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By M. Tomita

One of the most essential factors for a custom smelter to strengthen its competitive power is to Improve its comparative standing in purchase of concentrates from the world market. It is especially critical for Japanese smelters who depend almost 90% of their raw materials on import. In order to accomplish this breakthrough, the development of the new technology which enables us to treat concentrates containing higher Impurities is inevitable. Nippon Mining Company Ltd. made an intensive research on processing complex ore for three years from 1979, and successfully developed an original hydrometallurgical process to treat converter dust for eliminating impurities from the copper smelting circuit. The commercial plant was constructed at the Saganoseki Smelter & Refinery in 1982, and its nine years operation has been satisfactorily proven the advantages of the technology. The concept of this process and its operational performance are discussed.

Jan 1, 1992

By D. Purdie

"This paper aims to remind researchers, designers, operators, and managers about the benefits of seeding in the design of precipitation stages in their flowsheet. Including a high density solids (HDS™) process encourages the precipitating solids to form on the surface of existing precipitated particles. This paper discusses the application of the HDS technology at Kennecott Smelter, where the authors have witnessed significant improvements in settling and filtration rates. The authors have also applied this technology at various smelter bleed treatment plants worldwide with similar improvements in precipitation and filtration rates. HDS is a registered trademark of De Nora Water Technologies. RÉSUMÉ Cet article a pour objectif de rappeler aux chercheurs, aux concepteurs, aux exploitants et aux administrateurs les avantages de l’ensemencement dans la conception des étapes de précipitation de leur schéma de traitement. L’introduction d’un procédé des boues haute densité (procédé HDS™, de l’anglais high density sludge) encourage la formation de substances solides précipitantes à la surface des particules précipitées existantes. Cet article porte sur l’application de la technologie HDS à la fonderie Kennecott, où les auteurs ont observé des améliorations importantes au niveau de la vitesse de sédimentation et de filtration. Ils ont également appliqué cette technologie à diverses usines de traitement des rejets liquides des fonderies dans le monde entier, et ont constaté des améliorations similaires en termes de vitesse de précipitation et de filtration. Le procédé HDS est une marque de commerce déposée du fabricant De Nora Water Technologies.INTRODUCTION In 1966, the lead author worked as an assistant smelting metallurgist for the Tsumeb Corporation Limited copper and lead smelter in Tsumeb, Namibia. The smelter produced copper and lead, as well as cadmium and arsenic trioxide as byproducts. The cadmium was concentrated in the lead blast furnace off gas dust, and was collected by a baghouse. The baghouse dust was leached with dilute sulfuric acid (H2SO4) in a batch process. The iron and arsenic in the solution were oxidized with potassium permanganate (KMnO4) and basic ferric arsenate (BFAS; Fe(AsO4)x(SO4)y(OH)z·wH2O) was precipitated using milk of lime. The cadmium was cemented from the purified solution using zinc dust."

Jan 1, 2018

By Arnold E. Lamm

The degree of economic, progress of a nation is measured by its possession and use of energy, sources. The future of coal in the West hinges on its ability to participate and grow in the energy market. A source of energy is, in the long run, only as good as the ability of the industry to develop its reserves economically. The economic development of the tremendous coal reserves, literally hundreds of billions of tons of coal in the States of Colorado, Utah, Wyoming, Montana, New Mexico, and Arizona, poses a very real question in the light of the known mining technology of our day. Basically in America today, coal is mined from the earth either by the strip mine or underground mine method; in the West, the large long-term, contracts now in force with utilities are mostly from coal mines utilizing the strip mine method. However, the preponderance of the known coal reserves of the West are located deep underground and will have to be mined by the various; underground mining processes. The problems encountered in the West with regard to underground mining vary from state to state but, on the whole, do not present what might be considered a miner's bonanza. I do not mean to' infer that the underground coal of the West is unmineable, but I do want to emphasize that the tremendous reserve figures do not present a true picture in the light of present day technology.

Jan 1, 1965

By Jeffrey L. Zelms

Environmental issues and how they are addressed -- or not addressed -- by the lead industry in the 1990s will determine the eventual fate of lead mining in both the U.S. and worldwide. Clearly, governmental regulation throughout the West will become harsher. Equally clearly, the industry has? failed to educate the public regarding lead. Instead of public support for a critical mineral, we face widespread public ignorance and paranoia. If we can demonstrate the public interest benefits of the industry, the 1990s will be a decade of continuing growth -- not dynamic growth, certainly, but growth at least comparable to the world economy. If, however, we fail to demonstrate the industry's public interest benefits, the 1990s could mark the beginning of the end of our business.

Jan 1, 1990

By F. Scott Carpenter

During the past several years, more frequent reference to Wollastonite has appeared in print, both in this country and abroad. The reason for this is the apparent growing interest in this mineral as it approaches commercial maturity. Twelve years ago, wollastonite was available in only limited commercial quantity. In 1933, a deposit in California was worked for a short time to provide a calcium silicate raw .material for the manufacture of mineral wool* It was not until the spring of 1953 that Cabot Corporation put into operation a modem commercial plant to produce this material in a variety of grades. These grades covered both a range of particle size and of particle shape. At that time, applications for wollastonite were largely speculative, although a few commercial applications in glass frits and welding fluxes did exist, For all practical purposes, it was a new material for which few commercial uses had been fully proven.

Jan 1, 1964

By M Malec, J Szczerbinski

Hazards in underground mines are concomitant with the mining of mineral deposits and have their source in a minerÆs work environment. The authors of the paper have undertaken a trial classification of these hazards into three groups, depending on the sphere of their occurrence:lithosphere, ie rock mass, atmosphere, ie air in mine workings, and technosphere, ie machines, equipment and facilities in mine workings. The lithosphere creates such hazards as bumps, rock outbursts, the atmosphere is a factor causing fires, methane explosions and climatic hazards, whereas accidents concomitant with an operation of machines and equipment occur in the technosphere. Assuming that the number of accidents in the mining industry, concomitant with hazards, reflects the degree of safety, it has been shown, that in Poland they are under control to a large extent.

Jan 1, 1999

By D. A. Jacobson

Mining operations, whether new or existing, are constantly looking for ways to maximize production and improve energy efficiency, while keeping the footprint required to a minimum. The Nordberg MP1250 cone crusher was designed with these three goals in mind. A series of side-by-side evaluations comparing an MP1250 to an MP1000 were completed at two Freeport-McMoRan operations. The first evaluation began October 2009 in a tertiary position and the second began March 2010 in a secondary position, where it remains in full production today. Utilizing 25% higher power capacity than the existing MP1000 tertiary crushers, the MP1250 had 29% higher capacity and 17% lower specific energy, adjusted for differences in feed and product size. The MP1250 compared to the existing MP1000 secondary crushers achieved 30% higher capacity at a slightly reduced specific energy, while achieving a finer product. The MP1250?s higher capacity and energy efficiency may have application in many crushing plants. Depending on site specific economic factors, greenfield projects may benefit from a smaller footprint and less ancillary equipment, whereas brownfield projects may benefit from higher capacity or a finer product within the same footprint.

Jan 1, 2012

By D. Adiguzel

In this research, providing the sustainability of production quality was aimed for a quarry which is located in Istanbul western part of Turkey and producing concrete aggregates with different types of rock. First, research field was divided in 3 different areas in accordance with the geological differences and parameters that control their product quality, limit values of standards and effect levels were determined. Concrete aggregate conformity tests which are stated in international standards were applied on samples which were taken from these 3 different areas and physical, geometric and chemical properties of each rock type were revealed. The properties of the 3 different types of rock which were produced in the quary were determined and the binary blends were composed. Blending studies were conducted with linear programming technique. In the linear programming model, the cost of aggregate production was aimed to be minimal. The limit values that meet literature and national standards for usability of aggregates in concrete were defined as constraints in the linear programming model and evaluated with objective functions, thus the most suitable aggregate blends were composed. In conclusion, to provide the sustainability of product quality, the most appropriate product blends were composed for the research field and the usability of this model for those quarries were revealed.

Aug 1, 2013

By Michael F. Kitto

The production of sulphuric acid at base metals smelters is predominantly an involuntary activity and now comprises approximately 17% of all-forms sulphur supply in world terms. The majority of elemental sulphur is also produced involuntarily in response to environmental regulations regarding emissions from hydrocarbon processing plants. The paper examines the points of similarity and difference in the sulphur and smelter acid markets, and reviews their interactions. The reasons for the merchant acid market collapse of 1993 are analyzed, and the prospects of a recurrence are considered.

Jan 1, 1996

By Zhi-xiang Cui

Effects of flux, vulcanizing agent and reductant on slag cleaning in new-type slag cleaning furnace (Φ3.6 × 8.1 m) were investigated under the conditions including smelting temperature of 1200 and 1250 °C, settling time of 30 and 60 min, and Fe/SiO2 of 1.7–1.9. The results show that addition of SiO2, B2O3 or CaF2 into original copper smelting slag can improve settling separation effect. Though no effect on copper recovery, addition of FeS can provide heat required by reaction with oxygen and reduce copper dissolution in spinel phase and slag. Copper content in discarded slag can be controlled at 0.26% under the optimum comprehensive conditions with ratio of oxygen to natural gas of 1.6.

By Liu Wenyong, Huang Yucheng, Yang Ba

High-water rapid-solidifying material, called æhigh-water materialÆ, is a new material developed by the authors over many years. The material can solidify nine times its volume of water into solid. The material is a fine kind of binder with special properties. The solidifying body of high-water material with water has quite a high early strength. The compressive strength of the material within three days can reach the same strength as conventional Portland in 28 days. One ton of the material can replace three tons of conventional Portland cement as binder. Some important achievements have been made in application of high-water material. In metal mines, based on the material, a new full-tailing cemented backfill technology has been developed. The characteristic of the new technology is that high-water material is used as binder and full tailing or alluvial sand is used as backfill aggregate. Because of the application of the new technology, major technical problems in backfill technology such as classifying of tailing, dewatering, transportation of pulp, low strength of backfill body, environmental contamination and so on, have been solved.

Jan 1, 1998

By G. W. Luxbacher

With the advent of acid rain legislation included within the Clean Air Act Amendments of 1990, a great deal of uncertainty with regard to price, source and production quantities has been cast into the coal market. Powder River Basin and other western coals continue a rapidly accelerating migration eastward, South American coals move into the northern markets, states propose legislation to assist utilities in complying with the new regulations in hopes of maintaining their own coal industries, while some utilities question the long term availability of eastern compliance coal. Any major coal producer must make decisions now to assure their continuing presence in the market place; several companies have adopted a strategy to acquire eastern compliance reserves while others have invested in technology to compete as a low cost producer. This paper discusses some of these options in light of the uncertainties of the market place, from an eastern coal producer?s viewpoint.

Jan 1, 1992

By Hani Henein

"Heat transfer between droplets/particles and a gas phase plays an important role in the transport of numerous materials processing operations. These include rapid solidification operations such as gas atomization and spray forming, as well as chemical systems such flash furnaces. Chemical reaction rates and solidification are dependent on the rate of gas-particle or gasdroplet heat transport. Using a heat transport model validated using single fluid atomization of molten droplets; the effect of process variables on heat losses from droplets was examined. In this work, the effect of type of gas, droplet size, gas temperature, gas-droplet relative velocity on the heat transport from AA606 l droplets was examined. The most critical of these process variables to heat transfer is identified and will be presented.IntroductionIn materials processing, droplets are often encountered and used in processing a wide range of liquids and slurries. The small size of the droplet enables high reaction rates or high solidification rates in many systems. In order to capitalize on these high rates of transport processes, sprays are· also developed to maximize throughput. The design of these sprays, however, does not account for the transport steps and rate limiting mechanisms at the droplet surface. Rather, spray design focuses on maximizing the break-up of a stream or slurry into small size droplets or controlling the spread of the spray. Spray systems in industrial use typically generate droplets of wide size distribution leading to a wide range of reaction times for each of the droplets. Often the generation of a spray involves a number of coupled phenomena such as stream break-up, droplet-gas transport, droplet size distribution and spray geometry. Using gas generated sprays, it is not possible to identify how individual process variables contribute and control each of these coupled phenomena. While many mathematical models have been developed of sprays and they attempt to simulate coupled droplet transport, they do not provide insight into the contributions of different mechanisms in heat transfer. This is primarily because the basic fundamental heat transport between droplet and gas cannot be isolated from other gas spray phenomena experimentally such as two-way thermal coupling [l]. Thus, experimental validation of heart transfer of large and complex industrial spray models is not carried out. Hence, the validity of spray models remains in question and the approach required to optimize spray processes cannot be clearly identified"

Jan 1, 2004

By Jiang Fan, Liu Shi, Wang Haigang

Winter-time natural convection in gravel embankments has been suggested as a technique to provide passive cooling and thereby avoid thaw-settlement of roadways located in permafrost areas. Numerical simulation by finite volume method on the proposed model is perf9rmed using the software FLUENT. A gravels model, in which the embankment is composed of stones and air, has been adopted to investigate the temperature and velocity fields in embankment. Simulation results show that in summer, a weak clockwise circulation of the pore air extending throughout most of the embankment. The pore-air motion is very weak which results in relatively straight horizontal isotherm lines. And heat transfer is mainly maintained through conduction. But in winter, pore-air velocities are higher and multiple vortexes are formed in the embankment. Natural convection then becomes the dominant influence on the isotherm shapes within the embankment. As a result of low ambient temperatures exerted on the embankment surface during winter months, an unstable air density gradient develops within the embankment. This convection increases the heat flux out of the embankment. Therefore, the winter-time convection can further reduce the temperature of the foundation soil beneath the open-graded embankment. In addition, the effects of the size of the stones within the embankment have been analyzed and compared in the gravel model. It shows that in winter, 200mm stones lead to stronger vortexes in the embankment compared with those of 60mm stones. Consequently, the zone oflow-temperature beneath the embankment is extended.

Jan 1, 2004

By Robert P. Dufresne

Electrolytic cells are used in electrowinning (EW) and electrorefining (ER) of non-ferrous metals such as zinc and copper, and are a critical part of the purification process. The cell is a large basin and has an electrolyte or aqueous solution, an anode and a cathode, an insulator, and incoming high amperage. Cells are exposed to unfavourable internal and external factors that have a direct impact on their lifespan. Their deterioration can be caused by incorrect polarity, insufficient magnitude, their construction, tension stress, thermal shock, corrosion and other, and their maintenance and replacement can be time-consuming, costly, difficult and environmentally unsafe. Occupational health hazards and dangers posed by the maintenance and removal of the cell should also be taken into consideration. Modifying the design and fabrication method of the cell, using chemical-resistant reinforcement, and increasing tensile and mechanical strength will defer maintenance for a very long time. This can be achieved by a double hull system that comprises full-length composite reinforcement, polymer concrete reinforced with fiberglass pultruded rods and rebars, fiberglass structural layers, and special resin matrices. This will provide protection against thermal shocks, corrosion, leakage, cracks. The design of this cell incorporates a lifting system that will afford quick and easy install without having to move a great number of cells in close proximity, since it is strong enough to stand on its own and not have to be bonded to adjacent cells. As well, the cell can be anchored with ease as it remains stable. This is especially important because space is limited to lift and manoeuver between the cell and the double-girder overhead travelling cranes. The lifting system can also prevent electrocution and loss in product quality, while increasing efficiency and safety in the workplace. Considerable savings in terms of production downtime are also part of the equation. INTRODUCTION Maintenance and replacement of electrolytic cells in electrowinning and electrorefining are operations that pose many challenges, health and safety concerns, and give rise to substantial operational costs. These problems have existed since time immemorial. Electrolytic cells are made of conventional concrete or polymer concrete, and because of the very nature of their composition and their exposure to severe and environmental conditions, their lifespan is short. Although polymer concrete is composed of high-quality materials, and has good thermal stability and resistance to chemicals, nonetheless, maintenance is frequently required in order to maintain the integrity of the cell and to ensure the quality of refined metals. Repairing concrete is a non-permanent solution as cracks will reappear, and every repair weakens the integrity of the cell a bit more, until it reaches a knock- down point and the structure is compromised. The cell needs to be replaced, otherwise the cell will collapse.

Jan 1, 2019

By Slavoljub D. Maksimovic

At some coal mines, methane gas is released during raise drilling. At the request of the Mine Safety and Health Administration (MSHA), U.S. Department of Labor, the Bureau of Mines conducted ventilation surveys at different raise drill sites to assess various methods of reducing methane concentration. The resulting data indicate that raise drill shaft cavities are ventilated by air compressors, vacuum pumps, auxiliary blower fans, and free intake air from the surface. The compressors, pumps, and fans operate simultaneously or separately. At the bottom of the shaft cavities, ventilation is controlled by regulators and airlocks. Methane is monitored, measured, and periodically sampled on the surface, at the bottom, and at different levels in the shaft cavities. Maximum concentration of 3.5 percent was measured in one shaft in West Virginia. Air velocity down the raise drill shafts is always very low, Maximum recorded air down the drill stem was 3,000 cfm, which can be increased by adding air compressors. The best way to ventilate shaft cavities is through the simultaneous use of air compressors and vacuum pumps. If the methane concentration cannot be reduced with additional compressors, then the inside diameter of the drill rod should be increased, or larger pilot hole drill bits should be used.

Jan 1, 1981

By Robert H. Clark

Introduction During the last twenty years, science and industry have been strenuously endeavouring to discover new sources and new kinds of liquid fuels and to work out suitable chemical methods for their production. One of the new possibilities for the production of liquid fuel on a large scale is law-temperature carbonization of various grades of coal. The use of alcohol as motor spirit, in spite of its relatively low calorific value, is being widely investigated. Its production by fermentation of sugars, its recovery from the sulphite liquors of the paper industry, its production directly from wood and also from calcium carbide, have all been considered. At present the most promising line of investigation would appear to be the further development of those technical processes which yield liquid fuels from coal; since science has shown the possibility of preparing all kinds of liquid fuels and even the complete conversion of coal into oils. The present paper will consider briefly: 1. The production of primary tar by low temperature carbonization of coal. 2. The hydrogenation of coal. 3. The synthetic processes of Dr. Franz Fischer.

Jan 1, 1928

By Howard V. Sears

Prospecting in its modern context means simply the gathering of information on which, to base plans for the utilization of our mineral resources. One prospecting system familiar to T. V. viewers is the pan of the old gold prospector which, while he prospected, could produce the wealth which financed him in his search. Present day geophysical "prospecting" systems, which are based on the real or supposed responses of an ore specimen, to various stimuli finder controlled laboratory conditions, are promoted as means of reducing the cost of prospecting. The universal drawback to all geophysical systems is that they yield "soft" data which are only presumed to be analogous to ore mineralization until they can be calibrated, by conventional prospecting systems, to each actual mineral environment being tested. By this time the system usually is no longer cheap. Since the raw data are too esoteric to be used until interpreted by geophysicists, usually in the light of their own personal theories and experience, the certainty of multiple interpretation is introduced. The concept of prospecting, at St. Joe Minerals Corporation's Viburnum, Fletcher and Brushy Creek mines in the new Missouri Lead Belt, encompasses surface diamond drilling for preliminary exploration, the sub¬sequent development of ore body tonnages and grades and the establishment of mining parameters. The predominantly flat-lying mineralized formation is mined by room and pillar stoping. In an operating mine, jackhammer holer are drilled in backs and bottoms of stopes, and chip samples are taken for assay, concurrent with mining. Thus irregularities in ore bodies or nearby discontinuities are not overlooked which are above or below the general mine

Jan 1, 1971

By Z. Yang

The flotation behavior of the. green algae Chlorella vulgaris and a wild Chlamydomonas spp. was studied in the presence of Zn(II) using dodecylammonium chloride as collector. At about pH 6. both organisms readily float as amine concentration approaches lx10-3 kmol/m3. In addition, electrokinetic measurements were made on the organisms as a function of pH in both the presence and absence of Zn(II). It was found that the Zn(II) has a considerably greater effect on the zeta potential of C. vulgaris than on Chlamydomonas. Zn(II) adsorption studies also indicated that C. vulgaris is able to accumulate more Zn from solution than the Chlamydomonas.

Jan 1, 1991

By Craig Haase

A. Introduction

Jan 1, 2003