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By C. M. Acuña

Copper losses in slags are of great concern, specially in smelting and slag cleaning processes. It is widely accepted that the suspension of metallic copper and matte droplets is strongly affected by the viscosity of the slag. The Chuquicamata Division of Codelco- Chile produces concentrates high in zinc, an element which reports mainly to the slag phase. The ZnO may affect the viscosity and therefore the copper losses. This work aimed to investigate the effect of lime to control the viscosity of slags, and in turn to control the copper losses. By using the experimental viscosity data and the Stoke's law, the settling rate of matte prills in various slags was estimated. The results indicate the possibility of increasing the recovery of copper and/or decrease the process time.

Jan 1, 1999

By R. W. Hammack

Results for the treatment of a problematic mining wastewater using bacterial sulfate reduction (BSR) are presented. Specifically, a BSR pilot treatment plant (250 L per day) was used to treat Berkeley Pit simulant to discharge standards with the selective recovery of separate Cu- and Zn-sulfide concentrates. Concentrates recovered in these tests contained greater than 50 % of the target metal and met specifications for sale to existing smelters. The biological component of the treatment was found to be surprisingly robust. Scaling and solid/liquid separation problems were encountered but considered normal for sulfide treatment. For Berkeley Pit water, capital costs for BSR treatment was found to be comparable to high-density sludge lime treatment. The value received from the sale of recovered copper ands zinc concentrates paid for all the operating costs.

Jan 1, 1999

By David S. Dolan

To beat capital costs of US$10 per pound of installed capacity has appeared as a major hurdle for the "third generation laterite nickel plants. Forecast costs are escalating. Where can savings come from? Ore beneficiation can reduce the tonnage rate to be processed. High pressure acid leach options include the use of indirect slurry heating and higher operating temperatures to reduce flow rates and residence time. Progress has been reported in atmospheric leaching. High counter current decantation circuit settling rates and high underflow densities reduce CCD costs. Metal recovery options include direct from leach solution to metal production, as used by Bulong and espoused by Goro, and indirect recovery as used by Moa Bay, Murrin Murrin and Cawse. Plant location impacts on the costs of tailings disposal, power and energy costs, supply of consumables and labour costs, among others. Final nickel and cobalt metal production routes are electrowinning, hydrogen reduction or some innovative routes being proposed for Goro. This paper reviews the status in these developments, with particular reference to equipment and processes that offer lower capital costs. Keywords: Laterite, Nickel, Plant, Capital Cost

Jan 1, 2004

By A. Rohkohl, R. Piillenberg

The QSL plant at "BERZELIUS" Stolberg GmbH in Stolberg, Germany was commissioned in 1990, introducing a new era of lead smelting in the more than 150-year-old history of the lead smelter. The lead smelter in Stolberg has changed its appearance several times during its existence. Therefore, at many locations on the site, old and obsolete buildings and equipment parts can still be seen. They are often located side by side with new modern constructions like the QSL-plant and the mercury removal plant, and reflect the specific contrast between tradition and modern technology. After a brief description of the development of the smelter and its decision to implement the current novel plant, the most recent operating results are reported. Following some modifications to the process and equipment, which had become necessary along with the implementation of the new technology, the plant is in operation today at approximately 30% above its design capacity. These achieved production levels are not restricted by the QSL-reactor but by precedent and subsequent available equipment. The QSL-plant entirely complies with the demands of modern, energy-saving, ecologically compatible lead production technology. Stringent environmental standards are maintained on a continuing basis. The demonstrated viability and flexibility of the overall process permits the operation to adapt quickly to the prevailing economical situation worldwide.

Jan 1, 2000

By J. Y. Aubut

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

Jan 1, 1999

By T. V. Jayaraman

Fe-Ga alloys, with compositions around 27.5 at % Ga, can be heat treated to obtain ? (ordered bcc), DO19 (ordered hexagonal), and L12 (ordered fcc) ordered structures. Our earlier work using polycrystalline samples had shown that magnetostriction is strongly influenced by ordering in this alloy. Here more detailed study of the correlation between ordering and magnetostriction using single crystals of Fe 27.5 at. % Ga alloys is reported. Single crystals of Fe 27.5 at % Ga were grown using Bridgman single crystal growth technique. X-ray and electron diffraction were used to study the ordering in this alloy. Magnetostriction measurements were carried out at no load conditions. Elastic constants were measured using Resonant Ultrasound Spectroscopy.

Jan 1, 2006

By Michael J. Mankosa

The increased emphasis placed on recycling of consumer and industrial waste products has generated a need for advanced separation techniques for recovery of valuable by-products. As a result, the metals recycling industry has made great strides in the recovery of used wire products through the application of chopping and screening processes. Unfortunately, in many instances, the final plastic reject still contains a substantial portion of valuable metal. Typically, this material has been discarded, since an appropriate separation technique has not been available. Recent work conducted by Carpco, Inc. in Jacksonville, Florida indicates that a high-grade metal and/or plastic product can be recovered from this waste material using a novel density separation process. Extensive test work has been conducted using this procedure to validate separation performance as well as equipment capacity. This paper will present the basic operating principle of the separator, as well as results from tests conducted using various feed materials.

Jan 1, 1995

By Xiang Zhu

Xidagou is the largest waste water discharge channel of the Anshan Iron and Steel Complex (AISC) with average flow rate of 8000 cubic meters per hour, which is about 75% of the total effluent of the AISC. The waste water from Xidagou seriously polluted the Taizi River Basin. In order to meet the Chinese Class V Standard for Surface Water Discharge and the Standard for Recycled Industrial Water Reuse, with the aid of the World Bank, the AISC began the treatability studies in 1991. Based on the bench-scale test, the AISC carried out pilot-scale treatability studies on three different treatment processes and five different chemical coagulants for more than half a year in 1992. The study results show that the processes of primary sedimentation- chemical mixing and flocculation-secondary sedimentation-filtration can meet the requirement and that PFS and PAM are effective and economic chemical coagulants.

Jan 1, 1994

"Silver is traditionally recovered in base metal smelters (lead and copper), or as a by-product of other precious metals (gold and/or PGM's). This paper presents the results of non-conventional techniques to recover silver from complex materials. The PLATSOL® process has been developed to recover, in one step and without the use of cyanide, base metals (copper, cobalt, nickel) and precious metals (gold, PGM's) from sulphide concentrates too low in grade to enter the mainstream extraction processes. Silver is only partially recovered in solution with gold and the PGM's during the PLATSOL® process. However, the silver minerals are transformed into silver chloride, which can then be recovered from the PLATSOL® residue using conventional techniques. Some South American silver concentrates contain levels of impurity (mostly arsenic) so elevated that the penalties incurred significantly affect the process economics. The present results have shown that a low temperature calcination process transforms the concentrate into a product well suited for traditional recovery treatments. Metallurgical details will be provided, as well as the results of mineralogical studies that helped clarify the process mechanisms.IntroductionSilver occurrences in nature are very diversified, and, therefore, primary silver is produced as a by-product of many base metal and precious metal operations [1], as well as a co-product of most gold ores. However, difficulties can arise when high temperature processes are used for refractory gold ores or copper concentrates, or when the silver concentrate contains impurity elements such as arsenic that trigger high penalties."

Jan 1, 2012

By Suzzann Nordwick

Over the past decade, significant advances have been made in the development of sulfate-reducing bacteria (SRB) technology to treat acid mine drainage (AMD). Bench-scale testing, field demonstrations, and engineered applications of SRBs for the treatment of AMD will be presented. Designs include an in situ bioreactor installed in the subsurface workings of the Lilly Orphan Boy Mine in 1994, the SRB bioreactors installed at the Calliope Mine from 1998 to 2001, the integrated biological reactors built at the Surething Mine in 2001, and the ongoing development of a replaceable cartridge system. SRB technology benefits include the reduction of dissolved metal ions to insoluble metal sulfides and the neutralization of the AMD resulting from the production of bicarbonate from the oxidation of organic nutrients. This paper will address engineering design criteria including the selection of organic media and system permeability and complete mitigation of AMD. Research was funded under Interagency Agreement No. DW899388-70-01-1 between the US EPA and the US DOE and was conducted by MSE Technology Applications, Inc., through the National Environmental Technology Laboratory (DOE Contract No. DE-AC22-96EW96405) at the Western Environmental Technology Office located in Butte, Montana.

Jan 1, 2003

By D. C. Cupertino

Oxime based solvent extraction provides the user with a selective concentration process for copper prior to electrowinning. The selectivity required is largely for copper(II) over iron(III) and this is achieved by the preferential formation of the square planar copper-oxime complex in the organic phase. The copper/iron selectivity of oximes can however, be altered by modifiers or other types of oximes and may be enhanced in the presence of certain esters. Whilst the oxime based SX processes is important for operations leaching copper from laterite ores, the high selectivity will also be significant in processing streams arising from other leaching regimes which are currently under development, for example leaching of sulfide mineral ores. This paper presents some initial results using Molecular Modelling techniques to further our understanding of the nature of the copper/iron-oxime complexation processes together with some plant studies undertaken at a number of different mine sites investigating selectivity, and other properties, for some modified reagents. Some studies of the interfacial properties of the these systems are reported to explain in part the practical observations.

Jan 1, 1999

By G. A. Brooks

The problem of treating concentrates with increasingly higher levels of arsenic and antimony is compounded by the trend to stricter environmental guidelines regarding the disposal of smelter wastes. Much of the arsenic and antimony from non-ferrous processes is recovered as oxide fume. The options for handling these fumes include recycling them to the smelter, stabilising and disposing of them, and recovering values from them. Whilst arsenic oxide has little value, there is a market for antimony oxide and this provides an incentive for devising techniques for separating antimony oxide from arsenic oxide before disposal of the arsenic oxide. Arsenic can be separated from antimony oxide by selectively volatilising the more volatile arsenic trioxide from a mixed oxide sample or by selectively condensing the less volatile antimony tetroxide at high temperatures, leaving arsenic trioxide to condense out at lower temperatures. The results of selective volatilisation experiments at 379 to 587 °C indicate that it is difficult to achieve an arsenic content below 5.0 wt.% using air or nitrogen as carrier gas due to the formation of solid solutions between the two oxides. Injection of oxygen into a mixed vapor stream improved separation by selective condensation and antimony tetroxide containing as low as 0.23 wt.% was obtained in laboratory experiments.

Jan 1, 1994

By W. Persson

The first installation at a copper smelter of a Semtech OPC System for continuous, on-line production control of copper converting in PS converters took place in 1994. At present OPC systems are installed at 19 PS converters. The technology presents to the operator real-time information on the progress of the process he is controlling in the form of optical process parameters, thus facilitating dynamic process control. The optical process parameters are based on time- and wavelength resolved registrations of the light emitted by the off-gas flames and identification of correlation between these parameters and characteristic metallurgical process data. The present paper provides a description of the technology as seen by the furnace operators and a summary of operating experiences made during five years of full-scale, operation at various smelters, reviews influences from the technology on smelter operational practises and comments on recent developments as regards new applications of the technology.

Jan 1, 1999

By Shengli Wu, Mingyin Kou, Laixin Wang, Zhe Wang, Xinliang Liu

The sticking behavior of iron ores in the shaft furnace is one of the most important problems in the COREX melting progress, which directly influence the smooth operation and productivity of shaft furnace. Therefore, it is of great importance to study the sticking behavior of pellets in COREX shaft furnace. The results showed that porous metallic iron produced at the interface of pellets samples was the main reason for the sticking of pellets in the COREX shaft furnace. The SI (sticking index) and metallization rate increased with the reduction temperature and gas flow, and decreased with melting rate. However, the SI of pellets in the COREX shaft furnace could be decreased by the proper match of melting rate and reduction temperature, reduction temperature and gas flow, while the metallization rate of pellets were kept at a certain level. Furthermore, the matching of melting rate and reduction temperature was more effective than the matching of reduction temperature and gas flow.

Jan 1, 2016

By Tang Chaoho

Laboratory research on the reducing and matte smelting of Jamesonite concentrate has been carried out. The influence of the process conditions such as the smelting temperature, the amount of pyrite cinder (the agent of fixed sulfur) and the amount of additives on the smelting process have been studied. Under the optimum condition the direct recovery ratios of antimony and lead are 83.26% and 68.50% respectively. The ratio of fixed sulfur is 98.97% but more than 15% lead and 30% silver remained in the ferrous matte. The key problem to be solved of this new process is how economical and effective is the recovery of silver and lead in ferrous matte.

Jan 1, 2003

By Jin Liu

To improve value metals recovery, a new operating concept for the Inco flash furnace was investigated, in which the flash furnace coke addition practice would aim at establishing a reducing barrier on the surface of the molten bath. The descending partially oxidized sulfide mineral particles would reach the supernatant coke layer prior to the formation of slag. The key for success depends on the effectiveness of the coke layer to produce a sulfur deficient matte while maintaining furnace production capacity. The mechanism and rate of carbon reduction of the phases formed in the flash flame, i.e. sulfide (matte) and oxysulfide was investigated by means of crucible graphite reduction test work. The objective of these tests was to measure the rate of solid graphite reduction of matte, oxysulfide, slag, and matte+slag mixture at different temperatures. These tests were expected to permit understanding and explaining the reduction mechanism of each material by comparing the respective reaction rates, product reaction gas compositions, reduced material assays, and other relevant parameters. Direct visual inspection of the test crucibles would provide additional information.

Jan 1, 2006

By Michael S. Moats, Daniel Kim, Shijie Wang

"The behavior and deportment of lead, arsenic, antimony and bismuth are critical in producing high quality cathode by copper electrorefining. A critical review of research related to these elements is presented along with a comparison to industrial data, where appropriate. These elements exist predominantly in the anode as complex oxides along die grain boundaries. Upon dissolution, Group 15 elements report both to the electrolyte and slimes while lead essentially enters the slimes. The deportment of the Group 15 elements appears to be influenced by several chemical interactions which are discussed. The effect of these elements on floating slimes and anode passivation is reviewed. Under normal electrorefining conditions, lead, antimony and bismuth are thought to enter the cathode through the encapsulation of slime particles. The literature indicates that arsenic enters the cathode predominately by electrolyte entrainment. Finally, areas for future research regarding these elements are presented.IntroductionControlling lead, arsenic, antimony and bismuth is critically important for the production of high quality cathode in copper electrorefining. The reasons for this are twofold. First, ASTM Grade 1 Cathode specifications [1] for these elements are low, as listed in Table 1. Second, they can affect the efficiency of the electrorefining process (e.g., through passivation, current efficiency, slime processing)."

Jan 1, 2012

By He Zhi-jun, Ning Zhe, Pang Qing-hai, Zhang Jun-hong, Zhan Wen-long

The effect of microwave irradiation on grinding property of coal was studied by using Hardgrove grindability index tester. Superior grindability of coal was obtained to varying extent after microwave irradiation treatment. The variation in microstructure of pulverized coal during microwave irradiation was observed by utilizing scanning electronic microscope (SEM). The results indicated that the different microwave absorbance of minerals and carbon matrix led to cracks on their interface, by which coal particles were further pulverized and therefore the granularity of coal powder was reduced. Due to the different formation process of various coals, bituminite and anthracite are very different in physical and chemical properties. According to the content of coal pulverization, it can found that microwave irradiation has a stronger pulverizing effect on bituminite in comparison to anthracite.

Jan 1, 2016

By Peter Bates

"HIsmelt has faced and overcome many challenges in the understanding and development of injection technologies that satisfy process and engineering requirements for further scale up to a commercial plant.An overview of the design basis of bottom and top injection systems with plant results are described in this paper.IntroductionAn appropriate way to introduce this paper is to initially reflect on the genesis of the HIsmelt Process.It is appropriate that Professor Womer is the one we are honouring as it can be claimed that by the involvement of CRA in the WORCRA process that the concepts for irijection systems in iron and steel pyrometallurgical processes achieved significant attention by the company. The development of water cooled injection lances and their application injecting solids and gases with success was certainly a pre-cursor to the development of other injection systems commonly used today in arc furnaces and for top injection at HIsmelt.HistOrically it was the work of Savard and Lee in Canada with shrouded tuyeres and the subsequent commercialisation of this technology at the Maxhiitte Steelworks spawning the suite of bottom oxygen blown process as known as QBOP; OBM and the subsequent combined blowing process such as KOBM that first commercially succeeded in injecting solids under a molten metal bath. The next progressive step from the injection of calcined lime in the technology development was the injection of coal for coal gasification as developed by Klöckner technologies being called KG, KSG and KMS and also the injection of coal for increased scrap melting.A paradigm shift in thought process to leap from steelmaking and coal gasification to direct smelting by injecting coal and iron ore into a molten metal bath in the correct stoichiometric ratio to maintain the bath at a constant temperature and carbon level was the true genesis .of HIsmelt.A good overview of the state of the art of tuyere type injection technology is given in Ref. 1."

Jan 1, 1996

By Barry T. Kilbourn

There is a continuous quest for better-performing materials, for example, to withstand higher temperatures, to resist more efficiently degradation or to be electrically conductive under extreme conditions. The oxides, and similar compounds, of the lanthanides and yttrium can, in some cases, help provide such behavior. Other advanced materials, such as hydrocarbon catalysts, optical ceramics or sensitive phosphors, may also require these oxides for some essential function. The role of the oxides in a wide variety of technologies, some novel and developing, will be reviewed and the underlying physico-chemical principles, the common threads, between several less well-known and apparently unrelated uses discussed.

Jan 1, 1989