and mass balances yielded the overall progress of reaction. Experimental results are interpreted in terms of heterogeneous reaction kinetics and mass transport to the bubble-melt interface,

Jan 1, 1996

By J. W. Perez

In the treatment of process effluents containing metal ions, it is sometimes desired to remove all of the heave metal ions while at other time it is, desired to remove one heavy metal ion from another, selectively. Ion and precipitate flotation processes were evaluated to perform these functions using the copper-iron aqueous system as a model. Because preliminary foam fractionation experiments proved to be relatively inefficient, most of this work has focused on precipitate flotation using both hydroxide and sulfide precipitation. Test results indicate that by proper control of reagents and operating conditions, it is possible to substantially reduce the froth volume over that achieved with foam fractionation and to separate copper from iron selectively. Mechanisms for collector attachment to precipitates were studied.

Jan 1, 1992

By Tom McCullough

The purpose of this paper is to discuss the implementation and results derived from installing oxy-fuel burners in a l80 ton copper reverbatory melting furnace. Specific results will be discussed in the areas of melt chemistry, furnace modifications, productivity, process enhancements, and the combustion system capabilities.

Jan 1, 1996

By Sesha S. Srinivasan

Mechanochemical synthesis has been employed to prepare new light weight complex borohydrides, Zn(BH4)2. The thermal calorimetric and gravimetric analysis of these complex borohydrides shows the hydrogen decomposition temperature (Tdec) of about 100° C with theoretical capacity of ~8.0 wt%. This advanced materials based technology is considered to be suitable for attaining the US-DOE grand challenge technical targets. The powder x-ray diffraction analysis of the mechanically milled Zn(BH4)2 exhibits the presence of zinc borate and NaCl phase. The FTIR spectra of BH4-ion in NaBH4 has a characteristic band at 2290 cm-1,whereas in Zn(BH4)2, it occurs at ~2061 cm-1 (bridging B-H bonds) and ~2451 cm-1 (terminal B-H bonds) as well. The reversibility of hydrogen decomposition and recombination process is carried out by PCT measurements with multi-cycling procedure.

Jan 1, 2006

By Núbia Suely Silva Santos, Alexandre da Silva Crespo, Frederico Muylaert Margem, Sergio Neves Monteiro, Anderson de Paula Barbosa, Michel Picanço Oliveira

"Environmental considerations in addition to technical, economical and societal benefits are increasingly promoting the substitution of natural fibers for glass fiber in polymer matrix composites. However, natural fibers are heterogeneous in their dimensions, specially the cross section, which plays an important role in their mechanical strength. The fibers extracted from the petiole of the buriti palm tree is a relatively unknown but promising natural fiber for composite reinforcement. In this work, a statistical analysis of the density of buriti petiole fibers using the Weibull methodology was performed. An attempt to correlate the fiber density with the diameter, precisely measured by means of a profile projector, was carried out. The results revealed an inverse dependence between the buriti petiole fiber diameter and corresponding density. Fracture tip observation by SEM suggested a possible mechanism that could justify this inverse correlation.INTRODUTIONIn the past decade polymer composites reinforced with natural fibers obtained from cellulose-based plants, known as lignocellulosic fibers, have been applied in several engineering sectors, specially the automobile industry as both interior and outside component [1-4].Environmental benefits as well as economical, social, and technical advantages are actually promoting the substitution of these lignocellulosic for the traditional glass fiber in polymer matrix composites [5]. Today several lignocellulosic fiber are being extensively investigated [6-11] and considered for reinforcement of polymer composites. Some relatively unknown lignocellulosic fiber with reinforcement potential, however, still need to be characterized aiming at future application in composites. This is the case of the fibers stripped of from the petiole of the buriti palm tree, which is endemic in the central and northern regions of South America [12,13]. Preliminary works on the possibility of using the buriti petiole fibers as composite reinforcement, has shown favorable results [14,15]."

Jan 1, 2012

By Robert De Saro, Willis Bateman, Ramesh Jain

A Vertical Floatation Melter (VFM) has been developed (sponsored by DOE) which simultaneously decoats and melts organic laden scrap in a single unit. Scrap aluminum is fed into the top of the VFM where it falls through a cone. Hot gases flow upwards through the cone, imposing a variable drag force on the scrap. Equilibrium is reached in which the scrap weight equals the drag force and the scrap becomes suspended. The gases strip off and vaporize the organics. Next, the scrap reaches a liquid state, taking on a more aerodynamic teardrop shape, allowing it to fall into a holding furnace. Heat transfer coefficients are 10 times higher than that of a conventional furnace, allowing rapid melting at a low gas temperature. Typical energy use is well under 2,324 joules/g (1,000 Btu/lbm) with a metal yield from 92 to 98%. This paper reports on the operation and data of a 453 kg/hr (1,000 pph) pilot-scale VFM.

Jan 1, 2000

By Guo Xueyi

The nonferrous metal industry is facing the resource depletion, energy crisis and environmental deterioration. The resource recycling is a correct way to promote the nonferrous metal industry development towards sustainable. To realize the resource recycling, the technical support is most important. In this paper, the techniques barrier for nonferrous metal resource recycling are summarized, the fundamental on resource recycling of nonferrous metals are proposed.

Jan 1, 2006

By Ivan Van Herpe

"ABSTRACT NOT AVAILABLEPresentation"

Jan 1, 2000

By Rauno Peippo

Horizontal Waste Heat Boiler (WHB), today's proven and dominating technology for copper smelter gas cooling, has been utilized by the industry for over half a century. During this time development has taken place in geometry, flow characteristics, cleaning technology and design details. This development has been driven by improved understanding of the specific process requirements, gained both by wide experience and by utilizing new emerging design tools, like computer flow modeling. It had to wait till mid 90's to unite effective and proven Spring Hammer cleaning technology and the process benefits gained by gas guiding vanes or baffle wall in the copper smelter WHB design. The new design has demonstrated improvement in gas cooling efficiency and the process conditions down stream in form of less dust sticking problems in the boiler and precipitators. Reduced weak acid production has also been reported as a result of the design. The theoretical aspects, computer flow modeling results and actual benefits measured in old smelting line modernization are discussed. Experience £tom modernization projects such as Phelps Dodge, Atlantic Copper, Mexicana de Cobre, and Nippon Mining, Saganoseki, are discussed. In mechanical design there has been development resulting improved gas tightness with less corrosion and better control of dust sulfation. An essential improvement is the integration of the boiler hopper and dust removing conveyor. Having no steel plate casings in the hopper and conveyor section but using of boiler tube membrane instead eliminates thermal expansion differences. The dust conveyor will be effectively cooled against hot dust lumps falling down while the acid dew point corrosion is prevented in the cooler sections of the hopper. Conceptual features are presented of a new generation Copper Flash Smelter WHB presently under construction at Boliden Mineral, Skelleftehamn, Sweden, where the latest development and innovations are adopted.

Jan 1, 1999

By J. V. Happ

The investigation reported in this paper was prompted by the belief that vacuum processing of copper mattes could provide significant advancement to present-day copper smelting and converting technology. Specifically, vacuum distillation of copper mattes in a unit such as the R.H. vessel used in vacuum degassing of steel, can lead to improvements in: converter flue-gas-cleaning system, purity of acid (or liquid SO2), aisle hygiene, purity of electrorefined copper and smelter flexibility. In the study conducted, removal of Volatile impurities (arsenic, antimony, bismuth, lead and zinc) from liquid mattes, by vacuum distillation in a laboratory-scale equipment was performed. The conditions investigated covered a temperature range of 1123-1223K, absolute pressure of 6.5-0.5kPa (50 - 3 mm Hg) and with bleed gas consisting either of pure oxygen or argon. Six matte samples (four U.S. and two foreign) were tested. Under the "best" conditions arsenic and antimony were reduced to << 0.01% in the product matte. The removal of bismuth, lead and zinc was variable and appeared to be influenced by the matte composition of the sample. As might be expected, the rates of distillation of the various species were increased at higher temperatures and lower absolute pressures. The influence of a small flow rate of gas (02 or Ar) over the melt did not have a signifi¬cant influence on the extent of impurity removal. The magnetite content of the matte was reduced by up to 30% during vacuum treatment and was favored by a low partial pressure of oxygen over the melt. Substantial amounts of sulfur were also evaporated and an, overall increase in copper grade of the matte was realized. The paper concludes with an evaluation of industrial aspects of the process as applied to conventional smelters.

Jan 1, 1983

By Yeliz Demiraya, Onuralp Yucelb

"Production of strontium metal from its oxide was studied under the pressure of 1-5 mbar by methalothermic process. SrO with 99 % purity was used in the experiments. Effects of Al powder addition (100, 200, 300 % of stoichiometric ratio) and time were investigated on recovering of metallic strontium. Effects of BaO addition (100 %, 200 %, 300 %) was also investigated. The final residues were examined for their chemical composition. XRD, AAS and Flame Photometer were used for chemical analysis. More than 96 % of strontium metal recovery can be obtained.IntroductionStrontium is an element which is used in many advanced technology applications. Barium strontium titanat, strontium bismuth titanat, and strontium bismuth tantalat thin films are promising materials in ferroelectric and Schottky-based microelectronics technologies, especially for memory applications. Physical vapor deposition (PVD) techniques as magnetron sputtering, thermal evaporation and molecular beam epitaxy (MBE) are the most widely used methods for growth of these thin films [1-3]. In these techniques high-purity of Sr metal is used as evaporation sources and sputtering targets. Furthermore, metallic strontium is used as a ""getter"" in electron tubes, and as an alloying elements in aluminum alloys [4].The most used Sr compound is SrCO3 and widespread process used in production of SrCO3 is the hydrometallurgical carbonation of celestite. Although there are considerable amount of Selestite reserves, SrCO3 and strontinum metal are not being produced in Turkey, yet [5].Concentrated celestite (SrSO4) is conversed to SrCO3 in carbonate media. Black ash and direct conversion processes are currently used methods. There are many satisfactory studies about hydrometallurgical carbonation of celestite and decomposition of SrCO3 [6, 7]. Since strontium metal is produced from it’s oxide (SrO), SrCO3 needs to be decomposed to SrO."

Jan 1, 2011

By Jose Castro

The growing demand of scrap to supply the electric arc furnace has driven to search for new alternatives of raw material. The DRI produced using self-reducing pellets has become competitive due to the potential use of a wide range of carbonaceous materials such as coal, charcoal, biomass etc. In this context, the rotary kiln process using improved technologies such as post-combustion and self-reducing burden is a promising source of high quality raw materials. This paper presents a mathematical model of the rotary kiln process designed for self-reducing pellets and post-combustion. The model is based on the transport equation of two-phase flow, energy and mass transfer. The solid material is composed of a typical self-reducing pellet. The model considers the solid phase (C, volatiles, Fe2O3, Fe3O4, FeO, Fe, H2O, SiO2, Al2O3, MgO, P2O5, K2O, Na2O, FeS, CaO and gangue) and the gas phase (N2, O2, CO, CO2, H2, H2O, SO, SO2 and SiO). For each of the above components a conservation equation is solved and the mass and energy transport is accounted. The set of differential equations are coupled by the rate equations describing the kinetics of the several reactions, which take place within the rotary kiln. All the conservation equations are solved based on the finite volume method applied for a three-dimensional cylindrical coordinate system. Simulation results are presented for global parameters such as metallization degree, productivity, gas utilization ratio and calorific value. Inner conditions such as three-dimensional gas and solid temperature patter and compositions are discussed.

Jan 1, 2006

By Kunio Nakahara, Kashiwagim Junichi, Takao Hayashi

"There are many problems for electronic devices and parts which were caused electrostatic damage by static electricity. It is necessary for prevention of electrostatic charge to decrease surface resistivity of material using electroconductive coating. Mitsui Mining & Smelting Co., Ltd. developed metal oxide type electroconductive pigment PASSTRAN (trade mark) Type-IV which is barium sulfate coated with SnOz(Sb) thin electroconductive layer. This paper shows about pigment characteristics and film condition of antistatic transparency paint which contained PASS TRAN.L.IntroductionRecently rapid development of electronics technology diffused electronic devices and products to Office, Factory, Laboratory and our life. But the other side, there are many problems for electronics parts which were caused electrostatic damage under static electricity. Demand of antistatic materials were become lager by this situation.There is close relationship between surface resistivity of material and static electricity. If the surface resistivity of object is enough low (under 109 Q /Sq), static electricity is dissipated quickly. So it is necessary for prevention of electrostatic charge to decrease surface resistivity of material using electroconductive coating.1) There are many type of electroconductive materials, for example, carbon black, metal powder, electroconductive polymer and so on. Especially, carbon black is used for general purpose by reason of its low cost, but it has big problem of black color. It can not get any color without black, and it caused contamination of carbon.In recent years, metal oxide electroconductive pigment (ECP) was developed and used for special purpose which demands transparent coating or easy dispersion to make ECP paint or endurance under hard environment and so on. Mitsui Mining & Smelting Co., Ltd. developed electroconductive pigment PASSTRAN Type-IV which is BaS04 coated with electro-conductive Tin oxide layer."

Jan 1, 1998

By Eiichi Kuzuno, Atsushi Shibayama, Toyohisa Fujita, Kazuo Koike, Toshio Miyazaki, Hitoshi Masuda

"A solid sulfur is more useful to recover and store than a sulfuric acid as a by-product in the zinc hydrometallurgy. In this experiment a zin concentrate (sphalerite) was leached with ferric sulfate at about 373 K for 3 to 6 hours. Zinc was leached more than 95%. After a solid-liquid separation, the leached residue contained solid sulfur was obtained. The particles in the residue were dispersed by lignin and the solid sulfur of approximately 85% was recovered as float product by a flotation with frother in the pH 4. The dried float product was heated at 413K for 2 hours. The pure solid sulfur was recovered. On the other hand in the leached liquid a zinc oxide was ·added and ferrous .iron was oxidized to ferric iron by blowing oxygen. This ferric iron was returned to the zinc leached process after solid-liquid separation.IntroductionZinc concentrate is usually roasted as pretreatment in zinc hydrometallurgy and the produced S02 is changed to sulfuric acid. However, recently in Japan the utilization of sulfuric acid has been limited and it is more costly to store. Instead of producing sulfutic acid the solid sulfur recovery has been examined by direct leaching of zinc_ concentrate in this experiment.In the direct leaching, several kinds of effects have been studied for leaching of sphalerite in ferric sulfate solution. The addition of lignine siilfonate1 • 2) and fine· grinding3) increases the · speed arid leaching fraction of sphalerite. The leaching ratio depends on impurities in sphalerite ores4 • 5). Here, the zinc concentrate is leached ferric sulfate solution under atmospheric pressure at 373K. The solid sulfur in leached residue is separated as float products from other solids by sink-float separation and flotation. The sulfur in float products is purified by evaporation at 413K and recovered."

Jan 1, 2000

By S. Saptharishi

Selenium, which is a 6A group element of the periodic table, constitutes about 7x10-5 % of the earth?s crust. Even though selenium is a dispersed element with respect to its commercial exploitation, it is capable of forming number of minerals and nearly forty selenium minerals have been identified, out of which the copper ores are the richest sources of selenium. Electronics industries and glass industries are the major consumers of selenium, while pharma grade selenium used as micronutrient for humans and animals. Various methods have been developed to recover selenium as a by-product from copper anode slime during copper refining. Selenium being amphoteric in nature, it is soluble in both acid and alkali. While acid roast process is widely used, considerable work has been carried out in Russia for recovering selenium through alkali route. This paper enlightens the process developed at Central Research and Development Laboratory, for recovering selenium from decopperised slime through alkali pressure leaching. The decopperised slime is pressure leached with alkali under oxidizing conditions by which almost all the selenium present is converted to alkali selenate, which is easily separable from the rest of the decopperised slime. The solution so obtained is neutralized, during which, most of the impurities are precipitated out. Then selenium is precipitated in its elemental form upon purging sulphur-di-oxide under warm acidic medium. The purity of the selenium obtained by this process is higher than that of the selenium from acid roast process. Moreover selenium can be crystallized as sodium selenate and it can be marketed. The acidic content of the effluent is recovered and it is recycled back to the process. The sodium content of the effluent is converted into high purity sodium sulphate, which is marketable. The hazardous waste containing arsenic is precipitated as its sulphide and can be disposed off as landfill.

Jan 1, 2006