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By Merete Tangstad, Ragnar Tronstad

Ferromanganese production in electrical furnaces is quite an old process. However, as the furnaces are getting bigger, the requirements of cost, yield, product quality, emissions and security are raised. With the increased expectations, the fundamental knowledge must follow. Within the last 25 years there has been a great effort both in the industry as well as the academic environment to push the limits of this process. This article will show some examples of improvements within fundamental data, reaction mechanisms and emissions over this time period.

Jan 1, 2014

By Alaina Mallard, Katie Schumacher, Jannette Chorney, Grant C. Wallace, Jerome P. Downey

Commercial ceramic carbide operations require large thermal and mechanical energy inputs in order to produce a powder product. A process that could reduce the energy requirements needed to make these materials would allow for these materials to be implemented in a greater number of industrial applications. In this study, silicon carbide (SiC), tungsten carbide (WC), and molybdenum carbide (Mo2C) were synthesized via the carbothermal reduction of activated carbon loaded with silicate, tungstate, and molybdate anions adsorbed from aqueous solutions. Carburization was carried out under reducing and inert gas atmospheres, at temperatures lower than those utilized by commercial operations. Silicon carbide “whiskers” were synthesized under H2 at 1400 °C, while molybdenum carbide and mixed crystals of WC, W2C, and W were synthesized at temperatures below 1000 °C. X-ray diffraction and scanning electron microscopy were used to characterize the carburization products, and inductively coupled plasma-optical emission spectroscopy (ICP-OES) was used to determine the degree of adsorption onto the activated carbon matrix.

Mar 1, 2018

By James O'Brien, Lyman Frost, S. Elangovan, J. Stephen Herring, Joseph Hartvigsen, Carl Stoots, Anthony Nickens

"Carbon dioxide recovered from concentrated sources, such as metallurgical reduction furnaces, cement kilns and fossil power plants can provide a valuable feedstock for a synthetic fuels industry based on energy from nuclear, solar, wind and hydropower sources. High temperature co-electrolysis of CO2 and steam to produce synthesis gas has been demonstrated using reversible solid oxide fuel cell technology. Where a source of high temperature process heat is available, such as from an advanced high temperature nuclear reactor or solar dish concentrator, the endothermic electrolysis reactions can utilize both thermal and electrical inputs in such a way that the conversion efficiency within the cell is 100%. Synthesis gas produced in a coelectrolysis cell has been further reacted over a catalyst to produce conventional hydrocarbon fuels. Widespread implementation of synfuel production from CO2 will enable a much larger reliance on intermittent renewable energy than can be accommodated by conventional electric demand profiles.IntroductionFor the past several years, Ceramatec, Inc and the Idaho National Laboratory (INL), have been studying the feasibility of high temperature solid oxide electrolysis for large-scale, nuclearpowered hydrogen production under the U.S. DOE’s nuclear hydrogen initiative (NHI) as an alternative to the thermochemical process. Parallel to this effort, the INL and Ceramatec have been researching high temperature co-electrolysis of mixtures of steam and CO2 to produce syngas:"

Jan 1, 2008

By Eltefat Ahmadi

Iron-free titanium oxycarbonitride (TiOxCyNz) is a promising feedstock for production of titanium tetrachloride (TiCl4) at low temperatures. In this study, the effects of leaching variables such as temperature, time, particle size of staring material and concentration of the leaching solutions were evaluated on iron removal from nitrided Malaysian ilmenite by Becher process. The nitrided ilmenite was prepared by isothermal reduction with graphite at 1200 °C for 3 h in H2-N2 atmosphere. The aerated leaching experiments were conducted at 50–90 °C with addition of 0.3–2.0 wt% of NH4Cl catalyst. The highest extent of iron removal (XFe) was obtained at about 96.2% for the sample leached at 90 °C for 7 h with 2.0 wt% NH4Cl. The iron concentrate and titanium oxycarbonitride product were characterized by ICP-OES, XRD, XRF and SEM-EDX analyses. The results indicated that the aeration leaching process was a successful route to prepare low-iron titanium oxycarbonitride.

By Gavin Beer

The Chelopech Copper/Gold Mine, located in west-central Bulgaria, has been in operation since 1953 producing a low-grade copper/gold concentrate containing up to six percent arsenic by weight. The penalties and restrictions imposed on smelting this concentrate, have seen the past operators of the mine strive to find a balance between achieving acceptable metal returns from the smelters and installing novel or unproven technologies in the face of changing political and economic climates. This paper documents the colourful history of the concentrate processing alternatives that have been investigated and implemented over the 45 year life of the Chelopech Mine, culminating in the high pressure oxidation option that is now the focus of a Definitive Feasibility Study (DFS) presently being undertaken by GRD Minproc Limited. The fundamental chemistry of the preceding alternatives is outlined followed by a discussion as to why each was ultimately not employed. A detailed description of the technology proposed in the DFS is given including: pressure oxidation, arsenic fixation, SX/EW copper recovery, CIL gold recovery and AVR/SART cyanide/copper recovery processes. Keywords: Arsenic, Scorodite, HPOX, Chelopech, Dundee

Jan 1, 2005