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By Zenon R. Llanos

"The disposal of spent hydroprocessing (HDP) catalysts in the petroleum refining industry has been a concern in the past due to their classification as listed hazardous wastes. However, because these catalysts have higher metal concentrations than regular ores, and the recent surge in prices for molybdenum, vanadium, nickel and cobalt what used to be considered as a liability for generators is now viewed as a valuable renewable source of strategic metals. At the same time the generation of spent catalysts has steadily risen due to new environmental regulations for low sulfur fuels and an increased appetite of gasoline consumers. This paper will examine spent catalyst market and the role played by Gulf Chemical & Metallurgical Corporation in the reclamation of metals over the last sixty years. Introduction Hydroprocessing (HDP) catalysts are used in petroleum refineries for two main applications: desulfurization and cracking. The catalyst support is alumina or mixtures of alumina and silica. Active metals include molybdenum, nickel, cobalt and tungsten. The selection of catalysts depends on the application and sometimes the cost. The life cycle of HDP catalysts is represented in Figure 1. The catalyst cycle in a reactor varies from continuous to one-two years. Catalysts used in various refining processes are deactivated by coke, sulfur, vanadium and other impurities in the refinery feedstocks and become spent. Refineries can optionally send the spent catalysts for regeneration, metals reclamation or landfilling. Catalysts used for refining heavy crudes often can not be regenerated. Catalysts used with light oils can be reused twice or three times after regeneration. When the option for regeneration is not viable, spent catalysts are send metal reclamation facilities or landfills."

Jan 1, 2008

By B. G. Belew

Recent operating improvements at the Phelps Dodge Chino Smelter, coupled with intensive capital expenditures since 1987, have resulted in a safer, higher quality, more productive smelter. This paper briefly reviews the flowsheet of the Chino Smelter with emphasis on recent capital expenditures. The main focus of the paper is to provide case studies of how operating functions have been improved. Case studies presented include: (1) safety, (2) anode quality control, (3) flash furnace cross-over build-up control, and (4) flash furnace temperature control. Most of these accomplishments have been achieved by providing specific measurable goals and subsequent feedback to operating crews.

Jan 1, 1993

By F. Tanaka

In April 1999, a two-year campaign of the Mitsubishi furnaces was achieved at Naoshima Smelter; the present one is expected to be extended much longer. An overview of basic technology for decreasing refractory wear in the Mitsubishi Process is presented. One of the main features of the process is the use of top blowing lance technology which has a different effect on the furnace refractory than other conventional processes. The refractory wear of concern is hearth wear caused by top blown powder injection, wear of the side wall caused by splashing droplets, and wear of the bath level refractories caused by surface waves of melts in the furnace. These have been systematically investigated for many years. This paper describes the results of various model tests and their application to practical furnace design and operation.

Jan 1, 1999

By W. Persson

The first installation at a copper smelter of a Semtech OPC System for continuous, on-line production control of copper converting in PS converters took place in 1994. At present OPC systems are installed at 19 PS converters. The technology presents to the operator real-time information on the progress of the process he is controlling in the form of optical process parameters, thus facilitating dynamic process control. The optical process parameters are based on time- and wavelength resolved registrations of the light emitted by the off-gas flames and identification of correlation between these parameters and characteristic metallurgical process data. The present paper provides a description of the technology as seen by the furnace operators and a summary of operating experiences made during five years of full-scale, operation at various smelters, reviews influences from the technology on smelter operational practises and comments on recent developments as regards new applications of the technology.

Jan 1, 1999

By Kaixi Jiang, Lei Zhang, Sanping Liu, Yufang Wang, Xiaoping Zou

"Molybdenite concentrates are usually treated by roasting, but low concentration SO2 pollution is a problem. Extraction of molybdenum and rhenium from molybdenite concentrates with a pressure oxidative leaching (POX) and solvent extraction (SX) process was studied. A series of POX-SX laboratory and pilot tests were carried out on the molybdenite concentrate. In the POX stage, more than 95% rhenium and 15-20% molybdenum were leached into solution. Solvent extraction recovered the rhenium and molybdenum from the POX solution. The extraction rates of Re and Mo were above 98%. The loaded organic reagent is stripped with ammonia. The stripping ratio of Mo is more than 98%. Compared to the roasting process, the total recovery of Mo increased from 93% to 97%, and Re from 60% to 90%. In the coming five years, POX-SX technology will be competitive in China.IntroductionMolybdenite is the main resource for the production of molybdenum, and about 99% of the total molybdenum was extracted from molybdenite. Rhenium is one of the important new materials in national defense, space flights, nuclear energy and electronics, because of its high melting point, high strength, plastic properties and significant creep resistance. There are no single rhenium ores in the world; rhenium mainly co-exists with molybdenum. Consequently, molybdenite is also the main resource for the extraction of rhenium."

Jan 1, 2012

By Mingzhou Li, Lin Wu, Changren Tong, Fengli Yang, Shaohua Yang

"According to characteristics of Tm, Yb and Lu enriched oxides composition and problems in its traditional extraction separation process, the computer simulation of a optimized fuzzy extraction separation process, in which three products with high purity(>99.99%) could be obtained at same time, was carried out. Distributing Curves of every element in both organic and aqueous phases were worked out. Distribution rules of rare earth elements in every stage of the optimized extraction process were studied. The computation results of economical and technical index showed the consumption of the acid and base chemical reagents in the optimized process would be saved more than 30%.IntroductionFor the solvent extraction separation process of rare earths, countercurrent extraction process was widespread in the industrial practice. Normally, rare earth ions were extracted by the saponificated extractant and transferred into the organic phase, where the acidic extractant was saponificated by the base firstly. Then, the loaded rare earth ions were stripped from the organic phase into the aqueous phase by the acid. Therefore, the acid and the base were the main consumptions in the process, and the equilibrium acid of the stripped rare earth solution was one of the main pollution resources. Meanwhile, for the heavy rare earths, such as Tm, Yb and Lu, stripping was more difficult, and the equilibrium acidity of the stripped rare earth solution was higher, so the acid consumption increased greatly."

Jan 1, 2012

By Gordon Holcomb, George R. St. Pierre, Robert A. Rapp

Carbon/Carbon composites offer promise as high-temperature structural materials. A primary limitation on their application is the need to provide protection against oxidation in hot oxidizing environments. Silicon carbide conversion coatings have been shown to provide extended protection at temperatures of 1600°C. SiC coated C/C components have been used in several aerospace applications. In the present paper, the preparation of carbon fibers and their treatment during subsequent processing into coated components are discussed with particular emphasis on the processing variables that can result in improved oxidation resistance. In particular, the influence of substrate inhibitors and selective sealants for cracks in coated C/C components are analysed.

Jan 1, 1988

By Krishna Kumar

"Growth of electronics waste (e-waste) and lack of appropriate disposal mechanism are the great concern for developing countries like India. The domestic generation of e-waste in India is rapidly growing with the development. The imported substance is also substantially contributing to the e-waste inventory. Recycling of e-waste is mainly carried out in unorganized units in India. The primitive recycling technique used by the unorganized sector is a great threat to the environment and the health of the operators involved in these profession. Therefore, improvement of technology used by these units towards a cost effective, environmental friendly alternative could be the solution to the present crisis. Few initiatives of recycling have, however, come up in recent years in organized units. The precious metals are still recycled in the developed countries. This report discusses the inventory, technology status, legal legislative and existing practices of e-waste management in India.1. INTRODUCTIONInnovation, research and development in the field of electronics and information and communication technology (ICT) lead to convenient, independent human life. Consumption of electronics and hardware products has enhanced by manifold. Electronics and hardware sectors have, thus, become the fastest growing sector in the world. Faster obsolescence of these products is forcing users to replace products with an advanced technology. Life cycles of these products are few years. Discarded electronics products are, therefore, accumulating alarmingly in our society. Electronics waste (e-waste) is a crisis not only due to its volume but also for presence of its toxic ingredients, like heavy metals (e.g. lead, mercury, cadmium, hexavalent chromium) and flame retardants such as poly brominated biphenyles and poly brominated diphenyles ether. These substances create potential occupational and environmental health hazardous."

Jan 1, 2011

By Alim Ullah

Process, quality and management control are necessary in order to produce DRI of required quality and at minimum cost. Although the characteristics of the two (2) principal inputs, that is, iron oxide feed and natural gas (for gas-based DRI plants) can affect the operation of a DRI plant significantly, they are outside the control of plant operators, at least in the short run. The quantity of reduction gas, its composition and reduction gas temperature are some of the key process variables. Statistical Process Control (SPC) can be used in a DRI plant to minimize the production of off-grade material and costs, as well as to improve the overall operation of the plant. One of the key quality variables to be measured and controlled is percent metallization, defined as FeM/FeT*100 where, FeM and FeT respectively are metallic iron and total iron in DRI. Control charts are used to monitor the quality of DRI produced and, when necessary, corrective actions are taken to bring the product back within the control limits. Management control can consist of essentially following how well the plant performs against some pre-established standards of parameters like daily production, downtime, consumption of material and energy, etc. In this respect, it is suggested that yield, defined as theoretical consumption/actual consumption of iron oxide feed, be used to monitor the consumption of feed material. Similarly, instead of using natural gas per ton of DRI produced, a better criterion would be efficiency, defined as theoretical natural gas consumption/actual natural gas consumption.

Jan 1, 2006

By J. M. Brupbacher, D. C. Nagle

"The XD TM * approach to producing metal matrix composites employs an in-situ precipitation technique for the formation of the reinforcement directly in the matrix of interest. Key features include: thermodynamically stable reinforcement; clean particle/matrix interfaces, single-crystal reinforcement; size, chemistry, and shape control; uniform distribution; compatibility with conventional ingot techniques; and grain refinement.Using XD~ technology it is possible to simultaneously introduce a number of different reinforcements in a given matrix, thus allowing for designing the microstructure to meet a specific material need. Thus, XD1l'1 technology is a very useful technique for achieving ""designer"" or ""engineered"" microstructures. XD TM technology has been applied to a number of systems including AI, NiAI, TiAI and Cu. Materials property and processing benefits will be discussed."

Jan 1, 1988

By J. R. Wynnyckyj, R. Marr

Continuous measurement based on radiation pyrometry has often met with difficulties whose causes have been obscure. In this paper the experience gained with on-line pyrometry in utility and Kraft recovery boilers in the range 800-l400oC will be reported. It is shown that the inherent problems are best resolved by using a spectral pyrometer not sensitive to gas radiation. The radiation from the suspended particles thus provides the signal. It is further shown that the principle cause of difficulties is signal calibration drift caused by heat fluxes originating from surrounding surfaces and reflected by the particles to the pyrometer. Several examples are given how such problems may be resolved using process information and/or additional measurements, fed to and processed by and on-line microcomputer.

Jan 1, 1989

By P. J. Harrington

The recovery and recycling of low concentration metal and other ions has traditionally been carried out using adsorption or ion exchange processes which, however, become uneconomical at higher concentrations, such as those that occur with many intermediate or waste streams where recycling is now being required. This paper describes the development of a process based on non-dispersive solvent extraction for the recovery of chromium (VI) from electroplating rinse water. During the chromium plating of steel, the concentration of chromium (VI) in the rinse bath rises to concentrations in the order of 100 mg/L when it becomes unusable and is then disposed of. The aim of this work was to investigate processes for recovery and recycling of the chromium in the rinse bath. The recovered chromium is required to be concentrated and purified before reuse. Tertiary amines have been shown capable of concentrating and purifying the chromium (VI) in solution. However, solvent extraction processes that have been applied to the recovery and reuse of metals from waste streams have had only limited success in the past, primarily because of the relatively high solvent losses when existing contacting equipment is used on low feed concentrations. Attempts to eliminate losses by immobilizing these complexing agents on substrates have not been successful. In order to control the losses and maintain specificity, a hollow fibre-contained liquid membrane has recently been trailed in a pilot plant to recover chromium from chromium plating waste streams. Details of the trial and modeling of the results are presented, and show that the level of losses is significantly reduced. However, issues relating to fouling still need to be addressed. This type of equipment has many applications in the recovery and recycling of a range of materials in the manufacturing processes.

Jan 1, 2003

By Guozhu Ye, Eric’ Burstrom

"Despite of numerous solutions for recovery of zinc from EAF dust have been suggested and tested in laboratory scale over the last three decades, Waelz kiln process is still the most dominating process for treatment of EAF dust. Few of the proposed alternative methods have gone beyond the laboratory tests. This paper will give you insights to some of the concepts that have been pilot tested at MEFOS. The innovative aspects of these concepts will be shown and the major results will be highlighted. These include the following concepts: - Production of a crude zinc oxide product with low halide content for zinc electrowinning using a DC furnace with hollow electrode- Production of a bypass filter dust containing more than 50%ZnO by injection of EAF dust to the electric arc furnace during refining combined with a bypass filter system- Elimination of zinc ferrite by CaO treatment for electrowinning with EZINEX process - Selective reduction of iron oxide in zinc ferrite for simultaneous recovery of ZnO andmetallic ironIntroductionRecovery of zinc from EAF dust is dominated by the Waelz process since EAF dust has been classified as hazardous waste by EPA in the early 1980´s. A large number of alternative processes have been suggested and tested without commercial success due to two major reasons [1]:- High content of chlorine and fluorine for the pyrometallurgical alternatives- High content of ZnOFe2O3 for the hydrometallurgical processesMany innovative concepts for treatment of EAF dust for zinc recovery have been pilot tested at MEFOS in the past 20 years. This paper will review some of the concepts focusing on the two problems mentioned above."

Jan 1, 2008

By Tomoji Kawai

"The Pulsed Laser Deposition method using multi-targets is extremely useful for the creation of functional multi-layers and variety of artificial lattices. The topic of the present talk is on the creation of ''Function hannonized artificial lattices by laser ablation"" made of the combined magnetic, ferroelectiric and superconducting layers. The outline of talk is,1. Features of Pulsed Laser Deposition method (Laser Molecular RHEED and S1M/AFM.2. Creation of magnetic, dielectric and superconducting artificial lattices by Pulsed Laser Deposition.3. Novel properties of function harmonized artificial lattices: especially on the magnetic and magnetoresistive artificial The outline of talk is, lattices made of3d transition metal oxides."

Jan 1, 2000

By Susan A. Fredholm, Randolph E. Kirchain, Elsa A. Olivetti, Jeremy R. Gregory, Jeffrey B. Dahmus

"A general model for evaluating the economic and environmental performance of electronics recycling systems is developed. This model comprehends the three main functions in a recycling system – collection, processing, and system management – and aims to enable quantification of the impact of context and system architecture on the economic and environmental performance of electronics recycling systems. Such a model can be used both to evaluate and improve existing electronics recycling systems, as well as to design and implement new systems. A case study, based loosely on Maine, is presented to show the utility of such a model.IntroductionAs recycling systems for complex durable goods (CDGs), and in particular for waste electronics, become more widespread, understanding the economic and environmental performance of such systems becomes critical, both to enable improvement of existing systems and to inform the design of new systems. However, with the range of possible system architectures and the important role of locational characteristics (context), understanding the determinants of system performance is challenging [1]. To address this issue, a modeling framework to project the economic and environmental performance of CDG recycling systems, based on contextual and architectural characteristics, has been developed.The modeling framework presented here comprehends the three main functions – collection, processing, and system management – which are common to most recycling systems. These three functions are modeled using a variety of modeling techniques and serve as a bridge between inputs related to system context and system architecture, and outputs related to economic and environmental performance. The models developed here are intentionally meant to be both broad, in order to address entire recycling systems, and general, such that many different systems, both real and hypothetical, can be analyzed."

Jan 1, 2008

By Milance Mitovski, Milorad Cirkovic, Vlastimir Trujic, Dragana Živkovic

"In this article, it is analysed the possibilitis and the effects utility waste energy of process sulfuric acid production in the existing technical-technological conditions. The utility second process energy, reduction the fuels consumption, reduction environment pollution and its effects are shown, too. High heat quantity is produced as the result of exothermal reactions in the production process of sulfuric acid in Bor. A part of this heat is sufficient for the process development, and significant part of this heat presents low-temperature heat energy that is irretrievable lost. Investigations were carried out based on production of 485 t of monohydrate/day of sulfuric acid. By recovery of this heat quantity for heating purposes, about 20.000 – 25.000 t of coal/year would be saved, what would significantly improve the power efficiency of the smelter copper production. IntroductionTechnological process of copper production in RTB BOR (Serbia) produces a significant quantities of high temperature secondary (waste) heat energy that is uncontrolled “lost” in the vicinity. Secondary heat energy is produced in pyrometallurgical copper production in quantity of 1,621 kWth/kg of dry concentrate or existing heat (that presents a difference of heat at furnace outlet and heat at temperature over temperature of dew point of sulphuric acid gases) in quantity of 1,315 kWth/kg of dry concentrate. For designed capacity of Copper Smelter in Bor, the existing heat power of secondary energy is 92,111 MWt, what is an equivalent to the power of steam-turbo plant where the Rankine-Clausius heating cycle is done, and that is 28,334 MWe."

Jan 1, 2008

By Suk J. Im, I. S. Min, Daesoo Kim

UFP are defined by atoms or their clusters having diameter in the range of l0Å-0.l.um. Due to a ratio of very large surface area to volume, they have peculiar properties such as extra high surface energy. Recently UFP deposition technique may find its new applications to various areas such as conductive/resistive film formation. In this method, gas flow with UFP jet through the nozzle which is considered to be a free molecular flow is maintained at a very high speed (~100m/s). Using this technique, mixture film of Fe and Ni, and Ag/ Ag-Alloy etc. were obtained, and their mechanical and electro-magnetic properties were determined. The experimental results are pending. The test results and discussion will be presented in the main paper.

Jan 1, 1988

By Tracy Morris, Weldon Read, Luis Navarro

"Bismuth is a recognized contaminant in the electrolytic refining of copper that can render many cathodes to be outside ASTM standards and unsuitable for copper rod and other downstream products if not carefully controlled. This paper portrays the performance of Molecular Recognition Technology (MRT) for bismuth removal at the Amarillo Copper Refinery (ACR) and describes how the highly selectivity gel has been successfully used to achieve good bismuth removal and how many pit falls and draw backs have been overcome.IntroductionASARCO operates one of the largest copper refineries in the world at Amarillo, Texas. The main feed for this refinery is produced at the Hayden smelter in Arizona. During the operation of this smelter a variety of metals are carried as impurities in the copper anodes because of the diversity of concentrates and residue products used as raw materials in the smelter feed mix. Even though the impurities are concentrated enough to be detected at the smelter, it is difficult to remove them completely. A simple way to control impurities at the smelter is to minimize the addition of material with a high concentration of impurities to the charge in order to reduce the output of this metal species. All this leads us to have a ""refinery problem"" [1,2,3]."

Jan 1, 2012

By K. Kashiwaya, N. Hiroyoshi, H. Furuya, N. Sumiya, M. Tsunekawa, M. Ito

"The number of hybrid vehicles is increasing and this is causeing an increase in waste nickelmetal hydride batteries. The cathode activating agent of batteries is made of nickel hydroxide and the anode activating agent is an alloy of nickel and rare earth elements. Conventional rotary kiln methods cannot recover the rare earth elements, and hydrometallurgical treatment of crushed product consumes large volumes of agent. The physical separation of the anode alloy from the cathode hydroxide would make it possible to reuse the alloy. The authors have reported separation of anode and cathode components in the large size fractions using a newly developed dry magnetic separation method. Wet magnetic separation has been applied to the powder fraction and about 90% anode purity was achieved. This paper reviews experimental results from previous publications and proposes an integrated treatment process for crushed nickel-metal hydride batteries.IntroductionEnvironmentally-conscious clean energy vehicles have attracted much attention in developed countries and particularly hybrid vehicles are increasingly mass-produced as low emission vehicles. Hybrid vehicles have both a gasoline engine and an electric motor to save on gasoline usage and a nickel-metal hydride battery is used to store electric energy. The battery contains Nihydroxide and Co as the cathode activating agent and an alloy of Ni and mischmetal (mM), a rare-earth element mixture consisting of La, Ce, and Nd, as the anode hydrogen adsorption component. In conventional recycling, the Ni and Fe are recovered with a rotary kiln-electric melting process and the Co and mM go to the slag component [1] and hydrometallurgical treatment of crushed product consumes large volumes of agent. Japan Oil, Gas and Metals National Corporation have proposed a low energy and low cost recycling treatment process combining the physical and chemical treatments and the authors are investigating the physical treatment process."

Jan 1, 2008

By S. Pirzada, P. R. Taylor

A reactor was designed and constructed to perform experiments on the generation of value added products using a plasma heat source. The engineering drawings were developed to include multiple sample ports for temperature and velocity measurements and view ports were designed to allow the Physics group to make optical measurements. Two methods for feeding solids into the system were developed and installed. Preliminary experiments were performed to characterize the system at various flow rates and power settings. Experiments were performed using zinc metal and oxygen to form zinc oxide. The particles that were generated were characterized chemically using atomic absorption and x-ray diffraction; and physically using scanning electron microscopy. The particles appear to be of value added size; but there is a tendency for the fine particles to adhere to one another forming agglomerates. Additional experimental work will continue the evaluation of the major parameters.

Jan 1, 1988