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By M. Hashiuchi

In 1972, the tankhouse of the Tamano Smelter adopted a high current density electrolysis operation applying the PRC (Periodic Reverse Current) method. In 1994, the phase four production expansion project, which incorporated significant re-structuring of the organization, was completed and we have achieved an annual production capacity of 191,000 tons. The target of this project, the production capacity, was increased by 1'8% and labor productivity by 25%. After the expansion, some improvements in the starting sheet section and the verticality of the electrodes were carried out, and the efficiency of the operation was greatly enhanced, including the improvement of the quality of the electrolytic copper.

Jan 1, 1999

By M. Boussuge, M. -D. Dupuits, A. Piant

This paper summarises a part of the work that has been essentially carried out at the Ecole des Mines de Paris in the framework of an Eureka European programme funded by the French Ministry of Industry, in partnership with Metaleurop and Carborundum (subsidiary of Saint Gobain). It deals with the measurement of different properties (density, thermal linear expansion, elastic modulus, strength) of a SiC-based refractory constituting the trays that are used in the refining columns in the New Jersey zinc distillation process, especially in the boiling section. These parameters have been investigated to check the homogeneity of the asreceived trays as well as to estimate the influence of ageing of the material under operating conditions. With this aim, specimens have been sampled in used trays having more than two years of operation. The as-received trays exhibited a good homogeneity, the strength being slightly lower in the direction in which they are compacted. Despite microstructural changes, most of the properties measured at room temperature are not significantly affected by ageing. High temperature tests involved thermal treated under vacuum to remove metallic zinc before testing at high temperature. An increase in temperature, as well as ageing, induces a decrease in the elastic modulus and strength.

Jan 1, 2000

By Myung Bae Kim, Yong Hack Lee, Woll Seung Lee

The Slag Fumer is the first Ausmelt furnace system adopted at the Onsan Refinery of Korea Zinc. This plant continuously treats the QSL lead smelting slag in the molten state. It has developed progressively since its first commissioning in October 1992 and has generated a confidence that it can produce an environmentally acceptable slag for use in cement manufacture and recover the zinc and lead in the slag as a fume oxide. This paper provides the operating experiences accumulated during the last eight years of operation, a summary of problems and solutions, and the current status of the operation.

Jan 1, 2000

By R. D. MacDonald

The papers presented in this chapter cover a wide range of hydrometallurgical topics and might be considered to be unrelated to each other. All of the authors, however, utilized the basic methods of process mineralogy to characterize the reactants in their experiments and the products produced. The wide range of research topics which can be pursued successfully by the use of the methods of process mineralogy is a matter of interest in itself. One might speculate that the methods could be even more widely applied if only their utility were better recognized. These methods for characterizing reactants and products include principally x-ray diffraction, optical micros-copy, wet chemical analyses, instrumental chemical analyses, high intensity magnetic separation, micro-scale gravity separation, differential thermal analysis, micro-hardness testing, and judicious use of the sledgehammer and cold chisel. It is perhaps not by coincidence that most of the papers in this chapter were prepared not by mineralogists, but by hydrometallurgists, who are recognizing the importance of thinking in terms of mineral phases, and not just assays! It appears that the gap between process mineralogy and the mineral industry is closing, and that future AIME sessions promise to become established forums where mutual discussion of such topics as metallurgical "troubleshooting" and process design may become commonplace between plant engineer and process mineralogist.

Jan 1, 1981

By Daojin Cao

Aiming at many controversial reports on Raman spectral pattern of octamolybdate ion in aqueous solution appearing in the literature, a new method for the establishment of corresponding relation between Raman spectral pattern and chemical components of aqueous molybdate solution was put forward using spectroscopy measure and component analyses of saturated solution of ammonium octamolybdate hydrate known structure. It was found that the main characteristic of Raman spectral pattern of the saturated solution was described as the same ?double-peaks, hereinto a weak peak at the boundary? as some literature, but chemical components of the saturated solution were affirmed to be octamolybdate ion (Mo8O264-) and double protonated heptamolybdate ion (H2Mo7O244-), which were in equilibrium in aqueous solution each other. The authors propose that the pattern of the saturated solution can be regarded as the standard pattern of primiparous octamolybdate ion during acidified molybdate solution. It is satisfying that the standard pattern is applied to the identification of primiparous octamolybdate ion during acidified molybdate solution.

Jan 1, 2006

By Michael J. Nicol

One of the preferred methods for the recovery of gold from refractory gold ores and concentrates involves pressure oxidation in acidic solutions. The main refractory gold-containing minerals are pyrite and arsenopyrite and there is evidence that the presence of even small amounts of chloride can inhibit the oxidation of these minerals and also substantially reduce the recovery of gold. In this paper, the results of a study of the anodic (oxidation) and cathodic (reduction) behaviour of pyrite electrodes in acidic sulfate solutions containing ferric ions at different chloride concentrations and temperatures up to 200oC and pressures of 2000KPa are presented. The electrochemical studies have been complemented by pressure oxidation experiments on a refractory gold concentrate. Results have shown that, as the chloride concentration increases, the anodic reactivity of pyrite is largely unaffected but the rate of the cathodic reduction of iron(III) decreases. The rate of oxidation of a sulfide concentrate and the recovery of gold by cyanidation of the residues decreases at high concentrations of chloride.

Jan 1, 2003

By Nedam Abed

A fundamental study of the sonochemical leaching of chalcopyrite in ferric ion media has been performed to understand and quantify the effects of sonication and other parameters on leaching reactions. The study covers sulfate and chloride media. The main leaching reaction: CuFeS2(s) + 4Fe3+(aq) Cu2+(aq) + 5Fe2+(aq) + 2S(s) (1) was found to be dependent on temperature and initial particle size, but less dependent on ferric ion concentration. Leaching kinetics were not affected by ferrous ion concentration or the amount of chalcopyrite added. Leaching was performed under a variety of sonication and leaching conditions. Reaction stoichiometry was confirmed through detailed wet chemistry analysis and mass balance calculations. The use of ultrasound activation showed a clear improvement in leaching kinetics and amount of copper extracted, sonication having a catalytic-like effect on the leaching reaction. Compared to experiments without sonication, reaction rates were 2-3 times faster at the same temperature, and could be faster by a factor of 20 for the same initial particle size. Regardless of initial particle size, the amount of copper extracted was comparable under sonication, and could be twice that under chemical leaching, implying the avoidance of fine particle grinding. Sonochemical leaching was found to be only temperature dependent, where the best copper extraction was at 75C. Leaching was further enhanced by the use of a grinding aid. The leaching behavior of chalcopyrite particles remained similar with and without ultrasound activation, implying that the known passivation mechanism in the oxidative leaching was not eradicated. Sonication resulted in coarse particle breakage (ultrasonic milling). Sonication did not contribute to particle passivation, as affirmed from different leaching procedures and sonication in aqueous and organic media. Parabolic leaching kinetics were confirmed for leaching experiments.

Jan 1, 2003

By A. A. Shook

The off gas from the #5 converter at BHP Copper's San Manuel smelter was analyzed continuously over a period of several weeks using an online sulfur dioxide analyzer. These data have shown that the oxygen utilization efficiency of this copper converter was somewhat lower than anticipated, and that oxygen efficiency declines significantly during the copper blow. A sharp reduction in sulfur dioxide generation was consistently observed at the end of the copper blow, which could be used by converter operators to prevent over-blowing and minimize rolling out of stack.

Jan 1, 1999

By Dhanesh Chandra

Metal carbonyls are of great importance in chemical vapor deposition (CVD), composite materials fabrication, and other near-net shape technologies. Carbonyl CVD application applies to deposition of high-purity metallic/alloy coatings. Vapor pressures of solid Os3(CO)12,Rh6(CO)16, Ru3(CO)12, Ir4(CO)12, Re2(CO)10, Co2(CO)8, Cr(CO)12,, and W(CO)6carbonyls have been measured using gravimetric-torsion effusion system. The vapor pressure data is used for many low and high temperature CVD applications. Interesting decomposition/disproportionation vaporization behavior has been notedfor Rh6(CO)16, Ru3(CO)12 and Co2(CO)8. The vaporization studies of Rh6(CO)16 showed virtually complete decomposition to Rh metal and the measured molecular weight of the effusing gas from the solid Rh6(CO)16 was 27.75 g/mol, close to that of carbon monoxide as compared to 1065.56 g/mol for the value of solid Rh6(CO)16. Electron microscopic characterization, X-ray line broadening results for Rh carbonyl has been performed on the vaporization product. However, Ru3(CO)12, Co2(CO)8 showed very complex behavior. The molecular weights of the vaporizing species have been estimated and the numbers of vaporizing species are proposed. For example, there was partial decomposition of Ru3(CO)12to(approx. 52%) metallic Ru and CO gas during vaporization, as suggested by the difference in the molecular weight of the vaporizing species of 107.58 g/mol compared to the actual value of 639.33 g/mol. The dimer Co2(CO)8 partially disproportionates to tetramer Co4(CO)12, monomer Co(CO)4, and CO gas. Whereas, the Os3(CO)12, Cr(CO)12,, and W(CO)6have shown virtually no disproportionation. The total vapor pressures of all the above-motioned carbonyls, partial pressures of various species, average molecular weights of the effusing gases, equilibrium constants for the vaporization reactions, their enthalpies, entropies, and Gibbs energies will be presented.

Jan 1, 2006

By M. Giunti, R. Hampson, S. Gray, P. Kapoulitsas, J. Clark

In 1997 Pasminco's Port Pirie Lead Smelter began a modernisation of its lead and precious metals refinery operations. Driven by the anticipated closure of its Broken Hill mine, the new refining process replaced the locally developed continuous process, which had been in operation since the 1950's. Commissioning of the new plant was staged, beginning in late 1997, and finishing early in 1999. The new plant provides for batch refining of lead, and the use of vacuum induction retorting and bottom blown oxygen cupel technology in the silver refining area. The project has resulted in an increase of lead production capacity of 11% and allows the treatment of a wider range of concentrates than was formerly possible. The most significant change has been to double the smelter's silver capacity to over 400 tonnes per annum. This paper describes the successful implementation and optimisation of the new refinery, which is now consistently meeting design capacity.

Jan 1, 2000

By Kent D. Peaslee, Lifeng Zhang, Edith Martinez, Yufeng Wang

The current study investigated the multiphase fluid flow, heat transfer, solidification of the steel, and the motion and entrapment of inclusions during the centrifugal casting process using FLUENT software. User-defined functions (UDFs) were developed to add velocity with a value related to the rotation speed and radial distance to the solidified steel, to exert a centrifugal force to the motion of inclusions, and to add the entrapment condition of inclusions at the solidifying shell and export the entrapment locations of the inclusion. The calculation shows that there are two peaks of inclusions along the thickness of the produced tube: one at close to outer surface and another one close to the inner surface of the tube. With a larger rotation speed, inclusions tend to be entrapped more towards the inner surface. The calculation agrees well with the industrial measurements.

Jan 1, 2012

By Admire Chaendera

A gas jet was blown through submerged nozzles to stir the bath in the presence and absence of slag. Mixing and mass transfer rates were then studied. Water and kerosene (10% by volume) were used to simulate the metal and slag phases respectively in the cold model. The mixing time (Tmix), defined at 99.66% bath homogeneity level, increased with bath height and decreased with an increase in the gas injection rate. Its value in the model vessel was related to gas flow rate (Q), bath weight (W), and bath height (H) by, Tmix = 4.39Q-0.73W0.24H1.12. Inclusion of the slag phase increased Tmix by about 16% and the mass transfer parameter, [(Reloc,r)0.25(Ret)0.32], values by about 32%. Mass transfer rates were higher near the bath surface and in the gas-liquid plume region. They increased with gas flow rate but decreased with an increase in bath height. The relationship, K Q0.08, showing derived mass transfer coefficient (K) dependence on the gas injection rate (Q) was established. The proportionality constant in the equation varied with gas flow rate and sample location.

Jan 1, 2006

By P. J. Moor

Britannia Refined Metals Ltd. was built in 1931 to refine the lead bullion produced at the Mt. Isa mine in Queensland, Australia. Several periods of expansion and development have taken place over the intervening years, leading to major increases in the refining capacity for both lead and silver. A plant for treating recycled lead-acid batteries was added in 1976. This was redeveloped in the early 1990's to utilise Isasmelt technology for the smelting operations. Most recently the No. 2 refinery kettle floor was extended to enable it to process lead bullion produced from two Imperial Smelting Furnaces (ISF), at Britannia Zinc Ltd. in Avonmouth, England and at MIM Hüttenwerke in Duisburg, Germany. This expansion included the provision of a plant for the hygienic handling of drosses and skims. This paper briefly describes the present primary refining operations and gives an update on the most recent developments in the process metallurgy and operating practices that have taken place.

Jan 1, 2000

By Carl A. Kuehn

At Carlin, Nevada, non-indigenous hydrocarbons were introduced as a bitumen phase which was mobilized due to burial under the Roberts Mountains allochthon. similarly, some indigenous organic matter was locally mobilized. Fluid inclusion and paragenetic data of veinlets formed during this hydrocarbon stage, combined with quantitative modelling or organic maturation, indicate that host rocks had evolved past dry gas conditions of around 1550 and l.l+0.2 Kb in the presence of CH4-saturated, highly saline brine by no later than early to middle Cretaceous time. All hydrocarbons present would have been rendered immobile under these catagenic conditions. Crosscutting relationships at several scales suggest that hydrocarbon mobility may have ceased prior to the intrusion of a series of dikes in the mine which have subsequently been altered and mineralized. Apart from subsequent oxidation, the current distribution and high maturity of carbon-rich zones were established prior to gold introduction. No Evidence has been found supporting proposed hydrocarbon "remobilization" during or after gold mineralization and alteration. The high density of the CH4-bearing fluid requires formation at high pressures (near 1 Kb) and precludes their formation as a result of the "cracking-off" of CH4 from organic matter during a thermal event associated with a shallow hydrothermal system. The density and composition of the fluid inclusions restricted to the early hydrocarbon-stages of the Carlin paragenesis are not unique to the sediment-hosted gold deposit environment of north-central Nevada. Similar inclusions are found in authigenic quartz crystals from Paleozoic carbonaceous shales in central Pennsylvania which have experienced normal metagenesis of indigenous organic matter due to deep burial.

Jan 1, 1987

By Jean Frenay

Bacterial leaching tests have been carried out on Portugese pyritic ores containing zinc, copper, lead and silver as valuable elements. Both indigenous and isolated strains of Thiobacillus ferrooxidans were used. During the tests the factors pH, Eh and dissolved oxygen were measured and related to the leaching activity of the bacteria. Different means to estimate or determine the real bacteria concentration were examined. The influence of nutrient media and particle size has been evaluated. The role of galvanic couples was studied by electrical linking of mineralogical samples of pyrite, sphalerite and chalcopyrite. Leach residues were examined by optical microscopy to follow the mineralogical alterations during the leaching. The results show a rather good leaching of the sphalerite. However, the dissolution of copper from chalcopyrite is much more difficult, 50 % recovery never being obtained.

Jan 1, 1985

By Richard M. RusselI, Jerry Sweeney

"The disposal of Aluminum slag wastes continues to challenge an otherwise environmentally beneficial and highly desirable industry - Aluminum Recycling. Slag wastes contain soluble salts that can be reused in aluminum smelting. Reclaiming salt is a logical first step in eliminating slag waste.Reclaiming salt flux has been conducted on a limited basis in the United States for reasons of economy. Practical methods and rising landfill tipping fees will increase the number of plants which opt to recover salts from slag wastes.The authors share their experiences in the design, operation and startup of a commercial scale flux reclamation plant operated by Tennessee Aluminum Processors at Mt. Pleasant Tennessee. This paper identifies three elements that allow practical operations:• Minimizing Evaporator Heat Duty• Simplifying Evaporator Operations• Potassium Chloride Fortification of the Recycled Salt"

Jan 1, 2000

By Manfred Schmidt

Realizing an invention of Professors Queneau and Schuhmann, Lurgi GmbH has developed a radically new lead smelting technology, which was demonstrated on a ?30,000 tpy scale at Berzelius Metallhiltten GmbH between 1981 and 1986. Designed to treat all grades? of lead concentrates as well as complex secondaries, the novel QSL-Process applied one bottom-blown, refractory-lined long reactor and comprises two basic steps: Continuous oxygen smelting of the green charge is followed by continuous carbothermic slag reduction. Four firm orders and a number of serious inquiries from major lead producers confirm that the QSL-technology has convinced the industry of inherent process advantages. These include low investment and operating costs, flexibility and environmental acceptance. In the fall of 1986 Cominco Ltd. decided to erect a 120,000 tpy QSL plant at the site of the Trail lead smelter. Feed materials will consist of lead concentrates and zinc leach residues. The designed QSL reactor has a total length of approx. 41 m, and working diameters of 3.74 m for the oxidation section and 3. 24 m for the reduction section .. Separate gas offtakes on both sections will enable to? reduce the sulfur dioxide gas volume, and to recover a mixed zinc-lead oxide fume. Operation of the QSL reactor will start end of September 1989. First results will be presented.

Jan 1, 1990

By S. Kurama

Incorporation of de-watering sieve waste of borax (TSW) from Etibor Kirka Borax Company (Turkey) on the mechanical and physical properties of a commercial floor tile composition was investigated. In order to achieve this aim, TSW was partially employed in place of feldspar in the standard composition up to 20 wt %. The formulated compositions were wet milled, dried, shaped and then fired at 1190C for a total firing time of 38 minutes (from cold to cold) under industrial conditions. It was found that using of TSW up to 15 wt % improved the physical and mechanical properties of final product. The results indicated a good prospect for TSW as a co-flux in floor tile formulations.

Jan 1, 2006

By Samir N. Shoukry, Mourad Y. Riad, Gergis W. William

"Setting of concrete material is defined as the transitional period between states of true fluidity and true rigidity. Initial and final setting times are measured in the laboratory on the mortar sieved from the mix in a controlled environment where temperature and moisture values are constant. On the other hand, field applications are held in outdoor environments where environmental variations have direct impact on setting time values. In this study, initial setting time of class K concrete, usually used for bridge decks and concrete pavements, are investigated highlighting discrepancies between laboratory and field measurements. 72 mixes have been cast in variable environments and collected data from concrete mixes and the ambient conditions are reported. In light of the collected data, the effects of variable setting times on early age cracking of concrete material are studied and means to minimize such cracks are presented.BackgroundSetting of concrete material is defined as the transitional period between states of true fluidity and true rigidity [1]. Continuous hydration of the cement within the matrix transfers the mix from a state of setting to hardening. Initial and final Setting times are measured in a laboratory setting following ASTM C 403 specifications. Initial setting approximates the time at which the cement paste can no longer be plastic under compaction (or can be handled in a proper fashion), while the final setting approximates the time at which hardening occurs. The standard test described in ASTM C 403 is conducted on the mortar sieved from the mix (paste passing from 4.75 mm sieve opening). Initial and final settings are described as the elapsed time after the initial contact of water and cement till the mortar reaches a penetration resistances of 3.5 MPa (500 psi), and 27.6 MPa (4000 psi) respectively."

Jan 1, 2012

By Iain B. Mackenzie

In 1997, a thin layer of Microtherm Microporous Insulation was used to replace fireclay brick behind the magnesia/chrome working lining in #5 refining furnace at BHP?s San Manuel AZ smelter. A 23°C reduction in shell temperature was obtained, together with a large increase in the working capacity of the vessel. There was no sign of metal penetration as a result of the increased insulation. Following these highly favorable results, BHP have introduced this product into all of their refining furnaces.

Jan 1, 1999