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By Igor Zh. Bunim, Valentine A. Chanturiya, Alexey T. Kovalev, Irina A. Khabarova, Elizaveta V. Koporulina

This paper presents new theoretical and experimental data on possible mechanisms for the formation of micro- and nanophases on the surface of sulfide minerals un der the effect of high-power nanosecond electromagnetic pulses (HPEMP). The gas outflow from nanosecond breakdown channels of sulfide minerals under the effect of HPEMP is considered, with allowance for the condensation of iron vapors. The condensation of matter in an outflowing jet is shown to be an effective mechanism for structureal and chemical transformations of sulfide surfaces. It is established that electrode potential of pyrrhotite is moved together in the negative party owing to formation of iron oxides (hydroxides) and iron sulfates by HPEMP, that provides decrease of xanthate sorption and reduction flotation extraction of this sulfide, whereas electrode potential of pentlandite gets more positive values at the expense of additional formation of element sulfur, that causes increase of xanthate sorption and, as a consequence, increase of nickel sulfide extraction.

Jan 1, 2012

By R. W. Lee

The first prototype plant using the Imperial Smelting Process commenced operation in 1950. It is timely therefore to review the developments that have occurred with the process over the past half-century. A major advantage claimed initially for the process was its ability simultaneously to recover zinc and lead from bulk concentrates. This has remained a fundamental advantage, but it has been extended by the increasing treatment of secondary materials containing zinc and lead. This has been facilitated by the development of hot briquetting and tuyere injection. These techniques and their impact on the technology of the operation will be described. The other major advantage claimed for the process was its potential to achieve new levels of productivity in the pyrometallurgical smelting of zinc. This has been realised with operating furnaces producing up to 400 t/d of zinc. The technical developments that have enabled this scale of operation will be reviewed.

Jan 1, 2000

By J. Riccardi

Copper refineries use massive copper castings as moulds into which impure molten copper from the reverberatory furnace is poured to form anodes for further electrolytic refining. To facilitate removal of the copper anodes from the mould and to prolong the life of the mould itself, it is traditional to spray the mould surface prior to each use with a slurry of baryte in water. This slurry application leads to poor housekeeping, operating costs are escalated by the cost of the slurry, and additional problems in the subsequent refining process are experienced due to carry-over of excess undesirable baryte powder. A one-time application of a diffused layer of aluminum to the surface of the copper mould prior to putting the mould into service has been found to provide extended mould life and facilitate anode removal, as well as reducing baryte consumption; thereby reducing operating costs at both the anode manufacturing and refining stages.

Jan 1, 1999

By Patricio F. Mendez

This paper presents a formalism to automate portions of the traditional scaling procedure. This formalism, called here Order of Magnitude Scaling (OMS), captures essential components of the governing equations into a set of matrices and arrays amenable to computer implementation using standard linear algebra tools. This approach is valid and specially useful for large systems of multicoupled equations. The matrix approach proposed enables one to automate operations such as normalization, dominant balance, obtention of characteristic values, and check for self-consistency. Also, automation permits an exhaustive exploration of all possible balances and the discovery of unsuspected scaling laws. As an example, OMS is applied to the analysis of the viscous boundary layer with no external pressure gradient. The obtained scaling laws for boundary layer thickness and transverse velocity are the same as those obtained with traditional scaling, and in addition, a meaningful estimation for pressure variations within the boundary layer is obtained; this last estimation is typically not addressed in the manual analysis.

Jan 1, 2006

By Kaspar Tall, Dmitri Goljandin, Kristiina Vilsaar, Jaan Kers, Valdek Mikli, Lifeng Zhang, Riho Tarbe, Viktor Laurmaa, Mart Saarna, Priidu Peetsalu

In this paper, the mechanical milling of the Printed Circuit Boards (PCB) was carried out. First goal of the work was to examine the management of the WEEE, in particular the re-use of PCB. Firstly, recycling methods of PCBs were summarized. During the study mechanical separation methods (magnetic-, density- and air separaten), electrical, and chemical methods were examined. Secondly the optimal particle size for air-classification was determined. Several tests were carried out to find the most effective separation method for separation of different material groups from PCB scrap. The new air classification stand was developed for testing the separation of lightweight particles like tinfoil stripes and plastics. The test results showed sufficiently good separation of heavier Al and Cu. For milled materials characterization the SA, IA, laser diffraction analysis and SEM were used. The chemical composition of the PCB powders was studied by means of energy dispersive X-ray microanalysis (EDS).

Jan 1, 2011

By Jason Graetz

Aluminum hydride is a covalent, binary hydride that has been known for more than 60 years and is an attractive medium for on-board automotive hydrogen storage, since it contains 10.1 % by wt. hydrogen with a density of 1.48 g/ml. There are at least 7 non-solvated AlH3 phases, namely a, a', a, ?, d, e and ?. The properties of a-AlH3, obtained from the Dow Chemical Co. in 1980, have been previously reported. Here we present a description of the thermodynamic and kinetic properties of freshly prepared a, 0 and y phases of AlH3. In all cases the decomposition kinetics are appreciable below 100" C and all will meet the DOE 2010 gravimetric and volumetric vehicular system targets (6 wt% H2 and 0.045 kg/L). However, further research will be required to develop an efficient and economical process to regenerate AlH3 from the spent A1 powder.

Jan 1, 2006

By B. Rourke, O&apos

Copper Refineries Ltd. (CRL), Townsville is Australia's largest producer and exporter of refined copper cathode. This status has been maintained by the implementation of a significant capital works program that increased the production capacity to 270,000 t/y by June 1999. In 1979, CRL was the first in the world to commission the ISA Process Technology which has now been marketed to 47 licensees worldwide. The new tankhouse design has focused particular attention on customer requirements, operational improvements, materials handling and equipment modernisation. Equipment which has been upgraded includes cranes, anode preparation, cathode stripping and scrap washing machines along with the total replacement of the electrolyte and electrical reticulation systems. Side stream electrolyte filtration has been introduced. Improvements to electrode alignment afforded by the conversion to polymer concrete cells, precise electrode location, and the upgrade of the electrode handling machines will ensure that CRL. continues to be one of the world's major quality copper cathode producers.

Jan 1, 1999

By Ronald J. Roman

The shrinking core model for coarse particle leaching has been generally accepted as describing the leaching of a copper oxide or sulfide ore. However, when a mixed oxide/sulfide ore-is leached this model can not be used in its simple form because at least two and possibly three separate leaching processes are occurring simultaneously (dissolution of oxide copper minerals, secondary copper minerals and primarily copper minerals). It has been impossible to isolate their individual leaching curves from the recovery/time curve generated by the column leach test. This paper describes a tests program carried out at the Groupo Mexico, Mexicana de Cobre's La Caridad operation in which the individual recovery/time curves for the leaching of copper oxide mineral, secondary copper mineral and primary copper minerals were developed from standard column leach tests. Once the individual recovery/time curves were developed scale-up of the column leach test results to the commercial heap leaching operation is possible by using the shrinking core model.

Jan 1, 1999

By Roberto Parra

The selective reduction smelting of Cu2O in Cu2O-FeOx-SiO2 melts has been studied at laboratory level, using as a feed a dead roasted calcine from a copper concentrate. The purpose of the study was to evaluate the kinetic and mechanisms of the indirect reduction with CO and the direct reduction with graphite from 1260°C to 1350°C. The reduction rate by CO was found to be 10-2 to 10-1 mole Cu2O m-2s-1. The graphite reduction macrokinetics for FeO and. Fe2O3 containing melts, was found to be a first order reaction with respect to the Cu2O concentration, with a kinetic constant of 104 to 10-3 s-1. The reduction rate was not sensitive to temperature nor to stirring, in the range studied. The measured reduction rate is almost one order of magnitude larger than the observed rate for the direct reduction of FeO.

Jan 1, 1999

By J. F. Leroux

The Gaspé smelter at Murdochville, Quebec, Canada introduced concentrate injection into elongated Peirce-Smith converters sized 1.96m x 12.5m (13 ft. by 41 ft.) in 1996, and commissioned a large, converter-like bath smelting vessel in April 1998. The new vessel, which is sized 4.27m x 16.1 5m (14ft. by 53ft.) has several interesting features designed to effectively utilize bath smelting technology for the requirements of the Gaspé smelter. For example, the vessel can operate on concentrate injection at upwards of 60-80 tph rate on an instantaneous basis, can operate as a large Peirce-Smith converter, while it is also fitted with matte and slag tapholes much akin to Noranda Process reactor, and includes a novel cold charge addition system. The new technology will eventually allow the capacity of the plant to increase from about 300,000 tonnes of concentrate per year to over 350,000 tonnes of concentrate per year while improving sulfur capture.

Jan 1, 1999

By J. D. Sloop

This paper discusses the current state of EAF dust recycling at AmeriSteel's Dust Processing Division in Jackson, Tennessee. Included are a brief history of the plant, a description of the facility, a description of the process, and operating data.

Jan 1, 2000

By Roberto Javier Santiago

The main properties of Calcium Carbide seem to be the grain size and the CaC2 content. This paper tries to describe the Calcium Carbide used in the South-American steel plants and how and where it is added.

Jan 1, 2006

By Hidenori Okamoto, Katuto Itoh

"Nippon Mining & Metals' Hitachi Refinery refines 40% of the anodes produced at its Saganoseki Smelter & Refinery. Its current annual production stands at 180,000tons.The refinery always endeavors to increase productivity. One of the outcomes of its efforts is an originally developed automatic short-circuit detector used to inspect short-circuits between anode and cathode. The detector is designed to inspect the 56 pairs of anode and cathode in a cell by fluxgate sensors at once. It inspects 564 cells, automatically and un-manned, and gathers data to be put into a computer. The development of the detector led to a reduction of man-power and achieved a detection accuracy superior to that of a hand-held gauss-meter. In addition, statistical and historical processing of the data enabled early detection and early recovery of the cells with poor efficiency.The new system also contributed to raising the refining capacity and reducing the unit steam consumption, because it is possible to inspect even the cells covered with thermal insulation sheets.IntroductionInspection of cells is an important component of the operation management of a tank-house. At the Hitachi Plant, it used to be carried out by two workers who walked on and checked all the cells of its tank-house once a day to find out any short-circuits in the cells, using hand-held gauss-meters. They inspected about 33 thousand pairs of cathodes and anodes a day and removed nodules by hammers. This method had following problems:it needed much manpower.the walk on the cells sometimes deranged electrodes positions.there was radiation-loss connected with the inspection due tothe fact that the workers were obliged to uncover thermal insulation sheets on the cells while inspecting."

Jan 1, 2000

By Darryl Lovato, Ramiro Pereyra, Daniel S. Schwartz

"During an annual inventory of nuclear material, a plated steel container which contained plutonium oxide failed. The container had been packaged for temporary storage but had been overlooked and remained in storage for more than 23 years. Although it was determined that the failure occurred through the slip-top rim, a metallurgical evaluation was requested to help to determine the integrity of the container.Optical metallography and scanning electron microscopy were used to analyze the character and degree of corrosion in the container. The depth of corrosion, measured at approximately 10 µm, did not pose a threat to the integrity of the container. However, the corrosion morphology and chemistry did suggest that a galvanic cell had developed between the tin and steel from the condensation of water. The morphology also suggests that the attack of the steel took place over a series of cycles due to changes of the environment.IntroductionMetallographic analysis was requested as part of the investigation into the mechanism of the failure of a slip-top container (#38621) containing plutonium oxide (PuO2) powder. The container had leaked during a special nuclear material (SNM) annual inventory causing contamination and closure of the vault. A photograph of the container and interior container is shown on the right in Figure 1. An initial investigation established that the source of contamination was the consequence of the failure of multiple layers of containment. Initially by the deterioration of the interior plastic bottle and polyvinyl chloride (PVC) bagout bag, and finally through the lid and steel container interface at a location where tape had not adhered properly [1]. Although the source of the breach was established, it was determined that metallographic analysis was important to establish the extent of deterioration of the steel container."

Jan 1, 2008

By Alice Barreto Bevitori, Frederico Muylaert Margem, Noan Tonini SImonassi, Caroline Oliveyra, Sergio Neves Monteiro, Isabela Leão Amaral da Silva

"The mechanical behavior and the fracture characteristics of composites with DGEB/TETA epoxy matrix reinforced with up to 30% in volume of continuous and aligned ramie fibers were evaluated by tensile tests. Specimens with selected thin fibers aligned along the tensile axis were room temperature tested to rupture. The fracture surface was analyzed by scanning electron microscopy. The results showed significant increase in both the ultimate tensile strength and the elastic modulus. The fracture analysis indicated the possible mechanism for the fiber/matrix interaction, which could be responsible for the composite performance.IntroductionSince the middle of last century, polymer composites have substitute many conventional monolithic materials in applications ranging from aerospace to sport [l]. The main advantages of these composites are the low density and flexible properties specially using fiber as reinforcement to suit the mechanical performance requirements [2]. These are usually high strength and stiffuess requirements that could be reached with synthetic fibers such as gloss, carbon and aramid fibers. Its most commonly used example is ""fiberglass"", i.e., a thermoset polymer matrix composite reinforced with glass fiber. Indeed, ""fiberglass"" has a specific strength of the order of 500 MPa.cm3/g, which is the double of the strongest steels like the maraging. This motivated, at earlier times, ""fiberglass"" to replace many conventional materials including wood and natural fiber composites. Today, ""fiberglass"" has a wide range of uses from aerospace systems and appliances to sport and leisure components. However, its fabrication as well as those of any synthetic fiber such as carbon and aramid composites, requires a relatively large amount of energy. Presently, a growing concern exists regarding the consequences to the environmental by gases like C02 associated with both the energy consumption and the processing of synthetic fibers and their composites. These gases are well known responsible for global warming [3]."

Jan 1, 2013

By Shaohua Ju, Jin-hui Peng, Ya-jian Wang, Shuai-dan Lu, Li-bo Zhang, Lei Guo

"The granulation of a red mud is of great importance for recycling this material as an adsorbent for waste water or gas. A new granulating process was developed and its effect was evaluated. To reduce the cost of the granulation process, the wet filter cake (containing 25% water) was directly mixed with different cement contents (4%, 6%, 8% and 10% based on wet material). The mixtures were placed in a moist environment for 4 days, and then were washed with deionized water until the pH values of leachants were lower than 9.0. The efflorescence ratio, surface area and particle size of the aged mixture were determined, respectively, by bottle shaking experiments, N2 adsorption and screening. The results showed that the best addition of cement is 2%, and this yielded granulated material with a particle size of less than 2 mm, an efflorescence ratio of 4.83% and a specific surface area of 17.42 m2/g.IntroductionRed mud is a residue of the aluminium industry that is produced during the alkaline extraction of alumina from bauxite by the Bayer process. For every ton of alumina that is produced, the amount of red mud generated can vary from 0.3 to 2.5 tons, depending on the characteristics of the bauxite. In its typical form, red mud is brick red in colour, caustic, about three times as dense as water and, when un-neutralised, has a high pH, typically around pH 13 [1]. It is primarily composed of iron oxide, silica and alumina, along with traces of heavy metals. Red mud particles are quite small; typically 99% will pass through a 0.6 mm sieve and 87% through a 0.038 mm sieve [2],"

Jan 1, 2012

By Shigeo Asai

History of EPM is described and several functions utilized in EPM are reviewed. Main activities of EPM are summarized with the view on mass production and applications of high magnetic field related to nano-technology. Future trends and prospects of EPM are discussed.

Jan 1, 2006

By Hongmin Zhu, Suning Liu, Kai Huang

"Recovery of silicon particles from the cutting slurry for the manufacturing of solar grade silicon is very important to recycle this kind of special resource. The challenge is to separate the silicon particles from the mixed abrasive particles which contain SiC. Various methods such as sedimentation, centrifugation, and flotation have been conducted, while in present work, a simple and effective novel method was proposed to study the separation of Si and coexisting SiC particles in the cutting slurry. The new process is based on the size difference between the two kinds of microparticles. And the membranes with the different pore sizes of 1µm, 2µm, 3µm and 5µm were used to test the pass ratio and separation efficiency of the suspension. Results shows that the effective separation of Si and SiC microparticles was obtained under the optimal conditions, and indicating great potential of practical enrichment of Si from the coexisting abrasive particles.IntroductionWith the development of the world economy, energy shortage and environment problem is becoming more and more seriously. Solar energy, which is regarded as one of the most important new energy in the word, has received much attention and interest from the scientists [1, 2]. More than 80% solar cells are manufactured by the high purity polysilicon as the raw material. The main process of producing silicon wafer is by multi-wire slicing. In this slice processing, large amount of slurry is produced. The slurry contains more than 30% wt silicon powder, silicon carbide powder as the abrasive, scraps of metal chips, as well as cutting abrasive suspension polyethylene glycol (PEG). The high-purified silicon powders are worth recycling and reusing as the materials for preparing solar-grade silicon though it is a big challenge [3].Most of the current studies were focusing on the recycling of the silicon carbide and PEG, while work on the recycling of the high-purified silicon is not so been focused since there is lacking of very effective separation and recovery technologies till up now. Nishijima utilized the method of superconducting magnetic to recycle the abrasive [4]. Wang applied a combinational process of chemical treatment, high-gravity centrifugation, high-temperature precipitation technique and directional solidification to enrich the silicon [5]. And other purification methods, such as centrifugation [6], froth flotation technologies [7], electrical filed separation [8] and phase-transfer process [9] have been employed. The disadvantages such as using poisonous media or complex equipments decrease the feasibility and efficiency of the above mentioned techniques."

Jan 1, 2014

By Jian Li, S. Penttilä, P. Liu, W. Zheng, C. Bibby

"The materials selection for Gen IV supercritical water reactor in-core components faces major challenges due to severe operating condition. The current Canadian pressure-tube supercritical water (SCW) concept design requires core outlet temperature of 650 °C at 25 MPa with peak cladding temperature reaching as high as 850 °C. Aside from oilier challenges, there is currently very limited data on candidate stainless steels' corrosion resistance under this operating condition. Austenite stainless steels that include 316L, 304H, AL6XN and 3 l0S that cover a wide range of Cr contents are promising candidates for either direct in core applications or as base coating materials. However, their corrosion resistance has not been tested systematically under this stringent condition. In this study, these types of stainless steels are tested, and their corrosion resistances are compared.IntroductionThe Canadian pressure-tube supercritical water (SCW) concept will operate at a core outlet temperature of 650 °C at a pressure of 25 MPa, with potential peak cladding temperature reaching as high as 850 °C. High-temperature corrosion resistance is one of the key design requirements for fuel cladding components. As summarized by Allen [1 ], most testing to date has been carried out at temperatures below 730 °C. To date, SCW corrosion data above 600 °C is very limited. Even at relatively low temperature exposure to SCW (e.g. 500 °C), F/M steels develop a thick oxide layer rapidly, while some austenitic stainless steels develop thinner surface oxide. Ni based alloys appear to form very thin surface oxide, however pitting was observed in the vicinity of intermetallic precipitates [2-5]. Dissolution of major alloying components from all of these alloys could also pose significant problems for downstream piping [6]. Kaneda et al. [7] suggested some modified stainless steels provide better SCW general corrosion resistance, with no sign of SCC under the slow-strain rate test.Cho [8] suggested that as the Cr content increase, general corrosion resistance improved at 510 °C and 25 MPa. However, similar to Cho's work, most of the SCW corrosion resistance assessments were based on weight change measurement. This can be unreliable due to potential exfoliation of thick oxide film. Besides, there have been no systematic SCW corrosion resistance tests for candidate stainless steels under higher temperatures. SCW corrosion rate increase dramatically for alloys tested at 600 °C [1]. It is also important to understand the role of major alloying elements under this stringent operating condition, not only for fuel cladding components' materials selection, but also for coating materials development."

Jan 1, 2013

By Ovidiu Pasca

The Phelps Dodge Miami Smelter utilizes four Hoboken converters to process molten matte from the Isasmelt vessel. This paper presents past and present improvements in operation, maintenance and process optimization, based on data collection, which has led to increased converter campaign life and copper throughput.

Jan 1, 2005