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By Pengfu Tan

A thermodynamic model and computer program, CuModel, has been developed to model the distribution behaviors of Cu, Fe, S, O, Ni, Co, Sn, Pb, Zn, As, Sb, Bi, Au and Ag, copper loss in the slag, and heat balance in copper smelting process, matte converting process and copper con-tinuous smelting process. It can be predicted for any set of controllable process parameters such as feed composition, smelting temperature, degree of oxygen enrichment and volume of oxy-gen-enriched air. This model accounts for physical entrainment between matte and slag phases. It can be used in Isasmelt process, copper flash smelting process, Mitsubishi process, P-S con-verting process and Noranda process. The predictions by the present computer model are com-pared with the known commercial data from Guixi Smelter in China, PASAR Corporation in Philippines, Horne Smelter in Canada, MIM Limited in Australia and Naoshima Smelter in Ja-pan. The agreements between the computer predictions and the commercial data are excellent. In this paper, the applications of CuModel in the copper metallurgical industries have been pre-sented. CuModel has been used by Daye Smelter and Guixi Smelter in China, and by PASAR in Philippines as well.

Jan 1, 2004

By Shengfan Zhou, XUEWEN WANG, Changjun Jiang, Mingyu Wang

In the process of extracting vanadium from stone coal by sulfuric acid leaching - P204 solvent extraction, Fe(III) can accumulate in the organic phase which reduces the extraction of vanadium. In order to eliminate the effects of the accumulation of iron, oxalic acid was used as the stripping agent to strip the Fe(III). The effects of oxalic acid concentration, phase ratio O/A, stripping time and shake velocity on the stripping of Fe(III) were studied. The results showed that the Fe(III) stripping rate can reach beyond 96% at the room temperature with 70g/L oxalic acid using an O/A of 2 at 160 rpm shake velocity for 20min. After 2-stage stripping, the concentration of Fe(III) in organic phase was 0.008g/L.

Jan 1, 2016

By V. B. Telles, J. A. S. Tenorio, J. O. Alves, D. C. R. Espinosa

"The world production of crude steel in 2009 reached 1.2 billion tons. For each ton of steel produced, 150 kg of steelmaking slag and 20 kg of steelmaking dust are generated. These are wastes with considerable production and limited applications, therefore this work studied the recovery of these wastes into useful sub-products. The slag was used as raw material in the production of rock wool (a thermo-acoustic insulator) and the dust was inserted in the iron ore sintering process. Results showed that produced materials have exceptional proprieties, therefore the recovery of these wastes can contribute to decrease extraction of non-renewable resources, reduce the costs and impact of disposals, and aggregate value to the slag and dust.1. IntroductionSteel production using Eletric Arc Furnace (EAF) has grown over 119 million tones in the last years. In 2008 30.7% of all steel produced, was obtained through EAF. In United States of America (USA) the percentage of this process in the production of steel was about 58% in 2008, while in 2000 this percentage was only 47% [1]."

Jan 1, 2011

By Saad Elias Kaskah

"The Box-Behnken Design (BBD) is used to model the sacrificial Cathodic Protection System (SCPS) to find the factors effectiveness behaviour. For protection potential assessment the BBD receives (resistivity of environment, sacrificial anode alloy, distance between anode and cathode and surface area for the structure to be protected) as input and gives the protection potential as output. By applying BBD with their analysis tools we get many results. The important results which are the factors individual effectiveness on the sacrificial cathodic protection (SCP) process are the resistivity which has the greatest effect on the potential protection (rank=l) followed by sacrificial anode alloy type (rank=2), surface area for structure protected required (rank=3) and distance between anode and cathode (rank=4). The interaction of sacrificial anode alloy and cathode area {X2X4 ) has significant effect on CP process with the limits which are used in this work while the other factors interaction (X1X2, X1X3, X1X4,X2X3, X3X4 ) has insignificant effect on the limits which used in this work.IntroductionFor carbon steel in seawater the normal corrosion potential E '°""_is in the range -550 to -600 mV vs. Ag/AgCI [1]. The most effective method to overcome the corrosion is cathodic protection {CP) which represents a control method in the steel wall corrosion. Cathodic protection has been used in several areas including marine and underground structures, storage tanks, and pipelines [2]. Sacrificial anodes system generates protective current which depends upon the inherent potential difference between the anodes and the structure to be protected. If the structure is made of iron or steel, any metal that is more active in the electromotive force series can theoretically be used as anode material [3]. There are many factors influencing on cathodic protection like resistivity (NaCl content), chemical composition of sacrificial anode alloy, distance between anode and cathode, surface area of cathode, temperature, humidity, velocity of solution, dust, impurities, bacteria and etc .. The present work studied four factors: NaCl content, resistivity), chemical composition of sacrificial anode alloy, distance between anode and cathode, surface area of cathode) with different three levels of values for each one. Then this work will find the optimum value from the factors levels that tacked to investigated there influencing on sacrificial cathodic protection system."

Jan 1, 2013

By Walter Curlook

An atmospheric acid leaching process for leaching nickel and cobalt from highly-serpentinized saprolitic fractions of nickel laterite deposits has been developed and patented [I]. The process involves leaching the highly-serpentinized saprolitic portion of the nickel laterite ore profile in strong sulphuric acid solutions at atmospheric pressure and temperatures between 80°C and 100°C, essentially autogenously, to extract over 85% of its contained nickel content and a large proportion of its cobalt content after leaching times of about one hour. The amount of sulphuric acid used in the leaching process is between 80% and 100% by weight of the finely ground highly-serpentinized saprolite ore on a dry weight basis. The metal values are recovered as intermediate products. Key words: Atmospheric Leaching; Nickel Oxide Ores; Laterites

Jan 1, 2004

By M. Hamamoto, S. Tanaka, K. Noda

"Tamano Smelter or Hibi Kyodo Smelting Co. Ltd. is operating with the Tamano Type Flash Smelting Furnace method which is a flash smelting furnace without slag cleaning furnace but which can discharge a slag equivalent to that from the slag cleaning furnace and with the development or coke combustion technology which is the basis of this world's only one type flash smelting furnace process, the smelter exhibits a low operation cost under high productivity operation. Utilizing this experience and improving it we have developed and put to practice an operation guide system using a general purpose computer in order to further establish s stable operation. In this paper these improvements are described. Background of System DevelopmentWith the recent rapid progress of general purpose computers and improvements in their performance an environment for the use or computer in process simulation at low cost and simple operation has been established. If an accurate operation simulation can be done with the Tamano Type Flash Smelting Furnace the merits would be very great and thus we started development of the system. The official name of this system is Computer guide system for Coke Combustion in the T-FSF and taking the initial letters we call it CCCT. We aim to achieve operation with stable mane grade, temperature and slag loss in the furnace by maintaining the most suitable combustion conditions of concentrate and coke in the flash furnace with the assistance of CCCT to the flash smelting furnace operators.Through several production expansion projects clone in the past by oxygen enrichment the copper concentrate treatment quantity and matte grade have increased step by step as shown in Figure I. Following this increase the difference between the operation calculation results al the initial stage of coke combustion and the actual behavior of furnace (matte grade. temperature in the furnace. etc.) gradually became bigger. Further operation procedures taken by different operators against the same phenomenon were sometimes different depending on each individual, which from time to time caused the operation to become unstable. Prior to the development of the system we checked out thoroughly the weak points of operation calculation procedures which were in practice until that time. The results were analyzed and study was carried out to establish a most suitahle operation calculation procedure and finally we reached this system"

Jan 1, 2000

By J. J. Talja

An investigation of oxidation of various nickel concentrates was carried out using differential scanning calorimetry (DSC). The aim of this study was to determine the ignition temperature and investigate other oxidation behavior of various sulfide-based nickel concentrates. Variables in the experiments were mineralogy, particle size and partial pressure of oxygen with temperature increasing linearly at 25 K/min from 323 to 1023 K (50-750 °C). The igni¬tion temperature was determined to represent the starting point of rapid oxidation. The reac¬tion enthalpies of the concentrates were determined and the amount of heat generated up to various time were used to calculate the extent of reaction. Mineralogical changes at various stages of oxidation were also investigated. For this purpose a second set of DSC-experiments were carried out in which each experiment was interrupted at a desired temperature between 673-873 K. From these tests the weight loss of samples were determined and changes in the individual constituent of sulfide minerals were analyzed. For pentlandite-based Ni-concentrates the ignition temperature was 705-710 K (approximately 435 °C). Pyrite was the first sulfide to oxidize. Reactivity of the violarite-based concentrate was greater than those of the pentlandite-based concentrates. The stoi-chiometry of pentlandite changed before ignition because of preferential oxidation of iron. Rapid oxidation of the pentlandite mineral occurred at about 823 K (550 °C). By 900 K about 90 % of the iron in pentlandite was converted to hematite, and NiS containing some iron was formed.

Jan 1, 1994

By Roberto Parra

The classic criteria of the preparation of the charge for the smelting of copper concentrates in at flash furnace considers the mass and energy balance from the chemical and mineralogy composition of the concentrates. The operation parameters fixed with this method don't assure the stability of the operation and the critical problems of the slag quality and dust formation occurs very often. This paper presents the results of a laboratory test that allows the prediction of the behavior of concentrates blends in the view of the minimization of the dust formation and the magnetite control in the slag. The combustion of different copper concentrates and blends were done in a drop tube furnace The results show that the magnetite and dust formation don't have a linear behavior with the weight proportion of the blend and some optimal blends of 2 or 3 types of concentrates can be identified. From the reasonable hypothesis that the qualitative behavior of blends in the drop tube represents the real behavior in the burner, the preparation of the charge with this approach could help to solve those operational problems.

Jan 1, 2003

By Carvalho A. Felipe de

The search for environmentally friendly and cost-effective methods for gold extraction has been undertaken in order to provide alternatives to the use of cyanide leaching in the gold industry. Among such alternative reagents is the combination of chloride and hypochlorite ions due to their oxidation of metallic gold and its complexation. Therefore, the current work aims at investigating gold leaching from an oxidized material by means of a solution comprising calcium hypochlorite and sodium chlorite. The sample used in the current research contained 66.1% Fe2O3, 20.4%SiO2, and 35.7 g/t of Au. In addition, XRD and SEM-EDS analysis revealed iron oxide, quartz and muscovite as the main crystalline phases in the sample. For comparison purposes, cyanidation of the oxidized material resulted in 90% gold extraction in 24 h. The reference conditions for the leaching tests with the chlorite-hypochlorite system were: particle size −37 μm, solid/liquid ratio of 10% (w/v), 10 g/L NaCl, 10 g/L Ca (OCl)2, pH 5–6, 3 h of leaching. The effects of the: (i) Ca(OCl)2 concentration, (ii) NaCl concentration, (iii) pHrange and (iv) the effect of pulp density in the extraction of gold were assessed. In addition, the stability of the hypochlorite solutions (OCl−) was investigated. The ideal concentrations of Ca(OCl)2 and NaCl were determined as 25 g/L and 15 g/L, respectively, whereas the optimal pH range was 4–6. Under these conditions, the final gold extraction reached approximately 84%. By varying the solids content of the pulp (10%, 20% and 30%), it was observed that the lower solids value resulted in greater gold extraction (84%). The degradation of the hypochlorite solution and the possible catalytic effect of the presence of the solid were evidenced. To sumup, in the experiment, high gold extractions were achieved in shorter periods of time (3 h), as compared to the cyanidation of the same sample. On the other hand, itwas necessary to use significant amounts of the reagent due to hypochlorite instability at the pH conditions recommended for high gold extractions.

By Dolf Gielen

This paper discusses the results of a Western European energy and materials systems engineering study that analyses the impact of greenhouse gas (GHG) emission reduction on the future of the steel and aluminum industry. he technology selection will be significantly affected by future CO2 policies. The avail- ability of C02 removal and storage technology and the social acceptance of this strategy for GHG emission reduction is of key importance for the strategy selection. The use of coal based smelting reduction technologies is optimal in case of weak C02 policies or in case of strong C02 policies and low CO2 removal and storage costs. The selection of CCF or Corex technology depends on the penalty regime. However, if C02 removal proves to be problematic, CCF development fails and strong C02 policies are introduced, the gas based DRI production processes will become more attractive. In both cases, the energy efficiency of the iron and steel industry will further increase in the next decades. The impact of GHG emission reduction on aluminum prices and aluminum use can be significant. However contrary to common notions the aluminum production will be positively affected by GHG emission reduction, notwithstanding the currently high emissions in aluminum production. A combination of emission mitigation in production and significant GHG emission reduction effects further down the product chain cause this effect. A significant potential exists for improved materials efficiency. This potential is generally neglected in energy efficiency and CO2 reduction studies. However improved steel qualities are of similar importance for C02 emission reduction as increased energy efficiency. It remains to see if this potential will be used to its full extent in the next decades. Model calculations indicate that the impact of C02 policies on the competition with other materials will be limited. Greenhouse gas emission mitigation will have much more impact on materials production and waste handling than on materials consumption.

Jan 1, 1999

By Yoshinobu Fukumori, Testuya Watanabe, Futoshi Shikata, Hiroyuki Tokumitsu, Hideki Ichikawa, Masahito Miyamoto

Nano-particulate systems have attracted much attention recently in pharmaceutical field as drug carriers and functional components of pharmaceutical dosage forms. This paper describes our approaches in design and preparation of nano-particulate systems, including lipid nano-emulsions, chitosan nanoparticles and thermosensitive acrylic nanoparticles, for certain pharmaceutical applications mentioned below. The lipid nano-emulsions with their particle size smaller than 100 nm were prepared for gadolinium neutron-capture therapy (Gd-NCT) of cancer by a thin-film hydration method with sonication, and intraperitoneally injected into Greene's melanoma (melanotic No. 179)-bearing Syrian hamsters. This provided such a high gadolinium concentraton in tumor as 107 µg/g tumor (wet basis) at 48 h after administration. As an alternative gadolinium nano-carrier for Gd-NCT, biodegradable and highly gadopentetate-loaded chitosan nanoparticles (Gd-nanoCPs, 426 mTI in particle diameter and 9.3% in Gd content) were prepared by a novel emulsion-droplet coalescence technique. A significant tumor-killing effect could be obtained when Gd-nanoCP suspension was injected intratumorally twice 24 and 8 hours before neutron irradiation into B 16Fl O melanoma-bearing mice and subsequently thermalneutron was irradiated toward tumor site with a flux of 2 x 109 n/cm2/sec for 60 min. As one another application of nanoparticles, a novel acrylic composite latex with a hydrophobic core and a thermosenstively swellable shell was designed for fabricating microcapsules showing thermosensitive mode of drug release. The microcapsules with the composite latex-dispersing membranes exhibited an exceptionally rapid on-off response of drug-release in a thermosensitive manner.

Jan 1, 2000

By M. R. Baren

Unpublished results obtained by Baren on thermodynamic properties of sulfur in liquid Fe. Co. Ni. Fe-Co. Fe-Ni. and Co-Ni are reevaluated. correlated. and interpreted on the basis of recent developments in thermodynamics of alloys:. Existing reliable data are reviewed and compared with the? present results. Sulfur obeys Henry's law up to 0.04 mol fraction. and in this range the standard Gibbs energy of solution of sulfur is expressed as a linear function of temperature for each pure metal. The activity coefficient of sulfur in each binary metal solvent 1s correlated with the composition of alloy.

Jan 1, 1983

By David T. Hobbs

Large quantities of highly alkaline, radioactive, liquid wastes are stored in underground tanks throughout the Department of Energy complex. These wastes will be pretreated to separate radionuclides and the remaining decontaminated liquid wastes incorporated into solid waste forms for permanent disposal. Significant savings in disposal costs could result by recovering .the sodium as sodium hydroxide for reuse or disposal as nonradioactive waste. Recent testing demonstrated an electrochemical separation process for the recovery of sodium hydroxide from alkaline waste solutions; The separation process uses ion-selective membranes to separate sodium from the bulk of the waste constituents under an applied electrical field. The sodium is recovered as a 10-15 wt % solution of sodium hydroxide. Results of bench-sc3Ie and pilot-scale tests with simulated and radioactive waste solutions are presented.

Jan 1, 1999

By A. Dadgar

The adsorption kinetics of AuBr4 on Dowex ® -21K ion-exchange resin were studied and found to be independent of the initial gold, bromine, and base metals concentrations. A commercially-available undivided hypochlorite generating cell was used to generate bromine from simulated mixed halide (Br-/CI-) solutions. Electrolyses were performed with solutions containing very low Br' ion concentrations. The current efficiencies were 80-90%, and Br- ion utilization was maximized. A detailed economic assessment was made considering the capital and the operating costs for a 1000 mtpd gold ore processing plant. The toxicity and discharge levels of bromide, bromine, and cyanide were compared from a detailed analysis of the published literature data. Comparing bromine vapor with hydrogen cyanide gas for a given length of exposure, the lethal concentration of bromine is about 3 times less than hydrogen cyanide. The toxicity of sodium bromide is similar to that of sodium chloride. Acute poisoning to bromides and chlorides is rare because of their low toxicities. The allowed discharge levels of Br-, Br2, and CN- in fresh water are 250, 0.1, and 0.005 mg dm-3, respectively.

Jan 1, 1992

By D. W. Lawler

Prior to the manufacture of sulphuric acid in metallurgical plants, the SO2 rich gas from the smelter, roaster, or furnace must be cleaned to removed particulates, volatile contaminants, SO3, and water. Cleaning is accomplished by contacting the. gas with cooled weak acid. The system is designed so that all the contaminants, originally in the gas are captured in the weak acid, which then becomes an effluent from the plant. Historically, the entire weak acid effluent stream has been treated for disposal, with no attempt to recycle or recover any part if it. This is becoming increasingly environmentally unacceptable, and operators must consider better methods of treatment and recovery. In this paper, Kvaerner Chemetics discuss a number of options that allow the contaminants to 'be separated from the acid' value. This will result in an acid byproduct that can be sold or used elsewhere, and will minimize the volume of hazardous byproducts that must be discharged.

Jan 1, 1998

By Zhang Yongzhu

Sulfoxides are one kind of extractants for precious metals. The structure, the coordination reaction, the extraction behaviour and the precious metals complexes of sulfoxides are summarized. The differences between sulfides, sulfoxides and sulphones are also discussed.

Jan 1, 1992

By Wei Gao, Qing-cai Liu, Cun-fang Lu, Huimin Zheng, Jian Yang, Chun-ling Yao

"Mercury in flue gas of coal-fired plants was concerned as another serious pollution when sulfur dioxide pollution was controlled now. The adsorbent made from fly ash by thermal precipitation sulfur to remove mercury in fuel gas from coal combustion plant, SEM, BET, TGA and other measurement methods were used to characterize the effect on surface morphology, sulfur distribution and specific surface. High temperature deposition furnace was applied to increase sulfur content in fly ash based adsorbents produced in lab. The study found that sulfur attached to the adsorbent surface, mesopore and microporous structure, increasing its sulfur content of adsorbent. Sulfur was filled in interspace as small molecule S2, S5, increased their surface area and enhanced their adsorption capacity. The specific surface area increased by thermal precipitation sulfur, and specific surface area which increased with increasing temperature.1. IntroductionThe mercury emission caused by human activity has accounted for 10%-30% of total mercury emission all over the world[11, and the emission from coal-fired power plant have a huge proportion of these emission caused by human activity. Active carbon microstructure and surface morphology play an important role in its adsorption capability, which offers the potential for controlling environmental pollutant, such as sewage, fuel gas, atmosphere and et al [2,31, because it is a material with high specific surface area that long been considered as an excellent adsorbent. At present, include activated carbon, fly ash, calcium-based sorbents and other novel adsorbents. The adsorption capacity and production cost were very important in the process of mercury removal by adsorbents, so the mercury removal has focus on developing adsorbents of highly-efficient. In particular, the waste of metallurgical from coal combustion and the others have a significant advantage about the cost, and they have the highly-efficient in mercury removal after modified to enhance their adsorption capacity, such as fly ash of coal-fired. Apart from specific surface area, element content, pore structure, and surface morphology of activated carbon have great effect on its adsorption ability. Compared to adsorbents without modification, active carbon impregnated with other elements, such as chlorine, sulfur, bromine and et al. had more excellent characteristics to remove specific pollutants."

Jan 1, 2011

By Minting Li, Hailong Yang, ChangWei, Cunxiong Li, Gang Fan, Xingbin Li, ZhiganDeng

The filtration problems on acid leaching sludge of high silicon zinc ore have been paid extensive attention in zinc hydrometallurgy. It was found that soluble silica can be effectively converted into silica precipitate with good settling, filtration and washing properties, and the filtration rate can be in excess of 800 L/m2 · h under certain leaching conditions. According to investigating on the filtration rate, viscosity and concentration of silica of leaching sludge or liquor, the filtering temperature can tremendously improve the filtration property of pulp. At the same time, the experimental data indicated that the viscosity of leaching liquor was the key factor influencing filtration property of leaching sludge.

Jan 1, 2016

By Andreas Nolte

This paper includes a comprehensive report about the metallurgical utilisation of reusable products from electronic scrap recycling, car shredding industry, used glasses an various waste products, such as slimes and flue dusts, generated in a secondary copper smelter. Depending on the copper content, the type of copper compounds and the characteristics of accompanying substances, the materials are treated by smelting in furnaces, operating under reducing or oxidizing conditions. HKs pyro- and hydrometallurgical processes, blast furnaces, converters anode furnaces, tin lead alloy plant and tankhouse will be outlined. The reusable products are categorized according to the origin of the materials and then presented in the form of quantity and quality balances. Processing methods, process able quantities and quality requirements of inputs are described. The utilization degree of the most important metals (copper, tin, lead and zinc) is described with graphics. The report is rounded by information on operating licence according to the environmental regulations of the Federal Republic of Germany and data concerning supply and contracts

Jan 1, 1997

By T. R. A. Davey

Previous publications on the application of EIETSIM include the modelling of an electrolytic zinc plant and a copper flash smelter. In the present case METSIM has been used to model the desilverising of lead by the reagent zinc, whereby a silver-zinc intermetallic compound is formed, and floats out of the lead. This compound has a variable composition, depending upon the ratio of dissolved zinc/silver in the lead bath. Its solubility in lead decreases with falling temperature. A number of variations and modifications of the Davey Desilverising Procedure are modelled, and applied to a wide range of silver contents in lead bullions at several plants. METSIM uses both feed- back and feed-forward controls to simulate plant conditions, and a logic control to distinguish between different phases in the Zn-Ag system. Use is made of extensive (previously unpublished) fundamental data on the ternary Pb-Ag-Zn system, and of plant data, to establish certain operating parameters.

Jan 1, 1993