Search Documents

By Michael G. King

The primary non-ferrous metals industry is the principal supplier of the minor metals selenium, tellurium and bismuth. It is also a major supplier of antimony. These minor elements are recovered from by-products of base metals production. To ensure that these elements remain available, the cost of production must be compatible with four other factors - method of production, available supply, technological niches, and product stewardship. This paper first describes the relationship between the copper industry and the production of tellurium and selenium. The more complex relationship between the lead industry and bismuth production is then discussed, followed by comments on antimony availability. Product stewardship programs are essential to the growth or certain specialized markets for these metals. Smelters and refineries of non- ferrous metals will play a major role in the recycling of scraps and wastes from these markets. Examples on how such materials can be recycled are given in the paper.

Jan 1, 1995

By Lucas Lopes da Costa

Bamboo fibers were characterized in terms of diameter distribution and tensile properties. Polyester matrix composites reinforced with these fibers were investigated for their flexural mechanical behavior. Specimens with up to 30% in volume of continuous and aligned bamboo fiber composites were bend-tested until fracture. The results showed an improvement in the composite strength and stiffness with the amount of bamboo fiber. A microstructure analysis by scanning electron microscopy revealed a reasonable adhesion between the fiber and the polyester matrix which justifies the improved mechanical properties of the composites.

Jan 1, 2010

By J. M. Tourre

1995 have seen a continuation of a positive trend in the Rare Earth industry The availability of a greater diversity of Raw Material has brought additional flexibility to the Producers permitting better economics China remains the major raw material source; Chinese concentrate producers have increased capacity in 1995 (Baotou, Sichuan, etc) China's role in the Rare Earth industry will continue to evolve; the acquisition of a majority equity position by San Huan/CNNC will have a significant impact on both the Rare Earth and Magnet markets Chinese producers are increasing the quality of their products and realize their true values Chinese market, itself, is also changing as the internal needs for separated rare earth's grow Already already producer of Lamps, Loudspeakers, Magnets, and TV tubes, China is in an unique position where the potential of its internal market might be more promising than the prospects outside China 1995 has also seen the application market become more diverse and complex. There are new applications growing at a very strong pace (such as battery alloy), applications that are now penetrating their target markets with significantly increased growth rates (such as bonded NdFeB), and some applications that became more complex requiring much more sophisticated products (such as catalysis). Rare Earth producers have to spend significant ressources in order to monitor the market trends in order to predict the demand and then adjust their raw material mix. Even though there is a greater diversity of raw material available, there is still some Rare Earth elements that are in excess, while other are just in balance. As a consequence rare earth producers invest heavily in R&D in order to develop new applications for these excess elements.

Jan 1, 1997

By Gaifeng Xue, Lei Zhang, Aimin Duan, J. Y. Hwang, Lina Wang

"The removal of chemical oxygen demand (COD) from coking wastewater was experimentally investigated using a three-dimensional electrode reactor. The experimental results showed that the refractory organics in coking wastewater can be effectively removed by this process, and COD removal efficiency was affected by the operating parameters, such as electrolytic retention time, particle electrode dosage, initial pH, current density, aeration amount and electrical conductivity. The experimental results show that the three-dimensional electrode could have a COD removal efficiency of more than 60% and a running cost of no more than 6 YUAN (RMB)/t. This indicates the great potential of a three-dimensional electrode reactor in engineering applications as an advanced treatment methods for coking wastewater.IntroductionCoking wastewater is generated from coal coking, coal gas purification, and by-product recovery processes of coking; it is composed of phenolic compounds, heterocyclic compounds, polycyclic aromatic hydrocarbons, ammonia, cyanide, polycyclic nitrogen-containing aromatics, acyclic compounds, etc. Most of these constituents are refractory, poorly biodegradabile, toxic and carcinogenic [1-3]. Currently, coking wastewater is usually treated by different forms of A/O biological nitrogen removal processes as the primary treatment means, but the aforementioned processes are not efficient enough to meet the requirements of the National Discharge Standard in China (GB13456-1992). According to the continuous requirement on improving environmental protection for the coking industry (revised 2008), increasing wastewater utilization ratios and reducing the discharge of effluent in the coke industry have to be implemented for cleaner production and sustainable development. Therefore, advanced technologies need to be developed to treat coking wastewater and reutilize the product as industrial cooling water, which would be one of the best choices to achieve zero discharge of wastewater and reduce water consumption per ton of steel produced. In this study, a three-dimensional fluidized bed electrode reactor was adopted for the advanced treatment of coking wastewater, and the effects of operating conditions, including particle dosage, initial pH, current density, supporting electrolyte, as well as aeration amount on the COD removal rate, were investigated. Its running costs were also estimated."

Jan 1, 2012

By Daniel Kim, Justin McAllister, Shijie Wang

"At the Kennecott Utah Copper Refinery, impurities in the electrolyte are being precipitated in the circulation system and form a hard scale in the piping. This scale must be removed periodically for proper electrolyte flow. Distinct layers of differing composition form as the operating conditions of the tank house change. Scale samples from the inlet and outlet pipes were analyzed to discover the nature of the precipitates. Each sample was sectioned and examined under optical microscopy and SEM. The composition of the scale was analyzed using ICP, XRD, and SEM/EDX mapping. The rate of deposition was determined by measuring the amount deposited on new pipes after elapsed time intervals. In order to determine how to minimize the formation of the scale, the mechanism was studied and the results are presented in this paper.IntroductionIn copper electrorefining, impure copper anodes are refined into pure copper cathodes. The impurities from the anodes are either insoluble and report to the slimes or soluble and dissolve concentrating in the electrolyte. These impurities are controlled by bleeding electrolyte from the system. Over time, the impurities combine to precipitate a hard scale on the surfaces contacted by the electrolyte. The scale causes problems with tank house circulation systems. In order for the refinery to operate properly, the scale must be removed periodically from the walls of the pipes. The first step to control the buildup of scale on the pipes is to understand the composition and the phases that are present in the scale."

Jan 1, 2012

By Dale T. Peters

In the United States, the United Kingdom and numerous other countries, copper has long been the plumbing material of choice. This has been the case since the late 1920s in the United States and since World War II in the United Kingdom. However, in recent years the plumbing tube market has caught the eye of the chemical industry, and several plastic resins have been introduced to the marketplace as substitutes for copper in household plumbing systems. One of these, polybutylene tube, had so many failures in the United States that a class action law suit was filed, and the manufactures of this product were forced to create a trust fund of nearly one billion dollars to repair damages caused by their product. Chlorinated polyvinylchloride (CPVC), in rigid pipe form, on the other hand, has been mechanically acceptable albeit its recent introduction precludes the test of time enjoyed by copper tube in this application. This paper reviews the State of California's portrayal of copper's environmental effects and will be largely based on the data and information assembled by the Copper Development Association Inc. in its presentation to the State of California in August, 1998 in response to the State's Draft Environmental Impact Report for Chlorinated Polyvinyl Chloride (CVPC) Pipe for Use for Potable Water Piping in Residential Buildings. The paper is intended for use as a model for the use of other copper organizations and individuals in responding to similar situations.

Jan 1, 1999

By V. K. Handa

Sterlite Industries (I) Ltd. started its copper smelter in 1996 and worked through the common problems associated with smelter start-ups. Specific issues in the converter area included converter blower IGV problems, punching machine reliability, converter spitting, back collar burning, ,and short converter campaign life. With a very young and dedicated team of engineers and technicians, smelter management assigned teams of three to four members to work scientifically and systematically through each major problem area to recommend and implement appropriate solutions. The converter mouth was redesigned with respect to tuyere and metal height to eliminate spitting and back collar burning. The air line was changed in places to reduce the pressure drop. A new back-up compressed air line and vessel was installed to prevent tuyere blockage in the event of a blower trip or power failure. The converter mouth liners and bricking around the mouth was modified to eliminate metal leaking through the pouring lip Modifications to the punching machines were made to address specific problems and preventative maintenance practices were further streamlined and reinforced to ensure 100% availability of hot metal cranes, converter blowers, punching machines, and ID fans. Matte availability and matte temperatures were improved by streamlining the upstream ISA and Rotary Holding furnace areas. Implementation of a detailed training program for the converter operators significantly improved the operation and morale. Water-cooled double hoods and a third converter were installed as part of the smelter modernization plan. The new hoods dramatically improved hygiene in the crane aisle while the addition of the third converter posed new challenges for the same motivated group of crews with respect to flip flop operation to keep the idle converter hot and to maximize in-stack time, managing crane/ladle logistics, and managing revert generation. This paper describes the converter operation's journey from the initial days of long blowing times and large revert accumulations to present operations with two converter flip flop operation, and also describes the team work, constant focus on increasing productivity and reducing costs, and benchmarking.

Jan 1, 2002

By L. Béjar-Gómez

The aim of this research work is to study and characterize the precipitates in structural microalloyed steel by transmission electron microscopy and analysis by low resolution. Microalloyed steel with niobium was produced by casting in an electrical induction oven of 25 Kg capacity. Carbon content in steel was less than 0.1 % and 0.036% of niobium. Steel was processed thermomechanically; reheated to 1250 °C and hot rolled on a laboratory mill to a 13.0 mm thick plate with a finish rolling temperature of 900ºC and a thickness reduction of 80% . This work shows what precipitates are present in steel, the type of precipitates and their morphology. Analysis by transmission electron microscopy of low resolution was applied to obtain the chemical analysis of precipitates and the matrix. Spectroscopy of dispersive energy (STEM - EDS) was applied to obtain the element profile of precipitates. Particles of precipitates of NbC were found; with cubic morphology and size from 70 to 130 nm, circular morphology and size from 10 to 70 nm, polygonal morphology and size from 10 to 80 nm.

Jan 1, 2006

By Larry M. Southwick

The smelting of copper and other non-ferrous metals have made considerable advances over the last 125 years. Many of the ideas and processes currently in use were attempted early in the history of smelting and were unsuccessful. Often the cause was incomplete understanding of the metallurgy involved, inadequate refractories, poor materials of equipment fabrication or trying too many new ideas at once. With time, these problems get solved and the technologies become commercialized .These were processes whose time had not come when originally proposed, but did eventually. On the other hand, there have been some concepts whose time will never come. They were impossible then and they are impossible now. The people that dream these up were either crackpots (they didn't know what they were doing, but thought they did), or charlatans (they knew they didn't know what they were doing, but didn't care). Both rely on bad science to propose metallurgical absurdities. These too have their place in the development of technology, though mostly negative, and several examples will be discussed in this paper. Three from around the turn of the century will be covered, as well as one from this decade. The last demonstrates that the art of creating absurdities has not withered, even after ninety years of scientific sophistication, and some can even be patented. The first three reached field trials due to the gullibility of company management. The last arose from a fortuitous mis-operation of a plant which solved a problem, but the explanation and patent which arose are metallurgically impossible.

Jan 1, 1999

By Robert A. Reiley

Under the traditional environmental paradigm, industry, stakeholders, and government impact the environment through production, consumption, and regulation. For more than twenty years, this paradigm has survived more or less unchallenged. Environmental action has followed a typical pattern: industry pollutes, the public clamors, government enacts legislation, and industry expenditures for pollution-control equipment soar. In the 1990's, many groups realize that command-and-control techniques may not be the most effective method of dealing with environmental issues in the new millennium. The need for regulatory reform became apparent in the 1980's after an accident at the Union Carbide plant in Bhopal, India. In addition, the prospects of an integrated European market and increased global trade sparked a need for common standards regarding the production of goods and services, which led to the adoption of the International Standards Organization (ISO) 9000 Quality Standards. These factors, and others, triggered the development of the Environmental Management System (EMS). Over the past decade, country-and industry- specific EMSs were developed. However, the IS0 realized the need for a single, internationally recognized standard that would be workable for any type organization. The goal of this standard is to promote economic competitiveness, remove trade barriers, and promote environmental protection. To this end, the IS0 14000 Standards were developed to provide business with a structure for managing environmental impacts. This article argues that a new paradigm has begun to transcend the old. Protection of the environment if shifting from "government drivers" to "market drivers". This shift means that industry and stakeholders, instead of government, are taking the lead to develop ways to protect the environment. This article also argues that government can use this new paradigm, in a time of declining budgets and regulatory reform, to continue to protect the environment through increased compliance monitoring and rigorous enforcement. Specifically, the IS0 14000 Standards can allow the government to reduce compliance costs, streamline permit and reporting requirements, and provide business with regulatory flexibility. Finally, this article argues that IS0 14000 will be central to the regulatory reform effort, because it can be internally implemented with little need for legislative intervention.

Jan 1, 1999

By Carole Read

Hydrogen is under consideration by several countries for its potential as an energy carrier for transportation applications. In order to compete with vehicles in use today, hydrogen-powered vehicles will require a driving range of greater than 300-miles in order to meet customer needs and expectations. For the overall vehicular light-duty fleet, this dictates that a range of 5 to 13 kg of hydrogen be stored on-board (assuming a fuel cell power plant) within stringent system weight, volume, and cost constraints. Vehicular hydrogen storage thus constitutes a major scientific and technological challenge. To meet this challenge, the U.S. Department of Energy (DOE) initiated a ?National Hydrogen Storage Project? with roughly 40 universities, 15 companies and 10 federal laboratories, actively engaged in hydrogen storage research. Centers of Excellence in metal hydrides, chemical hydrides, and carbon-based materials have been established, as well as independent university and industry projects in the areas of new concepts/materials, hydrogen storage testing, and storage system analysis. Recent technical progress in each of these areas is discussed, as well as collaborative hydrogen storage activities under the recently established International Partnership for the Hydrogen Economy (IPHE).

Jan 1, 2006

By T. A. Edison

A distinct hydrocarbon maturation anomaly coincides with the Gold Acres open pit, Nevada (Figure 1). Both atomic hydrogen to carbon (H-C) ratios and reflectance measurements of contained organic matter indicate significantly higher maturity in samples collected within the confines of the open pit than in samples from the surrounding region (not shown in Figure 1).

Jan 1, 1987

By Keizo Uematsu, Kumiko Sanda, Nozomu Uchida

"Full understanding of mechanical properties is the most important assignment in ceramics. Establishment of defects-property relationship is crucial for fulfilling the assignment. This study reports detailed characteristics of defects and their relevance to the mechanical properties for alumina ceramics made through a typical industrial processing. Novel characterization methods were applied to evaluate their defects. A very simple direct correlation was successfully found between defects and properties in ceramics. This result is a great epoch in the field of ceramics. IntroductionThe ceramic materials are used in refractoriness, corrosion resistant materials and structural materials. The low fracture toughness and scatter of strength are very important problems in ceramics. The toughness of ceramics is lower than metal and polymer materials, and the allowed defect size is small. Very small internal defects (pore, crack, huge particle) can be a fracture origin in the brittle fracture. The characteristics of defects such as size, distribution and shape change markedly by process condition, which cause the scatter of strength. This study conducts quantitative evaluation and direct observation of the sizes, shape and a number of internal defects with a light microscope, and discusses the relationship for mechanical properties and defect sizes"

Jan 1, 2000

By E. A. Thiers

The causes of structural changes in the markets for high technology alloying metals are discussed in terms of technological, economic, and financial trends. Recent market imbalances have affected producers in developed and developing countries differently. Possible response strategies for suppliers in the two types of countries are examined that may alleviate future market imbalances.

Jan 1, 1988

By Jeff M. Kuhn

A new solvent extraction process for the removal of halides from zinc sulphate solution was tested in pilot plants at both a 0.1-L/min scale and at a 3-L/min scale. Teck Cominco?s process is called the HalogonTM process, for which patents are pending. Mixer-settlers were used for the 0.1-L/min pilot scale and two BATEMAN pulsed columns for the higher rates. Pilot testing was performed with commercial zinc sulphate solutions containing variable amounts of chloride and fluoride. Sulphate extraction was also controlled and deleterious halides were loaded and stripped into a form suitable for disposal. The engineering aspects and economics of this solvent extraction process for halide removal are also reported.

Jan 1, 2003

By J. C. Agarwal

Rare earth metal alloys are becoming increasingly important, particularly those of neodymium, because of their magnetic properties. This paper will present a generalized approach to the production economics of the metallic rare earth alloys. With appropriate regard for the chemistry of different rare earths and the large impact of economies of scale, it is possible to make fairly accurate estimates of the production costs of other rare earth alloys as well.

Jan 1, 1989

By Paul-Dominique Oudenne

This paper reviews the experience gained by CMI NESA over the last thirty years for the treatment of arsenical and antimonical bearing concentrates and other complex metallurgical by-products. The importance of preliminary mineralogical characterization is emphasized as a preliminary step for the success of the roasting. Stage selective roasting appears as an attractive and efficient route for the treatment of complex concentrates. Numerous examples will be given for confirmation of such thermal treatment.

Jan 1, 2006

By A. V. Tarasov

Based on the data available in the literature and the practical experience of new metallurgical plants, a method has been proposed and relevant studies conducted for metallurgical processing of zinc sulfide concentrates. Process conditions and parameters have been identified, which ensure high levels of recovery of zinc into solution. This is achieved by leaching concentrates under the normal pressure at a temperature of >90°C in the presence of ferric iron ions. Sulfide sulfur is converted to elemental sulfur in this process. To produce elemental sulfur it is necessary to maintain oxidizing conditions in the system, characterized by a positive Eh value. In order to eliminate the interfering effect of elemental sulfur formed in the process, it is possible to add surfactants into the concentrate pulp. The proposed technology has certain advantages as compared with the high-temperature pressure leaching and is considered as a basic technology to be applied to increase zinc production at one of the Russian zinc plants.

Jan 1, 2006

By S. Vellinga, G. H. R. Janssen, C. J. N. Buisman, C. F. M. Copini

Non-ferrous metallurgical plants are often confronted with the need to neutralize bleed streams or effluents containing sulfates. The treatment of these streams could produce large amounts of gypsum. With a biological sulfate-reduction process, the production of gypsum is avoided and the metals can be recovered as sulfides. In this paper, the biological treatment of an industrial stream is presented. The bleed solution from a roaster gas scrubber was treated by means of a two-step process. First, the acid was neutralized with calcine. The resulting zinc sulfate solution was converted to ZnS with bacteria using PAQUES-THIOPAQ® technology. The precipitated ZnS was de-watered to 70 wt% solids, and was returned to the roasters. The quality of the effluent stream complied with the environmental regulations.

Jan 1, 2000

By Sergio Demetrio

Over a period of nearly a hundred years throughout this century, the company direction and management of copper smelters in Chile has evolved from one characteristised by a paternalistic, autocratic style to one which empowers the local management team and people for running the smelter as a successful business. This paper discusses the evolution of the present style of management amidst changes in the Chilean Government, the mining industry and society since the beginning of this century.

Jan 1, 1999