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By D. J. Goodwill

BHP Copper operates a 3,400 tpd dry concentrate, single burner, Outokumpu flash smelting furnace (FSF) at their San Manuel copper smelter in Arizona. The very fine (-325 mesh), dry concentrate is fed to the burner from a 550 metric ton (nominal) capacity furnace feed bin via two drag chain feeders. During the 10-year history of the furnace, operations have been plagued by serious flooding problems. The fine concentrate sometimes becomes aerated during discharge from the bin and flows like a fluid at very high uncontrollable rates to the burner. This results in upset conditions at the concentrate burner leading to poor furnace metallurgy. This paper will examine the problems of uncontrolled feed from the furnace bin (i.e. flooding), and' instantaneously feeding a flash smelting burner. It will show that a drag chain is a poor choice of feeder when high rates are needed, and that drag chains always produce a funnel flow pattern in a bin. BHP's drag chains cause narrow diameter, high velocity flow channels within the stored material. Consequently, there is insufficient residence: time for the concentrate to fully de-aerate before discharge, hence flooding occurs. In addition to the flooding problem, drag chains create a pulsating flow to the concentrate burner due to the tendency for material to slough off in discrete chunks at the discharge end of the slow moving chain conveyor. During the scheduled FSF rebuild in May 1999, BHP intends to remove the drag chains, modify the bin to a mass flow design and to use STAMET® multi-disc feeders to accurately and instantaneously control the rate of discharge from the bins. Air slides will be used' to convey the concentrate to the burner.

Jan 1, 1999

By Leonel Contreras

The gas treatment system, MALIGAS (in Spanish MAnejo y Llmpieza de GASes which means handling and cleaning of gas), is part of the Codelco-Chile Potrerillos Smelter decontamination plan; which includes the newly designed system for the cooling and cleaning of the gas generated from a Teniente Converter and four Peirce Smith Converters. The gas generated in the process is captured by water cooled hoods and mixed with air. Then the gas enters a cooling pre-chamber which utilizes a water cooled screen to capture and remove the coarse and semi-fused particles. At this stage; the gas loses a portion of its heat with temperature falling below 608°C which is a necessary condition to avoid damage to the pipes, ducts and other metallic structure of the gas handling system. The gas is further cooled at the Radiation Cooler to a temperature ranging between 315 and 380°C. The gas is conditioned to avoid damage to the electrostatic precipitators that are designed to clean the gas by removing significant amount of dusts from the: gas stream. This gas stream is currently discharged to the stack, however, it will be treated in a sulfuric acid plant that is currently under construction and is scheduled for commissioning during the second half of 1999. The gas handing and cleaning system has been operated without any significant interruptions. Minimal emissions of SO2 and dusts in the work place are noted. The system requires minimum maintenance. The key to the high availability of the system is due to the good, performance of he Radiation Cooler, which efficiently cools the gas before entering the electrostatic precipitators (ESPs). This enables the ESPs to remove the dusts efficiently.

Jan 1, 1999

By Peter A. Spencer

Bacterial oxidation technology has the ability to selectively attack sulphide minerals. Selectivity allows oxidation of more reactive minerals and the extraction of valuable metals while leaving the bulk of the sulphide component unreacted. Partial oxidation can be used on arsenopyrite to recover gold and for the leaching of base metals, such as copper and nickel, from pyritic ore and concentrate without generation of large quantities of acidic iron solution, which must be neutralized. Thus, rejection of pyrite during the oxidation process can considerably reduce treatment costs. Acid generation in tailings dams would be minimal, compared with most Thiobacillus cultures, as the optimum growth temperature of Bactechts culture is above ambient.

Jan 1, 1992

By Liangju He, Peixuan Ouyang, Peijie Li

Single-pulse laser ablation of aluminum and titanium alloys under glass confinement is investigated. Processing parameters such as laser intensity and gap width between targets and glass are varied. Surface morphologies and crater profiles of the alloys after laser ablation are studied by SEM and white-light interferometric microscope, respectively. The effects of gap width and laser intensity on surface morphologies and crater profiles of targets are systematically analyzed. In addition, the generation of porous surface structures in Ti target is regarded as the result of phase explosion in the molten surface layer of targets and the thermodynamic condition in our experiment for phase explosion is evaluated.

Jan 1, 2016

By P. R. Taylor, B. N. Carlson

Rare earth magnets play an increasingly important role in high end technology, and the manufacture of rare earth magnets, such as the NdFeB type, consume a large amount of the rare earths produced. Recycling of this material could provide an important domestic source for these materials. A selective sulfation roast has been proposed; the central principle of which is to take advantage of the differing stabilities of the rare earth sulfates as compared to those of iron under an air/SO2 atmosphere. Experiments show iron is found to be stable as an oxide, however, neodymium is found to form an oxy-sulfate phase.

Mar 1, 2017

By F. W. H. Dean

A very sensitive sensor for the detection and measurement of hydrogen in solid steel is described. This technique is non-invasive and uses a collector to sweep the hydrogen emanating from a steel surface and feed to it sensor. This method is particularly sensitive, resolving fluxes to < 2 pI cm?2 S?I, with a linear measurement up to 1000 pI cm&apos;2 S?I, The collector is held on the steel substrate by magnets and it is shown that emanation of hydrogen from the steel is controlled by bulk diffusion of the hydrogen through the steel. The technique is demonstrated to have an excellent response time and reproducibility.

Jan 1, 2001

By Zhigang Liang

Effects of the configuration parameters of submerged entry nozzle on the flow field in slab mold were investigated through a water modeling. The experimental results showed, when the original submerged entry nozzle was applied, there was an appreciable level fluctuation in the mold with obviously naked surface and entrapment of mold flux at higher casting speed. By increasing the outlet area of submerged entry nozzle, without any change of other configuration parameters and submergence depth, a proper fluid field with active surface and good covering of mold flux can be obtained, which is proper to meet the requirement for increasing the casting speed and improving the slab quality simultaneously.

Jan 1, 2009

By Zuomei Jin

A laboratory study was conducted on the separation of Zn, Pb, Cu and Ag from a finely dissem-inated interlocked silver-rich multimetal sulphidc ore. These are often difficult to separate from each other by flotation. The thermodynamic calculations of Zn-S-O, Cu-S-O systems at different tem¬peratures were presented on predominance diagrams. Based on these diagrams the optimum temperature and gas composition were selected for roasting. The results of separating Zn, Cu from calcine by neutral leaching and acid leaching were found to be satisfactory. The distribution of silver in the roasting and leaching processes were tested. A flow sheet was proposed.

Jan 1, 1993

By Gordon Holcomb, George R. St. Pierre, Robert A. Rapp

Carbon/Carbon composites offer promise as high-temperature structural materials. A primary limitation on their application is the need to provide protection against oxidation in hot oxidizing environments. Silicon carbide conversion coatings have been shown to provide extended protection at temperatures of 1600°C. SiC coated C/C components have been used in several aerospace applications. In the present paper, the preparation of carbon fibers and their treatment during subsequent processing into coated components are discussed with particular emphasis on the processing variables that can result in improved oxidation resistance. In particular, the influence of substrate inhibitors and selective sealants for cracks in coated C/C components are analysed.

Jan 1, 1988

By Min Chen, Zhen Tian, Hongxu Cui

"The effects of adjusting technology on the phosphorous enrichment in converter slag were investigated. The results showed that the grain size of 2CaO·SiO2 with high phosphorus containing content increased slightly with the decreasing of cooling rate, and the proper cooling rate was confirmed to be about l.0°C.min-1. Moreover, the morphology of the phosphorus-rich phase of 2CaO·SiO2-3CaO·P2O 5 was changed from granular for the higher basicity of converter slag to the coexistence of granular shape and rod-like for the lower basicity of adjusted slag. With the addition of adjusting agent such as SiO2 to lower the basicity of converter slag, the phosphorus in converter slag could be transferred into 2CaO·Si02 phase effectively, and P2O 5 content in high phosphorus containing phase reached to above 30%.IntroductionThe yield of converter slag is very large in China, but most of the slag is stacked usually after the separation of iron, which not only takes up a lot of land, but also affects the ecological environment seriously. Therefore, improving the comprehensive utilization and value-added products of converter slag is of great significance to recycle the steelmaking slag[l-3]. On the other hand, the refining of hot metal with high phosphorous content is an unavoidable problem with the decreasing of high grade iron ore, and as a result, more amounts of high phosphorus containing steelmaking slag are produced. However, the current recycle of converter slag is more focused on the emission reduction and reuse of steelmaking slag inside the iron and steelmaking process without considering the recycle of phosphorous resources[4-6]. At the same time, the development and utilization of phosphate ore as a strategic resource is drawing more and more attention, but the phosphate ore in China is mostly low grade and significant amounts of tailings are produced which is harmful to the environment. Therefore, it is important to separate phosphorous resources in steelmaking slag which can be used as phosphate ore for fertilizer material[7-9].Literature studies showed that most of the phosphorus in steelmaking slag existing as 2CaO·SiO2-3CaO·P2O 5 solid solution phase in 2CaO·SiO2 particle. The P2O 5 content in the phosphorus containing phase is very low due to the fact that the basicity of converter slag is usually high and the precipitated amounts of 2CaO·SiO2 particles during cooling are very large, resulting in the fact that the P2O 5 contents in 2CaO·SiO2-3CaO·P2O 5 solid solution phase are much lower which is impossible to be used as phosphorous resources instead of phosphate ore. Thus, the enrichment of phosphorus in steelmaking slag is need[ 10-14]."

Jan 1, 2011

By Kang-In Rhee

Nonferrous metal recycling not only provides energy saving and environmental benefits but also is a significant factor in the supply of various types of metals used in our society. Recycling plays an important role in establishing the sustainability of materials. The total amount of recycled nonferrous metals by weight accounts for less than 5% but their value is larger than 50% compared to ferrous metal recycling which consists of about half of the total metal recycling in weight. This paper describes trends and typical achievements in nonferrous metal recycling and overviews the present and future of nonferrous metal recycling technology and business in Korea.

Jan 1, 2006

By Milind Deo, Neale R. Neelameggham

The mixture of carbon dioxide and water vapor - called Soda [as in carbonated water] can be converted to easily stored transportation fuels. Earlier papers on Soda- fuel metallurgy noted that this conversion is endothermic requiring energy. Reduced state metallic elements - preferably the alkali, alkaline earth elements, or aluminum can act as oxygen carriers. Availability of such a combination in commonly land fille waste materials is shown. Plant based wastes which are normally composted form a better-controlled reagent. The energy required for the reaction can come from solar energy. This paper describes possible reactor designs, which can accommodate this conversion effectively using carbon dioxide recovered from flue gases.

Jan 1, 2008

By Kang-In Rhee

Nonferrous metal recycling not only provides energy saving and environmental benefits but also is a significant factor in the supply of various types of metals used in our society. Recycling plays an important role in establishing the sustainability of materials. The total amount of recycled nonferrous metals by weight accounts for less than 5% but their value is larger than 50% compared to ferrous metal recycling which consists of about half of the total metal recycling in weight. This paper describes trends and typical achievements in nonferrous metal recycling and overviews the present and future of nonferrous metal recycling technology and business in Korea.

Jan 1, 2006

By Kang-In Rhee

Nonferrous metal recycling not only provides energy saving and environmental benefits but also is a significant factor in the supply of various types of metals used in our society. Recycling plays an important role in establishing the sustainability of materials. The total amount of recycled nonferrous metals by weight accounts for less than 5% but their value is larger than 50% compared to ferrous metal recycling which consists of about half of the total metal recycling in weight. This paper describes trends and typical achievements in nonferrous metal recycling and overviews the present and future of nonferrous metal recycling technology and business in Korea.

Jan 1, 2006

By Kang-In Rhee

Nonferrous metal recycling not only provides energy saving and environmental benefits but also is a significant factor in the supply of various types of metals used in our society. Recycling plays an important role in establishing the sustainability of materials. The total amount of recycled nonferrous metals by weight accounts for less than 5% but their value is larger than 50% compared to ferrous metal recycling which consists of about half of the total metal recycling in weight. This paper describes trends and typical achievements in nonferrous metal recycling and overviews the present and future of nonferrous metal recycling technology and business in Korea.

Jan 1, 2006

By Kang-In Rhee

Nonferrous metal recycling not only provides energy saving and environmental benefits but also is a significant factor in the supply of various types of metals used in our society. Recycling plays an important role in establishing the sustainability of materials. The total amount of recycled nonferrous metals by weight accounts for less than 5% but their value is larger than 50% compared to ferrous metal recycling which consists of about half of the total metal recycling in weight. This paper describes trends and typical achievements in nonferrous metal recycling and overviews the present and future of nonferrous metal recycling technology and business in Korea.

Jan 1, 2006

By Kang-In Rhee

Nonferrous metal recycling not only provides energy saving and environmental benefits but also is a significant factor in the supply of various types of metals used in our society. Recycling plays an important role in establishing the sustainability of materials. The total amount of recycled nonferrous metals by weight accounts for less than 5% but their value is larger than 50% compared to ferrous metal recycling which consists of about half of the total metal recycling in weight. This paper describes trends and typical achievements in nonferrous metal recycling and overviews the present and future of nonferrous metal recycling technology and business in Korea.

Jan 1, 2006

By Kang-In Rhee

Nonferrous metal recycling not only provides energy saving and environmental benefits but also is a significant factor in the supply of various types of metals used in our society. Recycling plays an important role in establishing the sustainability of materials. The total amount of recycled nonferrous metals by weight accounts for less than 5% but their value is larger than 50% compared to ferrous metal recycling which consists of about half of the total metal recycling in weight. This paper describes trends and typical achievements in nonferrous metal recycling and overviews the present and future of nonferrous metal recycling technology and business in Korea.

Jan 1, 2006

By Kang-In Rhee

Nonferrous metal recycling not only provides energy saving and environmental benefits but also is a significant factor in the supply of various types of metals used in our society. Recycling plays an important role in establishing the sustainability of materials. The total amount of recycled nonferrous metals by weight accounts for less than 5% but their value is larger than 50% compared to ferrous metal recycling which consists of about half of the total metal recycling in weight. This paper describes trends and typical achievements in nonferrous metal recycling and overviews the present and future of nonferrous metal recycling technology and business in Korea.

Jan 1, 2006

By M. H. Ghandehari

Sintered (Pr,Sm)Co5 displays a multi-phase microstructure in which closely related intermetallic compounds are formed during the process of fabricating useful magnets from over-stoichiornetric compositions. These compounds have much lower magnetic crystalline anisotropies compared to those of SmCo5 and PrCo5. Despite a careful control of the microstructure in producing "single phase" PrCo5 base magnets, sufficient concentrations of the lower anisotropy phases are formed which act as nucleation centers for domain reversal, resulting in a drop in coercivity. This article describes the use of sintering additives, primarily oxides, to prevent the formation of the magnetically soft phases in the final microstructure.

Jan 1, 1989