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By E. Gervais

Modern life in inconceivable without zinc. Zinc provides the most cost-effective and environmentally efficient method of protecting steel from corrosion. Zinc is also used to power electric vehicles and computers, to make brass, automotive equipment, household appliances, fittings, tools and toys, and to support the building and construction industries. It is also used in pharmaceuticals and cosmetics, in rubber, in fertilisers and in animal feeds. The links between properties, applications and performance, as well as zinc demand and market dynamics, will be reviewed along with market development opportunities and successes. The presentation will also include a progress report on the five-year plan of the International Zinc Association to increase the global market for zinc, over and above the natural growth, by 500,000 tonnes/year by 2002.

Jan 1, 2000

By N. L. Piret, E. N. Mounsey

Ausmelt technology is successfully used to process primary and secondary materials to produce lead in large-scale commercial operations and to meet stringent environmental standards. The development and commercial data covering these applications and the results with respect to metallurgical, cost and environmental performance are reviewed in commercial operations. A new smelter is scheduled for commissioning in 2000 at Korea Zinc's Onsan site to process lead fume and other secondary materials to produce 50,000 tonnes per annum of lead bullion. The unique features of Ausmelt technology also allow for the efficient processing of polymetallic concentrates and secondary materials, particularly copper and lead, through the effective separation of these elements into metal, slag and fume species. This capability has been successfully demonstrated at a commercial scale and the results and implications for the industry are discussed.

Jan 1, 2000

By Bohumír Cech, Jirí Hanika, Václav Veselý

"PET bottles are separated and subsequently crushed into flakes. Except for PET, these flakes contain PE, PVC, paper, adhesives, beverages remainders and mineral impurities. PET itself usually is a glycol and terephthalic and isophthalic acid polymer.The suggested method consists in PET flakes crystallization at 255°C. In the meantime, volatile substances evaporate and PVC disintegrates. Formed crystalline PET is crushed into small particles and then is subject to the basic hydrolysis at an atmospheric pressure. In addition to lye solution, glycol is added in the hydrolysis. Water is eliminated by boiling, which gives rise to suspension of sodium salt of terephthalic acid and glycol. The suspension is skimmed and the filtered glycol is vacuum distilled. Pure glycol is then the distillation product.Crystals are dissolved in water and the solution is filtered, which eliminates PE and impurities. Electrodialysis removes pure terephthalic acid salt from the solution. Glycol solution is returned to the hydrolysis. Terephthalic acid is precipitated by a mineral acid. Subsequently, it is washed and dried. The filtrate is separated through electrodialysis to lye and acid. The lye gets back to the hydrolysis and the acid is used for precipitation. Terephthalic acid and glycol are products in a “polymer grade” quality. The waste is a part of washing waters, distillation residues after glycol regeneration and a filter cake after the terephthalate solution filtration."

Jan 1, 2008

By F. L. Meng, C. S. Henkel, R. M. Alchalabi

For secondary aluminum producers to maintain a profitable melting operation, five technical factors have to be taken into account from the initial furnace building decision to the final operation and production. These factors are furnace design, furnace equipment selection, furnace control, furnace charge selection and inventory, and furnace operation. Any of these five factors, if not chosen or performed wisely, will likely result in sub-optimal melting operation. As a result the MeltSim melting optimization package has been developed by the collaborative effort of Chinook Sciences and AMCS Corporation to take into account these five factors. The package is a mixture of hardware, software, science and experience. The package incorporates years of reverb furnace operational observations, start-up installations, furnace operator experience and furnace physiochemical mathematical model development. The optimization package enables aluminum producers to design new furnaces, select and place proper equipment, optimize existing furnace operations, and convert air-fuel installations to oxy-fuel. The package provides furnace operation monitoring and advisory signals, and furnace automatic optimal control to furnace operators, shift supervisors and plant managers, all customized, based on plant and melter need and ease of information management.

Jan 1, 2000

By Jenifer S. Heath

Human health risk assessments can be used in mine permitting, and are frequently used to investigate areas of potential contamination and as a basis for remediation decision making. While some states and US Environmental Protection Agency (USEPA) Regions have their own guidance for the conduct of human health risk assessments, USEPA Headquarters guidance and the underlying science are changing and advancing rapidly. Even outside the US, USEPA guidance can affect risk assessment costs and conclusions, which in turn can affect cleanup costs or permitting options. This paper summarizes recent USEPA guidance and scientific evidence related to human health risk assessment for mining sites. This paper is designed for non-risk assessors, and so focuses on the potential applications and implications of the new guidance rather than the mathematical and theoretical details.

Jan 1, 1999

By N. A. McKay, J. G. Davison

"Heap leachable ore deposits from many countries have been submitted for process mineralogical evaluation and laboratory testwork. Numerous factors must be addressed and integrated by the mineralogist, geologist, metallurgist and engineer. Projects encompass grass roots exploration, preliminary petrographic analysis, predictive and process mineralogy, dye penetration analysis of rocks and thin sections, metallurgical beneficiation testwork and plant optimization studies. The significance of mineralogical factors, such as geological controls, degree of oxidation, dye amenability, liberation, deleterious minerals, refractoriness, and the impact of mineralogy on gold recovery and process considerations, will be presented.ABSTRACT ONLY"

Jan 1, 1997

By T. J. Weitz, J. E. Micheletti

"Pegasus Gold's Beal Mountain Mine is located near the Continental Divide, SW Montana. Conventional surface mining utilizes crushing, heap-leaching, carbon absorption/desorption, electrowinning and refining to produce approximately 60,000 oz gold annually. A leach pad sits at 2,300 meters (7,500 ft) elevation. Winters are long and cold with average snow accumulations ofl-2 meters; temperatures fall below minus 40'C and wind chill temperatures below 70°C. The Beal Mountain staff has developed special tools and procedures for burying drip emitter lines, and managing the heap and process solutions to allow for uninterrupted gold recovery during the winter season. Management of water balance and spring runoff is critical to the operations' success, due to mountainous terrain, high precipitation and proximity to a fishery and elk herd. The mine has an extensive network of land application disposal (LAD) and stormwater control systems to assure environmental protection and regulatory compliance.ABSTRACT ONLY"

Jan 1, 1997

By Kurt Westerlund

The design of the economically most profitable and technically most feasible smelter process gas handling .and treatment as an integrated part of the total metallurgical process is discussed and exemplified, with alternative flow sheets including material and energy balances, investment and operating costs. Retrofitting and de-bottlenecking of existing gas handling lines will be described and exemplified. Methods of increasing total gas handling line availability will be described.

Jan 1, 1992

By Kurt Westerlund

The design of the economically most profitable and technically most feasible smelter process gas handing and treatment as an integrated part of the total metallurgical process is discussed and exemplified, with alternative flow sheets including material and energy balances, investment and operating costs. Retrofitting and de-bottlenecking of existing gas handling lines wil1 be described and exemplified. Methods of increasing total gas handling line availability will be described.

Jan 1, 1992

By Robert Kozicki, Eric Graham, George Wrightson

"IntroductionThe manufacture of Ferro Chromium involves the smelting of various ores and fluxes to produce the metallic product.Slag is inherent in the process. It has a much lower density than the metallic FeCr. Some chrome may be trapped in the slag as either FeCr or Cr203.Previous methods to estimate the slag in the FeCr have revolved around separating the slag and metallic portions by exploiting the differences in density. The downside with that procedure is that material will often contain pieces that are adhered FeCr and slag. The Metallic FeCr may also be completely encapsulated in the slag.An alternative and more precise method involves calculating the slag content based on chemical analysis of Mg and Al. The Mg and Al will be at relatively low levels (less than 0.1 % ) in the Metallic FeCr pieces and considerably higher in the slag (3% or greater). The overall sample will have a proportional amount and is calculated using simultaneous equations with the assumption there is only one kind of slag and one kind ofFeCr present. ""Pure"" slag and ""pure"" FeCr are needed in order to determine the Mg and Al in each. The detemlination of the Mg and Al in the overall sample would then be used to calculate the amount of slag.When the particle size is small, it is difficult to sample and get ""pure"" pieces of the slag and FeCr of sufficient quantity to perform a proper analysis. Often, historic data is used but that is dependent on the source of the FeCr and the materials used in its production. Mg and Al levels in slag can vary between 3% and 20% in different FeCr slags depending on their origin."

Jan 1, 2013

By H. Cepin

Production of non-ferrous metals is still principally performed in shaft and flame fired furnaces. Electric furnaces increase metal recovery, reduce environmental burdens and decrease energy consumption compared to conventional processes. Because non-ferrous metals have low melting and boiling points and aggressive slags design of the furnace, energy input, and slag conductivity and composition are very important. Secondary materials are easily handled in electric furnaces. Since additional amounts of lead, zinc and tin will become available from secondary sources in the future, electric furnaces are expected to replace conventional smelting furnaces. The paper describes technical, electrical, and process designs of electric furnaces peculiar to the reduction of non-ferrous metals. Electric and various thermic furnace processes are compared.

Jan 1, 1990

By H. Fukushima, T. Ohgai, N. Baba

The electrodeposition behavior of Zn and the morphology of the deposited Zn were studied in electrowinning solutions containing polymer additives such as gelatin and polyethylene glycol (PEG). The cathode potential was shifted in a less noble direction and the polarization resistance for Zn deposition increased with increasing concentrations and molecular weights of both gelatin and PEG added to the electrolytic solutions. However, when the molecular weights of these additives exceeded about lxlO4, the cathode was depolarized and the polarization resistance for Zn deposition decreased with increasing molecular weight. The crystal grain size and the (002) orientation of the deposited Zn became smaller when the concentration and molecular weight of the additives increased, and the cathode was polarized.

Jan 1, 2000

By Wang Haibei

China is the important country in terms of Ga, Ge reserves and products. These elements usually associate with lead and zinc ores such as in Fankou, Dachang and Lanping mines. Until now these metals could not be extracted from zinc residues effectively. The main reason is that it is difficult to separate zinc and iron. BGRIMM has carried out considerable research on this subject and some hydrometallurgical processes were developed. Zinc residues were pressure leached with a reducing agent such as zinc concentrates or SO2 at 110~130C. The final concentrate of H2SO4 was 30~50g/L. The metals such as Zn, Fe, Ga and Ge were dissolved into solution. In the leaching residue Pb and Ag could reach 20% and 2000g/t. The feed of solvent extraction was prepared from the leaching solution by pre-neutralization ? precipitation of Ga, Ge and acid dissolving. Then Ga and Ge were extracted by solvent extraction through P204 and G315 produced by BGRIMM. After stripping, metallic Ga was produced by electrowinning. GeO2 was produced by precipitation. The iron in raffinate was removed by the hematite process. The solution after removal of iron came back at the zinc neutral leaching stage. In 2003-2004, pilot tests were finished in BGRIMM in cooperation with Fankou Lead and Zinc Mine Ltd. And the extraction rate of Ga and Ge in the leaching stage was 94% and 83% respectively. The total recovery rate was 90% and 80%. It is estimated that the technology has a wide commercial use in the coming five years.

Jan 1, 2006

By Kalyani Das Sarkar

"Steel Authority of India Limited, a Public Sector Undertaking with a production capacity of 14 million tones of crude steel, is India's largest steel maker and ranks among the leading steel producers in the world. SAIL owns and operates eight manufacturing plant – five integrated steel plants at Bhilai, Durgapur, Rourkela, Bokaro and Burnpur producing carbon steel, and three speciality steel plants. All integrated steel plants have hospitals of 650 – 750 bed capacity with modern facilities to serve it's employees and adjoining localities in a clean and sustainable environment.According to the Bio-Medical Waste(Management and Handling) Rules, 1998 and as amended to date, all Bio-Medical waste which is generated during the diagnosis, treatment or immunization of human beings or in research activities pertaining thereto or in the production or testing of biologicals are to be categorized and taken to any facility wherein treatment, disposal of this waste or processes incidental to such treatment or disposal is carried out.The hospital management has created adequate treatment facility for Sharp and Infectious Waste, Pathological Waste and Anatomical Waste through Autoclave, Shredding Machine and developing deep burial pits. Some of these hospitals is ISO 9000-14000 certified. Use of above said treatment facilities in these hospitals are discussed in this paper.INTRODUCTIONBio-Medical waste means any waste, which is generated during diagnosis, treatment or immunization of human beings or animals or in research activities pertaining to these or in the production or testing of biologicals.Steel Authority of India Limited, a Public Sector Undertaking with a production capacity of 14 million tones of crude steel, is India's largest steel maker and ranks among the leading steel producers in the world. SAIL owns and operates eight manufacturing plant – five integrated steel plants at Bhilai, Durgapur, Rourkela, Bokaro and Burnpur producing carbon steel, and three speciality steel plants. All integrated steel plants have hospitals of 650 – 750 bed capacity with modern facilities to serve it's employees and adjoining localities in a clean and sustainable environment."

Jan 1, 2008

By Li Fangi

This paper describes the characteristics and regularities of a process to recover rare earth minerals from Baotou Ore with H-205 collector. H-205 is a kind of hydroxamic acid with amide as a polar group and poly-cycle aromatic hydrocarbon as a non-polar group, having strong ability to capture RE minerals (bastnasite, monazite). When adding a certain dosage of water glass and some other modifying agents, and maintaining pH value between 8.5 and 9.5, RE minerals can be effectively separated from calcium and barium minerals, such as fluorite and barite, etc. Under normal flotation temperature and concentration, when using H-205 to float RE minerals, it needs a bit longer conditioning time (a few minutes longer than that for the conventional collectors). It is also shown that the reagent has the property of resistance to hard water. The laboratory scale and pilot scale tests of the process have been carried out on bulk froth containing RE minerals and fluorite taken from Ore Dressing Plant of Baotou Iron and Steel Company, in both cases, high grade RE concentrates were obtained and the recovery increased remarkably. Therefore, the process has a great practical value.

Jan 1, 1989

By M. Cross

Heap leaching presents a complex physico-chemical process to model and a significant challenge to develop a comprehensive model enabling reliable predictions of heap behavior over the long term. A computational modeling framework is described for the analysis of multi-phase flows in reactive porous media suitable for tracking metals recovery, for example, in heap leaching and environmental recovery processes. This modeling framework employs appropriately formulated, parameterized, and solution procedures to capture: 1) liquid and gas flow through heterogeneous porous media subject to variably saturated flow conditions, 2) the complex and dynamically changing nature of the porous media structure, 3) the transport of reactants and products of reaction, 4) the simultaneous mass and heat transfer, and 5) the role of bacteria as a catalyst for reactions. A second class of challenges to accurately model heap processes is to identify and then capture all the process data to characterize the reactivity of particular ores, the mine planning for the construction of the heap, leach schedules, meteorological data, etc. The objective of this paper is to outline these challenges and to describe a modeling framework that can cope with arbitrarily complex geometries and provide tools for rapid and accurate process assessment.

Jan 1, 2006

By W. Petruk

The silver-rich cobalt-nickel arsenides ores of the Cobalt area in Ontario, Canada were mined for silver from about 1904 to 1985. The ores contained about 8 oz to 100 oz Aglt and about 1 wt% Ni and 2 wt% Co. They were processed by gravitational techniques, screening and flotation to produce separate silver and Fe-Co-Ni arsenide concentrates. The silver concentrate was smelted, and in some cases the arsenide concentrate was sold to custom smelters which recovered silver and other metals. The ores display a wide variety of textures and contain many minor and trace elements. This paper presents an evaluation of mineral characteristics that have a bearing on extractive metallurgy and smelting of this type of ore.

Jan 1, 1993

By F. Tailoka

In order to decrease the voltage required for electrorefining, a recessed electrode cell has been developed in which the anode and cathode have recesses machined into their faces. The anode and cathode plates are separated by a thin refractory cloth and the cell is filled with fused salt. Bismuth containing 10 to 90 % lead with copper and silver as minor impurities has been electrorefmed at a current density of 10,000 to 20,000 Am-2. The cell voltage was between 285 and 635 millivolts and the bismuth was refined to a purity of 99.9 %. Flow patterns were observed in a room temperature model of the recessed channel cell using water and mercury to simulate molten metal and the fused salt electrolyte. The flow in the electrode recesses is characterized by discrete droplets when the liquid flow rate is low and thin streams and rivulets at higher flow rates.

Jan 1, 1995

By Petr Stehlík

"This paper is aimed at showing and demonstrating progress in technologies and improvements in units for the thermal processing of various types of waste. The following areas are covered: units for the thermal treatment of hazardous industrial waste and common MSW, technologies for the thermal treatment of industrial and sewage sludge, utilizing waste in cement production (material and energy recovery), up-to-date off-gas cleaning systems, original and unique units for the thermal processing of polluted gases, low-NOx burners. The paper represents a review based on industrial applications, papers published in reputable international journals and a monograph under preparation.IntroductionThe present contribution is an overview of the activities and achievements of the Institute of process and environmental engineering (UPEI) of the Brno University of Technology (VUT). The Institute belongs to European leading teams in the field of the thermal processing of various types of waste. The research in the institute currently revolves mainly around a strategic project “Waste and Biomass Utilization focused on Environment Protection and Energy Generation” that is supported by the national government. Due to the limited space this paper is conceived as a review of papers published especially in reputable international journals.Main (strategic) target of the research is development of new, efficient processes (eventually modernized processes with novel original elements) for effective and highly efficient treatment of waste and biomass, including their maximum utilization as renewable energy sources while minimizing harmful emissions. To this purpose, highly advanced know-how for the design and construction of the related technology lines is being developed, supported by mathematical modeling (see e.g. [1]), experimental validation and optimization.Municipal and Industrial Solid Waste – Concept of Waste-to-Energy CentersThermal processing of various types of wastes is not only waste disposal and/or treatment at present. It has to be regarded as waste to energy process wherever and whenever possible and feasible. This observation was at the origin of the concept of new regional Waste-to-Energy Centers (WTEC), outlined in the following paragraphs. The proposal of the centers is based on a combination of experience, know-how and sophisticated approach. The main fact influencing the concept of WTEC is the necessity to treat different types of wastes. Typical types of wastes as well as main products of the processes in a WTEC are shown in Figure 1."

Jan 1, 2008

By C. Frias, M. Garcia, G. Diaz

Advances in hydrometallurgy promoted by Tecnicas Reunidas are providing increasingly simple and clean means for controlling the entire lead recycling chain. Used in parallel with pyrometallurgy, these processes allow furnace temperatures to be reduced and fumes and atmospheric pollution to be minimised. Furnace slags are digested, and residues (mainly gypsum) are non-toxic and convertible into marketable products. In addition, the global economy of the process is substantially improved by reducing the operating cost, increasing the lead recovery above 99% and obtaining a 99.99% pure lead product. These new PLACID and PLINT processes may provide the cleanest and healthiest practicable means for recycling lead from batteries.

Jan 1, 2000