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By Guo Xueyi

The dissolution behaviors of valuable metals, lead and zinc, from secondary fly ash generated in municipal incineration plants were investigated using some lixiviants: sulfuric and hydrochloric acids, acetic acid and some chelating reagents including L-asparaginic-N,N-diacetic acid (ASDA), a biodegradable, and therefore, environmentally benign novel chelating reagent. It was found that zinc exists mainly as ZnO, whereas Pb probably as PbOHCI and PbO, and the easily soluble components in SFA are KCI and NaCl. Suitable amount of HCI can dissolve all of lead and zinc from SFA. Sulfuric acid can selectively extract zinc leaving lead in the residue. Ethylenediaminetetraacetic acid (EDTA) is an effective chelating reagent to extract both zinc and lead. Although ASDA and diethylene¬triaminepentaacetic acid (DTPA) can selectively extract more than half of lead from SFA, it would by no means be regarded as highly effective reagents for the extraction of these metal values. Keywords: Lead, Zinc, Secondary fly ash, Leaching, Dissolution

Jan 1, 2002

By Zhang Chuanfu, Tan Pengfu

"A thermodynamic model is developed to simulate nickel flash smelting process. In the nickel flash furnace, oxidation of concentrate occurs at one end, and reduction of slag occurs at the other. The model makes use two zones, namely the reaction shaft/settler zone and the appendage zone and accounts for 6 phases (matte, slag, silica, magnetite, Cu-Ni alloy and gaseous phase), 13 elements (Ni, Co, Cu, Fe, S, 0, N, C, H, Si, Al, Mg and Ca) and 33 chemical components in nickel flash smelting system. The compositions of matte, slag and gaseous phases in equilibrium are calculated by using the data of free energies of formation and activity coefficients of components. Two nickel sulfide species are used to allow for the modeling of sulfur-deficient mattes. The model predictions are compared with the known industrail data from Kalgoorlie Nickel Smelter, and excellent agreement is obtained. The model can be a very useful tool for monitoring and optimizing the actual industrial operations of nickel smelting process. The distribution behaviors of Ni, Co, Cu, Fe, S and 0 in the nickel smelting furnace depend on the process parameters such as smelting temperature, volumes of air, the content of the elements~ charge and oil.1. IntroductionThe nickel flash smelting furnace essentially consists of a reaction shaft where nickel sulfide concentrate is partially oxidized with air, a settle zone where matte and slag are allowed to separate, and a slag cleaning end where coke is added to provide for the reduction of the oxidized nickel from slag, and electrodes are used to provide heat.The theoretical model to consider a mass balance for copper flash furnace is developed by S. Goto and R. Shimpo[1][2J. However, this can not be true for nickel flash furnace as a whole since oxidation of concentrate occurs at one end (in the reaction shaft/settler), and reduction of slag occurs at the other (in the appendage). Despite these limitations, an acceptable pseudo-thermodynamic description of the furnace can be achieved using essentially two zones, namely the reaction shaft/settler zone and the appendage zone. Compositions of gas, slag and matte in two zones are calculated."

Jan 1, 1998

By Volovik A. V. Ivtan, Shelkov E. M. Ivtah

"One of the most power consumption Industrial process is production of Al from bauxites (about 45000KWt.hour electrical energy for production of 1 ton. of technical Al). This process is based at the low efficiency and productivity electrolysis technology.Last years IVTAN investigations give to .us information about possibility to use of high temperature shaft- furnaces for efficiency production of alumina (AL2O3 ) technical. aluminium and some all.oys on the base of the high temperature carbon- thermal reduction process. At this case power consumption for production of unit of last, product will be less at the 3-4 times.The carbon-thermal method is allow produce alumina (Al203 ), technical Al and its alloys not only from deficient bauxites, but practically inexhaustible reserve of other types of Al-contain row materials (cianite, sillimonite and so on/The thermal-chemical economical analises of fulfilled at the IVTAN, production of alumina. Base on facts of production and technical technology are especially for ones arguments at the high temperature shaft-furnace technical Al and its alloysIn the last decades of the 20-th century, the discharge into atmosphere of high temperature and. combustion gases places . problems before humanity more and more sharply and becomes of great importance task.But at the same time, as production of material values increases, intensity of pollution of environment increases all time. And the value of new processes and. technologies of material production, aimed at reducing the expenditure of power and pollution of· the environment, also increases."

Jan 1, 2000

By Chen-Ming Kuo, Esher Hsu

"The importers and manufacturers who import or produce products with packaging containers are charged a recycling fee in Taiwan. The amount of waste packaging containers used for calculating the recycling charge is based upon the amount declared by importers and manufacturers which might be underestimated. This study aims to estimate the amount of waste packaging containers generated by households in Taiwan and also explores its distribution. The sampling survey and ratio estimation are conducted for estimating the recycled amount; while the refuse sampling method for municipal solid waste composition is employed to estimate the un-recycled waste packaging containers. The estimated total amount of waste packaging containers in 2011 generated by households in Taiwan is 696,511 m.t., of which, 79.49% of the waste packaging containers were recycled and 20.51 % were landfilled or incinerated. This study shows that the amount of waste packaging containers declared by importers and producers is underestimated around 20%.IntroductionWaste packaging containers including iron cans, aluminum cans, glass bottles, plastic containers, paper containers, aluminum foiled paper packs are officially announced to be recycled in Taiwan. In order to create the economic incentive for raising recycling performance, associated manufacturers and importers are charged a recycling fee to subsidize recyclers. The amount of packaging containers declared by importers and manufacturers is used for calculating the recycling charge and recycling rate. The importers and manufacturers might underreport their producing (importing) amount to pay less recycling fees. Therefore, the estimated waste packaging containers based upon the amount declared by importers and manufacturers is usually underestimated. Related previous studies about waste packaging containers recycling in Taiwan are done by Hsu and co-workers [1-4]. Hsu and Kuo [1] estimated total production values of recycling and evaluated the performance of recycling performance based upon the estimated production values. Hsu and Liu [5] provided a cost analysis of recycling for waste packaging containers in Taiwan. Bor, Chien, and Hsu [2] presented a market-incentive recycling system for waste packaging containers in Taiwan. Hsu and Kuo [4] provided an amending mechanism for product charge and recycling subsidy in response to the social economic changes for waste packaging containers recycling. Lee and Hsu [ 6, 7] explored the distribution, fee rates, and collection rate of waste containers. This study aims to estimate the amount of waste packaging containers generated by households in Taiwan and also explore its distribution."

Jan 1, 2014

By William Petruk

Mineralogical and image analysis studies have been performed on four volcanogenic base metal ores that contain 0.01 to 4.5 wt% Pb to determine the behaviour of galena during mineral processing. The galena in these ores is fine grained and is poorly liberated in both the primacy and regrind mill discharges. Consequently, low grade Pb concentrates are produced to obtain relatively high Pb recoveries. The Pb concentrates contain many impurities including high amounts of pyrite and sphalerite, and small amount of CU-, As-, Ag-, Bi-, and Se-sulfides. These impurities need to be rejected from the Pb bullion during smelting. The galena commonly contains up to 1 wt% Ag in solid solution with an average of 600 to 1460 ppu for the deposits studied to date. The Ag in galena accounts for up to 65% of the Ag in some ores.

Jan 1, 1990

By J. P. Evans

The modem 'copper smelter today utilizes tonnage oxygen for smelting concentrates. ,generating a high strength S02 off-gas leaving the smelter vessel. This gas stream. which also contains any unreacted oxygen, plus CO2; N2 and H20. also carries with it the volatilized portion of heavy metals in the feed, plus partly oxidized sulfide concentrates, The time/temperature history and subsequent treatment of this off-gas stream emerging from the smelting furnace exit up to the acid plant can influence the partitioning and segregation of heavy metals, in the off-gas circuit. Depending on this history. the type and characteristics of the chemical and physical reactions which occur in the gas handling system 'can be influenced. This fact can also be used as a tool to adjust the separation of copper from heavy metals. In this paper, the impact of different time/temperature histories of the gas, due to different furnace geometries and design. on the subsequent formation and characteristics of the smelter dust is examined. Based on the available data. several case histories drawn from examples using both bath and flash smelting technologies are analyzed from this perspective.

Jan 1, 1992

By Nicola Baldo, Marco Pasetto

"Recycling of tyre rubber in the road pavement, may be one of the best way to reduce waste tires in large quantities and, at the same time, improve some engineering properties of asphalt mixtures. The paper discusses the results of an experimental study, developed in order to analyse the potentialities of crumb rubber from road tyres in bituminous mixtures, using the dry process. Two types of porous asphalt mixtures and reference mixes without rubber were formulated by the traditional Marshall methodology, and mechanically evaluated by means of the Indirect Tensile Stiffness Modulus test, the Creep test (with confinement), and the Indirect Tensile Fatigue Test. Results of this study indicate that the tyre rubber has a positive influence on the performance characteristics, depending also on the grading and volumetric properties of the mix being studied: an interesting increase of the fatigue life, a better stiffness behaviour at lower temperatures and a bigger permanent deformation resistance at high temperatures are guaranteed. Introduction Recycling the rubber from used tyres, in the construction of road pavement layers, is potentially one of the more interesting and advantageous solutions from both the technical and environmental points of view, in order to reduce the total amount of car and lorry tyres to dispose. In road-building techniques, a technology, termed “wet”, for modifying bituminous binders with crumb rubber has by now become well consolidated. There have been numerous scientific studies conducted on this technology and its applications, particularly in the United States, where it has been adopted and codified in specific technical regulations (ASTM D-6114). If the wet process can be considered amply tested, the same cannot be said for a second technology, termed “dry”, which deserves careful study to evaluate its suitability and advantages. In “dry” processes, the rubber is usually used as a partial substitute of aggregate of equivalent grading and mixed with bitumen after integrating the crumb rubber in the lithic skeleton."

Jan 1, 2008

By F. M. Nakla

Various methods of Applied Mineralogy were used for determining the nature and composition of products yielded by flotation tests for Maghara coal beneficiation. Coal samples obtained from the Sa fa mine in Northern Sinai, Egypt, were crushed, sieved, &apos;and <32 mesh size fraction was cleaned by froth flotation. Experiments were conducted to determine the effect of certain parameters on beneficiation of Maghara coal by flotation. The investigated factors included nature of frothing and/or collecting reagents, pH value of the medium, particle size distribution in the head sample, and pulp density of the coal slurry. The quality of head samples, coal concentrates, and tailing products were determined by chemical analysis, microscopic study, x-ray diffraction analysis, and occasionally by infrared (IR) absorption spectroscopy.

Jan 1, 1989

By Robert E. Brown

Magnesium recycling has been used to recover both new scrap and old scrap. It was used extensively in Germany during WWII to expand the magnesium supply. There were a large number of magnesium recyclers in the US who got their start smelting old scrap, old airplanes and old waste dumps from the WWII build up. As the world magnesium industry dwindled, only a few companies were left that did magnesium recycling as a primary business. The sand foundries tended to recycle of their production scrap in their melting furnaces. Even the original die casters tended to put scrap directly back into melting furnaces at the die casting machines. As high purity alloys were developed and the use of die castings in automotive work increased, the tendency was to let the magnesium recyclers convert the scrap back to high quality ingot. Automotive use has grown because of the low density of magnesium. This property is the one of the biggest problems to overcome in shipping scrap. Gates and runners from die casting are very irregular shapes and it is very hard to load a truck with enough material to get a low shipping cost per pound. Recent new equipment companies have developed magnesium equipment that is specifically designed to recycle, refine and cast secondary magnesium metal. These melt cells are supplied as integrated units to magnesium casting sites. The cost and effectiveness of this approach will be discussed.

Jan 1, 2000

By Nathanael Hudson, Ruel A. Overfelt, Sushil H. Bhavnani

"In the aerospace and automotive industries, complex shapes exist which require casting. The problem with these cast parts is the empiricism required to develop the casting process and the accompanying time and expense to develop that process.There has been an interest in using fluidized beds to allow molding sand to better encapsulate the complicated surface geometries of lost foam patterns. Fluidization coupled with a mixing jet helps to homogenize the sand through stirring and may improve the integrity of the casting.At issue is the hydrodynamics of the sand and air around the foam pattern. The commercial package PHOENlCSTM is used to simulate the flow around the pre-casting foam geometry. Employing a two fluid approach, each component is considered a fluid that interpenetrates the other phase. To this end, the kinetic theory of granular 'flow for the sand phase was incorporated into the re-compilable PHOENlCSTM code.The results of this study consist of time-averaged void fraction patterns, with voidage being defined as the fraction of air in the mixture, around the foam pattern submerged in a two-dimensional fluidized bed. The model was benchmarked against past fluidized bed experiments. In order to better understand the dependence of the void fraction pattern around the lost foam pattern, certain physical parameters are varied and the resultant void fraction maps are predicted with the model. Physical parameters such as the aspect ratio of length to width, the placement of the mixing jet, and different mixing jet velocities are varied to illustrate the dependence of the time-averaged void fraction on those variables.Results consistently indicate the presence of channeling around the lost foam pattern, with the extent of the channeling and void formation reliant to a greater degree upon the placement of the mixing jet, and to a lesser degree on mixing jet velocity and aspect ratio.The increase in radial position of the mixing jet from the bed centerline had the desirable effect of granting the churning benefits of a penetrating jet, while at the same time minimizing the formation of excess void fraction at the top of the pattern."

Jan 1, 2001

By M. A. Rabah, F. E. Farghaly, M. A. Motaleb

"Wastewater from industrial galvanization industry was reclaimed under current flow stream conditions. Results showed that the raw water contains 0.7 % by weight total suspended solids (TSS) causing turbidity amounting to 30. Measurements of Zeta potential as a function of pH revealed that solid separation takes place at pH 9. Addition of H2O2 to the polmer solution helps to oxdize ions of iron and zinc metals toinsoluble ferric oxide and zinc hydroxide to a higher state of oxidation. Addition of 5 mg/L of cationic magna flocculants polymeric solution helps the rapid separation of the turbidity. Separation of floccules so formed takes place by filtration. Addition of peroxide ions to the turbid wastewater confirms the physical stability of the flocs so formed. Impurity flocculation takes place in few seconds. Maximum temperature for safe solid removal was <30°C. The treated water was pure and safe for recycling or use in domestic purposes.IntroductionStocks and et. al. [1] show that the galvanizing process introduces spent pickling acid waste production, but its major constituent, could be used. Survey of the operational procedures adopted and the acid wastes produced by UK Galvanizers are reported. Various methods to recovery spent acid of suitable composition and to eliminate zinc contamination was considered. Application of the Kleingarn acid management system reduces waste volume, saves hydrochloric acid (HCl) and increases component throughput whilst, in conjunction with zinc elimination, could allow recycling of the majority of galvanizer’s acid wastes.Dahab [2]; Kerney [3] reported recycling of galvanizing products, including pickleliquor. Kerney suggested a mobile treatment plant for recycling pickling acids. Dahab found that pollution reduction could be achieved by relatively simple operational changes to the process that gave fairly short payback times.Rozenblat and et. al.[4] studied the extraction of zinc (II), iron(III) and iron(II) with Tributyl phosphate (TBP) from hydrochloric acid solutions containing high zinc(II) concentration. Two technological approaches for the separation are considered. Firstly, the selective extraction of iron(III) (iron(II) is oxidized to iron(III)) over zinc(II) with TBP deficiency. Secondly, iron(III) reduction to iron(II) followed by zinc(II) selective extraction with an excess of TBP. Prior stripping, the organic phase was washed with small amounts of water. Scrubbing of TBP solutions containing iron(III) contaminated with zinc(II) gives always a mixture of zinc(II) and iron(III) which must be recycled to the extraction step in continuous process. The following technological concept is proposed: reduction of iron(III) to iron(II), extraction of zinc(II) with 5-10 volume excess of TBP, washing of TBP phase contaminated with iron(II) with small volumes of water and recycling of the scrubbings and stripping of zinc with water."

Jan 1, 2008

By Brad Wahlquist

An ex-situ biological treatment system was implemented at a gold mine site in South Dakota. The system removes selenium and nitrate from a mixture of groundwater and surface water runoff at ambient water temperatures. The Applied Biosciences? system replaced a denitrification system that did not perform consistently, did not treat for selenium and required heating of the influent water. Installation was completed in phases starting with the selenium circuit being brought into operation in February, 2002 and the nitrate circuit in March, 2002. System design can accommodate average flows of 380 L/min (100 gallons/minute) and a maximum flow of 1,136 L/min (300 gallons/min). Four cells were designed to remove nitrate from approximately 30 mg/L to below 10 mg/L and two cells were designed to remove selenium from 0.01 mg/L and higher, to below 0.005 mg/L. No pretreatment is required to operate the system at ambient temperatures, which can fall as low as -12C in the winter, and treat water at temperatures ranging between 8C to 16C. Nutrient requirements are met using a sugar based nutrient mixture that includes a balanced C:N:P:S ratio, trace elements and vitamins. Since start up, the system has consistently been in compliance for nitrate and selenium, treating water to below detection limits for both contaminants. This paper discusses laboratory biotreatability testing of a system designed to remove selenium, arsenic, and nitrate and full-scale implementation and optimization of a system to remove nitrate and selenium.

Jan 1, 2003

By Nathaniel R. Quick

"Nd: YAG, KrF excimer, and Cu-vapor lasers are used in air to synthesize conductors and semiconductors as a second phase in silicon carbide and aluminum nitride. Conductor resistivities as low as 104 O-cm are formed in these substrates; the resistivities for the untreated substrates range from 10 11to 1014 O-cm. The silicon carbide conversion is relatively independent of wavelength while the aluminum nitride conversion shows a dependence on wavelength over the range 248 nm to 1064 nm. Silicon carbide conductors, evaluated over the range 15 K to greater than 300 K, exhibit metal like conductivity; resistivity increases with temperature. Silicon, carbon, and oxygen are identified as the principal chemical species associated with the conductor in SiC substrates while aluminum, nitrogen, and oxygen are identified as the principal chemical species associated with the conductor in aluminum nitride substrates. The silicon carbide system, which has the less complex phase diagram, is evaluated in more depth to explain the synthesis mechanism. Oxygen was principally on the surface and increasing SiC conductivity is associated with decreasing spacing between 5 µm, or less, diameter carbon globules. This technology is proposed as a replacement for metallization in electronic packages, sensors and devices. INTRODUCTIONCeramics are commonly used for multichip module, hybrid and multilayer electronic packaging; semiconductor device and sensor applications because of the insulating, conducting, semiconducting, or superconducting properties that these materials possess (1,2) The majority of ceramics, however, have not been known to exhibit conductive or semi conductive properties when exposed to rapid thermal heat processing. A ceramic and process which through selective conversion can combine two or more of these electrical properties to eliminate the need for metallization is of interest to both the commercial and military sectors."

Jan 1, 1994

By Bogdan Petkovic, Boban Todorovic

In the early 90's a completely unknown problem was encountered at the converter Department: it was a chronic shortage of the cold copper charge needed for the second operating period. A high temperature operating regime was caused which further provoked a chain of consequences such as a drastic drop of the number of operations in campaigns. The consumption of repair bricks reached the quantity of 8.3955 kg / tonne of anode Cu. In 1994, we won the process of cold material smelting during the "copper" blowing [2]. The number of operations per campaign reached 180-200 again. Also in 1994 we won the process of smelting cold materials to obtain "tin" blowing with the purpose of completing their processing cycle [2]. During the period 1994 – 2007 a total of 107,845 tonnes of cold material were remelted to make copper and 56,794 tonnes were re-smelted to obtain "tin". Upon synthesizing these two processes, a completely new model was achieved in 2005, by Bogdan Petkovic, which entirely utilized all available energy of the Peirce-Smith (PS) converters of the Bor Copper Smelter and now represents the basis of the time cycle. The cold material now enters the converter plant, copper recovery is increased and the method itself is environmentally friendly. 167

Jan 1, 2009

By Jian Li, S. Penttila, W. Zheng

"Materials selection for Gen IV supercritical water reactor in-core components faces major challenges due to severe operating condition. Beside high-temperature mechanical properties, SCC and general corrosion resistance of commercially available materials are also major focuses in recent research. Recent reports suggest that certain types of surface modifications are beneficial to SCW corrosion resistance. In this study, the effects of surface modifications are investigated, and possible mechanisms for improved corrosion performance are discussed.IntroductionThe current Canadian pressure-tube supercritical water reactor (SCW) design specifies a core outlet temperature of 625°C under 25 MPa of pressure, with peak cladding temperature as high as 850°C. Challenges in materials selection include high-temperature mechanical properties, corrosion resistance, SCC resistance and radiation damage. Most of the SCW corrosion test results available are below 730°C. Early work by Allen [1] summarized the corrosion resistance of alloy groups including Ni-based super alloys, stainless and ferritic/matensitic (F/M) steels that can potentially be used for SCW reactors. F/M steels can only be used at low temperature sites (e.g. down stream piping). At 500°C and 25 MPa, F/M steels develop a thick but mechanically stable oxide layer. However, the long term stability of the surface oxide layer is largely unknown. Ni-based alloys appear to form very thin surface oxide, however pitting was observed in the vicinity of some intermetallic precipitates [2-5], and dissolution of major alloying components could pose significant problems for down stream piping [6]. In addition, concerns of Helium formation due to Ni transmutation prevented this alloy group to be used as fuel cladding. The corrosion resistant austenitic stainless steels (e.g. 316L) are found to be susceptible to localized corrosion such as pitting, intergranular attack and stress corrosion cracking (SCC) [7]."

Jan 1, 2012

By Shun Fujieda, Shigeru Suzuki, Kozo Shinoda, Tetsuo Fujita

"Dowa's scorodite, synthesized by oxidation of Fe(II) ions in the presence of As(V) ions at atmospheric pressure, was characterized. The scorodite was well crystallized and had a very low solubility. To examine the conditions for stable storage of the scorodite for long periods, experiments with various synthesis and leaching conditions were done. The scorodite had a very low arsenic solubility in sea water. It was estimated in consecutive leaching tests that the arsenic concentration would eventually converge to zero. The prevention of arsenic leaching by adding goethite or ferrihydrite was limited in some cases. Very low toxicity was confirmed by toxicity tests. The investigation results suggest that disposal at a specifically designed well-controlled storage place is preferable for the scorodite whose toxicity had been made sufficiently low. Disposal to an isolated final disposal site with more stringent prevention for the outflow of toxic substances was thought another option.IntroductionArsenic is a considerable environmental concern. A system of technologies for the effective immobilization, storage and final disposal has been sought. Dowa Metals & Mining Co. Ltd. has developed a unique scorodite synthesis method (DMSP®) which works at ambient pressure [1]. The scorodite is precipitated by oxidizing Fe(II) ions in a high-concentration As(V) solution. The scorodite produced in this way does not readily release arsenic because of its high crystallinity. Final disposal is necessary because scorodite currently has no commercial value. A standard method for the final disposal of scorodite has not been established because its long-term stability under various conditions has not been fully examined."

Jan 1, 2012

By H. Tan

?Preg-robbing? is the active adsorption of gold from cyanide solution by the ore components. The role of carbonaceous coatings on chalcopyrite surfaces in the preg-robbing of chalcopyrite has been investigated by using pure chalcopyrite and a copper concentrate. Activated carbon and graphite were chosen as representative carbonaceous contaminants. It was found that the carbonaceous coatings enhanced the preg-robbing of chalcopyrite. Activated carbon coating increased gold adsorption onto chalcopyrite to a lager extent, in comparison with graphite coating. In the preg-robbing of the copper concentrate, gold adsorption was increased to larger extent at finer particle sizes and at higher contents of activated carbon or graphite. The preg-robbing of chalcopyrite was reduced or eliminated, depending on the concentrations of free cyanide. However, the gold adsorption on the carbon and graphite coated chalcopyrite could not be avoided even at higher cyanide concentrations, and this adsorption was solely attributed to the carbonaceous coatings. Zeta potential studies indicated that the carbonaceous coatings reduced the negativity of the chalcopyrite surface charge. As shown by SEM analysis, gold not only accumulated at the edges and defect sites, but was also spotted on the smooth surfaces of chalcopyrite with carbon or graphite present. XPS results revealed that gold was strongly reduced on chalcopyrite surfaces, with the sulfide ions of the chalcopyrite being oxidized to elemental sulfur. Diagnostic elution indicated three mechanisms contributing to gold take-up by chalcopyrite, i.e. gold reduction, physical adsorption and chemical adsorption.

Jan 1, 2003

By P. C. Guillaume

Global plant modernizations or expansions cannot be considered in the same light as any other industrial investment project. Relationships between the partners, relationships and communications with the client, structure and organisation of the teamwork, schedule of the work, and a lot of other tasks and missions devoted to external contractors have to be defined considering one fundamental input: an operating plant. For an engineering company expert in processing, like UM Engineering, such a context requires a specific approach as well as specific procedures able to efficiently challenge the generated constraints. First of all, even if a detailed audit had been conducted at the beginning of the conceptual engineering phase, new elements will be discovered during the preparation and realization of the project, and must be continuously integrated. Consequently, a close proximity to the site is necessary. This is one reason why UM Engineering, most often, works in partnership with a local engineering company. The second important point for the client is that the operation must not be interrupted during the realization. In order to make that possible, UM Engineering has defined a specific project structure and organisation, integrating on a permanent basis the operators (the "users") in the project teams. This paper presents the way UM Engineering copes with this type of "multi-constraints" context with reference to the recent copper cellhouse modernization under realization for the CCR Refinery of Noranda Inc. in Canada.

Jan 1, 1999

By Henk Dijkman

Existing metallurgical operations can be optimized by implementing engineered bioreactor systems in the process configuration. For instance, metals can be recovered safely and economically from process and waste streams using biogenic sulfide. This paper focuses upon possible applications of high rate biotechnology in metallurgy and mining. Metal recovery from liquid streams (process bleed streams, leach water, waste streams), integrated removal of (fugitive) SO2, treatment of acid blowdown and other options will be described. Practical examples are given. A large-scale application of biotechnology at Pasminco&apos;s Budel Zink refinery is described. Here, acid plant blowdown is treated together with electrolyte magnesium bleed. Concentrated zinc sulfide (10 tpd) is produced biologically, eliminating the production of gypsum and closing the refinery sulfur cycle. Recovery of metals from solution at Kovehute Pribram in the Czech Republic is the second practical example. In this case, H2S is produced on-site for metal removal from an alkaline slag dump leachate. At the Caribou mine in New Brunswick, Canada, acid mine drainage is treated with biogenic sulfide. This plant is situated upstream of a lime neutralization plant. As a result, reusable ZnS is produced, the volume of the sludge (gypsum and hydroxides) from the lime plant is reduced by 50%, the sludge is free of heavy metals and the final effluent concentration of heavy metals is in the ppb range. In the second phase of this project, metals will be recovered from stored tailings, resulting in significant revenues.

Jan 1, 2002

By P. S. Arthur

The ISASMELT? process is a submerged lance smelting technology operating in smelters in Australia, the USA, Belgium, India, Germany, Malaysia and China. Further plants are under construction in Peru and Zambia. Following the invention of the Sirosmelt lance technology Mount Isa Mines recognised the commercial potential in the novel top blown bath smelting process and embarked on a development program that has lasted more than 25 years. After successful operation of pilot plants and demonstration plants producing copper and lead, Mount Isa Mines decided to license the technology to external companies. Since the purchase of Mount Isa Mines by Xstrata in 2003, Xstrata Technology has assumed responsibility for transferring the technology to ISASMELT? licensees. In the 15 years since the first commercial furnaces started operation plants have been constructed (or are under construction) with a combined annual smelting capacity of more than six million tonnes of concentrates or secondary raw materials. Process development continues on the commercial scale plants at Mount Isa and elsewhere. Many of the improvements implemented by plant operators have been passed on to, and adopted by, other licensees. Exchange of ideas and technical improvements occurs through ad hoc visits to fellow licensee sites and through regular licensee workshops arranged by Xstrata Technology. This paper updates the reader on the status of various ISASMELT? plants either operating or under construction. It highlights the important role that the technology provider?s operational experience plays in ensuring that new smelting plants ramp up quickly to nameplate capacity.

Jan 1, 2006