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By William Phillips

This paper was prepared at the request of Capt. A. F. Lucas, Chairman of the Institute's Committee on Petroleum and Gas, as a preliminary discussion of the fuel oils which are used-in the Southwest, giving their composition, uses, prices, etc. Should it afterward be found desirable, these observations may be extended over a larger area. In this connection, J suggest that samples of all kinds of fuel oils, including various tars, from all over the country, be collected and sent to some testing laboratory for examination. We would be glad to extend the facilities of the laboratory of the Bureau of Economic Geology and Technology, at the University of Texas, for this purpose, and to do the work free of all expenses. After such examinations are made and the results classified and studied, it would be possible to suggest specifications under which fuel oils should be purchased, and to arrive at some conclusions respecting the uniformity of such specifications, with due allowance for climatic and other more or less local conditions. While such specifications do not now depart from a common standard anything like as much as specifications for illuminating oils do, yet there are discrepancies which should not exist. Some of these discrepancies are of lessening importance, due to the pronounced tendency to distill every crude oil that can be distilled with profit, and to send residues into the market for fuel oil. Residues from the refineries are of a more uniform chemical composition and physical nature than many of the crude oils that go direct into the fuel market. The lower flash-point oils are disappearing from the fuel trade and in place of them we are getting oils that do not flash below 220° F., nor burn under 320° F. In the Southwest, it has not been long since we had fuel oils that flashed at as low as 110° F., and the average flash point over a considerable period was 151° F. Now we are using oil that flashes at about 30° lower than the former burning point, which was 256° F. In other words, the flash point has risen, on the average, 100°; and the burning point about 75°.

Jan 6, 1914

By Steve Rogers

Nautilus Minerals was listed on the Toronto Stock Exchange in May 2006. The company now has major mining companies Anglo America (5.7%), Teck Cominco (7.2%) and Epion Holdings (22.4%) as significant shareholders, and has raised approximately $US346 million dollars to develop the world's first deep-water mine. The company is currently targeting high-grade copper and gold in seafloor massive sulphide mineralization, located near plate boundaries in back-arch basins of the Western Pacific. The first mine scheduled to be developed by the company is located in 1,600 meters of water at Solwara 1, in the relatively quite waters of the Bismarck Sea approximately 50 km from the port of Rabaul, within the Territorial Waters of Papua New Guinea. During 2006 and 2007 the company completed detailed environmental and geological studies, culminating in a number of world firsts, including the world?s first NI 43-101 compliant resource statement and environmental impact study for a seafloor massive sulphide system. Permitting is well advanced for the project, with initial production scheduled for late 2010, subject to timely grant of the permits. Extensive government and stakeholder liaison and engagement has been undertaken throughout the projects life, and is a core feature of Nautilus' desire to "do it right" in all aspects of this new industry.

Jan 1, 2008

By Qingyun Huang, Wei Lv, Junyi Xiang, Xuewei Lv, Chenguang Bai

The roasting is the key step for the extraction of vanadium from vanadium slag by calcification roasting–acid leaching process. In this study, thermogravimetric analysis and kinetic study of vanadium slag in the presence of calcium oxide was investigated. The maximum oxidation degree was slightly increased by increasing temperature from 700 to 900 °C then almost unchanged further increasing temperature to 1000 °C. The reaction mechanism was analyzed through both Sharp method and ln-ln method. Results showed that the mechanism the reaction in the a range of 0.1–0.8 corresponded to the random nucleation and subsequent growth, as represented as (G( a)=[ −ln(1−a)] 1/3 = kt. The apparent activation energy was calculated to be 3.5 kJ/mol according to Arrhenius equation.

Mar 1, 2018

By G. Rajesh

Mathematical modeling of bioremediation has gained importance as it is used as an optimization tool for the remediation process involved in contaminated sites. The bioremediation of Cr(VI) has been studied taking into consideration the initial Cr(VI) concentration Cr(VI)ini, bacterial growth substrate concentration (S), maximum growth rate (µmax), yield coefficient (Y), half saturation constant (Ks), and inhibition constant (KI). As the enzymatic reaction is also affected by initial substrate concentration (Sini) and Ks, different ratios of (Ks/Sini) are analyzed. As the inhibition constant (KI) is not constant for all the enzyme reactions and it varies with Cr(VI)ini, the correlation between (KI) and Cr(VI)ini is developed. A set of differential equations pertaining to bioremediation of Cr(VI) has been solved using FORTRAN 90 program adopting the model developed. The results are verified with the experimental data from the literature and a good correlation has been obtained between the experimental data and the model predictions. Keywords: bioremediation, hexavalent chromium, mathematical model, inhibition kinetics

Sep 1, 2012

By R. F. Hinds

A pressurizing system was designed and built to apply a radial pressure of 5.000 psi to rock samples. Samples of the Bradford, Weir and Kirkwood sandstones were subjected to radial pressures parallel and perpendicular to the bedding in the system and the changes in conductivity, porosity and permeability were deter-mined. Asymptotic decreases in conductivity, porosity and Klinkenberg permeability were observed over the 0- to 3,500-psi range. From these data, the increase of formation factor over the same range was calculated. The cementation exponent expressed in the Archie equation was found to increase with pressu,re. The rate of change varied from formation to formation. Only small differences were observed for samples taken parallel to the bedding as comnared to those taken perpendicular to it except for the Bradford sand. Above 3,500 psi the data are not good enough to tell if the properties continue to fall-off asymptotically or in a different manner. A possible explanation for the probable litnit of the asymptotic rate around 3,500 to 4,500 psi is that this represents the maximum pressure which the formations have unrdergone during their geological life as a result of burial. INTRODUCTION For many years measurements have been made in the laboratory of the properties of oil-bearing sandstones with little consideration being given to whether these properties had been changed when the samples were moved from their original position in the ground to the laboratory. Relatively little has been reported in the literature on the effect of pressure on the properties of sandstones. The changes in permeability for eight typical consolidated oil-bearing sandstone samples with overburden pressure (0- to 15,000-psi range) was presented by Fatt and Davis' in graphical form. In 1953 Fatt' also reported the relationship between porosity and overburden pressure for four typical consolidated oil-bearing sandstone samples (0- to 5,000-psi range). Fatt later described the changes of formation factor and porosity of 20 typical oil-bearing sandstone samples with overburden pressure changes (0- to 5,000-psi range) giving the values of the coefficients and exponents in the Archie' equation, and the more general Winsauer equation', where C, k and m are empirical constants, F is the formation factor, and + is the porosity. During the experiments of this investigation the core was contained in a neoprene rubber sleeve as shown in Fig. 1. It was held between two steel end members which were mounted in a steel cylinder. The unassembled pressure cylinder with its component parts is shown in Fig. 2. The core was insulated from the two steel end members by a Teflon sleeve with a small hole in the

By R. J. Wysor

Since the outbreak of the European war, few problems of raw-material supply have commanded more nation-wide attention than potash. It is well known that before the war the domestic production of potash was an insignificant percentage of the imports. The average annual importation of raw potash salts for several years prior to 1914 was slightly over 300,000 net tons, and of other potash manure salts about 700,000 tons. The sudden and almost total cessation of these imports created a unique and stringent situation. Methods of recovering potash from feldspar and other native mineral sources, and reclamation from hitherto waste products, have received a marked impetus. Soaring prices have been a keen incentive to research and industrial development. Although several brief articles concerning the possibilities of potash recovery have appeared in recent trade journals, it still may be a matter of some surprise to the average technical mind that potash might be reclaimed as a profitable byproduct in the manufacture of pig iron. At the present time it may be of special interest to present some data, largely of a technical nature, on this subject. A fairly thorough search of the literature reveals a number of articles concerning salts of the alkali metals in the blast furnace. Many of them deal with the theoretical rôle of alkali cyanides in the furnace. Several discuss the probable effect of the alkalies on the furnace brickwork. Two or three ambitious patents have been granted for reclaiming potash or other products from blast-furnace gas. However, we have heard nothing further as to the practical application of these patents. Little literature of importance has appeared during the last 10 years concerning alkalies in blast-furnace practice, and I have discovered no record whatsoever as to the actual sale or commercial disposal of flue dust for its potash content until this was inaugurated in our plant at Bethlehem. A bibliography of the most important articles discovered is appended. About 4 years ago, in the course of investigating blast-furnace stove efficiencies, I analyzed the fine, yellowish fume of which a considerable

Jan 1, 1917

By D Akis, A Clark

The Lihir gold operation, located in the New Ireland Province of Papua New Guinea (PNG), approximately 900 km north of Port Moresby, was commissioned in 1997 under the management of the Lihir Management Company, a subsidiary of Rio Tinto. This management period ended in 2005 with Lihir Gold Limited (LGL) becoming self-managed. LGL is now the largest listed company in PNG and a top tier mining company in Australia. The focus of the operation since 2005 has been to take advantage of strong market conditions to increase cash flow while driving operating costs into the lowest quartile of gold producers. During this period production has increased through capital expansions, most notably with the addition of a flotation circuit, and through culture change and efficiency improvements. The next step forward for the Lihir operation is a major plant upgrade to increase production to an average of around one million ounces per annum by matching the ore processing rate to the ore mining rate. The key benefits of this project will be the addition of approximately 240 000 ounces per annum of gold production, the access to an additional one million ounces of gold and the ability to meet all stockpiling requirements. The Lihir operation has come out of the boom period in a strong position, is undertaking a major upgrade at a time when prices are low and labour is available, and will be positioned to take advantage of future opportunities as they arise.

Jan 1, 2009

By G. P. Airey, R. F. Mehl, T. A. Hughes

The coarsening of cementite particles in a ferrite matrix has been studied in a series of steels with 0.15 pct C only and 0.15 pct C plus 1 pct Ni, Mn, and Cr, respectively. Two initial states were employed: quenched nartensite, and quenched and cold-rolled martensite. A series of tempering temperatures between 500' and 700" and tempering times of up to 190 hr were used. The structures were studied by replica and transmission electron microscopy. Particle size distribution curves were determined. From the average size value coarsening curves were obtained. These were plotted in accordance with the Wagner analysis assuming diffusion control. A discussion of the significance of the results is given. L HE reactions occuring upon the tempering of martensite have long engaged the attention of metallurgists. The latter stages, when cementite particles coarsen in a ferrite matrix, have been studied both qualitatively and quantitatively. Studies of such coarsening processes have recently been spurred by the publication of the Lifshitz-Wagner theory1, and the extension of this to the a Fe-Fe3C system by Oriani3 and by Li, Blakely, and einold. Following Wagner the coarsening process is often designated as "Ostwald Ripening". The only quantitative data on the rate of coarsening, except for the work of Hyam and uttin,' in the a Fe-Fe3C system are those of Bannyh, Modin, and odin' for a commercial eutectoid steel and those of Heckel and ereorio" using a pure eutectoid steel. The data of Bannyh, Modin, and Modin have been employed by 0riani3 to derive the a Fe-FeE interface energy. The reaction is one of the most important ones in steel and is worthy of detailed study. This is the purpose of the present study. Laboratory heats were prepared; these were steels with approximately 0.15 pct C, selected so that the num ber of carbide particles would be relatively small and thus so that the overlapping diffusion fluxes would be minimized, presumably a desirable circumstance.'-3 In addition to Fe-C alloys, comparable heats containing 1 pct of Ni, Mn, and Cr, respectively, were included with a view of appraising the effect of alloying elements. This report includes an account of the micro-structures observed, primarily with the electron microscope, and of kinetic data and their interpretation. MATERIALS AND TREATMENT The alloys were prepared from electrolytic iron ("Plastiron") and high-purity graphite; these were melted in a zirconia crucible using a vacuum furnace. The alloy steels were made by adding electrolytic nickel, electrolytic manganese, and "vacuum grade" chromium, respectively, under a partial pressure of argon. Each melt was poured into a mold within the vacuum furnace and cooled in the mold. The ingots were 2 in. in diam. and 8 to 10 in. long. The analysis of the alloys is given in Table I. These ingots were hot-rolled to strip 0.1 in. thick, then cold-rolled to 0.05 in. and each alloy split into two batches. One batch was austenitized at 1200 for 1 min, quenched in cold brine, then cold-rolled to 0.02 in.; samples given this treatment are hereinafter designated as "worked". The other batch was cold-rolled to 0.025 in., austenitized at 1200" for 1 min, and quenched in cold brine; such samples are hereinafter designated as "quenched". These two batches were then tempered, as below. The purpose of the treatment given the first batch was to provide an initial structure of cold-worked martensite, with the expectation that the additional defect structure created by cold work would encourage a higher rate of nucleation of cementite on tempering and hence a more uniform distribution of cementite particles. Individual specimens were sealed in evacuated quartz or Pyrex tubes, then tempered in a muffle furnace. The temperature control was better than 3'C at 700. Tempering treatments wer: performed at 400°, 500°, 550°, 600°, 65o°, and 700C for time periods between 15 min and 190 hr. PREPARATION OF SPECIMENS Specimens for optical and replicalelectron microscopy were mounted, polished conventionally, and etched with 2 pct nital. For electron microscopy, single-stage "formvar" replicas were made, dry-stripped and rotary-shadowed with chromium at an angle of 30 deg. Carbide extraction replicas were prepared from electropolished specimens usirig the method described by Smith and uttin.' Thin foils for electron transmission microscopy were prepared by chemical thinning in an H202-HF bath prior to electropolishing in a chromium trioxide-acetic acid solution. The most

Jan 1, 1969

By AIME AIME

MEXICO embraces one of the great metal and petroleum producing provinces of the world. In this respect its history dates back to the overthrow of the Aztec empire by a Spanish force under Hernando Cortes between 1519 and 1.521. Even before then, its richness in silver and other minerals was not unknown. But it was a treasure house for the Spanish conquerors until the country became independent in 1821. It has been computed that in the 400 years following 1521, Mexico yielded 1.55,000 metric tons of silver, worth $3,000,000,000, two-thirds of the entire world production. In 1935 the country accounted for 36 per cent of the world's silver output, 14 per cent of its antimony (in 1934), 13 per cent of its lead, 3 per cent of its zinc and copper, and 21/2 per cent of its petroleum. Contrary to the impression of some, its gold output is now comparatively small, though important in the past. Its oil, as well, formerly hulked much larger than now, in 1921 being one-fourth of the world output.

Jan 1, 1936

By Harry G. Dosh

Sillimanite, kyanite, and andalusite are aluminum silicates having the same chemical composition (Al2SiO5) and are used in the ceramics industry for the manufacture of high-grade refractories. Natural sillimanite with added corundum or other alumina to just short of mullite (3Al2O3 -2SiO2) proportions is unequalled for jobs wherein strength at high temperatures, resistance to spalling, and resistance to slagging by acid slags are desired. High-grade porcelain ware also requires these minerals. At the same cost, sillimanite would be preferred for most uses, but the lack of any large source of sillimanite bas given economic preference to kyanite or andalusite for special refractories and high-grade porcelain wares. Sillimanite-bearing schists were observed in Spartanburg County, S. C.; as early as 1937 by D. Hoye Eargle, geologist with the U. S. Soil Conservation Service. The mineral was not identified until 1942, when Miss Jewell Glass, of the U. S. Geological Survey, examined several of the deposits. This identification was confirmed in 1943 by Dr. Laurence L. Smith, of the University of South Carolina, when he examined the Spartanburg County deposits and found numerous additional occurrences of sillimanite schist in Greenville County. Subsequent work by the Bureau of Mines and the South Carolina Geological Survey has been responsible for the location of additional sillimanite-rich schist deposits in Spartanburg County. Between October 1, 1948, and November 21, 1948, the Bureau of Mines conducted an exploratory diamond-drilling project on the John Gideon property in the southeastern section of Spartanburg County (fig. 1) and drilled a total of 681.7 feet in six holes. Drilling indicated that the deposit is relatively shallow, as no ore was cut below the zone of weathering.

Jan 1, 1950

By J. L. Watson

The composite nature of titanomagnetites found on the west coast of the north island of New Zealand is an important parameter in the beneficiation of the black beach sands for export to Japan. To investigate this composite nature, borehole and plant samples from the Waipipi Ironsands Ltd property were subjected to a series of separations in heated Clerici solutions at densities varying from 3.2 to 4.6 g/cc. The resulting density fractons were analyzed magnetically and a set of distribution curves for composite grains proposed. In addition the experi¬mental data was plotted to produce titanomagnetite sand 'washability curves" which illustrate the possible problem areas in beneficiation that may arise due to composite titanomagnetite grains. From this data a set of guidelines are suggested for interpreting the curves in terms of ease of gravity concentration. The composite nature or liberation of titanomagnetite grains is shown to favor high and low grade composites with few intermediate compositions being isolated. The relationships between grain size, borehole depth and liberation are examined and related to beneficiation procedures for the black sand deposit.

Jan 1, 1982

By Constantine C. Popoff

"INTRODUCTION AND SUMMARYDuring 1946 several high-grade limestone deposits in western Washington were examined by the Bureau of Mines. This report presents the data obtained from investigation of the Sauk Mountain deposits in east-central Skagit County, Washington.The investigation consisted of transit and topcgraphic surveys and sampling. The areas selected for sampling were first cleaned by blasting; channel samples up to 40 pounds were cut where practical. Chip samples averaging 30 pounds were taken where channel samples could not be cut. A total of 21 samples in the Sauk Mountain area were taken and. analysed. The locations of the samples are shown in figures 2 and 4, and the analyses are listed in tables 1 and 2. This investigation is a part of a long-range program of general investigation of mineral resources for future industrial development of the Pacific Northwest. The Sauk Mountain deposits were investigated for the purpose of disclosing now sources of high-purity limestone, which could be mined and shipped at low cost to Seattle and other industrial cities in the Pacific Northwest."

Oct 1, 1948

By Greg Struble

The Homestake Gold Mine is one of the deepest and most extensively developed hardrock mines in North America. The mine is divided into five divisions which produce a total of 1.7 million metric tons of ore per year. In the past, labor intensive mining methods such as open cut-and-fill, shrinkage, and timber stoping were utilized. In recent years there has been an extensive change to the more productive methods including Vertical Crater Retreat and Mechanized Cut-and-Fill. Also, the percentage of production from the lower divisions below the 4850 level is increasing while upper level reserves are beginning to decline. Combined, these factors have strained the ventilation resources to the limit. By early 1984 it became clear that future production trends would require a detailed study of future ventilation resources. By November of 1984 the Ventilation Department completed a study to project these future requirements. This paper will detail the first phase of a scheduled two phase upgrade: the installation of a new surface fan.

Jan 1, 1987

By C. E. Tackett

The Greenwich Collieries Co. is a subsidiary of the Pennsylvania Mines Corporation, and a wholly owned subsidiary of the PP&L Co. which serves the northeastern portion of Pa. PP&L annually consumes about 11 million tons of coal per year and is the largest consumer of both bituminous and anthracite coal on the eastern seaboard. Development work for Greenwich started in 1969. The coarse coal plant was constructed in 1970, with the raw fines bypassed. This worked very well for our requirements at that time; however, the Greenwich mining plans were extensively changed, longwall mining units were installed and low coal was encountered, resulting in dirtier coal, a finer coal and an ever increasing ash in the shipped product. All this demanded a more efficient ash removal process for the fine coal fraction. In 1971, the Pennsylvania Department of Environmental Resources and the Federal Environmental Protection Agency were pushing for the now stringent sulphur emission limits at our power plants. The Greenwich Mine coal reserves contained large quantities of 3.5 to 4% sulphur along with some low sulphur reserves. It was, therefore, essential that any new plant have the capability of efficient sulphur removal to meet the Pennsylvania Department of Environmental Resources and the Federal Environmental Protection Agency required limits. To meet these limits our design would have to be capable of producing a product of 2.0% sulphur or less.

Jan 1, 1977

By E. G. Banks

THIS paper is presented in the belief that metallurgists and chemists will be interested in the practice of grinding in tube-mills in connection with stamps, especially since the records of working here given extend over a lengthy period of time (since May, 1905). The ore from the Waihi mine-more especially that produced in the upper levels-contains a large proportion of hard, chalcedonic quartz, and the gold exists in an exceedingly fine state, conditions which necessitate very fine crushing in order to ob¬tain a high extraction of the precious metal. Before the introduction of tube-mills at the 90-stamp Waihi mill, it was found necessary to stamp through 40-mesh (1,600 holes per sq. in.) woven wire-screens, having a fairly high discharge. The pulp then graded

Jan 1, 1907

By Ray D. Peterson

The hydrothermal enrichment of chalcopyrite by CuSO, occurs in the absence of oxidizing or reducing reagants. Kinetics of the enrichment process were determined under autoclave conditions in the temperature range of 398°K (125°C) to 473°K (200°C). Covellite (CuS) formed first, followed by digenite (Cu,,,S), with rejection of iron to the solution. The kinetics have been explained by a model which includes diffusion during the first stage formation of covellite followed by surface reaction rate control when digenite be. The effects of particle size, temperature, pH, and cupric and ferrous ion concentrations on the leaching kinetics were examined. Additions of ferrous ion to solution markedly increased the rate of reaction.

Jan 1, 1994

By P M. Larionov, V I. Zaikovskii

Transmission and scanning electron microscopy together with X-ray spectral microprobe analysis were used to investigate the structure and chemical composition of pathological calcified formations on the bioprostheses of heart valves. Controllable synthesis was carried out under the conditions (T = 37¦C, pH = 7.4) when the ion composition of the main elements (Ca, P, Mg and NaCl) is close to their concentrations in blood plasma. It is proposed on the basis of the obtained results that the formation of the hydroxyapatite of calcific inclusions on bioprostheses occurs as a result of spontaneous precipitation in the blood plasma. One of the factors determining the formation of massive calcified bodies on the bioprostheses of heart valves can be decreased magnesium concentration in blood.

Jan 1, 2008

By D. Pienaar, D. Stanton

This paper provides an overview of possible approaches for structuring the ventilation systems for mines that will become operational within the next decade. Features addressed in the paper include: aspects of airway design and layout in the absence of centralized vertical return shafts, the impact of using diesel-powered trackless equipment in conjunction with conveyor belts in the development and production phases of the project, and the need to balance increasing electrical power costs against the requirement for reduced capital expenditure. The paper provides brief descriptions of the strategies employed in real-life situations and presents an overview of various operational parameters affecting the design of ventilation systems that will be used as ?platforms? for much deeper mines in the future.

Jan 1, 2006

By R. A. Swalin, B. W. Roberts

ONSIDERABLE controversy has centered about the existence of an order-disorder transformation in alloys in the composition vicinity of 75 atomic pct Ni and 25 atomic pct Cr. All the evidence to date for such a transformation is of a rather indirect nature, since direct X-ray confirmation is difficult to obtain as a result of the small difference in X-ray scattering factors between nickel and chromium. As a result, superlattice lines would be very faint if present. Several investigators1-5 have observed anomalies in the electrical resistivity vs temperature curves of alloys in the vicinity of 25 atomic pct Cr. The observed change is characterized by a rather broad resistivity peak at about 540°C. A discontinuous drop in resistivity is normally associated with ordering. However, Taylor and Hin-ton4 have rationalized that the discrepancy could conceivably be caused by changes in the Brillouin zones upon ordering. The same investigators measured the specific heat as a function of temperature and have also observed anomalies in the vicinity of 540°C. Nordheim and Grant5 have proposed, because of the absence of superlattice lines and the absence of a discontinuity in the resistivity vs temperature curve, that long-range order is improbable and that the results could be better explained by short-range ordering. To date, however, the question has not been resolved satisfactorily. Neutron diffraction techniques provide a method for partially resolving the question since nickel and chromium have considerably different atomic scattering factors in the case of neutrons and, therefore, superlattice peaks, if ordering occurs, should be readily discernable. The results of a neutron diffraction investigation* coupled with a dilatometric in- vestigation are reported here. An alloy containing 28.0 atomic pct Cr was prepared from carbonyl nickel and electrolytic chromium in the form of a 1-in. diam x 10-in. ingot. Melting was done in an alumina crucible and casting in a graphite mold. The ingot was homogenized at 1250°C for seven days, after which a 5-in. long piece was cut into shavings in order to obtain a suitable neutron diffraction sample. Hardness samples and samples suitable for dilatometric analysis (% in. diam x 2 in.) were prepared from the remainlng piece. The neutron diffraction sample, along with a hardness sample, was annealed at 501°C for seven days, at which time the temperature was lowered to 479°C and held at this temperature for twenty-four more days. The hardness was observed to increase from 133 to 147 Vhn during the course of the annealing treatment, in qualitative agreement with Nordheim and Grant." Neutron diffraction traces taken at room temperature and at 42 °K are shown in Fig. 1. The insert shows the trace taken at room temperature with short counting times and thus only fair statistical accuracy. No evidence for superstructure reflections of Cu3Au-type ordering is observed. The statistical accuracy of the 4.2°K trace was improved by using longer counting periods. Several weak intensities are observed at small angles, including an aluminum reflection from the cryostat assembly and a very

Jan 1, 1958

By K. R. Barrett

The cupellation of dore/lead bullion to recover precious metals is one of the oldest metallurgical processes known to man. In recent times this has been carried out in small reverberatory furnaces but the process suffers from a number of disadvantages. A new process has been developed at the Northfleet refinery of Britannia Refined Metals Ltd, which gives much improved performance. The process depends upon the injection of oxygen through a nitrogen shrouded lance at the bottom of the furnace. The lance is consumable and of unique design. Reaction rates are high giving short process time; fuel consumption is low; oxygen efficiency is high and dore recirculation is low. The new process has resulted in substantially lower operation costs.

Jan 1, 1989