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By Mark William Kennedy

Modern metallurgical plants typically have complex flowsheets and operate on a continuous basis. Real time interactions within such processes can be complex and the impacts of streams such as recycles on process efficiency and stability can be highly unexpected prior to actual operation. Current desktop computing power, combined with state-of-the-art flowsheet simulation software like Metsim, allow for thorough analysis of designs to explore the interaction between operating rate, heat and mass balances and in particular the potential negative impact of recycles. Using plant information systems, it is possible to combine real plant data with simple steady state models, using dynamic data exchange links to allow for near real time de-bottlenecking of operations. Accurate analytical results can also be combined with detailed unit operations models to allow for feed-forward model-based-control. This paper will explore some examples of the application of Metsim to real world engineering and plant operational issues.

Jan 1, 2014

By Markus Reuter, Antoinette van Schaik

In this paper the link between process metallurgy, classical minerals processing, product centric recycling and urban/landfill mining is discussed. The depth that has to be achieved in urban mining and recycling must glean from the wealth of theoretical knowledge and insight that have been developed in the past in minerals and metallurgical processing. This background learns that recycling demands a product centric approach, which considers simultaneously the multi-material interactions in man-made complex ‘minerals’. Fast innovation in recycling and urban mining can be achieved by further evolving from this well developed basis, evolving the techniques and tools that have been developed over the years. This basis has already been used for many years to design, operate and control industrial plants for metal production. This has been the basis for Design for Recycling rules for End-of-Life products. Using, among others, the UNEP Metal Recycling report as a basis (authors are respectively Lead and Main authors of report), it is demonstrated that a common theoretical basis as developed in metallurgy and minerals processing can help much to level the playing field between primary processing, secondary processing, recycling, and urban/landfill mining and product design hence enhancing resource efficiency. Thus various scales of detail link product design with metallurgical process design and its fundamentals.

Jan 1, 2014

By Kai Tang, Casper van der Eijk

Natural gas has been used as reductant in the production of iron for several decades. Recently, the use of natural gas as reductant for other metals has been drawing attention because of the low price of natural gas, as well as the reduction of CO2 emissions compared to the use of coke and coal. In this work, the reduction of a mixture of Ti- and Ni-oxides by natural gas has been studied. Within the Ni-Ti system, the intermetallic compound Ni3Ti is thermodynamically the most stable one. Therefore, powders of Ni-oxide and Ti-oxides were mixed in an atomic ratio of three to one and subsequently pelletized. Reduction was performed in a TGA furnace at constant temperature with varying reducing gas atmospheres. In a natural gas containing atmosphere, the Ni-oxide was easily reduced to metallic nickel while the Ti was reduced to Ti-oxycarbides or Ti-oxynitride when nitrogen was present. Depending on the process parameters, several percent of Ti was dissolved in the nickel-based solid phase.

Jan 1, 2014

By Arthur E. Morris

The primary market driver for improving process technology is innovation, which requires a skilled and educated workforce. However, many Materials Science and Engineering departments have eliminated extractive metallurgy and chemical thermodynamics from their curricula, yet these topics contain the necessary fundamentals for process innovation. As a result, most MS&E students are ill-prepared for careers in processing. The dearth of processoriented MS&E curricula has prompted some Universities to develop a “shared” effort to offer distance education between multiple institutions [1]. A target audience for a shared process simulation course would not only benefit students, but also be a basis for an on-line course for practicing engineers faced with new or changing career choices. To fill the gap, the basics of a process simulation course was developed in an abbreviated form as series of eleven articles and Excel workbooks published in Industrial Heating magazine between July 2012 and July 2013.

Jan 1, 2014

By Gordon Irons, Kevin Graham, Krishnakumar Krishnapisharody

Ladle or secondary metallurgy in steelmaking is an essential process step for the production of high-quality steel. Professor David Robertson was a pioneer in the modeling of these processes, in particular gas-metal fluid dynamic interactions and the rates of slag-metal reactions. This is now a highly active area of research, and some of the recent developments in this area will be reviewed.

Jan 1, 2014

By Teuku A. R. Putra, Patrick R. Taylor

Various pyrometallurgical methods for treating copper concentrates that contain appreciable arsenic are reviewed. Various aspects of the engineering of these treatment methods are discussed. The methods discussed include: complete oxidation with arsenic fixation; selective volatilization of arsenic; acid baking, soda ash roasting, and others methods. Methods for the ultimate disposal, or marketing, of the arsenic are discussed.

Jan 1, 2014

By Lloyd Robert Nelson

The historical progression in installed electric furnace smelting capacity of some 1650 calcium, chromium, manganese, nickel and silicon ferro-alloys furnaces is reviewed. Key increases in the inherent installed electrical capacity, often achieved through uprating furnaces, are identified. Possible factors facilitating such advances are explored, including: specific process engineering and pyrometallurgical enhancements (e.g., improved control over the consistency, size and chemical form of raw materials, extents of preheating and pre-reduction delivered into the furnace; and patterns of feed distribution); furnace electrical configuration (AC or DC; immersed, submerged-, shielded- or open-arc); form of electrode (graphite, self-baking or composite); furnace configuration (circular or rectangular; closed or open and 1-, 3- or 6- electrodes); better engineering and equipment designs (e.g., high-intensity cooling) and state of furnace electrical and metallurgical control systems. A view is presented on the prevailing state of evolution of the Mega-scale in ferro-alloy smelting and opportunities for still further improvements.

Jan 1, 2014

By Cheng Pan, Qiugang Yuan, Xuewei Lv, Mei Liu, Enguang Guo

Land-based nickel resources include nickel sulfide and nickel laterite. With the consumption of high grade nickel sulfide, use of nickel laterite has received more and more attention. The mineralogy and sintering behavior of limonitic nickel laterite with high iron and low nickel and silica was studied to offer technical support for producing ferronickel through sintering–blast furnace route. The mineralogy results showed that the main phases in this kind of nickel laterite are goethite (FeO(OH)), gibbsite (Al(OH)3) and NiFe2O4. The TGA (Thermogravimetric Analysis) and DSC (Differential Scanning Calorimetry) revealed hydroxide minerals in addition to absorbed water. After the sintering experiments the chemical composition, phases present (XRD analysis) and physical properties of the sinter were studied. The content of FeO in the sinter increased with increasing basicity up to 1.3, and then decreased with further increase in basicity. The yield of sinter increased (from 73% to 80%) with increase in the basicity from 1.1 to 1.7, and then the yield decreased with the further increase in basicity. Mg(Ni)(Fe,Al)2O4 is the main phase in the sinter while MgCaSiO4 and Fe2SiO4 is the main binder phase when the basicity is 1.1~1.5, and MgCaSiO4, Fe2SiO4 and SFCA is the main binder phase when the basicity is 1.7~2.1.

Jan 1, 2014

By Mark Cross, Diane McBride, Nick Croft

Extractive metallurgical processes rate amongst the most complex from the perspective of computational modeling. They typically involve multi-phase and multi-component fluid flow in very complex geometries, heat transfer driven by a number of interacting phenomena, solidliquid- gaseous phase change and mass transfer together with complex thermodynamics and associated chemical reactions. Beyond the model building itself, key challenges have always involved being able to identify the phenomena present together with interactions to characterize processes and experimental laboratory and plant data to parameterize the arising models – it is in this milieu, which require considerable process understanding and subtlety of thought, that David Robertson has made his contributions. We will review the achievements, over the last couple of decades, in computational modeling of extractive metallurgical processes and address some of the remaining challenges to enable simulation based process design, as we move through the 21st century.

Jan 1, 2014

By Xue Sun, Dengfu Chen, Yuting Chen, Mujun Long, Song Xu, Helin Fan

In order to seek an effective extraction process for vanadium, the recovery of vanadium from a high Ca/V ratio vanadium slag was studied by sodium roasting and ammonia leaching. In the present paper, the oxidation and leaching process of vanadium slag was investigated by X-ray diffraction (XRD), scanning electron microscopy and energy dispersive X-ray spectrometry (SEM/EDS) techniques. The effects of ammonium carbonate concentration, leaching temperature and leaching time on the leaching ratio of vanadium were discussed. As indicated in the experimental result, the optimal (NH4)2CO3 concentration was 120g/L, leaching temperature was 60°C and leaching time was 20 min. Approximately 92% of the vanadium was recovered under the optimal conditions. Furthermore, by means of X-ray diffraction analysis, the phase transformations of the vanadium slag during roasting and leaching processes were analyzed and discussed.

Jan 1, 2014

By Joo Hyun Park, Kyu Yeol Ko

The viscosity of the CaO-SiO2-xMnO-yCaF2 slags (C/S=1.0; x=10, 40%; y=0 to 15%) was measured to clarify the effect of CaF2 on the viscous flow of molten slags at high temperatures. Furthermore, the Raman spectra of the quenched glass samples were quantitatively analyzed to investigate the structural role of CaF2 in a depolymerization of silicate networks. The critical temperature of the slags abruptly increased at 15%CaF2, which was confirmed to originate from a crystallization of cuspidine using XRD analysis. The viscosity of the slags continuously decreased by CaF2 addition in the 10%MnO system, whereas the viscosity of the 40%MnO system was not significantly affected by CaF2 addition. The effect of CaF2 on the viscosity of the slags was quantitatively analyzed using micro-Raman spectra of quenched glass samples accompanying with a concept of silicate polymerization index, Q3/Q2 ratio. A polymerization index continuously decreased with increasing content of CaF2 in the 10%MnO system, whereas it was not affected by CaF2 in the 40%MnO system. Consequently, the bulk thermophysical property of the CaO-SiO2-MnO-CaF2 slags was quantitatively correlated to the structural information.

Jan 1, 2014

By Vinay Kumar, Manis Kumar Jha, J. Rajesh Kumar, Archana Kumari, Rekha Panda, Jin Young Lee

Rare earth metals (REMs) play a significant role in the manufacture of permanent magnets, fluorescent lamps, catalysts, medicines, super alloys etc. Recently, China, which controls 97% of world trade in REMs, imposed restriction on its export. Consequently, the global demand of REMs is escalating and is expected to exceed the supply by 40,000 tonnes annually. Present review paper reports the flow-sheets of commercial processes based on pyro-hydro and hybrid techniques as well as systematic research for process development to recover REMs from primary and secondary resources. This review paper also reports the recommendation and future prospective to fulfill its demand and supply gap keeping in view environmental prospective.

Jan 1, 2014

By Joo Hyun Park, Soo Sang Park

The distribution behavior of Pb between molten copper and FetO-SiO2 (-CaO, Al2O3) slags was investigated at 1473 K (1200 oC) and p(O2)=10-10 atm in view of the reaction mechanism of Pb dissolution into the slag. The distribution ratio of Pb (LPb) decreases with increasing CaO content (~6 mass pct) irrespective of Fe/SiO2 ratio (1.4~1.7). However, the addition of alumina into a slag with Fe/SiO2=1.5 linearly decreases the LPb, whereas a minimum value is observed at about 4 mass pct Al2O3 at Fe/SiO2=1.3. The log LPb continuously decreases with increasing Fe/SiO2 ratio, and the addition of Al2O3 (5 to 15 mass pct) into the silica-saturated iron silicate slag (Fe/SiO2 < 1.0) yields the highest Pb distribution ratio. The log LPb linearly decreases by increasing the log (Fe3+/Fe2+) value. The Pb distribution ratio increases and the excess free energy of PbO decreases with increasing Cu2O content in the slag. However, from the viewpoint of copper loss into the slag, the silica-saturated system containing small amounts of alumina is strongly recommended to stabilize PbO in the slag phase at a low Cu2O content.

Jan 1, 2014

By B. R. Davis, Neale R. Neelameggham, R. E. Brown

The element Calcium element has a unique place in the production of etals, intermetallics and other compounds. The unusualness arises from the fact that we have several possible reductants – metallic calcium, calcium carbide, calcium cyanamide and calcium hydride. A review of how metallic calcium is manufactured and utilized is presented. The difficulties involved in producing the metal in large quantities and price implications are noted. . Fundamental thermodynamics of how these act as reductants are shown, along with the historic application of these in metal production during the past century and a half. Alternate applications as to how to control the cost of the reductant is indicated, such as the numerous attempts in making low cost titanium utilizing direct or indirect calcium reductant.

Jan 1, 2014

By Ki Joo Sim, Sung Beom An, Joonho Lee, Minsoo Shin

Valorization of the electrical arc furnace oxidizing slag by coke was carried out by the reduction of iron oxide in the slag. Since the reduction of iron oxide by solid carbon is an endothermic reaction, supply of heat energy is required. In addition, slag has a low thermal conductivity; traditional fuel injection is not suitable for this reaction. Microwave can be used to supply heat energy to the system. Commercial oxidizing slag was reduced by coke under the microwave irradiation (1.7 kW, 2.45 GHz). The maximum recovery ratio of iron was 87%. In addition, slag composition modification was attempted to use the remaining slag for a mixture in cement clinker. Free-CaO in the slag was successfully suppressed, and the use of the remaining slag as a potential mixture was confirmed.

Jan 1, 2014

By Ben Bowman

For certain ferroalloy furnaces, such as ferrochrome or ferromanganese, there is still doubt about the mechanisms operating under the electrode tips. In this paper a model is built that does not call upon an arc. The medium is best described as an electrically conducting slurry, a mixture of liquids, solids and gas. There are two sources of propulsion, the Lorentz force within the conducting part and buoyancy generated by CO bubbles, creating two opposed poloidal circulation loops, downward below the electrode axis and upward further out.

Jan 1, 2014

By Andreas Andenæs, Arne Schram Simonsen

"AbstractThe Tresfjord bridge is with its variety in foundation concepts and difficult soil conditions one of the most geotechnically challenging projects in Norway at the time. The project comprises design of large concrete caissons, steel core piles through large rock fills, and closed end steel pipe piles in up to 40m water depth driven in very hard moraine. Test piling has also been conducted to check feasibility of the concept, and PDA measurements have been used to verify sufficient capacity of piles. FactsThe Tresfjord bridge is part of the new export road from Ålesund to Åndalsnes on the North-West coast of Norway built by the Norwegian Road Administration. The bridge will reduce travel time with about 30 min between the cities, see Figure 1. The bridge is planned to open summer 2015.The Bridge crosses the Tresfjord and will be 1290 m long. The bridge is built as a free cantilever bridge and will be resting on a total of 20 nos. of foundations, where two are abutments resting on steel core piles, three are casted directly on bed rock and 13 are foundations resting on steel pipe piles. The last two foundations holding the main span will be concrete caissons resting on bed rock and moraine. Figure 2 shows a 3D model of how the finished bridge will look. Multiconsult AS is responsible for design and pile supervision , while the Joint-Venture Bilfinger-Tresfjordbridge ANS is responsible contractor.Soil ConditionsPercussion soundings and sampling together with coring have been performed in the individual foundations using a small geotechnical equipped vessel. Acoustic and refraction seismic profiling have also been carried out to tie in the layers between the boreholes.The soil conditions are varying over the length, but are in general dominated by a soft top layer (2-4 m) of sediments over very hard moraine with occasionally large boulders. Piles in the two foundations closest to shore on the western side of the bridge are piled to bed rock with penetrations up to about 27 m in soil.Water depth varies from about 10 to 40 m for the piled foundations. Figure 3 show how the topography of the seabed varies over the bridges length."

Jan 1, 2014

By K. M. Kim

An analysis was conducted to determine the effects of blasting on slope stability and downstream comminution processes. To investigate these effects, the extent of blast-induced rock damage and the magnitude of induced stress were examined. This analysis showed that damage may extend up to 500 m (1 MPa, tensile strength) into the rock mass, a distance that is sufficient to have an impact on the pitscale slope over the long term. In addition, the damage zone was calculated using the assumption that compressive waves are the primary agent in microfracturing during blast fragmentation. The calculated damage zone — up to 2.2 m (43 MPa, rock mass compressive strength) — indicates that microfracturing can occur throughout 20-50% of the entire rock mass in the blasting area, depending on the blast geometry, burden and spacing. Finally, an economic analysis was conducted by comparing two assumed blasts in a copper mine. The change in energy required for crushing and grinding was demonstrated using Bond’s law after increasing the blast energy from 180 kcal/t to 350 kcal/t. A total cost saving of 13.3% ($9.4M) was achieved with the increase. However, the benefits of blast-induced microfracturing must be balanced against the potential impacts to slope stability to ensure safe conditions, a top priority in mining operations.

Jan 1, 2014

By C. J. Bise, M. F. Sindelar

Regulations, such as the MINER Act of 2006, require the installation of redundant and secondary communication systems to assure that contact can be established with coal miners who may become trapped underground as a result of an event such as a fire, explosion or inundation. For half a century, the orientation towards underground communications has been that more complex systems better serve the coal miner. However, if a goal is to provide for an alternative means of establishing communication between the surface and trapped miners underground, then some of the technology employed should be simple, reliable and cost-effective. Coal mines spend hundreds of thousands of dollars on exploratory drillholes to characterize reserves, sometimes decades ahead of mine development. During the pre-mine planning phases, certain exploratory drillholes could be located and then outfitted with a simple communication link that would remain compatible with the continuing evolution of communication systems. Inexpensive links, whose locations would be accurately recorded, would be exposed by continuous miners during mine entry development, thereby allowing an underground phone to be connected to a surface station in the event of an emergency. A latent network of these communication links could be installed for less than $500 each, minimally affecting drilling and grouting operations, and could be designed to be compatible with many communication devices. This research examines methods and materials for incorporating an embedded communication link during pre-mine exploration drilling, addresses significant factors affecting its implementation, and presents a recommended design. Since mine plans are known to change, the objective is to minimize cost so that, if not used, the investment is minimal for a potential secondary means of communication between the surface and underground workings.

Jan 1, 2014

By R. Wisniewski, S. Schafrik

Every underground coal mine in the United States must deploy and operate a wireless communication and electronic tracking system. This paper addresses the reliability and availability of an installed tracking system and the communications infrastructure that supports it. This paper assumes that the tracking system uses the communication system to perform its operation. A particular interest is the requirements for the systems to operate continuously without failure after a mine disaster for 24 hours, and the requirements in the MINER Act for the tracking systems to be “functional, reliable and calculated to be serviceable” and the communications systems “redundancy.” These requirements imply a certain reliability and availability. This paper describes a quantitative way to assess these systems requirements, using tools that are available to and commonly used by the reliability, maintainability and availability community.

Jan 1, 2014