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By S. E. Jackson, L. J. Cabri

Quantitative determination of gold at sub-ppm concentrations in sulphide minerals is an important component of deportment studies for sulphide-gold deposits. Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS) analysis is preferred for this application because it rapidly and cost-effectively provides spatially resolved (<20 pm), low ppb concentration data for gold and other elements in mineral grains. Recent advances in LA-ICP-MS analysis include the development and application of elemental mapping. Raw signals from multiple line scans or lines-of-spots are deconvoluted and calibrated to generate elemental maps which provide detailed information on spatial variations of gold and other elements within and between grains.

Jan 1, 2011

By Stephen A. Hare, O&apos

Powder metallurgy processing of commercial Raney nickel powders was examined. The typical angular particle shape, in conjuction with aluminum present in a eutectic phase, facilitated interlocking leading to excellent green strength after compaction. Density and porosity as influenced by the compacting pressure were studied over the range of 37.5 to 207 meganewton per square meter (MN/m2). Sintering in an inert atmosphere from 575° to 850° C caused a volume increase which is attributed to a solid state reaction between Al and Ni2Al3 phases. The reaction is 3Al + Ni2Al3 ? 2NiA13. A thermal pretreatment of 70 hours at 700° C was required to prevent this reaction from occurring during sintering. Density and porosity as a function of compacting pressure and sintering temperature were determined after a thermal pretreatment of the powder.

Jan 1, 1976

By Benny Langston, Frank M. Stephens

Although little information is available concerning small-scale equipment for dust collection in laboratories, it is possible to adapt standard equipment for laboratory use. Dust from laboratory processes may be collected by cyclone separators, filters, electrostatic separators, scrubbers, and settling chambers. IN recent years much attention has been given to recovery, treatment, and disposal of dusts discharged into the atmosphere from operations of industry. considerable data has been accumulated on both operation and design of dust-collector equipment for commercial installations. On the other hand, there is almost no published data on design and construction of small-scale equipment to handle dust problems that arise in the ore-dressing laboratory. Dust-collection equipment such as multiclones, single-cyclones, scrubbers, chemical and mechanical filters, settling chambers, and electrostatic separators has proved its efficiency for collecting dust in industry. In the laboratory, however, the engineer is faced with the problem of collecting small quantities of dust, inexpensively, without diverting the major effort from the metallurgical problem to the problem of collecting dust produced by the process. For most applications standard dust-collection equipment is too large for use in the laboratory; however, for control of dust in large working areas it is often possible to use a standard dust collector, such as an air filter, with branch ducts to eliminate a health hazard. For example, the well-furnished sample-preparation room containing small jaw crushers, rolls, and pulverizers, in addition to the riffles and screens necessary for preparation of samples, presents a perennial source of dust. The authors&apos; experience has shown that a combination system consisting of overhead branch ducts to the individual equipment and floor ducts with grills, where applicable, connected to a central dust collector effectively removes dust generated in preparation of samples. Fig. 1 is a sketch of a downdraft dust-collector for table installation. Similar systems can be built with floor grids. For portable equipment such as laboratory vibrating screens this type of installation with a steel grill to support the heavy load is reasonably efficient. Overhead branch ducts to individual crushing and grinding equipment, although efficient, must be carefully controlled by dampers to prevent excess loss or a change in the composition of the sample. Change in sample composition can result from excess velocity, which causes selective removal of constituents of low specific gravity. Fig. 2&apos; shows the theoretical effect of terminal velocity on spherical particles of different specific gravities in air and water under action of gravity. Fig. 3 shows the effect of air velocity on composition of CaCO, coal mixtures. Although the entrainment of dust particles in a moving air stream is the basic mechanism by which all dust-collection equipment functions, usually intake velocity of the dust-collection system must be controlled to prevent loss of part of the sample. As an example of what may happen when excess velocities are used, a mixture of 50 pct coal and 50 pct limestone was crushed to —10 mesh and fed to a pulverizer equipped with an overhead dust-collection system. Fig. 4 shows the overhead dust-collection equipment used in this test. The pulverizer was set to give a product 95 pct —100 mesh in two stages. Velocity of air passing over the lip of the pulverizer was measured with an anemometer. After grinding, the finished product was analyzed to show the amount of calcium carbonate present. Fig. 3 shows graphically the increase in calcium carbonate as velocity through the dust-collection duct was increased. These data show that at a velocity of 1 ft per sec little if any of the coal was entrained by the overhead draft. At the maximum velocity, about 6.5 ft per sec, approximately 7 pct more coal was entrained than calcium carbonate. From an operating standpoint, this problem can be remedied easily by dampering the line to control velocity. The lowest velocity commensurate with satisfactory dust control should be used to prevent excess loss and, in some cases, selective dust loss. Collection of Dust in Laboratory Processes As in industry, the engineer desires to collect efficiently the dust produced by processes being investigated on a laboratory scale. However, in the collection of laboratory dusts he is faced with two additional problems: 1—The volumes of gas and the quantity of dust that must be recovered are small when compared with the capacity of standard dust-collector equipment, which must be scaled down in design except for collection of dust from large pilot-plant operations. 2—In addition, because of the variety of problems studied in the process laboratory, the engineer cannot design today a dust collector that will meet the conditions imposed by the processes of tomorrow. Sometimes, therefore, he must compromise collection efficiency to minimize the cost of fabrication and the amount of time diverted from the metallurgical to the dust-control problem. For collection of dust from laboratory processes a cyclone separator, filters, electrostatic separators, scrubbers, and settling chambers can usually be adapted for small-scale operations. The following

Jan 1, 1955

By J. R. Donald

Electric arc furnace (EAF) dust, which can be considered as a by-product of the steel recycling process, contains significant quantities of recoverable zinc and iron, as well as hazardous elements such as cadmium, lead and chromium, which can be leached by ground water. The zinc in the EAF dust is found almost entirely in the form of either zinc oxide or zinc ferrite, the latter accounting for 20 to 50 percent of the total zinc. It is important that an efficient process be developed which renders the dust inert, while reclaiming the valuable metals to off-set processing costs. During the conventional carbothermic reduction processes, iron is formed, and this iron can participate in the reduction of the zinc oxide in zinc ferrite. In the present work, the reduction of the zinc oxide in zinc ferrite by iron according to the following reaction: ZnO-Fe2O3(s,s) + 2 Fe(s) = Zn(g) + 4 FeO(s) was studied in an argon atmosphere using a thennogravimetric technique. First, a thermodynamic analysis was performed using the F*A*C*T computational system. Then, the effects of briquette aspect ratio (lid), temperature, zinc ferrite particle size, amount of iron added, as well as additions such as lime, sodium chloride, and calcium fluoride were investigated. It was found that, initially, the reaction was chemically controlled with an activation energy of 178.1 kJ/mol. Then, after a product layer had formed on the outer surface of the briquette, the reaction was restricted by the diffusion of zinc gas away from the reaction interface. The parabolic rate law was fitted to the experimental data, and the parabolic rate constant was found to be: = -6.2275 + 0.0054 T (K)

Jan 1, 1995

By J. F. Butler

The degree and type of carbide dispersion resulting from changes in the cooling rate from austenite determine the amount of carbon remaining in solution after slow cooling- from a subsequent subcritical annealing treatment. A difjusion model has been proposecl to explain the effect of carbide dispersion on the amount of carbon retained in solution and the amount of carbon in solution has been related to the degree of carbon strain aging. COTTRELL and Leak&apos; have shown that the rate of strain aging in low-carbon steels is dependent upon the amount of carbon and nitrogen in solution. Carbon can be effectively removed from solution as Fe , C by quench aging at temperatures of 200" C or lower; however, the relatively higher solubility of nitrogen at these temperatures prevents sufficient removal of nitrogen as iron nitrides. For this reason, nitrogen in solution has been considered the major cause of strain aging in rimming grades of commercial low-carbon steels. Nitrogen can be effectively removed from solution and nonaging steel produced through the addition of aluminum to form the stable nitride, AlN; however, the aluminum also causes deoxidation resulting in a killed steel. III an attempt to produce a rimmed steel which was also nonaging, Morgan and Shyne 2 investigated tile strain-aging properties of low-carban steels containing boron and found that strain aging was suplx-essed in steels containing as little as 0.007 pet B. The original purpose of this investigation was to determine the mechanism of strain-aging suppression by boron. Early in the study, the function of boron was discovered to be much like that of aluminum in that the formation of a nitride, BN, removed the nitrogen from solution.&apos; However, during the course of the investigation, an effect of heat treatment upon the strain-aging properties and the amount of carbon in solution was found which could be related to the microstructure of the steel. The purpose of this paper is to examine these relationships among heat treatment, microstructure, carbon in solution, and strain aging in steels where nondetectable amounts of nitrogen are present in solution. EXPERIMENTAL PROCEDURE The investigation was carried out using 0.030 in. by 12. in wire specimens which had been cold swaged and drawn to the final diameter. Table I lists the compositions of the low-carbon steels used. Those with &apos;V&apos; designations were vacuum melted and cast; the alloys designated &apos;AISI&apos; were prepared from high-purity iron obtained from the American

Jan 1, 1962

By Carl M. Fellman

LABOR disputes caused considerable turbulence in the coal mining industry during 1946. As an outcome of these disputes, a definitely fundamental change in safety procedure was instituted: establishment of safety regultions for coal mines through the agency of agreements between the miners&apos; union and the agency or agencies operating the coal mines. Although a temporary plan at present, the future will determine the. extent to which it may become permanent. Notwithstanding the turmoil in the industry extending through much of the year, the safety record for the first eleven months of 1946 was the best in the history of the industry for that period. The fatality rate for 1946 is lower than in any other year in the history of coal mining in the United States. This follows a pattern inasmuch as new low coal-mine fatality records were also made in 1945, 1944, and 1943. The five-year period 1942 to 1946 inclusive has a coal-mining fatality rate far lower than any other five-year period in the history of the industry. It is significant that this period exactly coincides with the operation of Federal coal mine inspection which got under way early in 1942.

Jan 1, 1947

By J Carrillo, A King

Gravity recoverable gold (GRG) is largely distinguished from other gold by its non-mineralised, metallic form, its high degree of liberation from the ore and its appreciable particle size. The gold mining industry has so widely accepted the use of batch centrifugal concentrators (BCC) and intensive cyanidation (IC) systems for the recovery of GRG that these may well be considered requirements of any plant processing ore containing appreciable GRG. The recovery of gold by gravity is quick, easy and cheap by comparison to alternatives. However, there are cases where attributes of the ore make recovery of gold by gravity and IC unusually challenging. This paper describes three examples where such challenges have been encountered and met, including those where the ore contains cyanide soluble base metals and where fine GRG is to be recovered from flotation concentrate.CITATION:King, A and Carrillo, J, 2018. Addressing challenging applications of intensive cyanidation in gravity gold recovery, in Proceedings 14th AusIMM Mill Operators&#39; Conference 2018, pp 283–290 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By J. S. Stickling, P. J. Whittaker, N. O. Lotter

"Assessment of opportunities to improve mineral processing performance in existing concentrators and in describing undeveloped orebodies is key to improving the business case of a mining company. This assessment has traditionally been performed using the distinct and separate inputs from mineral processing and mineral science.More recently, process mineralogy has been used to integrate these two disciplines. This trend has been driven by the need to develop and process more challenging ore deposits, and has been assisted by the availability of modern automated instruments. Together with the acquisition of a QemSCAN (quantitative evaluation of materials by scanning electron microscope) from CSIRO in Australia, and with the use of a supporting SEM with EDX/WDX capabilities and an XRD, the development of process mineralogy at Falconbridge commenced in 1997.The sampling challenges in presenting a QemSCAN with representative sample material at the polished section level are significant, but have been effectively addressed. The full description of this aspect is beyond the scope of this paper.It is shown that, by use of this approach, the set nature of an orebody can be best exploited with selected flowsheet changes in a concentrator which address the generic characteristics of the orebody. In this way, the flowsheet provides a process that more effectively fits the mineral processing requirements of the ore. This leads to clear and tangible improvements in grade and recovery."

Jan 1, 2002

By Robert W. Bartlett

"Economic and other factors, mostly outside of metallurgy, that strongly influence applied research, development and especially successful commercial adoption of new processes for producing primary metals and other commodity materials are reviewed. These factors, which can be both positive and negative in their influence, are often too lightly regarded in the research planning stage. They include continuing imperatives that have long influenced new process development as well as more recent trends. Both are discussed. Nearly all new materials eventually become commodities--products made to standard specifications with no producer control over price. Success requires being a low cost producer on a world wide basis. Composites and other complex material assemblages are unlikely to escape this fate as they mature.INTRODUCTIONThe adoption of new processes, beginning with research and development, for primary metals and other commodity materials is particularly difficult because each new process must supplant an existing process that is already being used commercially. There are many requirements besides technical innovation and cost superiority that must be met by the new process. Consequently, few innovations make it all the way from the research laboratory to commercial success.This paper discusses some of the factors that influence success in developing new processes for primary metals and commodity materials, based on the authors experience as a research metallurgist and industrial research manager. It begins with some of the factors that are always present and constrain successful process research and development, and proceeds to current trends that are expected to continue long enough to influence processes in the year 2000. Many of these trends are contradictory in their effect on new process development, and the future remains uncertain.The prevailing importance of these trends will vary with the material, process concept and other factors intrinsic to each case. Nevertheless, an awareness of these influences can help to avoid some of the R&D pitfalls and dead ends. Such awareness is deemed to be a necessary condition to avoid failure when commercial adoption of a new process is the goal."

Jan 1, 1988

By T. Gupta, T. Ghosh

"Rare Earth Elements (REEs) and their compounds are essential for numerous modern high tech applications such as renewable energy technologies, catalysts and defense applications. The destabilization of REE pricing owing to the global demand and supply deficit has forced many countries to re-evaluate the possibility of indigenous production of REEs. Cost effective and eco-friendly opportunities are being widely explored for extraction of REEs from non-conventional mineral sources such as coal and coal byproducts to stabilize the supply chain. Coal from Central Alaska (Healy Coal Mine) and Southern Alaska-Cook Inlet (Wishbone Hill) province have been found to possess elevated REE concentrations as compared to average world coal estimates. The objective of the study is to enrich the REEs in the fine size fraction (-75 Microns) from Healy and Wishbone Hill by froth flotation technique. A Box-Behnken design was applied for modeling and optimization of some operating variables on the flotation to maximize REE enrichment. The variables studies were frother dosage, pulp density (% Solids) and collector dosage. Experiments were carried out using a statistical design and the main and interaction effects on response variable was evaluated by analyzing 3D response surfaces. Based on the experimental results the optimum flotation conditions for maximum REE enrichment in the froth fraction was obtained at 4.2% Solids and 32.7 ppm of frother dosage for Healy coal sample and 10% Solids and 37.9 ppm of frother dosage for Wishbone Hill coal sample. The quadratic equation for modelling and optimizing the response variable is found to be independent of collector dosage for both the coal samples. INTRODUCTION Alaskan coal deposits are distributed in three major coal provinces and are in Cretaceous and Tertiary rocks. The climate, vegetation type and sedimentation process has attributed to low sulfur content (averaging 0.3 percent) in Alaskan coals compared to other coal deposits found across the globe. In Central Alaska-Nenana and Southern Alaska-Cook Inlet coal province coal resources are contained in Tertiary rocks while bulk of the Coal resource in North Slope coal province is contained in Cretaceous and Tertiary coal bearing rocks [1]. Coals from Central Alaska- Nenana (Healy) and Southern Alaska-Cook Inlet province (Wishbone Hill) have been found to possess elevated concentrations of critical REEs as compared to the amounts present in world coals (Figure 1). The Wishbone Hill deposit is considered a relatively small deposit, with about 14 million tons of identified reserves, compared to Healy which has over 500 million tons identified [2]. The REE concentrations up to 286 ppm and 524 ppm on ash basis have been reported by Gupta et al. in 2016 with elevated concentrations Ce, La, Y and Nd which are expressed to be of critical importance by US Department of Energy. Accordingly, the two coal samples possess the potential to be used as a REE resource in the near future under favorable socio-economic and geo-political scenarios. [3, 4]"

Jan 1, 2017

By Lisa Morrison

The 11th Annual Mineral Economics and Management Society (MEMS) conference was held April10-12, 2002, in Montreal, Quebec. It consisted of a series of technical sessions. Each paper addressed the economic issues that are related to the changes that many people believe are now required in the mining industry. Some of the papers were directed at how the mining industry will handle the changes that will be required in its philosophy and operations management. Of equal importance was whether the industry possesses the toolkit necessary to effect these changes and emerge stronger from its challenges.

Jan 1, 2002

By Drew Sinha

Success of the environmentally benign semiconductor manufacturing depends on the cost-effective integration of the principles of reduce, recover, reuse and recycle from source material to final product disposal. Increasing demand combined with current shortage of polysilicon provided unique opportunities to recover the silicon waste, caused by various defects, in wafer manufacturing process. Current practices relating to recovery and reuse of waste silicon produced, from crystal growth process to finally polished and epitaxially deposited silicon wafer, at Mitsubishi Silicon America is presented. Future plan to recycle the process generated silicon fines produced during the intermediate steps of the wafer manufacturing process such as grinding, slicing, lapping and polishing is also discussed.

Jan 1, 1998

By F. E. Wagner, L. J. Cabri, Y. G. Safonov, N. S. Bortnikov, A. D. Genkin, J. Friedl, G. N. Gamyanin

"A multidisciplinary investigation (including INAA, SIMS, EPMA, and Mossbauer Spectroscopy) was used to characterize gold in four of the largest Siberian mesothermal sulfide gold deposits. These are the Olympiada (""'750 metric tons gold) and Veduga (estimated at 75-100 metric tons gold) deposits in the Enisei Mountain Range and the Nezhdaninskoye (z500 metric tons gold) and Sentachan deposits in the Verchoyansk-Kolyma area. It was found that some of the mineralization is refractory in all four deposits, largely due to the occurrence of ""invisible"" gold in arsenopyrite as well as within pyrite, but with a lesser concentration. The gold concentration and its distribution varies considerably both within and between arsenopyrite grains, with implications for processing options such as heap leaching. The ore most likely to be amenable to heap leaching is the oxidized ore of the #4 orebody of the Olympiada deposit, but further quantitative mineralogical investigations are recommended for this orebody's sulfide ore and for the ores of the Nezhdaninskoye deposit. Following a full mineralogical characterization, it is possible that economic viability will depend on a combination of pre-concentration with or without pre-treatment, followed by heap leaching of some tailings products.Acknowledgements· The Russian authors performed this study under an ""Eco res"" Project which was financially supported by the Ministry of Science and New Technology of the Russian Federation. C.J. Stanley wishes to thank John Spratt and Terry Williams for help with EPMA. F.E. Wagner acknowledges the Deutsche Forschungsgemeinschaft for a grant supporting the Mossbauer studies. L.J. Cabri is grateful to the following: M. Beaulne, D. Carson and J.H.G. Laflamme for technical support, K.E. Haque for technical comments, and D.M. Hausen and W. Petruk for editorial suggestions."

Jan 1, 1997

William B. Phillips, Birmingham, Ala.: The analysis of Pratt coal made by myself, and given by Mr. Ormsbee in his paper (p. 113), is likely to mislead the reader as to the real nature of this coal. It represents the very purest coal that I have been able to get, and does not represent the average composition of the lump-coal as prepared for market. I wish it were true that the coal had no more than 2.50 ash and 0.83 sulphur. The analysis of McCalley is nearer the real figures than any of the others. There is no use in giving an

Jan 1, 1896

By R. Viljoen, K. Manns

"The mining industry instinctively follows rule-of-thumb design velocities often based on very simplistic theoretical “economic velocity” optimization calculations to determine airway sizes. Although these are important building blocks in ventilation planning it should be recognized that mines are far more complex and various, often opposing factors, are at play. Therefore, it is important that each ventilation situation be analyzed on a case-by-case basis to determine the best-fit solution for an operation. The ventilation design process should not necessarily be constrained by theoretical optimal economic velocities that become rules-of-thumb. In some cases, this could lead to unrealistic infrastructure requirements and exorbitant capital expenditure. This type of design often lacks corporate support leading to a scenario where no ventilation upgrades are implemented. Economic velocities typically consider the cost of power, development costs and operational risk. These typical rules-of-thumb work reasonably well as a starting off point when considering feasibility of greenfield projects. For established mines that are looking at expansion these rules may not be appropriate due to capital expenditure constraints or geotechnical ground conditions. The theoretical optimum should be reviewed in the case of an established mine where existing infrastructure could perhaps be maximized. For example, the geotechnical risk of large diameter raises at depth may require multiple small diameter raise to maintain the theoretical economic velocity. If a mine has a life of less than 5 years, then the cost of power is an insignificant proportion of the total owning cost. For these mines, operating the ventilation raises at an increased velocity to avoid a complicated and expensive capital upgrade might be the more appropriate option, even though it opposes the traditional rules-of-thumb. Mines which are capital constrained may be better off accepting a higher operating cost for the interim or settle for minor infrastructure upgrades rather than run the risk of the entire ventilation upgrade not being approved at all. This paper explores a number of examples derived from case studies undertaken by the authors for several deep mechanized mining projects in Australasia. The examples explore conditions under which higher than the economic norm would be applicable."

Jan 1, 2019

By Roswell W. Prouty

As part of a general plan for control and economic utilization of the waters of the Missouri River Basin as well as development of its inherent power resources, the Corps of Engineers of the United States Army has under construction a rolled earth dam near the site of old Fort Randall in South Dakota. The dam is in Charles Mix and Gregory Counties on the Missouri River at a point about 922 miles above its mouth. It is approximately 125 air-line miles southeast of Pierre and 55 miles southwest of Mitchell, S. Dak. The storage reservoir to be formed by the dam will extend upstream for 150 miles and, at maximum operating pool level, will cover an area of some 107,000 acres. It will have a storage capacity of 6.2 million acre feat.

Jun 1, 1949

By Michael Rehbock-Sander

The Gotthard Base Tunnel (GBT) is 57 km (35 miles) long and consists of two par-allel single-track tubes with an ex-cavation diameter ranging from 8.8 to 9.5 m (28.8 to 31.2 ft). These are interlinked by cross-passages every 312 m (1,000 ft). Two multifunction stations (MFS) are located in the sections Sedrun and Faido, at one-third and two-thirds of the entire tunnel length (Fig. 1). These will be used for the diversion of trains to the other main tube via tunnel crossovers, for the housing of tech-nical infrastructure and equipment and for potential emergency stops. To reduce construction time, the GBT was divided into five sections and was excavated from several sites simultaneously. The tunnel was excavated from the two portals, Erstfeld in the north and Bodio in the south, and also from three intermediate attacks, with their corresponding access tunnels, in Amsteg and Faido and two vertical 800-m (2,624-ft) deep shafts in Sedrun.

Jan 1, 2012

By A. F. Baker

The Bureau of Mines conducted pressure-drop studies in a 4-foot-diameter simulated blast furnace shaft to compare anthracite metallurgical briquets with coke and formcoke. The test materials were used alone, layered, and in mixed burdens of commercial fuel-to-ore ratios. Anthracite briquets had a higher pressure drop per foot than furnace coke, but they had a lower pressure drop per foot than formcoke. This appears to be due to packing and shape, as well as to particle size. The superficial air velocities at which beds of briquets and furnace coke disrupted were about the same. However, if briquets of the shapes and sizes tested are substituted for furnace coke in commercial metallurgical furnaces, higher blowing pressures will be required to deliver comparable amounts of air. Test burdens with more than 5 percent material smaller than 1/4-inch diameter showed significant increases in resistance to airflow.

Jan 1, 1967

&nbsp;Increasing concern about the impact of alluvial mining discharges on the water quality of some West Coast rivers lead to a joint West Coast Gold Miners Associate, Trade and Industry funded study by Water Technology (NZ) Ltd. The objective of the study was to assess the treatability of West Coast alluvial gold mining discharges and to develop simple treatment systems which could be effectively adapted to a variety of sites in the region. &nbsp; The approach was to apply standard water treatment techniques to field situations using low cost technology. Initially the various types of alluvial gold mining operations were identified then after preliminary site investigations and laboratory studies were carried out, site pilot plants were set up. The results of the trials particularly those using chemical aids were encouraging and it was found that chemical aid performance was largely dependent on the degree of mixing at and downstream of the chemical addition point. Design alterations to settling pond configurations in conjunction with optimised chemical addition yielded dramatic results in the form of reduced effluent turbidities. &nbsp; A generalised approach to effluent treatment was developed and some of the specific &apos;mix and match&apos; requirements were identified for different types of sites. The general conclusion is that improved physical treatment combined with good plant management and operation and (where necessary) chemical treatment, will produce water of acceptable discharge quality.

Jan 1, 1989

By Débora Cardoso de Oliveira Silveira, Jean-Christophe Huber, Hamzeh Hamadeh, Kateryna Pastel, Guillaume Brosse

The dynamic behavior of oxygen gas flow, determined by the lance nozzle and blow pattern, is a key factor for determining jet efficiency in BOF Steelmaking. The present work compares the performances of Laval and parabolic nozzles with the aid of the Computational Fluid Dynamics (CFD). The Method of Characteristics (MOC) was applied to design a minimum length parabolic nozzle. The results show that the parabolic nozzle generates more uniform and stable jet, with 2% longer potential core and supersonic length and less shock waves. For the parabolic nozzle, the pressure nearby the nozzle wall is higher, which can protect this region from reverse flow of converter gases and offer longer life for the lance tip. Likewise, the flow rate variations would affect less this nozzle. In addition, the nozzle wear was investigated, and the parabolic nozzle has proven relatively less sensitivity to the presence of this deformity.

Oct 1, 2019