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By Yong Hack Lee

Nonferrous smelting processes have been through a rapid transformation since the beginning of 1980. The copper smelting technology has changed from the conventional Blast Furnace process to the Flash Smelting and MIB process. In the field of lead smelting, the technology has changed from the Blast Furnace Smelting to the Direct Smelting such as QSL and KIVCET. In 1992, Onsan Refinery successfully commissioned Direct Smelting QSL technology for lead. The QSL could produce more than 160,000 ton per year of lead bullion from lead concentrate and various residues. Moreover, since the year 2000, the TSL (Top Submerged Lance) Technology utilizing the same Direct Smelting process has been successfully commissioned to treat lead concentrate as well as lead sulfate residue produced from a hydrometallurgical zinc plant. This paper presents and compares the energy flows of lead smelting processes such as a conventional process and the Direct Smelting Processes plotted on the Pb-O-S phase diagram. The oxygen potential diagram suggests how to control the oxygen potential in the furnace. Also, it describes the recent operational experience in the TSL plant of Onsan Refinery with necessary mass balance of key elements.

Jan 1, 2003

By Takeshi Azakami

By combining the iron reduction process with the usual rotary kiln process, the direct production of metallic zinc from EAF dust is proposed. After thermodynamic estimation and desk-top experiments it is confirmed that the process is hopeful under suitable conditions. In order to get some practical test data the enlargement of the process scale was planned and the bench scale tests were carried on successfully. In these experiments a zinc ingot of PW grade was produced from EAF dust.

Jan 1, 2003

By Joseph C. Milbourne

Tetra Technologies CCIX? (continuous countercurrent ion exchange) system has been involved in a wide range of uranium concentration, separation and purification applications over the past 40 years. Uranium ion exchange applications have ranged from the treatment of copper heap leach solution containing 5 parts per million of uranium to the treatment of high strength sulfuric acid solutions containing several thousand parts per million of uranium. The flexibility and the countercurrent mode of operation and other unique features of the CCIX? have resulted in successful uranium recovery from these solutions and many others.

Jan 1, 1995

By Min Zhu, Yu Ji, An-chao Ren

"After being welded in the weld plant, the 100-meter heavy rails with the specification of 60kg/m are found broken during the straightening process in four planes. Failure analysis is made using the optical microscope and SEM with the result showing that the broken rail contains the imperfection of protrusion which exists at the edge of rail foot, about 1 00mm away from the rail end. When the protrusion is peeled off by deseamer from rail surface, cold scratch is generated which causes the rail to be broken during the subsequent straightening process. By adjusting the roll diameter differences between top and bottom roll of universal finishing mill and the height of pass line, it is possible to maintain the rails flat when leaving the mill. This prevents the upsweep and downsweep phenomena and, thus, the imperfection of protrusion can be eliminated. IntroductionThe development of rail transit worldwide has entered into a new era since the 1960s. The hi-tech rail transit system has gradually gained recognition over the world. In particular, the emergence of new-type passenger trains represented by TGV of France, ICE of Germany and Shinkansen of Japan and heavy haul trains as well, has revealed the charming way and more prosperous future of the modern and hi-tech rail transit system to the people all over the world. It should be pointed out that rail transit system is still the most effective solution to traffic jams among urban cities and in the central cities during the 21 '1 century, especially high-speed railway and subway which take overwhelming advantages over air transport, marine transport and road transport in terms of high speed, high efficiency, safety, comfort, environment protection and high flow. With the trend of increasing speed and heavier load of trains, higher product quality of rails is demanded. The rails for passenger dedicated lines require high cleanness, high accuracy in size, high flatness, high surface quality and large size (100-meter fixed length). The rail quality has direct influence on the operating performance of rail and railway traffic safety. The 100-meter heavy rails with the specification of 60kg/m are broken subject to the straightening process in four planes after being welded in the weld plant. This paper analyzes the reason for rails being broken and provides the theoretical proof for determining the rolling process."

Jan 1, 2013

By Louis J. Cabri

The ion microprobe (dynamic SIMS technique) is a very sensitive instrument for the quantitative determination of trace concentrations of precious metals (often at the ppb level) occurring in common sulfide minerals, either chemically-bound or as discrete particles too small for resolution by SEM. The technique involves sputtering a 250 x 250 Jim area of the grains to a depth of about one ILm and analysing the secondary ions emitted from a circular central region in the sputter crater with a 62.5 I'm diameter. The combination of quantitative mineral-specific sub-ppm analyses together with depth-profiling and the ability to produce secondary ion maps of trace precious metals makes this a very powerful technique in quantifying the precious metal distribution in refractory and other sulfide ores and process products. The technique is particularly well-established for analysis of gold-and platinum-bearing ores and process products.

Jan 1, 1996

By Robert R. Grinstead

Two new ion exchange resins have been developed, which selectively absorb copper and nickel in preference to ferric iron from dilute sulfuric acid solutions of pH 1-3. The first absorbs copper and not nickel and can be readily eluted with 1-2N sulfuric acid. This resin is well adapted to the processing of copper leach liquors, including relatively low grade liquors obtained from dump leaching. The second resin absorbs nickel as well as copper in the same pH region, but only the nickel is eluted with 1-2N sulfuric acid. Elution of the copper requires much stronger (ca. ION) acid, altho both species are readily eluted with dilute (ca. lN) ammonium hydroxide. This resin, which should be useful in processing of certain types of copper-bearing solutions, may also be suitable for treating acidic nickel leach solutions of laterites and other non-sulfide ores.

Jan 1, 1976

By Rodney T. Jones

DC arc furnaces were first used industrially for the reductive smelting of chromite fines to produce ferrochromium thirty years ago. Since then, they have been used for a variety of applications, including the smelting of ilmenite to produce titania slag and pig iron, the recovery of cobalt from non-ferrous smelter slags, and the smelting of nickel laterite ores to produce ferronickel. The power of these furnaces has increased from 12 MW to 72 MW for ferrochromium, and to 80 MW for ferronickel. The largest of these furnaces requires two electrodes to carry sufficient current to generate this much power. A review is presented of various DC arc furnaces in use, along with a discussion of the likely ways in which furnace power might be increased further in the future.

Jan 1, 2014

By A. J. Schindler, F-P Sawyer, T. Logan, M. L. Shutey-McCann, R. M. Perry

"Test work on biooxidation pretreatment of low-grade refractory gold ores has been ongoing at Newmont Gold Company since 1988, including laboratory testing and pilot biooxidation heaps (360 to 23,000 tonne). Metallurgical results of the biooxidation process utilizing Thiobacillus ferrooxidans (T. ferrooxiddans) have culminated in the design, construction, and operation of a biooxidation demonstration facility. The facility has processed 708,000 tonnes of refractory ore, using a batched process with separate pads for biooxidation and ammonium thiosulfate gold extraction. Siliceous sulfidic refractory (SSR) and carbonaceous sulfidic refractory (CSR) ores are treated separately during biooxidation pretreatment unit operation. Following biooxidation, the ores are neutralization with lime and placed on oxide leach pads or stacked on the ammonium thiosulfate leach pad. Gold is leached with either cyanide for SSR ores or ammonium thiosulfate for preg-robbing CSR ores.This paper will only address the biooxidation pretreatment process of the SSR and CSR ores.AcknowledgmentsThe authors appreciate the cooperation and approval of Newmont Gold Company Carlin Operations management for its support and permission to publish this paper. The paper draws on efforts and assistance of the following people and several others which are to many to list who participated over the past five years in bringing this project to its fruition: Dr. James A. Brierley, Chief Microbiologist, Newmont Metallurgical Services; Dr. Rong-Yu Wan, Metallurgical Manager, Newmont Metallurgical Services."

Jan 1, 1997

By Fatma Arslan

The lateritic nickel ore sample subjected to this experimental study was taken from Çalda ore deposit (Turkey) and contains 1.43% Ni and 0.105% Co. Mineralogical investigations showed that the ore sample contains asbolane, chromite, limonite, hematite, goethite, lepidocrocite, magnetite, serpentine, and clay type minerals together with chalcedon, quartz, calcite, and chlorite. In the acidic leaching experiments, the effects of temperature, acid (H2SO4) concentration, and leaching time on nickel leaching recoveries were investigated. Leaching recovery versus time curves showed a parabolic trend and increasing the temperature shifted that curves to the higher values. The dissolution of nickel from lateritic ore can be explained by a shrinking core model and the apparent activation energy was found as 47.34 kJ/mol in the range given by the literature. The highest Ni and Co leaching efficiencies as 90.2% and 96.8% respectively were obtained at 80°C temperature, 200 g/L H2SO4 concentration, and 8 hours of leaching time.

Jan 1, 2006

By Viktor. P. Popov, Oleksandr. V. Derev'yanko, Oleksandr. I. Raychenko

"This paper is devoted to scrutiny problem of obtaining electro-contacts by electro-discharge sintering technology. A new unconventional method of electro contacts production (on Aggraphite base) can yield essential optimization resource.Review of three electro-technological methods of processing contacts materials is presented:- using graphite powder cladded by Ag;- mixture of graphite powder(which is a non-cladded powder) with Ag powder and addition of Fe powder particles;- method of infiltration of melted Ag into graphite piece without deformation and rupture of object.This technological approach can give the possibility to increase of compression strength of electro-contacts materials up to 340 MPa and more under conditions of additional reinforcing components (for example, by Fe).IntroductionThe electric current can be an active ""participator"" of the powder metallurgy technology [l]. At the passage of electric current through powders or some powder mixtures the phenomena including phase transformations arise. Here such effects, which are observed in the Ag-graphite and Ag-Fe-graphite powder mixtures and in the pair Ag-porous graphite, are described.The Ag-graphite composition materials (CM) are used, for example, as electric contacts [2, 3]. Since a material being produced is destined for the contacts it is necessary to take into account the following aspects: commutating current, its character and voltage, active or reactive character of working load, geometrical dimensions of contacts, quantity and frequency of switching on and switching off, pressure on contacts, distance between contacts, method of arc control, surrounding medium, its content, pressure and temperature. Thus, these and, maybe, choice of some other circumstances influence design, materials and production technology of contacts. The range of problems concerned dictates such steps as alloying of contact materials, optimization of structure, selection of kind of graphite, its connection with metal [4-10]. It is expedient to recall the main procedures of the first stage of the conventional technology: dosage of the initial graphite powder and binder-phenolic resin plastic varnish (for example, Bakelite), mixing, densification, thermal treatment, crushing, grinding, sieving, drying, dosage of grained graphite, dosage of the initial silver powder, obtaining of the silver salt solution, settling of salt, filtration, washing, drying of the cladded graphite powder, thermal treatment, obtaining of the graphite powder of particles cladded by silver. The second stage of the convectional technology starts by obtaining of the cladded graphite powder and finishes by annealing of the pressed blanks (Fig. 1)."

Jan 1, 2004

By Jack S. McPartland

Historically, research on thiosulfate leaching of precious metals ores has been focused on processing of difficult to treat ores. Thiosulfate leaching of ores and concentrates containing sulfide minerals, copper, manganese and preg-robbing carbon constituents has been evaluated. Cyanide leaching is generally considered an efficient, environmentally acceptable means for processing of non-refractory precious metal ores, Consequently, commercial processing of finely disseminated, oxidized precious metal ores is normally accomplished using alkaline cyanide leaching. Recent changes in regulatory climate have, however, called into question the acceptability of cyanide leaching in a number of locations worldwide. In some cases where the use of cyanide is being questioned, thiosulfate leaching may provide an acceptable alternative. Developments in thiosulfate leaching of precious metal ores are reviewed in this paper.

Jan 1, 1999

By Dean G. Heitt

"The Rain and SMZ mines from 1987 to 1994 produced a total of22.0 t of gold from a pre-mine reserve of 14.24 Mt of ore grading 2.13 g/t Au.Gold at Rain is hosted within the basal portion of the Mississippian Webb Formation. ·Mineralization is closely tied to the Rain Fault which is interpreted to be the main feeder for the deposit. Multiple collapse and hydrothermal breccia events provided permeability for the mineralizing fluids in the otherwise unreactive siltstones. Major alteration events include: decalcification and dolomitization of the Devils Gate Limestone; and silicification, baritization, argillization and oxidation of the Webb Fm. Six ore types based on XRD and visual rock chip Jogging have been identified: siliceous ore containing >40% quartz and <30% barite; siliceous-baritic ore containing mostly silica but >30% barite; baritic ore containing >40% barite; argillaceous ore containing >40% total clays (including alunite); calcareous ore containing mostly calcite and dolomite; and carbonaceous ore which has significant pyrite and organic carbon. Metallurgical testing of the oxide leach grade ores found that recoveries, on -1.3 cm crushed material, were greater than 70%. Results also found that Rain ore has strong grind dependency due to silica encapsulation.The Rain leach pad was commissioned in 1988, and to date 9.3·Mt at an average grade of0.65 g/t Au have been placed. Life to date recovery, through December 1995, is approximately 51 %, for a total of3.87 t of gold produced. Two major factors have contributed to the low leach recoveries at Rain when compared with the metallurgical testing: 1) More argillaceous ore than expected was placed on the pad especially late in the mine life and 2) approximately 50% of the tons placed were run-of-mine with no agglomeration."

Jan 1, 1997

By John J. J. Chen, Barry J. Welch

"The production of primary aluminium can potentially lead to metal that, with minimum treatment, meets a high purity standard. Smelters that can achieve a significant proportion of their production in this manner have a competitive edge which is of growing importance as the use grows for such items as compact discs and the like. Superimposed on the desire to produce high quality metal are stringent environmental requirements that the industry must adhere to. The environmental legislation focuses on fluoride emissions and the approach adopted is towards a zero waste management philosophy. The fluoride recycling process does, however, result in volatile impurities being captured and recycled to the cell. Aluminium has an extremely high reduction potential and this results in a significant proportion of the recycled impurities being reduced at the electrolyte metal interface and thus contaminating the metal. This paper reviews sources of impurities and the impact of the operating procedures adopted on metal treatment.IntroductionSeveral factors have contributed to the immense growth in the aluminium smelting industry. Initially the ready availability of hydro electricity provided a primary reduction energy source for the production of the light-weight metal. Because of its unique properties and innovation in the industry there has been a continued exploitation of its unique properties, especially at the high purity end of the metal. The industry has shown considerably versatility and innovation in adapting to the ever increasing demands of quality and purity. It is however a competitive industry and the ability to produce high purity grade metal (>99.9% pure) gives a competitive edge. Emerging markets such as for CD ROM disc production etc, will keep the quality demand stringent.While the industry has met the continuing demands for metal quality, it has also had to respond to stringent environmental requirements for emissions from the production plant. Like all extractive metallurgical processes carbon dioxide is an inevitable reaction byproduct. However, the volatilization and hydrolysis of the solvent electrolyte leads to fluoride emissions that are potentially harmful. Accordingly, the industry has adopted essentially a zero non-process waste management approach. All cell emissions, including reducible impurities, are recycled back to the cell. This has had a significant influence on the metal treatment processes."

Jan 1, 1996

By Henrlk Gripenberg

To solve the environmental and financial problems of the traditional Rotary Salt Furnace process, a new salt-free method for aluminum dross and scrap melting, ALUREC, has been developed by AGA and its partners, Hoogovens Aluminium and MAN GHH. AGA and Hoogovens Aluminium developed the main process concept and jointly carried out trials on pilot plant scale. Owing to excellent results" the partners decided to jointly erect a commercial scale test plant. The order for the design and erection of the furnace went to MAN GHH. The three companies designed the test plant and began operation in the spring of 1994. The results have been excellent and the process is expected to be a technical and commercial success.

Jan 1, 1995

By Behrouz Abedian, Livia M. Racz

"We address dynamic interactions between high-energy, reactive surfaces of polymer-matrix composites and solid surfaces. A common characteristic of these interfaces is that bonding occurs readily upon contact. In many industrial and biomedical applications, it is desirable to suppress this bonding phenomenon. This interfacial effect is discussed in light of the development of our new method of handling polymer-matrix composites in dental applications. This method involves vibration of the solid-polymer interface at different frequencies. For each material, there is a critical frequency at which the sum of the viscoelastic and inertial energies of the fluid at the surface exceeds the energy available for bonding. When the polymer is vibrated at or beyond this frequency, it does not adhere to solid surfaces. An important aspect of the developed process is that it can be used to characterize surface and interfacial properties of polymers under dynamic conditions, whereas existing techniques are restricted to the study of bulk dynamic properties.IntroductionThe purpose of this paper is to report on the development of a new method for manipulating polymer-matrix composite materials used in dental applications, and the potential of this process for use in materials characterization. The materials under discussion have polymer matrices of a combination of bisphenol A-glycidyl methacrylate (BIS-GMA) and triethylene glycol dimethacrylate (TEGDMA), and contain filler particles of silica and/or zirconia glasses. These materials are called direct aesthetic restorative materials, and are used for filling of cavities, repairing chipped teeth, and for other restorations in which appearance is of importance. They have the appearance of natural tooth material, and are therefore in great demand for use in the anterior portion of the mouth(l,2)."

Jan 1, 1998

By Ian F. Hughes

"Concepts of an integrated steel plant for sheet products to be built and operating in the year 2000 will be described. The design and operating methodology of this market driven facility will integrate process uniqueness, standardization, manufacturing automation, artificial intelligence and information flow.An integrated steel plant for the year 2000 is defined for this article as one that will be built on a greenfield site and ""started up"" in the year 2000 with a capacity of three million tons per year of flat rolled products ranging from cold rolled and electrical steels to high strength formable steels and a full range of coated products.It may seem that the 21st century and the steel plant we're discussing are far into the future. The startling truth, however, is quite the opposite. As shown in Figure 1, even with accelerated development, a new process on which laboratory development work is begun today might just barely pass through the laboratory phase, pilot plant, and commercial feasibility stages such that it can be considered viable for construction and start up in the year 2000.On that basis, it is very unlikely that this 21st century steel plant will utilize any technology that isn't at least under investigation in the laboratory in 1988. As a result, we recognize that planning and selecting the facilities for this plant is, in fact, a pragmatic rather than futuristic process, and that its main value is in providing a bridge to longer-term predictions."

Jan 1, 1988

By William Petruk

The behaviour of sphalerite during mineral beneficiation of base metal ores has been studied at CANMET and other institutes for at least 15 years by determining the liberations of sphalerite in mill products and calculating the recoveries of liberated and unliberated sphalerite in zinc concentrates. Sphalerite in base metal ores commonly occurs as layers and as interstitial material between pyrite. Layered sphalerite is generally liberated during primary grinding, but interstitial sphalerite requires re-grinding to achieve liberation. Around 95% of liberated sphalerite is generally recovered in zinc concentrates frau zinc circuit feeds. A series of tests was conducted on sphalerite in the ore of Brunswick Mining and smelting during a continuous fine tuning operation of the concentrator. It was found that a grind of 80% minus 37 micrometres was required to liberate the interstitial sphalerite. The fine grind increased Zn recoveries from 75% to 78-80%, but produced liberated slimed sphalerite which was lost. Since regrinding to a fine grain size is needed to obtain the desired sphalerite liberation, a method of recovering the slimed sphalerite is required.

Jan 1, 1990

By F. L. Marley

Small and medium-sized flotation plants with no assaying instrumentation still depend much upon the art of the operator to produce acceptable and consistent results. Improved performance can be accomplished by the use of the simple microscope set up as a control device. The visual recognition of products in the circuit does much to eliminate uncertain shift operating decisions and is an easy technique to acquire. Mineral staining methods further assist in the determination of components within the mill products. Simple mounting upon scotch tape and other adhesives is rapid and convenient. The microscope also has a practical role for the plant metallurgist or laboratory technician when evaluating middling products, and their routing within the circuit. Examples are reviewed where the microscope has been used for operational control in both sulfide and nonmetallic mineral flotation plants.

Jan 1, 1981

By John A. Mavrogenes

The Texaco gasification system developed at the Monte Bello pilot plant efficiently bums petroleum-coke thereby producing syn-gas and electricity. This system produces more electricity than conventional burners, yet the only by-products are pharmaceutical grade sulfur and V -rich slag. Vanadium is known to exist in multiple valence states in compounds which possess a wide range of melting points and physical properties. Consequently, it becomes important to carefully regulate oxygen fugacity throughout the system in order to control vanadium valence state. Vanadium phase equilibria is presently poorly understood, in large part because of the multiple oxidation states of vanadium (-I, 0, +2, +3, +4, and +5) and the difficulty of unequivocally identifying the valence state(s) in many compounds. The operation of these gasifiers at approximately 1400°C is well above the melting point of V20S but considerably below the melting temperature of V02 and V 203. If J02 can be regulated to keep the burner within the V 205 field, slag material would more likely remain molten and more easily flow out of the bottom of the burner. In pure V oxides. the oxidation state is readily determined by microprobe analysis. where V20S (V+5) is 56% V, V02 (V+4) is 61.4% V, and V203 (V+3) is 68% V. However, V valence in multi-element phases (especially phases containing other elements of variable valence) cannot be resolved by microprobe analysis alone. Petroleum-coke gasification slags collected from within the gasifier under different oxidation conditions were studied by electron microprobe analysis (EMPA). X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Raman spectrometry in conjunction with microprobe analysis was found to resolve the valence of vanadium in the phases of these slags. Raman spectra collected from homogeneous single phase V-oxide standards in vacuum at low temperatures (-150°C) yielded peaks characteristic to each valence state. Gasifier slag samples are, however, much more complicated. Oxidized samples contain: fine grained (Ca. Mg, Fe. V) oxide matrix of variable composition, (Fe. V, Ni) spinel. (Fe, AI, V, Ni, Mg) spinel, V205laths, AI-Si glass blebs and Ni sulfides. Reduced samples contain: crystalline Ca-siIicate matrix, subhedral to euhedral (V, Fe, Mg, AI) spinel, subhedral V02, Fe and Fe-Ni sulfides, Fe-Ni alloys, and complex Ca-oxide matrix. The different spinel assemblages, the characteristic V-oxides and the distinctly different character of the matrices makes the oxidized and reduced slags readily discernible.

Jan 1, 1995

By Corby G. Anderson

For over a century, the Sunshine Mine in Idaho has been a major producer of silver. An estimated 335,000,000 troy ounces of silver has been mined. This has established the Sunshine Mine as the largest single source of silver in the world. Because the dominant silver containing mineral is tetrahedrite, a copper and antimony sulfide, normal metallurgical treatments to recover the precious metal are not practical. Thus, over the course of the company&apos;s history, novel, hydrometallurgical technologies have been developed on-site to handle complex, precious metal containing materials. Recently, the use of Sunshine technology has been extended to the recycle of secondary materials. As well, the use of Sunshine technology by other organizations for treatment of both primary and secondary feedstocks containing precious and base metals is an area of growing interest. This paper will provide an overview of Sunshine hydrometallurgical technologies including the applicability of Sunshine technology to the recycling of precious and base metals.

Jan 1, 1995