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By Neil E. Izatt, Ronald L. Bruening, Steven R. Izatt

"IBC has developed environmentally friendly Molecular Recognition Technology (MRT) processes to selectively extract, recover, and purify a wide range of metals from a variety of process streams. The incorporation of MRT into process flow sheets can improve the economics of the processes. MRT separations are effective even at low (mg/L to \i%JV) metal levels. MRT processes are sustainable, being economically viable, energy efficient, and environmentally friendly as well as having a low carbon footprint. Examples of MRT processes will be presented and discussed involving platinum group metals, gold, rhenium, and other metals of interest to the mining community.IntroductionA significant portion of the earth's precious metal resources has been moved during the past century from underground to above ground [1]. This movement has important economic, health, environmental, ecological, and sustainability implications for the earth and its population. There is concern that recycling of certain precious and specialty metals from end-of-life (EOL) electronic wastes (e-wastes), catalyst wastes, mining waste streams, and other waste products such as rechargeable batteries is not adequate to maintain supplies of these metals sufficient for future needs [2-4]. Improved metal recycling rates and more efficient metal recovery from the enumerated wastes would significantly reduce the amount of virgin metals that must be mined to support our lifestyle [5]. More efficient separation procedures in ore processing flow sheets and more effective recovery of metals from low-grade waste streams would reduce metal loss in the mining industry."

Jan 1, 2012

By Guozhu Ye, Eric’ Burstrom

"Despite of numerous solutions for recovery of zinc from EAF dust have been suggested and tested in laboratory scale over the last three decades, Waelz kiln process is still the most dominating process for treatment of EAF dust. Few of the proposed alternative methods have gone beyond the laboratory tests. This paper will give you insights to some of the concepts that have been pilot tested at MEFOS. The innovative aspects of these concepts will be shown and the major results will be highlighted. These include the following concepts: - Production of a crude zinc oxide product with low halide content for zinc electrowinning using a DC furnace with hollow electrode- Production of a bypass filter dust containing more than 50%ZnO by injection of EAF dust to the electric arc furnace during refining combined with a bypass filter system- Elimination of zinc ferrite by CaO treatment for electrowinning with EZINEX process - Selective reduction of iron oxide in zinc ferrite for simultaneous recovery of ZnO andmetallic ironIntroductionRecovery of zinc from EAF dust is dominated by the Waelz process since EAF dust has been classified as hazardous waste by EPA in the early 1980´s. A large number of alternative processes have been suggested and tested without commercial success due to two major reasons [1]:- High content of chlorine and fluorine for the pyrometallurgical alternatives- High content of ZnOFe2O3 for the hydrometallurgical processesMany innovative concepts for treatment of EAF dust for zinc recovery have been pilot tested at MEFOS in the past 20 years. This paper will review some of the concepts focusing on the two problems mentioned above."

Jan 1, 2008

By J. Y. Aubut

The modernization of the CCR Refinery to permanent cathode technology is presently underway. The 360,000 mt/y refinery is being retrofitted to accept the Kidd process. Part of this modernization includes the installation of Kidd stripping machines, and the total replacement of the materials handling equipment. It also involves the reinforcement of building structures to accept the new equipment and the ability to operate in different modes. The future equipment will interface with some existing apparatus, which is being retained for future operations. The whole operation will be automated and will allow product traceability for quality purposes. This retrofit poses important challenges given the size and scope of the modernization project and because it is being undertaken concurrently with normal plant operations.

Jan 1, 1999

By Leandro Voisin

A new pyrometallurgical treatment alternative is proposed for cleaning complex copper matte with high content of impurities in the copper smelting process, thus, in a suitable furnace, a given amount of pig iron will be added to the liquid complex matte with a matte grade between 65 and 75 % Cu under reducing condition and will produce three liquid phases of matte, copper-rich alloy and iron-rich alloy. Hence, in this study, firstly, a mass balance calculation was made on the basis of the reported data for the distribution ratios of the components among the three phases to define the optimum condition where most of the arsenic can be fixed in the less valuable liquid iron-rich alloy. By taking advantage of the high concentration of arsenic in the iron-rich alloy, the small volume alloy may be disposed in a yard, while the precious elements may be recovered effectively in the liquid copper-rich alloy and/or in the liquid matte. Secondly, laboratory-scale experiments were conducted to apply the proposed process to the matte produced from the slag-cleaning electrical furnace and the Teniente Converter of the Codelco-Norte smelter. The obtained results indicate that the proposed process for cleaning complex matte is promising.

Jan 1, 2006

By M. I. Zinigrad

A model of an ideal associated solution is presented. This model takes into account the existence of complexes of various compositions, sizes and geometries and allows calculating thermodynamic properties and phase diagrams of binary alloys. The model has been used formerly to calculate thermodynamic parameters and the position of the liquidus line for binary eutectic systems and also those having a stable compound in the solid phase. In all the cases the model parameters were not adjusted rather estimated from melting temperatures of the components. The recent studies dealt with the influence of arbitrary-stoichiometry associates on the equilibrium thermodynamic properties of liquid alloys. The application of the model to eutectic systems and systems having an unlimited solubility in solid and liquid states close to liquidus has been considered. It was shown that if the difference in melting temperatures of the components was small, different types of fusibility diagrams were possible: eutectic diagrams, cigar-shaped diagrams or diagrams with upper or lower azeotropic points. Peritectic transformations could take place when the difference in melting temperatures of the components was large. The present work is devoted to calculation of phase diagrams and thermodynamic properties of binary systems on the basis of chrome.

Jan 1, 2006

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By P. A. Olubambi

The effect of ore mineralogy on the bioleaching of metals from complex sulphides was studied by investigating the bioleaching of zinc and copper from a bulk complex sulphide ore from Ishiagu, Nigeria, using mixed cultures of Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Leptospirillum in mechanically stirred reactors at varying particle sizes. Mineral phases within the varied particle sizes of -53, 53, 75 and 106µm were identified using X-Ray Diffraction (XRD), while the elemental distribution within the varied particles sizes was determined by X-Ray Fluorescence (XRF) and Optical Emission Spectrometry using Inductively Coupled Plasma- Optical Emission Spectrometer (ICP-OES). Bulk ore and the leached residues were examined by X-Ray Diffraction. The highest bioleaching recoveries were obtained at particle size of 75µm, while particle size of 106µm gave the least recoveries. Lower recoveries at particle sizes of 53 and -53µm were as a result of their higher silica and siderite content which affects pH, iron mobility and oxidation.

Jan 1, 2006

By Taner Kavas

In the present study the utilization of coal ashes that appear at the end of firing process of brick production in cement pastes was examined. Ashes with three different particle sizes of 75 µm, 106 µm and 150 µm were used to replace ordinary Portland cement (PC) as 5 % and 15 % by weight. Seven samples were prepared and physical, mechanical, chemical and microstructural analyses were carried out. The compressive and bending strength values of samples were determined at the ages of 2, 7 and 28 days. It was found that cementitious pastes with finer particle sizes possessed the highest compressive and bending strength values at all curing ages. Both values after 2 and 7 days cure increased with an increase in ash content, no matter what the particle sizes of ashes were. However, strength decreased after 28 days cure as a result of ash addition of 15 %, although it was still above that of the PC.

Jan 1, 2006

By Guo Jun

In this study, BaTiO3 ultrafine particles surface-modified with stearic acid were synthesized by the hydrothermal method in a system of BaCl2-TiCl4-NaOH. The effects of NaOH/TiCl4 molar ratio, Ba/Ti ratio and time on structure and morphology of BaTiO3 ultrafine particles were investigated experimentally. The formation mechanism of different crystalline BaTiO3 particles was discussed, and it is considered that in a hydrothermal system, the main factors determining BaTiO3 crystalline are H+ replacement of Ba2+ causing H+ deficiency and anatase growth units involving in crystal growth, which clogs the axial channel for Ba2+ transference. By means of increasing the alkalinity of system and barium content, H+ deficiency and involvement of anatase growth units in crystal growth could be effectively controlled. The results show that when molar ratio of NaOH to TiCl4 is 9 and ratio of Ba to Ti 1.5, and time 8 hours, high purity tetragonal BaTiO3 ultrafine particles with a narrow grain-size distribution and nonpolar surface are obtained at 240oC. The particles have excellent flowability, which is ascribed that the surface polarity of barium titanium powder modified with stearic acid is changed and the interaction between the particles is weakened.

Jan 1, 2006

By R. Upadhyaya

Aluminium alloy matrix cast composites have been synthesised by incorporating fine graphite powders (0.5 - 20 µm size) and chopped carbon fibres (6.5 pm P). 3-6 mm length) by liquid metallurgy technique. Incorporation of these second phase materials exceeding 6-8 wt% invariably resulted in agglomeration of the dispersoids and sometimes leading to even total rejection. It was found that small additions of mischmetal (1-3 wt%) during dispersion resulted in better incorporation without much agglomeration of the dispersoid as evident from the macro and micro structures of the composites. Further, the additions of mischmetal increased the volume of the effective incorporation of the dispersoid even to the extent 50- 60%. The mischmetal addition results in a significant increase in the power factor of the stirrer motor indicating an apparent increase in the viscosity of the system. The higher viscosity of the melt increase the shear transmission conditions within the melt during stirring thereby breaking the agglomerates of the dispersoids. The increased viscosity of the melt seems to be due to the formation rare earth - aluminium inter metallics precipitation, as observed in the metallographic studies, thereby making the process a "pseudorheocasting? technique. A provisional patent has been filed based on this work.

Jan 1, 1989

By C. M. Acuna

Scarcity of high grade copper low impurity content ores is a reality and processing of low grade dirty concentrates is a need. In spite of this fact, innovative strategies have to be looked at to comply with day to day more stringent environmental regulations. From this perspective the production of matte grades over 70% in copper presents several merits, but it must be contrasted with the fractional distribution of impurities reporting to the condensed phases. Converting of white metal high in arsenic content results in moderate fraction of arsenic to gas, but high deportment to blister. Therefore, production of anode copper, as required by the electrolytic refinery, may result in several operational difficulties. Furthermore, by recycling the flue dust and slag produced in the smelting-fire refining cycle, the arsenic content in the feed to smelting increases and so does in the resulting anode copper. The Teniente Converter, as a smelting unity, has probed suitable for production of high matte grade near white metal composition but regarding distribution behaviour of impurities there is lack of reliable data, specially when processing concentrates over 1% in arsenic content. In the new scenario, i.e. low grade copper high arsenic content concentrates, to fully asses the merits of this technology the effect of matte grade, secondary materials recycling and arsenic in feed upon the distribution coefficient of arsenic between slag and matte, mainly, must be evaluated both from a theoretical approach and by use of industrial data. Based on available data correlations of distribution coefficient, matte grade and matte/slag ratios with arsenic in feed and copper content in slag are worked out. Based on these results suggestions as to matte grades facilitating to deal more efficiently with the handling of smelting byproducts are proposed.

Jan 1, 2006

By S. H. Castro

The El Teniente molybdenite plant (Chile), with a nominal capacity of 3,200 tpd of bulk Cu-Mo concentrate, produced approximately 3,385 metric tonnes of Mo during 1998 by using the phosphate Nokes process (LR-744 reagent). This is the only Chilean moly plant which traditionally has depressed copper and iron sulfides with LR 744 reagent, which is a hydrolysis product of P2S5 and NaOH. El Teniente's ore Mo grade is 0.02%Mo and is concentrated to 0.45%-0.50% Mo in bulk Cu-Mo flotation. Subsequently, molybdenite is floated by selective flotation to depress Cu and Fe sulfides, such as chalcopyrite, bornite, digenite and pyrite, to produce typically a 49%-50%Mo molybdenite concentrate. An optimisation program during the last two years was undertaken to improve molybdenite recoveries. Current molybdenite plant technology at El Teniente and use of phosphate Nokes in the process process is reported. Use of phosphate Nokes reagent has increased average Mo recovery from 70.5% in 1977 to a mean 74.7% for the first 4 months of 1999. The global Mo recovery, including bulk flotation, incresed from 42.3% in 1997 to 46.8% in 1998, with a projection of 55.5% for 1999. Mo production per year has increased from 3,181 tons in 1997 to 3,385 tons in 1998 and a projected 4,000 tons for 1999.

Jan 1, 1999

By Andreas Ludwig, Abdellah Kharicha, Menghuai Wu

"In order to demonstrate how CFD can help scientists and engineers to better understand the fundamentals of engineering processes, a number of examples are shown and discussed. The paper will cover (i) special aspects of continuous casting of steel including turbulence, motion and entrapment of non-metallic inclusions, and impact of softreduction; (ii) multiple flow phenomena and multiscale aspects during casting of large ingots including flow induced columnar-toequiaxed transition and 3D formation of channel segregation; (iii) multiphase magneto hydrodynamics during electro-slag remelting; and (iv) melt flow and solidification of thin but large centrifugal castings.IntroductionSince the Bronze and the Iron Ages, material processing, and here especially metallurgy, has got a global importance for the economic well-being of the societies. It is thus understandable that metallurgy has changed from arts and crafts into an engineering specialty, where the knowledge of centuries has lead to an enormous commercial and technical efficiency. However, increasing competition and the necessitation of energy and CO2 reduced manufacturing methods requires the improvement of existing techniques and even the development of new, alternative production technologies. On the other hand, the opacity of liquid and solid materials and the involved high temperatures makes the experimental penetration of metallurgical processes and with that the attainment of detailed process knowledge quite difficult."

Jan 1, 2012

By Milance Mitovski, Milorad Cirkovic, Vlastimir Trujic, Dragana Živkovic

"In this article, it is analysed the possibilitis and the effects utility waste energy of process sulfuric acid production in the existing technical-technological conditions. The utility second process energy, reduction the fuels consumption, reduction environment pollution and its effects are shown, too. High heat quantity is produced as the result of exothermal reactions in the production process of sulfuric acid in Bor. A part of this heat is sufficient for the process development, and significant part of this heat presents low-temperature heat energy that is irretrievable lost. Investigations were carried out based on production of 485 t of monohydrate/day of sulfuric acid. By recovery of this heat quantity for heating purposes, about 20.000 – 25.000 t of coal/year would be saved, what would significantly improve the power efficiency of the smelter copper production. IntroductionTechnological process of copper production in RTB BOR (Serbia) produces a significant quantities of high temperature secondary (waste) heat energy that is uncontrolled “lost” in the vicinity. Secondary heat energy is produced in pyrometallurgical copper production in quantity of 1,621 kWth/kg of dry concentrate or existing heat (that presents a difference of heat at furnace outlet and heat at temperature over temperature of dew point of sulphuric acid gases) in quantity of 1,315 kWth/kg of dry concentrate. For designed capacity of Copper Smelter in Bor, the existing heat power of secondary energy is 92,111 MWt, what is an equivalent to the power of steam-turbo plant where the Rankine-Clausius heating cycle is done, and that is 28,334 MWe."

Jan 1, 2008

By Seung-Whee Rhee

Characteristics of ceramic support made by spent foundry sand-loess mixtures are investigated by bulk density, porosity, durability, and compressive strength. And the basic properties of SFS and loess are estimated. The effect of drying time after cutting process, elevated temperature time, sintering temperature, and sintering time is also estimated to obtain the optimal condition in the process of manufacture ceramic supports. From the basic properties of SFS and loess, the content of SiO2 in furan sand is much higher than that in loess but the content of Al2O3and Fe2O3 in furan sand is much lower than that in loess. In order to make ceramic supports cylinder shape is the most desirable to sustain the properties of ceramic support. If annulus shape has a enough compressive strength, however, annulus shape may be decided. For the optimal condition to manufacture ceramic supports, drying time after cutting process is decided to 24 hrs and elevated temperature time is decided by 9hrs. And sintering temperature and sintering time are decided to 900 and 9hrs, respectively in order to prevent solidification of sand materials.

Jan 1, 2006

By Ronald J. Roman

The shrinking core model for coarse particle leaching has been generally accepted as describing the leaching of a copper oxide or sulfide ore. However, when a mixed oxide/sulfide ore-is leached this model can not be used in its simple form because at least two and possibly three separate leaching processes are occurring simultaneously (dissolution of oxide copper minerals, secondary copper minerals and primarily copper minerals). It has been impossible to isolate their individual leaching curves from the recovery/time curve generated by the column leach test. This paper describes a tests program carried out at the Groupo Mexico, Mexicana de Cobre's La Caridad operation in which the individual recovery/time curves for the leaching of copper oxide mineral, secondary copper mineral and primary copper minerals were developed from standard column leach tests. Once the individual recovery/time curves were developed scale-up of the column leach test results to the commercial heap leaching operation is possible by using the shrinking core model.

Jan 1, 1999

By Catherine Williams-Beam

Thallium is more toxic to humans than mercury, cadmium, lead, copper or zinc. Its chemical behavior resembles the alkali metals (K, Rb, Cs). It occurs almost exclusively in natural waters the monovalent thallous cation. The solubilities of thallous compounds are relatively high so that monovalent thallium is readily transported through aqueous routes into the environment. The major sources of thallium are the base metal sulfides and precious metal bearing sulfides. Therefore, it is often present as a contaminant constituent in waters emanating from heavy metal sulfide bearing deposits. Thallium can be effectively removed from wastewater to <2 µg/L by reductive precipitation of thallium sulfide. Effective thallium sulfide precipitation requires a controlled solution potential/pH combination. The required potential can be effectively achieved by utilizing a particulate iron slurry or packed column environment. Experimental results will be presented and discussed.

Jan 1, 2003

By Johan Sundström

Anhydrous DyC13 was prepared by dehydration of DyCl3?6H20 in a fluidized bed using both batch- wise and continuous feeding. A gas mixture with varied composition of argon and HCl was used. The productivity was high, reaching values of 0.25 mol H20/m2-st during the reaction step 6- 1 and 0.062 mol H2O/m2.s during the reaction step 1-0. The product was free from hydrolytic compounds, such as DyOCI, if control of inlet gas composition versus temperature was achieved. From the results of various experiments, some relations between HCI-concentration and temperature in order to avoid hydrolysis have been deduced. The fluidization process efficiency decreases drastically after the dehydration has proceeded down to about 10 mol% of remaining water. Therefore, in a final treatment the last traces of water were removed by slowly purging gas through a packed bed. The water content could thereby be reduced to less than 1 mol%.

Jan 1, 1997

By S. Bagchi

The LaNi5-xMnx-hydrides have potential applications in cryocooling devices for non-mechanical method to compress hydrogen gas. Thermal aging behavior of LaNi5-xMnx-hydrides of compositions x=0.4 and x=1.5 has been investigated. The hydriding properties of the La1.02Ni4.6Mno.4 alloy do not change significantly after thermal aging at 453K for 260 hours. X-ray diffraction analyses of this aged alloy do not reveal the presence of any new phases but the Bragg peaks become broader. Line profile analyses show anisotropic microstrains with an average <e2>1/2 value of -5x103. Thermal aging of the other hydride, LaNi3.5Mn1.5 hydride, at 623K for 280 hours, showed significant disproportionation; the hydrogen capacity reduced significantly from an H/M value of 0.75 in the activated condition to -0.15 after aging. X-ray diffraction analyses showed disproportionated lanthanum dihydride, metallic Ni, and Mn phases. The Bragg peaks were very broad indicative of microstrains or small crystalline domains.

Jan 1, 1997

By Kim Fagerlund

A novel apparatus for studying refractory infiltration and dissolution/degradation under a temperature gradient was developed. To supersede conventional isothermal refractory testing, a new temperature gradient technique, based on a crucible equipped with a cooling element, has been developed to provide practical information on the penetration and dissolution of refractory materials under cooled conditions. This technique was adopted and applied to several refractory-slag systems. Commercially available magnesia chrome refractory bricks against a copper-containing calcium ferrite type of slag were tested and compared using both a conventional crucible test and the new temperature gradient method. The experiments were conducted at 1300-1420°C under a controlled atmosphere of nitrogen or air. It was noticed that the type of porosity has a significant effect on infiltration of magnesia chrome refractories. Furthemore, the copper-containing calcium ferrite slag caused a severe slag attack and refractory failure in some cases, due to its fluidity and corrosive nature.

Jan 1, 2002