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The effect of composition on electrical conductivity (resistivity), viscosity and liquidus temperature of the slags encountered in electric smelting of PGM-containing suphide concentrates is reviewed along with the relationsip between slag composition, slag-matte separation and metal losses to slag. Optimization of slag composition at furnace temperature is attempted on the basis of opposite and parabolic trends of the viscosity-conductivity relationships of the slags. The importance of surface tension of slags is emphasized using available and estimated information, which are grouped into a useful correlation. These values are coupled with or incorporated into slag viscosity plots to illustrate the correlation between the two factors which influence slag-matte separation as well as refractory attack. The electrode in the slag-resistance furnace is the central factor in the design and operation of the furnace by its role of conveying the smelting power. The obvious parameters are the size and positioning in the slag bath, which are defined by slag resistivity, furnace resistance, cell constant and power input. The flow of heat generated by the electrode current determines the energy distribution and furnace dimensions creating viscosity profiles, which in turn affect flow conditions. Thus the flow of slag and matte isdiscussed in conjunction with the furnace geometry, stirring action of the electrodes, buoyancy and electromagnetic effects. The action of the electric furnace as a settler is discussed. The rectangular furnace is considered as a channel reactor in this analysis and the action of the electrodes is described to indicate a balanced settling rate in the area of electrode action. Discussion of the design and production capacity of the electric furnace with reference to operating current, power input, furnace dimensions and electrode size are based on considerations derived mainly from slag properties such as its resistivity, viscosity and liquidus temperature.

Jan 1, 2004

By AIME AIME

NAPOLEON'S dictum that an Army travels on its stomach has not changed in this present war, but the things an Army's stomach calls for would be more than strange to Napoleon. Today one of the main articles of diet for the mechanized army is oil and gasoline, and the chief and most efficient source of 'apply overland is the pipe line. It was a flexible 4-in. pipe line that supplied the voracious appetite of tanks, trucks, jeeps, and planes across the North African desert. and it is the 1800-mile pipe line from Calcutta to Kunming, Yunnan Province in China, the longest in the world, that supplied oil and 100-octane gas for the trucks, tanks, Jeeps, and planes fighting on the Assam-Burma-China front in recent months. Completion of this approximately 1800-mile pipe line to China over rivers that had never been bridged, over hill that towered 9000 ft., and over swamps

Jan 1, 1945

By D Mcleod, S Brindley, S Green

The design and engineering of flotation circuits is driven by numerous inputs, including (in no particular order) testwork outcomes, site considerations, type of separation required, energy sensitivity of the flotation response, personal experience and preference for flotation machines, maintenance access requirements, operability, level of automation and capital constraints.This paper discusses these and other issues in the Australian context and covers the flotation of copper/gold ores and polymetallic (copper/lead/zinc) ores. The paper discusses aspects of the following: how should testwork be done and what are the important inputs and outcomes? how should testwork results be interpreted and how does this impact on equipment selection? what processes can have a critical impact on flotation circuit performance, eg thickening and regrind? what options are available with the typical æflatÆ Australia site? how do you minimise capital cost and what impact can this have on flotation circuit operation and maintenance? how should circuits be controlled and operated? Particular focus is placed on some practical aspects of process design and engineering and the potential impact that engineering decisions can have on flotation plant operation.

Jan 1, 2005

By C. E. Wood

[Because of the renewed i~,ortanc of the strate ic netal ~ngane8e the Bureau of Mines is conductin further ro~aarch on pyrometallurgica1 ~ethods of boneficiating 0 ngani.foro'l iron ores nnn lo\,f-~~r de oanganesc ores. Published data on .the l2~roI'let llurgica.l treatnent of tl::1.nganse8 ores have been revi .. \-'en by Jose-ph ? .2]

Jan 1, 1940

By Clarence Karr

RESINS from a bituminous pitch, a bituminous coal, a lignite tar, a subbituminous pitch, and an electrode binder pitch wore investigated by the Bureau of Mines. The compositions of these resins were determined by four independent methods of structural detemination: (1) Molecular formula and ring analysis, including ring (2) infrared and ultraviolet spectra; (3) combined pyrolysis/gas chromatography, and (4) catalytic dehyrogenation followed by spectra and pyrolysis. The resin structure was correlated with coal structure, and it was concluded that pitch resins probably consist of essentially unaltered coal molecules carried over with the tar vapors in low-temperature carbonization.

Jan 1, 1966

By L. A. Cramer

Platinum metal was first utilized by the Inca civilization in South America where it was found in alluvial deposits along the San Juan and Atrato rivers that lie between the Andean mountain range in Colombia and the Pacific Ocean. The nuggets found in these rivers average between 77% and 86%platinum, 7%?8% iron and small amounts of copper, gold and other Platinum Group Metals (PGMs). The Incas often alloyed platinum with copper to increase its workability and fabricated various ornaments from it.

Jan 1, 2001

By Jinwang Zhang, Zhaohui Wang, Jiachen Wang

"Thick coal seams (seam height larger than 3.5 m) account for a large portion of the proven coal reserves of China, and underground thick coal seam mining provides about 50% of the Chinese annual coal production. Such seams are mainly mined using the longwall top-coal caving (LTCC) method. For safe and successful mining, a number of analyses on the stability of surrounding rocks in the LTCC face area have been extensively performed, and certain research achievements have been made. This paper introduces the main findings on rock pressure occurrence in the LTCC face during the last few decades and presents face and roof stability control techniques. INTRODUCTIONUnderground thick coal seams in China provide 1.8 billion tons of coal every year, which accounts for approximately 50% of the total Chinese annual coal production and 25% of the world, indicating that thick coal seams stand an important position in Chinese coal mining industry (Wang, 2005). Before the 1980s, thick coal seams were mined mainly by using the multiple-slice mining method. With the improvement of mining techniques and equipment in last two decades, longwall top-coal caving (LTCC) and high-seam, single-cut longwall are employed for thick coal seam extraction, offering advantages over multiple slicing from entry excavation and production perspectives (Wang, 2013).. The primary author of this paper introduced the most popular thick coal seam mining methods in China at the 30th ICGCM (Wang, 2015). This paper presents the stability of surrounding rocks in face area and ground control techniques for mining thick coal seams. For traditional longwall faces (seam height less than 3.5 m), the well-developed VoussoirVoussoir beam theory has been successfully used to analyze the movement of overlaying strata, which indicates that ground control techniques have become mature for this mining system. In such faces, the four-leg support with loading capacity of 4000–8000 kN is considered adequate for safe and successful mining. These faces normally have an annual yield of 1–2 million tons (Wang, 2007). For thick coal seams, however, the traditional support becomes inadequate and the ground control problem change to be more difficult and complex. Thus, development of large-scale mining equipment and ground control techniques for enlarged mined-out space and entries have been recognized as the most basic technical problems in mining thick coal seams."

Jan 1, 2017

[Dr. N.A. Barcza (Chairman) Mr. R.J. Linnell (Vice Chairman) Mr. J. Basson Dr. L.A. Cramer Mr. W.A. Gericke Dr. N.C. Machingawuta Mr. C.S. Mahony Dr. L.R. Nelson Mr. D. St J. Slater Mr. B.J. van der Walt INFACON X TECHNICAL PROGRAMME COMMITTEE Dr. L.R. Nelson (Chairman) Mr. W.A. Gericke (Vice Chairman) Mr. W. Barrett Mr. T.R. Curr Dr. O.F.R.A. Damm Prof. R.H. Eric Mr A.M. Hearn Mr. A.R. Jamieson Dr. N.C. Machingawuta Mrs. L. Mthombeni Mr. F.X. Prins Mr. J. van Tonder ]

Jan 1, 2004

By E. Robert Ruhlman

["Phosphate rock" is a broad term applied to natural deposits of minerals valued chiefly for their phosphorus content. More specifically, phosphate rock may be defined as a natural rock containing one or more phosphate minerals, usually calcium phosphate, of sufficient purity and in sufficient quantity to permit its use directly, or after beneficiation, in the manufacture of phosphorus-bearing products. The grade or quality of phosphate rock is expressed either in terms of its phosphorus oxide (P20S) content or the equivalent in tricalcium phosphate (Ca3(P04)2). The trade name for tricalcium phosphate is bone phosphate of lime (B. P. L.).]

Jan 1, 1958

By N. S. Dalal, X. Shi

It has been known for more than a decade that vanadium (V) stimulates the oxidation of NADH by plasma membranes (1) but the underlying mechanism is still not fully understood. This effect has been attributed to a membrane-associated NADH-dependent vanadium (V) oxidoreductase (1). Subsequent studies suggest that vanadium ( V) can accept an electron from fiavoprotein dehydrogenase that oxidizes NADH (2). The phenomenon ofNAD(P)H oxidation coupled to vanadium(V) reduction has also been demonstrated in other biological systems (3-6). A recent electron spin resonance (ESR) study from our laboratory reported on the accumulation of vanadium (IV) duringthe reduction ofvanadate (vanadium(V)) by the ftavoenzymes glutathione reductase (GSSG-R),4 lipoyl dehydrogenase, and ferredoxin-NADP+ oxidoreductase in the presence of NAD(P)H (7). It was concluded therein (7) that these ftavoenzymes function as NAD(P)H-dependent vanadium(V) reductases. More recently, however, Liochev and Fridovich (8) have argued that the ESR data (7) do not demonstrate that the investigated fiavoenzymes act as vanadate reductases. They suggest an alternative mechanism in which the fiavoenzyme simply serves as a generator ofsuperoxide (02) radical, which acts as a propagator of the radical chain reaction leading to NAD(P)H oxidation (9, 10), as summarized below:

Nov 1, 1995

By Regina Maria Pinheiro

This work has for objectives to characterize a waste generated in the form of sludge during the treatment of the effluent of a paper making industry and to evaluate the effect of its incorporation in the amount of 10 wt.% on the properties and microstructure of a clayey body used for brick production. For the characterization of the waste the following techniques were used: X-ray diffraction, X-ray fluorescence, differential thermal analysis and termogravimetric analysis. Incorporated bricks were produced in industrial scale before firing at 750°C in a Modified Caieira type furnace. The physical and mechanical properties evaluated were water absorption and compression strength. The microstructure of the fired ceramic was evaluated by optical microscopy. The environmental evaluation was made by solution test and atmospheric emission by monitoring the release of SO2, NOx and particulate material. The results showed that, in agreement with the characteristics of the waste, its recycling into red ceramic can contribute to decrease the consumption of fuel during the firing stage. The properties of the fired ceramic attend the norms. With respect to the environmental aspect, the incorporation of the waste did not impact the environment.

Jan 1, 2009

By E. H. Myrhaug, K. Aasly, T. Malvik

Six different types of quartz and quartzites used as raw materials by ferroalloy plants have been investigated with respect to their thermo mechanical properties. In order to investigate the effect of the thermal shock caused by the rapid heating of quartz when it enters the furnace, the following techniques have been used for both in situ investigations and investigations of pre-heated quartz: -Heating stage microscopy for in situ observation of heating effects. -Shock heating of quartz in an induction furnace An optical microscope-mounted heating stage was used for in situ observations of the microscopic effects of heating up to 1300 ºC. The effects of heating were observed at different temperature intervals in different samples. The main temperature intervals were below 573 ºC and above 1000 ºC. The cause of the observed effects is interpreted as fluid inclusion decrepitation for T<573 °C and structural implications (micro cracks, grain boundaries and remaining fluid inclusions) at T>1200 °C. Shock heating of the samples was carried out in an induction furnace to 1300 ºC for ten minutes. The effects of the heating were studied with different techniques such as direct observation during and directly after heating, optical microscopy and XRD. Combined transmitted and fluorescence light microscopy shows that the heated quartz show an opening of the grain boundaries and evenly distributed micro cracks that were not present in the unheated reference samples. In some of the heated samples, weak generation of cristobalite was detected by XRD.

Jan 1, 2007

By Elmer Palmer

As part of the Goldcorp Inc growth plan Minera Peñasquito SA de CV has developed its polymetallic deposit with a large ?state of the art? concentrator to process lead and zinc ores. The plant consists of two grinding lines including 38ft diameter SAG mills and 24ft diameter ball mills. During mid to late 2009 concentrator commissioning activities commenced. First concentrates were produced in October 2009 and now the plant is meeting its design basis of 65,000 mtpd per line. This paper describes the design and operational experience to date for its grinding circuit design, together with the recently commissioned HPGR crushing circuit.

Jan 1, 2012

By Paul M. Tyler

One of the best present-day yardsticks of the material welfare of a nation is its consumption of minerals, The United States, with only 7 percent of the world population, consumes 45 percent of the world wealth, pays the highest real wages, has the shortest working hours, and numbers the largest percentages of home owners among its population, and at the same time its per-capita consumption of minerals is far greater than that of any other nation. In 1937, British India, with roughly twice the population of the United States, used less than 2 percent as much lead, 4 percent as muck zinc, and 13 percent as much copper; even in Europe, which has three times our population and where war preparations have greatly expanded the normal needs of peaceful industries, the aggregate consumption of metals and industrial minerals other than lignite is less than the total for the United States alone. The march of civilization passed from the Stone Age to the Bronze Age before the dawn of history. It may be questioned whether man or monkey first threw stones at an enemy, but only man could have fashioned rough stones into weapons. Eoliths rudely shaped by apelike men are believed by archaeologists to have antedated by hundreds of thousands of years the existence of our own human ancestors. The primitive people that followed the retreating Ice Cap northward in early quaternary period - at least a million years ago - were fairly adept in the shaping of flints and even used a little copper. The Bronze Age, so-called, superseded the Stone Age when, around 8,000 B. C., the news spread that chunk s of natural copper could be pounded into better weapons or cutting implements than ever could be made by chipping stones. The Bronze Age gave place to the Iron Age about 1,000 B, C., and though students of modern history may speak of the Coal Age, the Petroleum Age, and the Automobile Age, and so on, these ages have all been crowded into a brief century and a half. The truth is that we still are in the Iron Age, unless perhaps we choose to call it the Age of Many Metals.

Jan 1, 1940

By Pavel Vasak

Microseismic monitoring has become standard practice in the mining industry as a ground control monitoring tool at depth. Translating the information into practical hazard assessment tools for the rock mechanics practitioner is the focus of research jointly conducted at Creighton Mine by INCO Mines Technology Centre (MTC) and the Geomechanics Research Centre (GRC) in Sudbury, Ontario. Rock mass damage mechanisms are typically related to stress and the presence of geological structures. Due to well executed de-stress blasting practices at the mine, stress related problems are minimized. However, structurally related damage mechanisms associated with shear zones, faults and joints pose a substantial hazard. Identifying active structures from the dataset of seismic and microseismic events is generally problematic. We propose a new methodology that uses a combination of spacetime event density, hierarchical clustering and principal component analysis to identify planes of microseismic activity, termed active planes (APs). Once identified, the presence and intersection of active planes can be used to provide a hazard ranking for nearby excavations. The ranking is based on the standard Q rock mass classification system, with emphasis on the joint set number (Jn) and stress reduction factor (SRF) parameters. If the rock is treated as a fractured continuum, then, the Jn indicates the degree of freedom for blocks to move and hence, increased potential hazard. An increased hazard can also result if the APs are larger-scale and discrete (faults) rather than ubiquitous (joints). In this case the SRF is used as a measure of the degree of looseness in the rock mass.

May 1, 2004

Sm-Co alloy is a kind of magnetic material with high power and has been applied in modern industry widely. In this study, the wet chemical co-precipitation was developed for synthesis of the Sm-Co alloy oxide precursor. The thermodynamic analysis of the studied system was done to clarify the solution behavior theoretically based on the thermodynamic equilibrium and simultaneous equilibrium. Then, the experiments were done to address the various effects on the wet chemical process, including solution pH, reactant concentration, dispersant, reaction temperature and time, etc. It is found that by precise control of the process, the Sm-Co alloy oxide precursor was synthesized with fine crystallization and special size & size distribution.

Jan 1, 2005

By O. J. C. Runnalls

"Canada became the world&apos;s largest uranium producer in 1984. That leadership position is likely to be maintained for many years into the future because of a firm production base, many undeveloped known deposits with commercial promise, and a large geologicalpotential for new discoveries.There are some uncertainties on the horizon, principally because of restrictive actions in process within the U.S.A., which are aimed at preserving a deteriorating domestic uranium industry. Should such actions result in import restrictions, for example, there would be a negative effect on foreign producers at least in the short term. Canada may avoid such difficulties under a tentative U.S.-Canada free-trade agreement where restrictions on the import of Canadian uranium into the United States would be eliminated. Over the longer term, demand for Canada&apos;s uranium resources will grow because of the foreseen growth in the world&apos;s installed nuclear power capacity. IntroductionSince the phenomenon of nuclear fission was discovered in 1938, the utilization of uranium has grown substantially. Initially, the principal use for uranium was in the production of nuclear weapons. However, once civilian nuclear power reactors began to be built in the 1950s, an increasing fraction of uranium output was directed to the production of fuel elements for use in electricity generating stations.The cumulative uranium production by those countries in the World Outside Centrally-Planned-Economies Areas, WOCA, during the period 1938 to 1985 exceeded 800 000 tonnes of uranium. Some 60% of that was mined in the United States and Canada, as indicated in Figure 1. In 1986, nearly 80% of WOCA output came from five countries, Canada, United States, South Africa, Australia, and Namibia, as indicated in Table 1 and illustrated in Figure 2.During the past decade the world annual consumption of nuclear energy has more than tripled (Fig. 3). As of December 31, 1986, the world total of nuclear power reactors had reached 394 with a total net capacity of 270 GWe. The thermal output from nuclear power plants in 1985 exceeded 60% of the energy contained in all of the oil produced that year in the Middle East. Thus, nuclear power has already become an important component in the world energy supply picture."

Jan 1, 1988

By Susumu Okabe

Injection metallurgy is widely adopted in various fields of metallurgical operations to achieve high productivity. The Mitsubishi Continuous Copper Smelting and Converting Process employs the top blown lance technique for the continuous supply of solid charges and reaction gases into the molten bath, where the agitated bath contributes to enhance the heat and mass transfer and the increased gas/liquid interface area accelerates the reaction. However, excessive splashing of the molten materials accompanied by the injection may cause an unexpected wear of the furnace lining. In order to estimate the splashing rate quantitatively, and to optimize the furnace design and the blowing condition, a physical model study of the top blown gas injection onto the liquid bath was carried out. An equation of the splashing rate was obtained as the function of cavity size, gas velocity and bath properties.

Jan 1, 1995

By Habib Zughbi, Paul Zulli

"A key step towards sustainability in iron and steelmaking is to optimise the use of raw materials and energy consumption, and consequently minimise CO2 emissions. Models based on a Process Integration (PI) approach play a key role in evaluating various scenarios and the impact of introducing changes in raw materials and operational conditions on the overall energy consumption and CO2 emissions. BlueScope uses a PI based comprehensive model for its Port Kembla Steelworks (PKSW), called the Integrated Steelworks Energy and Emissions Model (ISEEM). ISEEM is tightly coupled to the configuration of PKSW. It is based on mass and energy balances as well as thermodynamic relationships. ISEEM is a steady-state model and is used to predict overall and detailed unit-by-unit energy consumptions and CO2 emissions. It is also used for plant-based scenario modelling. This paper investigates the impact of major changes to PKSW configuration, including the shutting down of a blast furnace and cokemaking battery, on the energy consumption and CO2 emissions of the plant. It discusses some of the issues involved in updating the model and some identified opportunities."

Jan 1, 2015

By M. Ahrens

The paper describes the main drive systems of an iron ore pelletizing plant and related important design aspects. It is shown how today?s drive systems provide the desired flexibility for the process and lead to high energy efficiency and system reliability. With respect to electric drives expansion projects have many technical issues in common with green-field installations. However, there are aspects where important, distinct differences occur. It is shown which considerations for selecting and sizing drive systems for such a plant as well as for integrating them into an overall plant control concept need to be taken into account. Besides the design of the drive systems a key aspect for such an expansion project is the network interaction. Harmonics levels at different points in the plant network need to be checked carefully with simulations during the design phase to avoid problems later-on during operation. The power factor compensation and the harmonic filtering of the new production line cannot be designed independently of the already existing plant. The paper highlights areas where problems could occur and which points need to be paid attention to when a plant is expanded.

Jan 1, 2008