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By Tom McCullough

The purpose of this paper is to discuss the implementation and results derived from installing oxy-fuel burners in a l80 ton copper reverbatory melting furnace. Specific results will be discussed in the areas of melt chemistry, furnace modifications, productivity, process enhancements, and the combustion system capabilities.

Jan 1, 1996

By Toshio Kurikami, Koichi Yamazaki

"Toho Zinc Co., Ltd Chigirishima Refinery has the production capacity of electrolytic lead for 95000t/y by sintering- blast furnace electrolytic process. Lead raw materials are lead concentrates, spent batteries and dusts that contain lead from other companies, and these are handled by existing smelting process. There are many circulation materials in the process, because the system has been constructed with improving the recovery rate and protecting the environment. This report describes material balance in each process, distribution of the lead and various components, and it examines present state of the processing. In addition, we report the result that we have tried to improve the work environment.IntroductionThe Chigirishima Refinery of the Toho Zinc Co., Ltd. is located in Chigirishima, an island 4km off the coast of Takehara-city, Hiroshima, Japan. The Chigirishima Refinery began lead smelting operations in 1951.The Chigirishima Refinery adopted the sintering-blast furnace-electrolytic process and has an electrolytic lead production capacity of 95,000 tons/year. The existing smelting process handles raw materials from lead concentrates, spent batteries, and lead-bearing dust from other companies. This system was constructed with the intentions of improving material recovery ratios and protecting the environment; therefore, there are many materials recirculating throughout the smelting process. This report describes the material balance in each process and the distribution ciflead and various components, and it examines the present state of processing. In addition, we report the results of our attempts to improve the work environment."

Jan 1, 2000

By Tobias Dubberstein, Hans-Peter Heller

The viscosity of Fe-Cr-Mn-Ni TRIP/TWIP (Transformation Induced Plasticity, Twinning Induced Plasticity) steel with varied nickel content is investigated using a vibrating finger viscometer. The viscosity of the melt is calculated from the change in power input in the field coil by an immersed finger into the liquid steel to maintain a constant peak-to-peak amplitude of the sine wave of oscillator compared to the idle state. Nickel content in steel is varied from 3 wt% to 9 wt%. The dynamic viscosity (η) at 1600 °C for 3 wt% Ni is 3.73±0.14 mPas, for 6 wt% Ni 3.50±0.03 mPas, and for 9 wt% Ni 3.93±0.09 mPas. There is a kink from low to high nickel content in viscosity values of Fe-Cr-Mn-Ni alloys. This phenomenon can be explained by a change in coordination number in the melt, as reported for Fe-Ni binary system in literature. The availability of viscosity data delivers relevant input to model free fall atomization processes of FeCrMnNi alloys.

Jan 1, 2015

By Patricio Barrios

In February 1996, ATLANTIC, COPPER completed the construction of a Project for Expansion and Environmental Improvements in its Smelter and Electrolytic Refinery located in Huelva. Following the expansion, the new operating concept is based on the simultaneous blowing of two converters, while increasing throughput in the Flash Furnace up to the level required to deliver matte to both converters. While the production level planned with the Project.(270,000 MTPY of copper from concentrates) was reached the following June, work since then has been carried out to optimize the new equipment .and to develop a new operating shedule. This paper describes operational experiences from the start up of the Expansion Project, difficulties encountered and operating improvements introduced, which have allow an increase of production levels up to 300,000 MTPY of copper.

Jan 1, 1998

By Saskia Duyvesteyn

Ion flotation is a technique applicable to the removal of metal ions from dilute solutions, using ionic surfactants.- While there are a number of physical and chemical parameters that influence the ion flotation process, this paper focuses on two of the important chemical ones, namely frother concentration and ionic strength. The effect of several frothers, including ethanol, iso-propanol and MIBC at concentrations ranging from 0% to 0.4%, was studied for the model Cd-dodecylsulfate and Cu-dodecylsulfate systems. The ionic strength, as well as the effect of monovalent and multivalent counter ions, was also studied in the range of 1@3 - 1 M, at constant pH. The results are discussed in terms of applicability to a range of effluents from minerals and materials processing operations.

Jan 1, 1994

By Nobuaki Sato, Tetsuo Fukasawa, Akira Kirishima

To apply the fluoride volatility process for the treatment of fuel debris formed in the damaged nuclear reactors, study on the fluorination behavior of main constituents, such as fuel and cladding is essential. The mixture of uranium and zirconium oxides is formed under severe conditions such as high temperature and oxidizing atmospheres. In this paper, fluorination and volatilization behavior of uranium and zirconium oxides have been studied by TG-DTA method in the presence of fluorine. From the TG-DTA result of UO2 in F2 atmosphere, the weight gradually increased up to 7% at 350 oC followed by rapid weight decrease with exothermic peak showing the vaporization of uranium as UF6. ZrO2 showed similar fluorination behavior to that of UO2. However, fluorination of UO2-ZrO2 seemed to be suppressed with increasing ZrO2 amount. This may be caused by the formation of solid solution.

Jan 1, 2016

By R. Burkhard

Recovery of metals from complex mixed wastes is a challenging task of modem material and waste management strategies. Thermal methods are an important tool in this respect. Plasma turned out to be particularly useful for treatment of complex or toxic wastes and residuals. In order to study plasma processes at reasonable costs, a pilot plasma plant has been used and wastes like ~pent Raney-Nickel catalysts, copper and ah.:lminum drosses, and. other metal containing wastes were investigated. The paper summarizes the most significant findings

Jan 1, 1995

By P. Balachandran

The paper outlines the existing facilities and working practices at the Khetri electro-refinery of Hindustan Copper Limited. Plans have been drawn up to mechanize some key operations to improve the quality of cathodes and the working environment as well as economize the refinery operations. The economic analysis for determining various optimum operational parameters under conditions existing in India have also been outlined. The impact of capacity utilization and mechanization under different sets of conditions on operational costs have been highlighted.

Jan 1, 1987

By V. V. Khristenko, V. I. Dubodelov, V. A. Seredenko, B. A. Kyryyevsky, H. V. Seredenko

"During the last decades investigators of many countries shows an increased interest to alloys which are characterized by miscibility gap in a liquid state. It is connected with essential possibilities of control of structurization in such alloys because of the melt at certain temperature parameters is · emulsion with disperse phase inclusions. These ensure essential influence ·on structurizations.The certain inclusions can play a role of lubrication ensuring ""wearless"" process. The sizes of inclusions of this phase can be rather large proportional to sizes of strengthening phase (up to 1000 nm). Other inclusions ensure process of strengthening of a main material. In this case requests to a dispersibility character of distribution and structure of such inclusions are much higher.The multicomponent alloys of system of copper - (Fe - Cr - C)- alloy concern to the number of advanced compositions. The copper alloys with structure of a type of a ""frozen emulsion"" in which strengthening phase· is a chromium pig-iron are characterized by high thermal stability in the extreme operating conditions. The mechanism of inclusions forming is emulsifying of a melt in miscibility gap at temperatures close to temperature of binodal under superimposition of external effects.The main complexity of producing of ware from such alloys is .a providing in their structure of necessary dispersible inclusions uniformly distributed all over the volume. Thanks to a selective action of electromagnetic fields on liquid phases with various electroconductivity relative velocity of phases is created and is regulated the ratio of their ""apparent"" specific gravity is changed. Excitation of pulsing force effects with the certain frequency on interphase surface allow actively to influence on process of a dispersion of a liquid metal medium."

Jan 1, 2000

By David Seymour

Newmont Gold Company (NGC) located in Northeastern Nevada has been processing carbonaceous and sulfide refractory gold ores through a chlorination circuit prior to cyanidation. A "Flash Chlorination" pilot plant was installed in 1987 in an effort to obtain higher chlorine utilization efficiency and increase gold extraction. The Flash Chlorination process oxidizes organic carbon and sulfide sulfur. It also deactivates preg-robbing carbon, making the ore amenable to cyanidation. Significant recovery improvements were observed using this new process. This scheme has also been instrumental in the processing of higher than normal grade ores at economic chlorine levels. The Flash Chlorination pilot plant has been successfully treating carbonaceous ore on a production scale since April 1988. This paper summarizes laboratory and pilot plant optimization test work, using conventional and statistical methods.

Jan 1, 1989

By Seong-Jong Kim

The formation behavior and corrosion characteristics of anodic oxide films on pure Mg and Mg-AI alloys were investigated focusing on the effects of anodizing potential, Al content, temperature and NaOH concentration. Pure Mg and Mg-AI alloys were anodized for 10 min at 3, 10, 40, and 80 V in NaOH solutions. Mg(OH)2 was generated by an active dissolution reaction at the surface of the specimen and the product was affected by temperature while MgO generation increased with NaOH concentration. Moreover, the current density after anodizing for 10 min at a constant potential decreased with increasing AI content in Mg-AI alloys,

Jan 1, 2003

By Peter Brown

The present work involves the study of Chemical Vapor Deposition (CVD) of silicon carbide from the methyltrichlorosilane (MTS) - hydrogen system. A computer program, SOLGASMIX has been employed to calculate the equilibrium compositions of the gaseous and condensed phases in the MTS - H2 system. The results indicate the range of parameters such as temperature, pressure and species concentrations, required to deposit the single phase Sic under thermodynamic equilibrium conditions. A mathematical model for describing the transport phenomena and the rate of deposition of Sic onto a thin rod in a vertically-oriented hot-walled CVD reactor has been developed. Exper iments were conducted using the same operating conditions as those used in the model in order to validate the mathematical predictions. The predicted rates of deposition were found to be in good agreement with those obtained experimentally. The model can be used to study the effects of various operating parameters on the rate of Sic deposition on a fiber.

Jan 1, 1992

By Raymond F. Dalton

Despite the ready availability of numerous zinc sources, the process of solvent extraction- electrowinning (SX-EW) has as yet found little favour in the zinc industry. It is suggested that this is largely due to the previous lack of availability of suitable selective reagents having the particular features required to enable them to fit in to a solvent extraction-electrowinning based process for zinc, particularly with regard to strength and selectivity for zinc over iron. This paper describes work on the development of new selective extractants for the recovery of zinc from both sulfate and chloride aqueous solutions and suggests how they might be integrated into new zinc processes.

Jan 1, 1994

By John J. Dunkley

Recent years have seen the increased use of hydrometallurgy in the smelting and refining of metals. However this is often used as a final refining step, following an initial pyrometallurgical smelting process. Huge amounts of material are produced as melts which have to be cast, comminuted, and taken up into solution or leached. A common method is to granulate the melt and then grind it. In the case of metallic melts this can be difficult or unfeasible due to the ductility of the granulated particles. Water atomisation is capable of replacing the granulation and grinding stages with a single process step that can process in excess of 30t/hour of melt into particles as fine as 50 microns. Applications in operation in Co, Cu, Ni, Ag, Au, Pt and Rh refining are discussed together with potential applications in copper smelting.

Jan 1, 2003

By Mansoor Barati

The present paper is based on a term project for final year undergraduate students, requiring them to evaluate a process for producing silicon from rice husk. The traditional method for production of silicon involves carbothermal reduction of quartz in electric arc furnaces at temperatures exceeding 2000 °C. The technology consumes a considerable amount of electrical energy as well as fossil fuels, resulting in significant CO2 emissions. A flowsheet for production of silicon metal from rice husk is laid out in this paper. The technology will consist of combustors, which will generate steam using the rice husk biomass, power generator, and electric furnace for reduction of the rice husk. Materials and energy balance calculations presented here indicate that such process can be operated independent of external electricity.

Jan 1, 2014

By Yang Jian-guang, Deng Zi-xiang, Zhang Xu-liang, Li Jun-yuan

"Hyperaccumulator biomass harvested after heavy-metal phytoremediation must be considered as hazardous waste that should be contained or treated appropriately before disposal or reuse. As a potential method to detoxify the biomass and to convert this material to a suitable bio-energy resource, the hydrothermal upgrading process was applied to remove heavy metals and upgrading crude bio-oil from Pteris vittata stems and leaves harvest. Parameters such as material granularity, temperature, Liquid/Solid (L/S, ml/g), pressure, duration and catalysts were examined for their effect on the removal efficiency of heavy metals and upgrading efficiency of crude bio-oil. Maximum heavy metal removal efficiency of>99% and crude bio-oil upgrading efficiency of 83% were attained with an 200 mesh (75 µm) granularity, LIS 40:1and23 MPa at 380°C in the presence ofO.l mol L-1 K2C03 for 30 min. GC-MS analysis results show that the resulting bio-oil mainly consists of benzene 11 %, ketone 42%, alcohols 14%, alkene 15% and ester 11 %, etc., and the relative molecular weight distribution lies in 94-282, carbon number distribution lies in 6-18, calorific value is 32MJkg-1.IntroductionPhytoremediation of soil or water with hyperaccumulator has been extensively explored in recent years [1-4]. Living plants can clean up soils or waterways. This approach exploits the ability of various plant species to thrive in high metal environments where large amounts of toxic elements are accumulated, such as heavy metals, and is particularly appropriate when slow remediation of relatively low metal concentrations is acceptable. Advantages compared with existing remediation methods include the minimal site destruction and destabilization, low environmental impact, and favourable aesthetics; advantages compared with biosorption include continuous in situ regeneration of the biomass, and the ability of living plant cells to supplement passive sorption of metals with metabolic mechanisms of metal uptake and detoxification [5-8]."

Jan 1, 2014

By Bogidar Mihaylov

A laboratory study was conducted on continuous precipitation of copper, cadmium, mercury and arsenic using thiourea, thioacetamide, sodium sulfide and ammonium sulfide as precipitating agents. Depending on the experimental conditions the metals precipitate with the sulfide donors at different orders and rates. These differences were employed as a basis of several techniques for continuous separation of copper and arsenic, cadmium and arsenic, mercury and copper, and copper, mercury and arsenic. The separation of the metals from industrial waste solutions was also studied. The precipitates obtained were inspected using x-ray diffraction, scanning electron microscope, atomic absorption spectrometer and plasma particle counter.

Jan 1, 1992

By Gregor Kücher

Lack of basic knowledge on the semi-direct recycling methods for hard metals hinders the application on an industrial scale. However, advantages like reduced expenses and lower environmental impact draw interest at future potentials. Consequently, this report aims to offer insight into the influence of varying bulky hard metal substrates during their lixiviation in acidic media with an oxidant. The statistical software Modde 11 assisted in the development of a design of experiments (DOE) for evaluation of the impact of average grain size, binder and tantalum carbide (TaC) content on the leaching characteristics. The other experimental parameters were constant. Among them were temperature, solution concentration and quantity, duration and substrate surface exposed to liquid volume. Eventually, prediction plots and factors of the computed model equation describe the effects of varying substrate qualities on leached binder metal and selectivity.

By Jean Goldschmidt

Recycling of fine oxidized particles of non-ferrous metals usually cannot be carried out by pyrometallurgical methods. 'Hydrometallurgy provides an alternative technology to reintroduce? the resulting products as secondary raw materials into the industrial cycle, thereby saving resources and energy while keeping the environment a little cleaner. The paper summarizes the methods employed by Hydrometal to achieve these objectives and? stigmatizes the latest counterproductive international regulations which create ever more obstacles to environmentally sound recycling.

Jan 1, 1995

By M. Kobayashi, Y. Nishisu

"Fine multicomponent particles of yttrium and europium were synthesized through the precipitation from homogeneous solution, and the various characteristics related with the fluorescence were investigated. The morphology and the fluorescent characteristics of the synthesized particles were affected by ionic species in the stock solution. In the presence of sulfate ion, some parts of the precipitated particles were aggregated, and _the fluorescent characteristics were not good. On the other hand, in the presence of chloride ion or nitrate ion, the particles precipitated were almost monodispersed, and, the intensity of the fluorescent emission were strong after calcination. Further, these particles were also very attractive as the red phosphor in the mercury-free fluorescent systems.Introduction Eu doped Y oxide particles have been widely investigated for the application to the fluorescent lamps and displays: Recently, the fluorescent lamps are pointed as harmful electric equipments because of using mercury for excitation. Therefore, the use of the mercury in the fluorescent- system will be limited or prohibited worldwide in near future. Then, the development of the mercury-free fluorescent lamp is strongly required without delay. Inert gas such as neon and/or xenon seem to be applicable as new excitation element that replaces the mercury. However, in case xenon the excitation wavelength,' 146 and 172nm, is different from that of the mercury, 254nm, and then, the commercial phosphors which are used in the present fluorescent lamp system are not available. Therefore, the invention of the novel phosphors is essential for the development of the mercury-free fluorescent lamp. Further, the controls of the size and shape of the particles precipitated are also important, because the homogeneity of the size and the shape is very important for the fabrication of the layer of the phosphor particles. That is to say, the development of the phosphor particles with controlled components, size and shape is essential. The precise control of size and shape improves the packing density, and so, the screen performance of the lamp [1]. In addition, these phosphor particles should be also useful for the application of the flat-plane displays, for example, PDP, etc. [2,3]. In the present work, first, the particles including yttrium and europium for the precursor for red phosphor were prepared through precipitation from homogeneous solution. This process was precisely controlled for the control of the components, size and shape of the particles precipitated. Next, the particles precipitated were calcined, and then, their fluorescent properties were characterized. As a result, some of them showed the possibly available characteristics as the red phosphor for mercury-free fluorescent lamp system. These experimental results are presented in this paper."

Jan 1, 2000