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By E H. O Meyer, K van Dyk

Fine powders normally exhibit, to a more or lesser extent, some ability to participate in dust explosions. Zinc dust as used in the extractive metallurgy of zinc, is not known to be a reactive powder in the industry. No evidence could be found in the literature where zinc dust was involved in an explosion or explosive type event. On 3 May 2002 an explosive type incident occurred at Zincor in Springs, South Africa, which led to a fatal accident. Given the history of relative benign behaviour of zinc powders under conditions conducive to dust explosions, it was decided to share the information of this incident with industry in an effort to prevent similar incidents. Therefore, the purpose of this paper is to describe the incident that occurred at Zincor, discuss the major findings, report on corrective actions, as well as publish the results of subsequent tests that were performed to determine the conditions under which zinc powder exhibits explosive characteristics.

Jan 1, 2005

By A. F. Lee

A pick-up apparatus capable of yielding quantitative results has been described. Studies of some collector-mineral systems have been presented to illustrate the versatility of the apparatus and prove the validity of results.

By K. Dagdelen , S. K. A. Owusu

Uncertainty with regard to estimated grades and tonnages of a mineral deposit demands risk assessment in order to build investor confidence and attract the interest of other stakeholders in the success of a project. Uncertainties associated with Mineral Resource estimates can lead to unreliable production schedules and unpredictable cash flows. However, the techniques used in the mining industry to determine these uncertainties are inconsistent, because the important decisions taken in the process are solely dependent on the responsible Competent Person (CP), without limitations. This leads to disparities between different CPs’ results, using data-sets from the same drill-holes. The various standard codes for public disclosure provide guidelines and recommendations for the classification of Mineral Resources and Reserves but do not provide details on, for example, the amount of geological and geostatistical information needed to qualify for each category of Resources and Reserves. The parameters used to generate the classification categories are subjectively assumed by the responsible CP. In this paper we investigate the impacts of different CPs’ judgements on resource classification, using the same data-sets. The results underpin the need for the mining industry to develop a uniform Mineral Resources and Reserves classification framework that can minimize or avoid significant discrepancies that lead to potential misleading public disclosures.

Aug 8, 2024

INFACON conjures up many things for many people. For the fortunate few who have been actively involved with this event since its inception, it brings back memories of far places, stimulating debates and above all, the people who have over the years contributed to the outstanding success of the Congress and who have added to the wealth of knowledge on all aspects of ferroalloys. The International Ferroalloy Congress (INFACON) has been held every three years since 1974. INFACON X will be held in Cape Town in February 2004. Simple arithmetic shows that next year?s Congress should in fact be INFACON XI. Thus, one Congress was skipped. INFACON 74, as the name implies, was held in 1974, in Johannesburg, South Africa. The event was sponsored by the Ferro Alloy Producers? Association of South Africa (FAPA), the National Institute for Metallurgy (NIM - Mintek as it is known today) and the South African Institute of Mining and Metallurgy (SAIMM). You will see some of the same sponsors involved in INFACON X. Dr. Robbie Robinson, renowned academic and past president of the SAIMM, was the Chairman of the Organising Committee. The editor was Dr. Helen Glen. Anyone fortunate enough to possess a copy of the proceedings of this first Congress will agree that from a literary and technical perspective, it is still the benchmark for subsequent events. A unique feature of INFACON 74 was the use of rapporteurs (my first duty) to ensure that the discussions following the presentations were recorded (in direct speech) as accurately as possible. This involved time-consuming correspondence (can you imagine life before e-mail?) to all parts of the world between the author and the person posing the question, with the rapporteurs acting as go-betweens. It is understandable that the much-awaited proceedings only saw the light in 1975. The names recorded in the proceedings as the members of all six committees read like the who?s-who of the South African ferroalloy industry at the time: Dr. Peter Jochens, Mr. Harvey Reid, Mr. Piet Streicher, Prof David Howat, Mr. Sigurd Selmer-Olsen - to name but a few. The Congress was held in the new, very fashionable and upmarket Carlton Hotel in the CBD. In the Foreword of the proceedings, Dr. Robinson provides an insight into the event. Three hundred and thirty six delegates from twenty two countries attended the Congress, which was opened by the Honourable P.G.J. Koornhof, Minister of Mines. Again, the opening address makes fascinating reading. During the Congress an ad hoc committee was convened as the first International Committee on the Organisation of Ferroalloys Congresses, with representation from the main ferroalloy associations of the world. The following decisions were recorded: ? The Congress would be continued at three-yearly intervals under the name of INFACON ? Every third Congress would be held in South Africa ? NIM (Mintek) would provide the permanent secretariat. Six technical sessions were held, each preceded by a plenary address with a closing address by the session chairman. In all, thirty technical papers were presented. Prior to the closing address, a panel discussion on factors affecting the future of the ferrochromium industry provided stimulating debate in the form of a question-and-answer session. The hosting country for the next INFACON would be announced. Eventually, word got round that the next INFACON would be held in Japan. However, due to unforeseen circumstances, the event was cancelled ? thus no INFACON 77. INFACON 80 was subsequently held in Lausanne, Switzerland from 12th to 16th October 1980. The event was organised by IFPEO, Institut des Producteurs de Ferro-Alliages d?Europe Occidentale. The Congress was officially opened by the President of IPFEO, Mr. R. Björklund, who was also President of the Organising Committee. The technical sessions were held in the Palais de Beaulieu. The Congress was well attended by 400 participants from 28 countries as well as 100 accompanying ladies. A total of four plenary addresses and 18 technical papers were presented. As with the first event, an international panel discussion (questions and answers) preceded the closing address. In his closing address, Dr. Louw Alberts, Chairman of the International Committee on Ferroalloys and President of NIM, presented an insight into the factors affecting growth in the industry and where growth was likely to take place. Twelve exhibitors had stands at the Congress. Attendees could choose from four post-event tours to Belguim/France (SADACEM/Compagnie Universelle d?Acetylene et d?Electro-Metallurgie), France (CUAEM), Finland (Outokumpu Oy) and Norway (Elkem Fiskaa plant).

Jan 1, 2004

By G. Kleyn

"Sub-standard practices and their adverse impact on safety performance remain a challenge in the South African gold mining industry. The purpose of this study was to investigate the root causes of sub-standard practices and the effect on safety performance in South African gold mines. The focus of the study was on the underground production operations at a gold mine in the Free State. The study consisted of three parts: a personal investigation into the causes of sub-standard practices at the mine, a comparison with the results of a cultural study performed at the West Wits mines, and a behavioural survey.The studies described in this article yielded similar results in terms of the key drivers behind sub-standard practices. It was found that substandard practices had a number of causes, and the origin lies within the habits, attitude, and behaviour of employees. Current methods of addressing sub-standard practices and improving safety performance were found to discourage employees from performing work safely and according to procedure. It was concluded that the lack of critical behavioural habits for the given work environment and job title could possibly be the primary reason for the occurrence of sub-standard practices. IntroductionSince the implementation of the Mine Health and Safety Act, 1996 (Act 29 of 1996) and the Mine Health and Safety Regulations, the South African mining industry has been striving to improve health and safety performance and has placed great emphasis on adherence to mine standards.The Act requires employers in the mining industry to report accidents, incidents, and dangerous situations to the Regional Principal Inspector of Mines in their area. The data provided by employers is captured and analysed by the South African Mines Reportable Accident Statistical System (SAMRASS) and made available for public viewing (Department of Mineral Resources, 2011).A review of the national mine-related accident statistics shows clearly that the South African gold mining industry has improved its safety performance markedly over the past decade, but is still facing major challenges (Figure 1). These include meeting the Mine Health and Safety Milestones (Department of Mineral Resources, 2011)."

Jan 1, 2016

By X. J. Lyu, Q. Liu, M. J. Lian, X. Q. Cao, X. F. You, B. O. Erdenekhuyag, H. Y. Zang

The slag-tailings based artificial reef concrete (ARC) is made of CaO-CaSO4 activated granulated blast furnace slag (GBFS) as cementitious material and deslimed gold ore tailings as aggregate. In order to investigate the potential application of the material as ARC, the strength development, hydration characteristics and application performance were investigated under different preparation conditions. Results indicated that using seawater as the mixing water can effectively promote the hydration of slag and generate a large amount of hydration products such as ettringite, CSH gel, hydrotalcite and Friedel ’s salt in the early curing period and so render the material with good early compressive strength. Seawater curing can also accelerate the hydration reaction in the early stage of hydration. The hydration reaction of slag and the compressive strength of ARC can be effectively promoted by increasing the specific surface area of slag. The 28-day compressive strength of the slag-tailings based ARC prepared with 30-50% CaO-CaSO4 activated slag and 50-70% tailings can reach to 19.88-42.87 MPa. Also, the material has a low surface pH value, good resistance to chloride ion penetration, and sulfate corrosion. Keywords: Artificial reef concrete, granulated blast furnace slag, deslimed gold ore tailings, compressive strength, hydration characteristics

Jan 1, 2020

By J. H. Van Reenen, H. Thiele, C. Bergman

For some time spirals have been the process equipment chosen to recover metal in the size range 0.15 to 3mm from ferrochrome and silico/ferro manganese slags. Recoveries of metal obtained using spirals are usually about 70%. Spirals are also difficult to control. By combining a novel gate on the Apic pneumatic fines jig with the recently developed Apic classifier, metal recoveries of 76% and grades of over 90% have been obtained for FeCr and SiMn slags in the size range 0.15 to 3 mm. The paper compares classifier operating performance and costs with those spirals for FeCr and SiMn metal recovery from slags. The classifier technology can also be applied to chromite and iron ores and coal fines.

Jan 1, 2004

By R. Uwaoma, A. Goosen, R. Matjie, K. Mphahlele, J. Bunt

Coal properties that are associated with wear and damage of grinding equipment during pulverization prior to combustion were investigated. A South African Highveld feed coal and its beneficiated fractions were crushed to <1 >0.25 mm particles for the grindability tests. These particles were milled and screened into <75 μm and >75 μm fractions, which were analysed by different techniques to establish a correlation with the conventional Hardgrove Grindability Index (HGI). The <1.5 g.cm-3 float fraction, which contained 93 vol.% (mineral matter free) total -macerals,9% kaolinite, and had the lowest HGI (57) (hardest to grind) was pulverized for 15, 30, 60, and 120 minutes for particle size distribution analysis. This analysis indicated that the content of <75 μm particles increases with increased grinding time. The >1.9 g.cm-3 sink fraction, with the highest HGI (76), 44% kaolinite, and 20 vol.% total macerals, was ground easily to generate the highest proportion of <75 μm particles. Based on higher correlation coefficients (R2 = 0.77–0.91), the ash yield, mineral matter, petrographic composition, and fixed-carbon have significant effects on the HGI. Conversely, the inherent moisture and total sulphur (R2 = 0.48–0.62) have only minor effects on the HGI. Results from this investigation could be implemented in the preparation of a suitable pulverized fuel with little equipment wear, as well as utilizing mineralogical and petrographic compositions. Finally, the effect of microlithotypes and maceral types in South African feed coals on the HGI should be investigated in further pulverization and grindability studies.

Jul 5, 2023

By W. Jilowa, C. Nguni, M. Simukoko, C. Nampungwe

The upsurge in cobalt price and demand is propelled by high demand from the electronics and electric vehicle industry. Konkola Copper Mines has cobalt occurring with copper in the ratio 1:10 in ore. The ore is treated in the concentrator and recovered at the smelter as an alloy (Cu 70%, Co 4%–7%, 15% Fe). Subsequent processing of the cobalt alloy is challenging, with very few plants able to treat it, leading to marketing challenges. Konkola Copper Mines sought to improve the cobalt alloy by producing a slag that is easier to handle and process in subsequent processes. Cobalt alloy (3.60% Co, 85.4% Cu) was re-melted in a copper bath four times the mass of the alloy. Silica and lime were added for phase separation and fire refining commenced. Following completion of fire refining and after holding the temperature at 1200°C, cobalt-rich slag was skimmed and blister copper was cast into anodes for electrorefining

Jan 1, 2023

By S. Lohmeier, D. Gallhofer, B. G. Lottermoser

In Southern Africa, historic mining and mineral processing of base metal deposits have almost exclusively focussed on the extraction of major metals, leading to the loss of remaining valuable raw materials into tailings dumps and waste rock piles. At the Namib Pb–Zn mine (Erongo Region, Namibia), historic base metal tailings deposits are present as unreclaimed exposed waste piles. The tailings comprise silt- (fraction A: d50 = 25 to 48 μm) to sand-sized (fraction B: d50 = 86 to 185 μm; fraction C: d50 = 210 to 230 μm) material and contain major concentrations of base metals (Pb av. 1.15 mass%, Zn av. 3.20 mass%), S (av. 9.95 mass%), as well as lower values of other metals (Cu av. 490 μg/g, Cd av. 133 μg/g, Ag av. 22 μg/g), and critical elements like Sb (av. 14.7 μg/g) and In (14.3 μg/g). Former mineral processing only targeted the extraction of galena and sphalerite. As a consequence, qualitative mineralogical composition of the tailings is similar to that of the primary ore. Ca–Fe–Mg(–Mn) carbonates, quartz, micas, chlorite, minor graphite, magnetite, and rare parisite relate to the former host rock and gangue matrix, whereas Fe-rich sphalerite, galena, magnetite, pyrite with minor pyrrhotite, rare arsenopyrite, marcasite, cassiterite, and accessory scheelite are original constituents of the primary ore. Reprocessing of such a material would be challenging, but a mixed Pb–Zn concentrate enriched in Cd and Ag might be obtained. In future, possible reprocessing of Namib tailings and associated disposal of wastes into an appropriately designed repository would not only generate valuable metal commodities, but such activities would also eliminate a major metal pollution source from the local environment.

Sep 9, 2024

By S. Sun

Recent studies on the physico-chemical properties of molten slags and oxide solid solutions of interest is reviewed. The review covers redox and phase equilibria in slags, viscosity, diffusivity, electrical conductivity, kinetics of interfacial reactions between slags and CO-CO2, interfacial properties and phenomena. Some highlights from ongoing work on modelling phase diagrams, component activity, viscosity and electrical conductivity of multi-component slags will be presented and results compared with published experimental data on slags with or without suspended solid phases.

Jan 1, 2004

By Peter W. Lotz

Contents of: ?Sampling for Cyanide in Metallurgical Processes? ?Sampling at process level of operation ?Sampling at environmental level ?Sample stability and integrity issues ?each citing possible objectives, practical example and reasons for surprises Overall recommendations on sampling plans and procedures to maintain sample integrity

Jan 1, 2005

By R. Flatabø, K-E. Johansen, L. Hunsbedt, P. M. Cowx, J. A. Bustnes

Eramet and Tinfos are two producers of manganese alloys in Norway, which have worked hard for several decades to improve both the internal and external environment. Furnaces producing ferro- and silico- manganese alloys generate large amounts of off-gas that contains substantial amounts of dust, heavy metals and organic by-products. The dust is separated from the gas in venturi scrubbers by washing with water. The water is cleaned and recirculated, and the surplus water coming from moisture in the raw materials, is discharged to the adjacent fjords after further treatment. Emission figures show that the discharge of suspended solids, manganese, zinc and PAH (polycyclic aromatic hydrocarbons) have been reduced substantially over the last three decades as a result of process improvements and installation of state of the art environmental control measures. The two plants were the first world wide to install mercury cleaning of the off-gases from the furnaces. Mercury emission reduction has exceeded 90%. Concerning other environmental issues, such as utilisation of off-gases for energy recovery and chemical purposes, both plants have achieved good results. Major effort in the environmental work has come from the plants themselves, but other players like FFF, The Norwegian Ferroalloy Producers Research Association, and SFT, The Norwegian Pollution Control Authority, have contributed to the achieved results.

Jan 1, 2007

By S. Govender, J. J. L. du Plessis, R. C. W. Webber-Youngman

Spontaneous combustion (SC) is a cold oxidation reaction that generates heat, causing a temperature rise of the reactant and leading, with limited heat dissipation, to self-ignition of the reactant, which occurs without an external heat source. Although not limited to coal, the most significant hazard of SC are the fires that occur in coal mining operations around the world. These fires pose a serious risk to the safety of workers in the mines as well as adverse effects on the environment, and can affect the quality of life for current and future generations. We investigated the occurrence of SC in raw coal storage bunkers with the purpose of compiling a decision analyser for engineers designing or working with coal storage bunkers. Specific experts were interviewed from different backgrounds and companies, followed by field research at a coal mine. The important factors affecting the possibility of SC occurring were the type of coal supplied to the bunker, the mining practice, and physical conditions around the bunker. The information presented here will assist in reducing the SC risk in raw coal storage bunkers. These findings, together with the systematic decision analyser developed, will assist design engineers and mine personnel to take early preventative steps in managing SC. The decision analyser was tested for many different scenarios and gave good guidance on how to minimize and prevent SC in bunkers

May 1, 2021

By V. Yahorava

Efficient recovery of precious metals from process solutions is essential for improving process economics. Traditionally, precious metals are relatively effectively recovered from waste streams via precipitation or cementation. However, these approaches have a number of drawbacks, including poor water balance, creation of environmentally unfriendly waste streams, and losses of precious metals. Ion exchange technology is an alternative for the recovery of precious metals from waste or low-grade streams. This technology allows the recovery of the precious metals to extremely low levels (micrograms per litre) with relatively high upgrade ratios from the solution onto the resin without major water balance concerns, while the impact on the environment could be minimized or avoided. Research was conducted on the recovery of platinum group metals and gold from different low-grade and waste streams from one of the precious metals refineries in South Africa by means of ion exchange. Various functionalities and matrices (granular and fibrous) of ion exchange materials were evaluated. The results from these studies indicated that in some cases ion exchange could be very effective for the recovery of precious metals, and that the PGM concentration could be reduced to < 1 mg/L. The upgrading ratios of the various PGMs onto the specific fibres were relatively high for the specific streams evaluated, which might in some cases justify incineration of the loaded material instead of stripping and recycling the adsorbent. The cost of direct incineration for one of the waste streams tested would be less than 1% of the value of the PGMs recovered. However, the adsorbent has to be carefully selected and the process design optimized for each specific stream.

Jan 1, 2014

By F. T. Cawood, T. Chikande, H. R. Phillips

Underground mines require electricity to operate both the main surface fans and auxiliary systems, with primary ventilation systems typically accounting for approximately 40–60% of the mine’s overall electricity consumption. The primary reason for this considerable expense is that most underground ventilation systems are designed for peak demand, regardless of the actual demand, which is commonly dictated by diesel equipment usage in trackless mining operations. Most platinum mines on the Great Dyke in Zimbabwe tend to operate their ventilation systems at this peak level, despite the mine’s air quantity being well in excess of the ‘true’ ventilation needs. This is due to a lack of appropriate ventilation controls. The authors designed and installed a ventilation-on-demand system at one of the bord and pillar platinum mines to minimize the use of redundant air in underground operations. Fourth industrial revolution techniques were applied to the environmental monitoring and tracking systems thereby optimizing air quantity demands. The mine managed to reduce its annual power consumption by 23% through the implementation of manual control and time-of-day scheduling levels of the ventilationon- demand concept. There was also a 6% productivity improvement, mainly attributable to an increased face time as a result of the significant reduction in the re-entry period following a blast. This paper introduces a novel concept of ventilation optimization through digital transformation targeting mainly room and pillar platinum mines. A system was designed, installed, and commissioned, though there is currently an ongoing optimization process to harness the full benefits such as productivity enhancement, reduced power costs, and improved worker health.

Dec 13, 2022

By M. Bhandari, D. Norval

The bulk of plain carbon steel is produced through conventional Basic Oxygen or Electric Arc Furnace routes where the development of the AC Ladle Furnace has made it possible to also produce alloy steels. Smaller Ladle Furnaces have limitations such as lower efficiency; high electrode consumption and diminutive yields rendering them uneconomical to operate and making the processing of low carbon steel grades difficult due to carbon pick up. The demand for special steels and alloys with strict specifications is increasing while commodity prices remain competitive. The production of special steels and alloys have specific process control requirements and the development of the induction melting furnace (IMF) has made it possible to produce smaller batches economically. Refining and alloying of the melt in the IMF further enhance the efficiency. The INDUREF furnace offers increased productivity and flexibility through increased thermal efficiency and can be utilised for holding molten metal for further processing such as granulating, atomising, nitriding, alloy additions and desulphurisation of Ferro-alloys and steels. The system utilises a specially engineered ladle which is placed in an induction-heating assembly comprised of a stationary water-cooled copper coil and lamination packs. The addition of equipment for vacuum degassing and decarburisation of steels and alloys is also feasible. Benefits are: ? No electrode consumption or carbon pick-up ? Lower installation, operation and maintenance cost. ? No line-flicker facilitates operation on a weak power grid. ? Good power factor and balanced load ? No skull formation and reduced refractory consumption ? Higher yield of Fe-alloys ? Automatic controlled stirring

Jan 1, 2004

By R. H. Matjie, J. R. Bunt, A. C. Collins, J. C. van Dyk, C. A. Strydom

South African discard coal fines and K₂CO₃ blends were heated in a laboratory-scale rotary kiln to produce ashes for H₂SO₄ leaching tests. The optimized H₂SO₄ leaching conditions of 6.12 mol.dm³ (M) H₂SO₄, solid to liquid ratios 1:5 and 1:10, and 80°C for 8 hours were used. K₂CO₃ was added to increase the dissolution efficiency of K. The objective was to determine if the Al present in metakaolinite (Al₂O₃.2SiO₂), the Al, K, and Ti in the alumino-silicate glasses, and the Ti in rutile (TiO₂) in the ashes could be selectively dissolved in H₂SO₄. XRF results show that the ashes formed at 700°C dissolved more efficiently (87% Al, 89% K and 23% Ti) compared to the ashes formed at 1050°C. This can be attributed to the presence of Al₂O₃.2SiO₂, K₂CO₃ melt, K₂CO₃ remnants, KAl(SO₄)₂, and K-aluminosilicate glass in these ashes. XRD results indicate that the ashes prepared at 1050°C contained anorthite (CaAl₂Si₂O₈), microcline (KAlSi₃O₈), pseudomullite (Al₂O₃.SiO₂), and silicon spinel (2Al₂O₃.3SiO₂), which are either insoluble or only sparingly soluble in H₂SO₄. These minerals resulted in the lower dissolution efficiencies of Al and K. Based on the high dissolution efficiencies of Al and K for the ashes produced at 700°C, coal fines blended with K₂CO₃ could possibly be utilized as feedstocks for the production of aluminium(III), potassium(I), and titanium(IV) and a sulphate-containing leach liquor. Furthermore, the environmental issues and costs associated with the handling and disposal of large volumes of coal fines will also be resolved.

Aug 2, 2022

By N. Baloyi, P. Popoola, M. Tlotleng, S. L. Pityana

"The advantages of using Nb and Ti-Nb coatings for improving the hardness and corrosion resistance of Ti6Al4V were investigated. It has been reported that Ti6Al4V used in orthopaedic implants tends to release toxic Al and V ions into the surrounding tissue. Thin layers of Nb and Ti-Nb were deposited on Ti6Al4V substrates using a laser metal deposition technique. The deposited material was analysed using optical microscopy, scanning electron microscopy coupled with energy dispersive spectroscopy, and X-ray diffraction. The corrosion behaviour of the deposited layers was investigated using a Metrohm Autolab PG Stat101 compact potentiostat at 25°C in simulated body fluid. A Vickers hardness system was used to study the mechanical properties. Both Nb and Ti-Nb coatings exhibited good metallurgical bonding with the substrate. The microstructure and the XRD analyses for the Nb system showed that the ??-Nb phase was most dominant, while the Ti-Nb system comprised a mixture of the ?? and ?? phases. The average hardness of the Ti6Al4V substrate was 350 HV0.3, with a slight increase for the Nb coating (363 HV0.3) and a much higher hardness from the Ti-Nb coating at 423 HV0.3. The corrosion results show that the deposited Nb was more corrosion-resistant in the solution than either the Ti6Al4V substrate or the Ti-Nb coating. IntroductionMetals such as CoCrMo, 316L stainless steel, and NiTi alloy are used for manufacturing biomedical implants because of their distinct properties, including low Young’s modulus and resistance to corrosion (Ryan, Pandit, and Apatsidis, 2006). These implants are required to remain in the body of the patient for many years. Due to a favourable combination of mechanical and corrosion properties, titanium (Ti) and its alloys have emerged as the material of choice for biomedical implants. Nevertheless, their use is not entirely without challenges. For example, in total hip replacement, surface degradation and release of metal debris from metal erosion caused by friction limit the service life of the implant (Oldani and Dominguez, 2012; Manivasagam, Dhinasekaran, and Rajamanickam, 2010). Ti6Al4V is generally regarded as the material of choice, but it has been found that over extended periods of time, the combination of surface corrosion and erosion releases toxic aluminium (Al) and vanadium (V) ions into the body (Khan, Williams, and Williams, 1996). This has led to the investigation of titanium alloys containing niobium (Nb), zirconium (Zr), tantalum (Ta), and molybdenum (Mo) as substitutes for the aluminium- and vanadium-containing Ti6Al4V (Okazaki et al., 1997)."

Apr 1, 2019

By K. M. Godiwalla, S. Ranganathan

The thermal state in submerged-arc furnaces (S.A.F.) producing ferro alloys is important for the conditions of both the grade of alloy produced as well as specific energy consumption. The temperature profile in the S.A.F. is affected by the endothermic chemical reactions and the rate of gas evolution. The gas evolution commences at about 900 C due to the reduction of iron in the ore. A first-principle-based 2-D model has been developed to predict the temperature profile in the furnace. In this study, four ores of different grades have been considered in order to simulate the thermal profile in the S.A.F. The influence of the composition of the ore on the thermal profile and its significance in rationalisation of charge distribution to optimise the process are discussed.

Jan 1, 2007