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By Daojin Cao

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

Jan 1, 2006

By Li Cheng

The SKS copper smelting process was jointly developed by Shuikoushan Mining Corp. and ENFI (Beijing Central Engineering and Research Institute for Non-ferrous Metallurgical Industries) in China. It is a new bath copper concentrate smelting process with oxygen enriched air. The pilot plant testwork was completed successfully in 1993. SKS has demonstrated to be an advanced bottom blown smelting process. This technology got the First Class Prize of Scientific and Technological Progress awarded by CNNC (China National Non-ferrous Metal Industry Corp.) in 1994. The SKS process has significant capital and operating cost advantages. Its environmental and industrial safety and hygiene performance represents a substantial improvement when compared to conventional technologies. The technology has generated great interest in the Chinese metallurgical industry. Feasibility studies and basic designs have been carried out to incorporate in retrofit and green field smelter projects in China and abroad. This paper describes the history of the pilot plant operating data (50 tonnes dry feed/day), and discusses the features of the SKS technology, its application and possible future trends.

Jan 1, 1999

By Nicholas S. Lynn

"A new process has been developed to bioleach refractory gold ores to expose the precious metal values using Thiobacillus ferrooxidans bacteria.The ore is hosted in a limestone rock with secondary replacement of carbonaceous and pyritic minerals. Crushing, stacking, bioleaching, rinsing and neutralization have been completed in a 45-day total time cycle. The use of sulfuric acid operation, and concentrated Thiobacillus ferrooxidans population allows the short bioleaching cycle.The ore is then processed using conventional Carbon-In-Leach Cyanide recovery techniques.ABSTRACT ONLY"

Jan 1, 1997

By V. B. Chernyavsky, Ladokhin S. V.

Equipment and continuous casting technology for the production of small diameter copper rods and tubes are described. Industrial copper wastes, such as scrap and shavings, were used as the charge. An electron-beam installation for rod and tube production includes a crucible with an electromagnetic stirring system and a pouring hole in its bottom, a bottomless mold, .and a special cooling system, which includes an oil and water cooling devices. For the first time in the electron-beam technology, rods of 8 mm and 14 mm diameter mm tubes of 14 mm external diameter and 7 mm internal diameter were produced through continuous casting by pulling them out of the vacuum chamder into the atmosphere with depressurizing the vacuum chamber. The production capacity of a single strand continuous casting machine was 200 mm/tnin for rod casting and 150 mm/min for tube casting.

Jan 1, 2000

By M. S. Moats

The treatment of oxidized residues of zinc with high iron content continues to present a technical challenge in both the steel and zinc industries. Two main problems are commonly identified and include high treatment costs and environmental concerns about contaminated, iron-bearing residuals. A new approach to this problem is described in which selective separation of the iron and zinc into salable products may be potentially feasible. The waste material is first leached to give a solution having an approximate concentration of 110 g/l Zn, 15 g/1 Fe and 40 g/1 H2SO4 and other impurities such as Pb, Cd, Cu and Sb. A suitable organic, such as D2EHPA, is used to load the majority of the iron. The aqueous phase is then acceptable for zinc electrowinning after standard solution purification. The novel step in the flow sheet is the efficient recovery of the ferric iron from the organic solvent using a solid metal to reduce the iron to the ferrous state. The Fe+2 is easily stripped into an aqueous phase in a relatively pure form, suitable for use in water treatment. Process parameters and possible flow sheet designs are described and discussed.

Jan 1, 1995

By C. Liliane Carvalho

In the current study, bio-oxidation tests were carried out in shaking flasks with a flotation concentrate containing the sulphides pyrite, arsenopyrite and gudmidite. The tests were performed with mesophilic microorganisms (At. ferrooxidans) at 30 °C and also with the moderate thermophile S. thermosulfidooxidans, at 50 °C. The effects of (i) previous adaptation of the microorganisms to the concentrate, (ii) ferrous iron concentration and (iii) pulp density (2%, 4% and 6% (w/v)) on the dissolution of the sulphide were studied through arsenic extractions. S. thermosulfidooxidans was more sensitive to the pulp density in comparison to At. ferrooxidans as a reduction in sulphide oxidation was observed with the increase in the solid content to 6%. Therefore, the mesophilic strain was selected for further work, which comprised a rolling bottle experiment at 10% solids. After 40 days of bio-oxidation, the solid material was subjected to cyanidation, which revealed 85% gold extraction as compared to 21% from the original concentrate. The antimony sulphide grains in the bio-oxidized product showed similarity to what was observed in the original sample, suggesting such particles were not susceptible to the bio-oxidation process.

By Batric Pesic

A hydrometallurgical process for recovery of Zn and Mn from Bunker Hill Water Treatment Plant sludge was developed. The process is unique because it treats an unusual combination of metals, Zn and Mn. Another non-standard feature of the process is that leaching takes place with ~S04 in the presence of a reductant (SO2). Zn and Mn are recovered simultaneously by electrowinning, Zn on a cathode and Mn on an anode, as MnO2 The major purpose of the process is to detoxify the sludge by removing toxic heavy metals. The recovered metal values could be marketed to offset the overall costs of water and sludge processing. This work is presented in two separate parts, 1. Leaching and Solution Purification, and II. Electrowinning. This paper covers only the first part of the hydrometallurgical process: Leaching and Solution Purification. Initially, the paper briefly discusses the history of the pollution problem at the Bunker Hill Superfund Site, the origin of heavy metals in the mine waters, and the development and use of the water treatment plant. The leaching of sludge was examined as a function of the following parameters: constant vs. initial pH, initial vs. delayed addition of SO2, temperature, and pulp density. It was found that leaching with H2SO4 at pH 2.0 for 15 minutes (at 60°C), followed by S02 addition for another 15 minutes, could completely dissolve Zn and Mn. Solution purifIcation was done in three stages. In the first stage iron was removed by adjustment of pH (to pH 5.0) and oxidation offerrous to ferric iron (with H2O2). In the second stage, Cu and Cd were removed by Zn dust cementation. Finally, Co and Ni were precipitated with the organic reagents 1-2 nitroso-naphthol and nitroso, respectively. Electrowinning of Zn and Mn is discussed separately in Part II of this paper.

Jan 1, 1996

By A. G. Guézennec

Electric Arc Furnace (EAF) steelmaking co-produces amounts of dust (15 to 25 kg per ton of steel), which require to be collected and stored in specific landfills. The collection, handling, and possible beneficiation of EAF dust depend on its composition and morphology. We first studied theoretically the chemical evolution of dust particles along the fume extraction system, from the furnace down to the filters, using thermodynamic calculations of the Fe-Zn-O system. We show how it would be possible to favor zincite formation in dust and therefore increase further zinc recovery. Then, we developed a new morphological model, based on population balances, for predicting the granulometric evolution of dust particles as a result of agglomeration and sintering in the fume extraction ducts. The contribution of the various mechanisms (Brownian, turbulent, and sedimentary agglomeration; thermophoretic deposition; coalescence and sintering) is assessed. The influence of the exhausting conditions on dust granulometry is detailed. For the extraction system studied, intense agglomeration of the sub-micronic particles and complete coalescence take place inside the furnace; micronic particles then undergo little evolution from the elbow to the water-jacket, whereas big agglomerates are formed downstream. These results are in good agreement with dust particle observations.

Jan 1, 2006

By Esperidiana A. B. Moura, Michelle Gomes, Cordelia M. F. Escanhoela, Francisco R. V. Diaz, Angel Ortiz, Rene R. Oliveira

"This work evaluates changes in morphological, mechanical and thermo-mechanical properties of electron-beam irradiated HDPE/nanoclay and HDPE/Piassava fiber/nanoclay. Material samples irradiated with 100 and 200 kGy using a 1.5 Me V electron beam accelerator (room temperature, presence of air) were submitted to tensile, flexural, and HDT tests. MFI, SEM and XRD analyses were carried out. Correlation between properties was discussed. Results showed that incorporation of piassava (Attalea funifera Mart) fiber and nanoclay, followed by irradiation represented significant gain in thermo-mechanical properties. Changes in surface morphology and reduction in MFI were observed. In conclusion, it may be claimed that the incorporation of piassava fiber in small size particles and nanoclay in the HDPE followed by electron-beam irradiation effectively improved the polymer properties and led to materials with superior properties suitable for several industrial applications.1. IntroductionIn recent years, the preference for using natural fibers instead of synthetic ones in polymer composites has been growing significantly. In Brazil, due to the great diversity of woody and fibrous plants of our forests, a vast potential of natural fibers is found, presenting good mechanical strength properties, chemical and biological stability, fire resistance, abrasion resistance, shear strength and lightness, among other which may contribute to the development of new materials for different applications such as automotive, aerospace, construction, food segment, cosmetics and others [ 1]."

Jan 1, 2013

By Fumiatsu Sato

In recent years, an increasing number of urban soil contamination cases have been found during redevelopment of former factory sites. Hydroclassification technique, separating heavily contaminated fine soil particles from contaminated sites, is one of the economical remediation techniques for contaminated soil by heavy metals, but the separated fine soil particles are generally landfilled because of the difficulty in removing strongly adsorbed heavy metals on them. In the previous study, the authors have investigated the mechanism and the optimum condition of chlorination-volatilization technique to eliminate heavy metals from inorganic waste and found it was needed to heat up around 1273K. In this paper, a new remediation technique for lead contaminated fine soil particles is proposed. This technique is composed of chlorination and subsequent warm water extraction. In the chlorination step, water-insoluble lead complex is chlorinated to be water-soluble lead chloride without volatilization, by heating the soils with MgCl2-CaCl2-KCl salt mixture at relatively low temperature. By subsequent warm water extraction, lead chloride is leached out. Effects of chlorination conditions, such as time, temperature, composition of the salt and added salt ratio, on lead behavior were investigated. It was proved that lead concentration could be reduced below Japanese environmental standard.

Jan 1, 2006

By Berndt Moeller

Mercury-cell chlor-alkali production plants generate mercury contaminated wastewater streams from which mercury must be precipitated and filtered, resulting in a sludge containing 2% mercury (designated KI06) that cannot be landfilled in the United States without treatment. REMERC is a chemical treatment process used to recover 99% of the mercury from wastewater sludge generated at these plants. The process uses leaching to oxidize mercury compounds to mercuric chloride, washing and filtration to separate mercuric chloride from the treated sludge, and cementation to reduce the mercuric chloride to metallic mercury. Mercury not recovered in cementation is recycled to the wastewater process for precipitation and filtration. Treated sludge contains less than 260 ppm total mercury and 0.2 ppm TCLP, meeting the USEPA low mercury subcategory specifications that allow landfill disposal. REMERC uses readily available chemicals, is straightforward to control and inexpensive to operate, has no mercury emissions to air, and recovers metallic mercury. REMERC enabled significant cost savings including lower solids disposal costs, recovery and reuse of metallic mercury in the chlor-alkali process, and ability to treat non-wastewater sludge. No new EPA permits were required. REMERC was shown to be a viable process for recovery of metallic mercury from K106 designated sludge.

Jan 1, 2003

By D. R. Spink

A partial desulfurization roasting (PDR) technique has been developed for use on zinc concentrates whereby the sulfide sulfur associated with the iron content is selectively removed over a very short residence ?time in the roaster. The resulting PDR product is then leached for the selective removal of the iron. The resulting leach restdite is an upgraded zinc sulfide concentrate which has a very low iron content. The up-graded zinc concentrate can be subjected to a conventional dead roast without formation of deleterious zinc ferrite so that hot acid leaching and jarosite (or other) iron precipitation steps are obviated. Examples are presented for the treatment of three very different types of zinc concentrates.

Jan 1, 1990

By Howard K. Worner

"In a rewarding career spanning nearly two thirds of a century, the author has worked at the frontier of such diverse fields as the creep of metals, structure properties and production of novel dental and surgical materials, molten salt electrolysis for titanium production, greatly improving the productivity of large iron blast furnaces and of oxygen steelmaking. While each of these has given great satisfaction, special thrills have derived from the development of new methods for the continuous production or refining of both ferrous and non ferrous metals. A rewarding segment was the evolution of various aspects of WORCRA technology. Unfortunately, several of these inventions have been ""ahead of their time"". Introduction""I am greatly honoured by the convening of this meeting to recognise my contributions to pyrometallurgy. My appreciation is the greater because this is the third Howard Worner Symposium; the first took place in the University of Newcastle in 1988, close to my 75th birthday. It was arranged by the local branch of The Australasian Institute of Mining and Metallurgy with the theme, ""Frontiers in Pyrometallurgy"". The second was organised by the University of Wollongong in conjunction with the Australian Academy of Science and the Australian Academy of Technological Sciences and Engineering; it celebrated my 80th birthday and, at my request, covered a broad range of topics under the heading of ""Recent Advances in Science and Technology"". Now, this very international meeting on ""Injection in Pyrometallurgy"" has been convened by the G K Williams Co-operative Research Centre for Extractive Metallurgy in my alma mater. I am both delighted and honoured that the cosponsors are the TMS (USA) and ISIJ (Japan).Dr Madhu Nilmani consulted me about the field to be covered and I readily concurred because ""injection"" has been of keen interest to me since the beginning of the 1960s when I began my pioneering work on sequential oxygen (or air) injection into flowing streams for both refining of blast furnace hot metal to steel and for the continuous smelting-converting of copper and nickel."

Jan 1, 1996

BHP Hartley Platinum operates an electric smelting furnace to treat Cu-Ni-PGM concentrate at its plant in Selous, Zimbabwe. The furnace, originally built by others, has experienced problems including severe refractory erosion of the sidewall. Hatch Associates has designed several important improvements to the furnace, including: ? water-cooled copper cooling elements in the slag zone ?air-cooled copper cooling fins at the metal level ?water-cooled copper tapholes ?binding system providing vertical refractory compression ?electrode seals ?new feed pipes Novel construction techniques employed on this project to reduce shutdown duration are discussed.

Jan 1, 1999

By G. Sterzik, W. A. Jankola, T. L. Salway, D. J. McKay

At Trail, British Columbia, Cominco's zinc leaching and solution purification processes include direct pressure leaching of zinc concentrates, leaching of fume from the lead smelter, leaching of calcine and electrolyte purification. These processes have been adapted to match the unique characteristics of Cominco's integrated zinc and lead operations. Recent modifications include changes to the purification process and iron-residue handling circuits. In 1997, a new five-compartment autoclave, complete with ancillary equipment, was installed in the pressure leaching plant. This paper discusses these changes, the current flowsheet and further improvements.

Jan 1, 2000

By Edgar Blanco

At the Deer Trail Mine, interest in recovering noble metals from oxide ore and tailings oxide ore with 6.0/1.0 g/t Au and 200/140 g/t Ag respectively has led to metallurgic studies focused on finding an adequate treatment for these materials. Using cyanide leaching, the silver/gold recoveries from oxide ore and oxide tailings were 39%/95% and 36%/96%, respectively. Since these recoveries were less than spectacular for silver, it was decided to explore a non-cyanide leaching process that would extract silver and gold better. Based on previous research the possibility of using aqua regia in combination with sulfuric acid was evaluated. On a laboratory scale, variables such as mineralogical composition, concentration of reagents, dissolved oxygen, reaction time, pH and temperature were evaluated. Under optimal conditions it was possible to achieve >65% silver recovery and >85% gold recovery for both oxide ore and tailings.

Jan 1, 2009

By Stephen C. Britten

An in-situ amperometric slag sensor for measuring the concentration of easily dissociable oxides in slags at temperatures between 1200-1600°C is being developed. The sensor provides the same information as potentiometric sensors while also providing data on the concentration of the transition metal species and the diffision kinetics within the slag. The electrochemical technique utilized in the sensor is similar to methods utilized in aqueous voltammetry.

Jan 1, 1998

By Bruno Lebon, Koulis Pericleous, Georgi Djambazov, Mayur Patel

"High speed compressible jets are used in a number of steel-making applications. In the case of the BOF, a compressible oxygen jet reacts with a carbon-rich iron bath to reduce carbon levels and produce steel. The intensity of the process is governed by the speed of the jet and by the size and shape of the depression created in the metal and slag by the force of the jet, i.e. by the corresponding free surface. This is a difficult CFD problem, since there are compressible and incompressible regions in the flow domain, which need to be handled differently in a finite-volume (FV) pressure-correction scheme. Also, standard turbulence models do not account for compressibility, or the large difference in density between the cold oxygen jet and the hot reacting surroundings. Corrections are introduced to the k-E model to remedy this deficiency and the results are validated against experimental data. The compressible/incompressible boundary is handled through a transition region, based on Mach number.IntroductionThe deformation of a free surface by a compressible high speed jet is of paramount engineering interest, particularly for understanding the physical processes within a Basic Oxygen Furnace (BOF). In a BOF, a supersonic oxygen jet impinges on a molten iron surface, thereby creating a cavity. Oxygen penetrates the bath and removes carbon, resulting in low carbon steel [1].The challenges in modelling such a process lie in coupling a solution domain with distinct compressible and incompressible regions and in dealing with large density differences between the modelled gas and liquid. The modelling of compressibility within the jet is crucial, since the correct velocity profile in the jet is required to determine the cavity depth with accuracy."

Jan 1, 2012

By Ivanildo Hespanhol

"DALYs are a measure of the health of a population or burden of disease due to a specific disease or risk factor. It evaluates the time lost because of disability or death from diseases compared with a long life free of disability in the absence of disease. DALYs are calculated as the sum of years of life lost by premature mortality (YLL) and years of healthy life lost in states of less than fully health, i.e., years lived with a disability (YDL), which are standardized by means of severity weights, thus: DALY=YLL+YLD.WHO has established for wastewater use in irrigation (1) the same reference level of health protection as established for drinking water quality (2), i.e., the additional burden of disease from consuming water irrigated food should not exceed 10-6 DALY(Disability-Adjusted Life Years) loss per person per year (pppy). This level of risk means that a single additional case of disease may occur in a population of 1 million, during a life time (70 years). In a individual basis is equivalent to the occurrence of a mild disease during about 31,5 seconds.Such a restrictive risk is almost impossible to be attained in most developing countries which may not be able to afford the cost of wastewater treatment and of other protective measures, even for restrict irrigation.This paper presents proposals to adapt the reference level of risk to local technical, cultural, economical and social conditions of developing countries on the basis of a risk benefit approach."

Jan 1, 2008

By Andreas H. Vassiliou

Organic materials are major constituents of the ore in several uranium deposits. Some of these deposits have been described as "urano-organic" because, the organic materials are believed to have provided the dominant control for the accumulation and deposition of uranium and are directly and intimately intermingled with the uranium. The nature of these urano-organic deposits has been problematic in terms of (a) the origin of the associated organic materials and (b) the specific form of' occurrence of uranium. The organic materials in urano-organic deposits have been genetically related to both coal and petroleum or their progenitors or deriva-tives. Analytical data presented here (infrared, chemical. D.T.A.) suggest that coaliferous materials or related plant derivatives represent the main source of the organic fractions in practically all major urano-organic ores analyzed from the Colorado Plateau and other areas. Recognition of the specific form of occurrence of uranium in urano-organic deposits has been problematic mainly because the uranium is usually in an extremely fine-grained and disseminated state in the organic matrix. Electron microprobe and X-ray diffraction analyses presented here show that fine-grained uranium minerals, specifically uraninite or coffinite. are disseminated in the organic matrix as the predominant form of uranium in most major deposits; however. the presence of true organo-uranium compounds is also suggested for some deposits.

Jan 1, 1981