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By Yoichi Takeda

Copper solubility in SiO2-CaO-FeOx slag equilibrated with copper matte in 10% SO2 atmosphere at 1573K was estimated. Essential parameters are activity coefficients of copper oxide and sulfide, oxygen and sulfur potentials and activity of copper in the slag-matte system. A large number of experiments provide proper parameters to calculate copper solubility in slag, A classical thcrmodynamic model postulating CuO0.5 and CuS0.5 moleculcs assists in estimating copper solubility in slag. Additions of Si02 and CaO reduce copper solubility almost in any condition. Copper loss, that is function copper solubility and slag volume, in the silica saturated SiO2-FeO. binary slag is minimally equilibrated with less than 66% copper matte while copper loss in the 50% FeO.-SiO2-CaO ternary slag saturated with 2CaOSiO2 is minimally equilibrated with over 66% copper matte. This slag composition has potential for continuous copper converting, direct copper production or high-grade matte production.

Jan 1, 2003

By P. N. Anyalebechi

The effects of Si (0.19-0.52 wI. %), Fe (0.20 wI. %-0.44 wI. %), and Cr (0-0.10 wI.%) on the response of ingots of aluminum alloy 3004 solidified at different rates (O.IO°C/s to 30°C/s), to homogenization heat treatment have been investigated. Response to homogenization was determined by quantifying the following microstructural parameters: (i) amount of Mn retained in solid solution; (ii) types, relative amounts, sizes, size distributions, shapes, and chemical compositions of second phases; (iii) extent of the alpha-transformation (i.e., AI6(Fe,Mn) --7 (XAI12( Fe,MnhSi) reaction; (iv) dispersoid formation; and (v) alleviation of dendritic microsegregation. Of the three alloying elements investigated, Si had the greatest effect on the response of aluminum alloy 3004 to heat treatment. Increase in Si content, fineness of cast microstructure, and homogenization temperature facilitated alpha-transformation reaction, dissolution of Mg2Si, loss of Mn supersaturation, and formation of AldFe,Mn)3Si and Mg2Si dispersoids.

Jan 1, 2008

By J. Gartelmann, B. Zaslavsky, Y. Vojta, D. J. Chaiko, W. Mego, A. N. Rollins

"Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that we have studied are generated by combining an aqueous salt solution with an aqueous polymer solution.We have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. We have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). In this chapter we review the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation.IntroductionAqueous biphasic extraction (ABE) is a highly adaptable separation technique that can be used in a wide range of applications. We have been evaluating various types of ABE systems for possible applications in the treatment of solid radioactive wastes (1,2), liquid nuclear wastes (3,4), and contaminated soils (5-7), and in the removal of organics from aqueous salt solutions (8). We have also conducted fundamental studies of the solution microstructure of ABE systems using small angle neutron scattering (SANS) (9).The extraction systems are generated by combining an aqueous salt solution and an aqueous polymer solution. This produces two distinct liquid layers that are as immiscible as oil and water, yet each liquid layer contains at least 70 to 80 wt % water. The biphasic systems that we have been working with consist of immiscible polyethylene glycol (PEG) and salt solutions. Some inorganic salts that promote biphase formation with PEG solutions include the sodium/potassium salts of sulfate, carbonate, phosphate, and hydroxide (10)."

Jan 1, 1996

By I. S. Blair

The Mufulira smelter (1, 2,' 3, 4,) is one of three smelters situated on the Zambian Copperbelt to treat concentrates and other intermediate products produced in the area. Two mining companies, Roan Consolidated Mines Limited (RCM) and Nchanga Consolidated Copper Mines Limited (NCCM) each have 51% Zambia Government participation. RCM operates two smelters, one at its Mufulira Division and the other at its Luanshya Dl vision. NCCM operates one smelter at its Rokana Division (5). The Mufulira smelter was commissioned in 1937 with two reverberatory furnaces and four converters. The final product, blister copper, was cast from a holding furnace. In 1952 two anode furnaces and a common casting wheel were installed to feed a new and adjacent electrolytic refinery. In 1956 the smelter was extended to accommodate increasing production from the new Chibuluma mine and expansion at Mufulira mine. A third reverberatory furnace, a fifth converter and duplicate anode processing and casting facility were added. The Copperbelt smelters suffered a loss of production potential when higher ash content coals were used in reverberatory smelting furnaces from 1966 onwards. This, and the planned production increases from Mufulira and other RCM mines, indicated a smelting shortfall of 55,000 tonnes of copper a year in the combined capacity of the RCM smelters.

Jan 1, 1976

By Zhengjie Chen, Wenhui Ma, Jijun Wu, Kuixian Wei

The gasification reactivity of PC (petroleum coke), strengthened by addition of different potassium carbonate proportions using different grinding medium, was investigated by using thermogravimetric analysis (TGA). Results showed that the gasification reactivity of PC not only increased with the increase of catalyst-loaded, but also showed the effective improvement by anhydrous alcohol. The PC was mixed with potassium carbonate [K2CO3] catalyst at 0.5%, 0.8%, 1.0% and 1.5%, and then ground wet with distilled water. The CO2-gasification rate of PC was only 77.35%, 80.55%, 84.07% and 85.88% under the gasification temperature 1100 °C and holding time 120 min, at different K2CO3 respectively. However, when the PC was ground in anhydrous alcohol at the same condition of catalyst-loading, the gasification rate of PC reached 95.43%, 96.63%, 95.50% and 95.61% at the holding time of 108 min, 101 min, 74 min and 35 min, respectively. It was shown by FTIR, SEM and EDX determinations that the anhydrous alcohol used as the grinding medium can further improve the gasification reactivity of PC when compared with the distilled water.

Jan 1, 2016

By Shinroku Matsuzaki

Data the measurement sensor installed with spatial distribution on the blast furnace were successively accumulated online from the process computer to the database system over a long period. This is a new system that accurately considers the relation with the installation position of each sensor, and picture computerization of the measurement data was developed. The overall operation state of a blast furnace, which skilled operators can see in their mind?s eye, was objectively visualized as pictorial information.

Jan 1, 2006

By Robert E. Moore

Synthetic spinel is proving to be a highly effective refractory for specific applications, but its cost limits applications. Formation of spinel from a raw material such as diaspore or bauxite could provide a simple and less costly starting material. In the study reported here, finely ground (-325 mesh) diaspore from Missouri and bauxite from Guyana and China are combined with hard burned MgO (-325 mesh) in appropriate proportions to yield spinel and spinel with secondary phases. A classical sintering and dilatometer study was completed, followed by a microstructure study to determine completeness of the reactions and morphologies of the reaction products.

Jan 1, 1993

By William Petruk, J. H. Gilles Laflamme, Jean Robitaille, Louis J. Cabri

"A quantitative mineralogical study using ore microscopy, electron microscopy, proton-microprobe, image analysis, and material balances was done on samples from the circuit of a concentrator in Quebec, with particular emphasis on the Cu concentrate. The ore contains many different minerals, of which the principal ones, in decreasing order of abundance, are pyrite, sphalerite, chalcopyrite, bornite, galena, tennantite, and pyrrhotite. Minor to trace amounts of covellite, chalcocite, stannoidite, mawsonite, colusite, wittichenite, miharaite, hessite, petzite, electrum, and an unidentified Cu-Pb-Bi-sulfide also occur.Liberation of pyrite is very high in all size fractions for all samples (ranging from 80-91 %). Liberation of chalcopyrite, bomite, sphalerite, and tennantite is relatively high, on average, in the head .sample and Cu concentrate (55-78% and 66-88%, respectively). Most of the chalcopyrite in the flotation tails is not liberated, whereas about one half of the tennantite and sphalerite are liberated in both the flotation and :final tails. Recoveries calculated for the Cu concentrate (on the basis of assays, mineralogy, and image analysis) are chalcopyrite 72. 5%, bornite 73. 7%, sphalerite 41.0%, tennantite 70.9 %, and galena (together with some trace minerals) 34.2%. It was also calculated that the Cu concentrate contains 10.0 % of the pyrrhotite and i.4 % of the pyrite.Materials balance calculations were done on the five major sulfide minerals to determine the mineralogical distribution of 13 major, minor, and trace elements (as determined by protonmicroprobe analyses). It was determined that tennantite is the principal carrier of Bi (67%), As (90%), and Te (86%) in the Cu concentrate. Therefore, removal oftennantite, which is mostly liberated in the Cu concentrate would significantly reduce these three contaminant elements, but at a loss of9% of the Cu, 2.0% of the Zn, and 0.7% of the Ag. The precious metals (Au, Ag) occur as discrete minerals (electrum, petzite, hessite). Some of the Ag also occurs in solid solution in bornite (23.1% of Ag in Cu concentrate), tennantite, and sphalerite. Four of the major sulfides (chalcopyrite, bomite, sphalerite, tennantite) in the ore also contain measurable concentrations of the following trace elements: Se, Cd, In, Sn, and Sb, occurring mostly as solid solutions. Some of these elements are also concentrated (up to about 18%) in minor and trace minerals such as colusite, stannoidite, and mawsonite."

Jan 1, 1999

By . Menad Gaballah I

Three samples of solid wastes generated by the non ferrous metallurgy were characterized. These residues contain up to 42 % of valuable metal compounds ( Cu, Pb and Zn ) and 23 %of toxic compounds t As, Hg, Cd and Se ). These sample were subjected to thermal treatments between 200 DC and 800 °C in controlled oxidizing. reducing and chlorinating atmospheres. Up to 99 % of As, Cd, Hg and Se were eliminated from these industrial wastes. Cu, Pb, and Zn compounds were concentrated in the treatments' residues of these samples. A Global Decontamination Factor' GDF ' was defined to measure the efficiency of the elimination of toxic elements and the recovery of valuable elements for a specific sample submitted to a given treatment. It seems that the thermal treatment in a reducing atmosphere was the most efficient in decontaminating these solids and the concentration of valuable elements. a.

Jan 1, 1995

By Stephen W. Paff

The EPA has estimated that there are over 3,000 sites across the United States contaminated with lead. Techniques to remediate these sites include standard stabilization/disposal technologies, reclamation of lead using secondary lead smelters, soil washing, and biological removal technologies. In this paper, the current technologies used for lead remediation will be reviewed. Factors affecting the use of each technology, such as range of applicable concentrations, soil types, interferences from other contaminants, economics, and current technology status will be assessed. The paper will also focus on the results of a recent study completed by the Center for Hazardous Materials Research (CHMR), in conjunction with a major lead smelter, which demonstrates that secondary lead smelters may be used economically to reclaim lead from a wide range of lead-containing materials frequently found at Superfund sites. Such materials include battery case materials, lead dross, and debris containing between 3 and 70% lead. The results of development work completed by CHMR on the Acid Extraction Treatment System (AETS), which has been demonstrated to extract Lead from soils containing up to 30,000 mg/kg lead, will also be presented. The use of these technologies will be compared with other options for the remediation of sites.

Jan 1, 1994

By Devon A. Hannan

Thermodynamic modeling calculations were undertaken for the recovery of mercury from HgTe using a vacuum retort reactor. However, discrepancies were noted in the available thermodynamic data which introduced uncertainty in the model results. Consequently, a series of transpiration experiments were first undertaken on the thermal decomposition of HgTe into an inert carrier gas stream according to the following reaction: HgTe(s) Hg(g) + Te(s) From the measured weight loss of the HgTe samples, the Gibhs free energy change for the above volatilization reaction was determined as a function of temperature. The experimentally determined Gibbs free energy values were found to be approximately 30% larger (more posi-tive) than the values available in databases such as HSC Chemistry. By conducting a second-law analysis on the experimental data, the heat of formation of HgTe at 298.15 K and the en-tropyat 298.15 K were determined, which then formed the basis for a new database for the modeling calculations. The results of this study showed that HgTe was more stable at elevated temperatures than was generally indicated in the literature. The new database is given in a for-mat for direct insertion in HSC Chemistry. Using the new database, modeling calculations were conducted to examine the effects of the re-tort pressure and the molar ratio of purge gas to HgTe on the volatilization of mercury from HgTe. A diagram is presented that shows the minimum temperature for 100% volatilization of mercury from HgTe as a function of retort pressure for different molar ratios of purge gas (N2) to HgTe. For example, it was found that the minimum temperature for 100% volatilization could be decreased by 175 K, at a retort pressure of 0.05 bar, if the molar ratio ofN2 to HgTe is increased from 1.0: 1 to 100.0: I.

Jan 1, 2003

By H. K. Fouad, L. A. Guirguis

The starting mill strip solution· for this study· is an ammonium uranyl tricarbonate solution of pH 8.2 containing 20g uranium/liter, after a DEPA/TOPO extraction process from sulfuric acid leaching liquor. To the first portion of the concentrated acidified strip solution, hydrofuoric acid is added at 95°C in reduced condition to obtain uranium tetrafluoride. The second portion of the uranyl carbonate strip is subjected to a precipitation step by admixing 0.3 volume of non-solvent precipitating agent such as acetone per volume of uranium. ·Uranium oxide (U30 8) is obtained from this precipitate by calcination for half an hour at 800°C in air. The third portion of the strip solution is neutralized to a pH 6.5 with sulfuric acid to precipitate iron and other contaminants. The solution is further acidified to a pH 1.85 with continuous air bubbling to remove CO2, followed by H2Ch precipitation at pH 3.5 to obtain uranyl peroxide. The latter is reduced by stannous chloride to obtain uranium trioxide dihydrate UO3. 2H20. Identifications, characterization· and purity of these products are carried out by complete chemical analyses, Scanning electron microscope study, tap density determination, X-ray diffraction and infrared spectroscopic investigations. The achieved results agreed well with that of the published data for these nuclear grade purity products.

Jan 1, 2000

By B. Bichel

For the last 70 years, molten blister copper has been transferred by rail in hot metal cars from the Copper Cliff Smelter to the Copper Cliff Copper Refinery (ex Ontario Refining Company) where it was processed in two (2) reverberatory anode furnaces by poling with logs, cast on four (4) wheels, and then electrorefined. This practice was modernized in 2001 with the installation of two (2) rotary anode furnaces at the. Copper Cliff Smelter which employ steam and. natural gas for reducing and which provide a significant reduction in emissions. A new casting shop with a single anode casting wheel is used to cast regular and stripper constant weight anodes which are transported by truck to the Copper Cliff Copper Refinery for anode preparation and electrorefining. This paper provides an overview of the copper circuit at the Copper Cliff Smelter and a description of the CDN$31 million capital project.

Jan 1, 2002

By G. C. Yao

Branch and needle-shaped intermctallic compounds of iron, silicon and aluminum normally exist in the molten aluminum. If a suitable amount of manganese metal is added into molten aluminum, the shape of the intermallie compound particlcs may become lumpish and spherical. According to the difference in electric and magnetic properties of these impurity particles and molten aluminum, these impurity intermctallie compound particles can be separated by applying an alternating magnetic field. In this experiment the alternating magnetic field was formed by a "C" type loop with AC (50Hz) current. The inner vacuum of the fireclay refractory separator is 25>< 15" 130mm3 with a lateral baffle inside. The separator was put into the interspace of the "C" type loop. It was found that the longer the separation time, the larger the amount transferred of impurities. The amount of transferred impurities increases with the increase of separation time and intensity of magnetic field. The addition of manganese metal enhanees signifieantly the efficiency of impurity separation.

Jan 1, 2003

By Varadarajan Seshadri

A physical model based on similarity principles was constructed for simulating the RH degasser of CST (Companhia Siderurgica Tubarao, Vitoria, ES, Brazil) to evaluate the circulation rate of the metal which essentially defines the degree of exposure of the metal to vacuum in the chamber and thus of the refining rate, The circulation rate on the other hand will influence the decarburization rate and removal of dissolved gases like nitrogen and hence it is essential to optimise this parameter to get maximum refining efficiency with minimum refining times, thus improving the productivity of the secondary refining process. Mixing characteristics in the ladle is evaluated by pulse tracer addition using conductivity-meters located at the down leg as well as at several locations in the ladle. The influence of gas injection through nozzles in the upleg with simultaneous bottom injection of gas as well as nozzle blockage on the circulation rates were investigated. Also simulation experiments of kinetics of decarburization were carried out using CO2 adsorption-desorption process in sodium hydroxide solution as circulating fluid and the effect of, bottom gas flow rate in this case was also evaluated. The results were carried over to prototype and to optimize the process.

Jan 1, 2003

By Courtney A. Young

Cyanide is a critically important chemical to the mining and metallurgical industry. It has a strong affinity for metals making it favorable as an agent for metal finishing and treatment as well as a lixiviant for metal leaching, particularly gold. These technologies are environmentally sound but, because cyanide is very toxic, safeguards are required to prevent accidental spills and treat effluents before being discharged. Various methods of cyanide remediation by separation and destruction for cyanide management purposes are therefore reviewed. The methods have been broadly categorized as physical, -adsorption. complexation and oxidation methods including photolysis and other advanced-oxidation processes. Reaction mechanisms for these methods are presented throughout this paper, Finally, the methods are compared in regards to their effectiveness in treating various cyanide species: free cyanide, thiocyanate, weak-acid dissociables, and strong-acid dissociables.

Jan 1, 1998

By Ari I. Kogut

Impurity minerals in fluorspar ores and concentrates from a deposit in Southern Africa have been studied by reflected light, transmitted light, and cathodoluminescence microscopy. The principal impurities are quartz, calcite, aegirine, apatite, ankerite, magnetite, goethite, and synchysite [Ca(La,Ce,Nd)(C03l2Fj. Cathodoluminescence microscopy was found to be very useful in studying the character of the fluorite and especially for recognizing the presence of apatite and calcite impurities. Fluorite exhibits blue, calcite shows yellow, and apatite has white, light purple, and pink cathodoluminescence. The cathodoluminescent character of apatite varies with its geological environment and position in the orebody. The results of this microscopic study show that phosphorus present in flUorite concentrates occurs principally in binary locked apatite-fluorite particles. Successive fluorite cleaner concentrates contain progressively smaller amounts of locked apatite-fluorite particles. Free apatite has been effectively partitioned to the final tailings.

Jan 1, 1995

By Wayne C. Stewart

Freezing of high pressure air lines and pneumatic equipment has been a recurring problem in the Thompson Smelter. The particular severity during the winter of 1989-90 resulted in costly process disruptions and repairs. A process improvement team with representatives from operations, engineering and both maintenance supervision and the shop floor was established to develop solutions. Their mandate included process evaluation, design, equipment and in-plant commissioning. In 1990, upon recommendation of the team, we installed three Refrigerant/Desiccant air dryers with a total capacity of 20,000 S.C.F.M. to service the Smelter. This paper discusses processes and process improvements associated with this installation.

Jan 1, 1993

By C. J. Newman

The Kidd Creek Copper Smelter has been expanded from its original design of 59,000 tonnes of copper per year to over 120,000 tonnes per year. Modifications to the process gas handling system and acid plant have been made to accommodate this higher production rate and to generally optimize the operation. The gas handling system associated with the continuous smelting process is discussed in terms of boiler accretions and modifications to minimize their impact on operations; design changes to effect reductions in high pressure drop duct configurations; material changes to overcome corrosion and plant additions to improve gas cleaning capability. The acid plant is reviewed with references to changes? made to accommodate the increased SO2 gas strength resulting from the higher smelting rates.

Jan 1, 1992

By R. J. St. Eloi

The Kidd Creek Copper Smelter has been expanded from its original design of 59,000 tonnes of copper per year to over 120,000 tonnes per year .. Modifications to the process gas handling system and acid plant have been made to accommodate this higher production rate and to .generally optimize the operation. The gas handling system associated with the continuous smelting process is discussed in terms of boiler accretions and modifications to minimize their impact on operations; design changes to effect reductions in high pressure drop duct configurations; material changes to overcome corrosion and plant additions to &apos;improve gas cleaning capability. The acid plant is reviewed with references to changes made to accommodate the increased S02 gas strength resulting from the higher smelting rates;

Jan 1, 1992