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By J. W. Matousek

Cobalt behavior in pyrometallurgical processes is traditionally analyzed using slaglmatte distribution coefficients as functions of matte grades or matte iron contents. L(s/m) = (%Co) I [%Co] = f [%CuNi] or f [%Fe] The method is inconvenient to use in predictive mass balance work because of the interdependence of assays and mass quantities. An alternative procedure is proposed based on cobaltliron ratios for slags and mattes: Js = (%Co) / (%Fe), Jm = [%Co] / [%Fe], and J, = b + m [Jm]

Jan 1, 1993

By Feng Liu

A thermal upgrading process by which nickel value can be concentrated in a ferronickel alloy is a possible alternative to treat Sudbury pyrrhotite (Po) tailings with nickel content of 0.5–1.5 wt%. The basis of this process is precipitation of Ni from Po at high temperature once Fe/S ratio in the iron-deficient Po is shifted towards stoichiometric or near stoichiometric FeS (troilite) either by the addition of iron and/or the removal of sulfur. For the iron addition route, the reaction between elemental iron and nickeliferous pyrrhotite to produce ferronickel alloy and Ni-depleted iron sulfide phase plays a critical rule. In this paper, the formation mechanism of ferronickel alloy was investigated using the diffusion couple technique to better understand the nickel diffusion behavior in the iron and sulfide phases.

By Jagdish C. Agarwal

Although copper ranks very low in the order of abundance of elements in the crust of the earth, it has been one of the first metals utilized by mar, at his emergence from the Stone Age, about 10,000 years ago. Use of copper for weapons, tools, utensils and ornaments dates back to the twilight of history, 6,000-5,000 B.C. Native copper outcrops and the malleability of the metal explain its very early use by the cave-dwellers. The working, melting and extraction of copper from its minerals are among the oldest metallurgical achievements of the human race. The oldest complete smelting installations for the extraction of copper from its minerals, dated about the fourth millenium B.C., were recently discovered in the Timna Valley, Wadi Arabah, Israel. (1) The history of the developments of the extractive metallurgy of copper has been adequately reviewed recently. (2,3) The center of copper production migrated from the Eastern Mediterranean to Northern Europe (Mansfeld, Germany, Swansea, Wales) towards the end of the Middle Ages (1500 A.D.). The production of the metal was boosted tremendously in North America since the end of the nineteenth century (Fig. 1).

Jan 1, 1976

By Lincoln McCrabb

Correct measurement and interpretation of viscosity data is critical for design of any thickening and pumping process that involves a non Newtonian slurry. The nickel laterite pressure acid leach (PAL) process relies on producing a slurry of maximum achievable solids concentration. Small variations of 1-2% solids concentration can alter economics significantly. For the Ravensthorpe Nickel Project, a rheology protocol has been developed which optimizes the solids concentration across a range of ore types. The vane yield stress technique has been utilized to accurately quantify the flow of thickened slurry in the lower shear range. A yield stress of 100Pa has been used as a benchmark to determine the optimum solids concentration achievable utilizing deep cone thickening. Statistical analysis of the data shows critical rheology distinctions between ore type, particle size, lithology and geochemistry. Linear and power law models have been applied to rheology flow curves to reconcile the material transport properties with the anticipated thickener underflow solids concentration. Keywords: Vane Yield Stress, Thickening, Rheograms

Jan 1, 2004

By J. Wong

We report a successful use of x-ray absorption spectroscopy to probe the chemical and structural environment of trace elements in coal. When applied to vanadium in coal, it was found that vanadium exists in at least two environments: a trivalent site 6-fold coordinated by oxygens at ca. 2.0~ and a tetravalent site 5-or 6-fold coordinated also by oxygens, one of which forms a short V=O bond at ca. 1.6a. No evidence of nitrogen (porphyrin)1'or sulfide environment was found. It was also found that the vanadium environ-ments in the raw coal did not survive unchanged in a liquefaction process. These findings have implications for coal cleaning processes and for trace element release into liquefaction process streams.

Jan 1, 1982

By D. J. Murdock

Cominco Ltd. has developed a number of innovative technologies for electrowinning. The paper discusses the application of these technologies to the copper industry. Tankhouse and cell design will be discussed in addition to anode cleaning and cathode handling. Specific examples of the application of this technology to the copper industry are cited.

Jan 1, 1987

By Shize Jin

Effect of four polyols, namely ethylene glycol (EGL), glycerol (GCL), propanediol (PDL), butanediol (BDL) and three organic acids, namely oxalic acid (OA), malonic acid (MA) and succinic acid (SA) on the current efficiency (CE) and the cell voltage during zinc electrowinning was studied. Galvanostatic polarization was conducted in a supporting electrolyte (SE) containing 180 g dm-³ H2SO4, 60 g dm-³ Zn2+ and 8 g dm-³ Mn2+ at 38°C with magnetic stirring. The imposed current density was 50 mA cm-². The anodes were made of a Pb-Ag alloy and the cathodes were made of an aluminum alloy. The results showed that all the polyols tested in this study decreased the current efficiency and the cell voltage, but the decrease of the cell voltage was not important. Oxalic and succinic acids decreased the current efficiency to a less extent than the polyols, but did not decrease the cell voltage much. The only compound that increased the current efficiency was malonic acid, and its capacity of decreasing the cell voltage was the highest within the seven tested organic compounds.

Jan 1, 2003

By Rafael Padilla

In the production of copper from chalcopyrite (CuFeS2) concentrates by the smelting and converting technology, the ambient pollution with gaseous S02 and toxic metals such as arsenic compounds is still a serious problem, especial1y in the converting step due to the batch nature of the conventional Peirce Smith process. Non-SO2 emitting alternatives are leaching processes. However, few of them have had a limited industrial application and they are not very effective in discarding safely the toxic impurities. A combination of pyro-hydrometal1urgical methods: the sulfidation of chalcopyrite and subsequent leaching of the sulfidized material is a non-polluting alternative to treat not only clean chalcopyrite concentrates but also complex chalcopyrite-enargite concentrates. In this article, this alternative is discussed concerning the thermodynamics and kinetics of the sulfidation of chalcopyrite with gaseous sulfur. The kinetics of the leaching of the sulfidized concentrate in an H2SO4-NaCI-O2 system is also discussed.

Jan 1, 2003

By Michael Sheedy

Sulfuric acid is widely used as an electrolyte for the electrorefming and electrowinning or metals. Impurities in this electrolyte are controlled by continuously bleeding solution from the tank house. In addition to the contaminant these bleed streams contain high levels of sulfuric acid and the metal being recovered. Subsequent treatment of these bleed streams often requires neutralization which generates large volumes of solid waste. Absorption resin technology employing a novel ion exchange technique known as Recoflo® allows the separation of the mineral acid from dissolved metal salts. The recovered acid is suitable for recycle back to the electrolyte circuit. The metal salt and other contaminants leave the process free .of the sulfuric acid. In this process, known commercially as the APU®, ion exchange resin is used to sorb sulfuric acid while excluding the metal salts. The purified acid is then removed by washing the resin with water. The process has been extensively used for the recovery of waste pickling acids in the steel industry and anodizing solutions in the aluminum industry. In the mining and metallurgical industries the process has been successfully evaluated for the separation of excess sulfuric acid from copper electrolytes, the removal of magnesium and manganese contaminants from zinc electrolytes, and nickel and copper from copper electrolytes. A full scale installation on a copper refinery bleed stream at Palconbridge's Kidd Creek plant in Timmins, Ontario has now been operating successfully for more than 1 year while pilot field trials have been successfully completed on other applications.

Jan 1, 1997

By Wenya Du, Qingbo Yu, Peng Li, Qin Qin

"A new heat recovery system is proposed. This system uses the endothermic heat of gasification reaction instead of sensible heat to recover the energy of molten blast furnace slag. The gasification technological parameter in molten blast furnace was calculated and the exergy of the system was analyzed. The gasification reactions were studied kinetically by the isothermal thermogravimetry using STA409PC thermal analyzer. The results showed that, according to different gasification agent, this system can produce syngas with different C-H ratio. The exergy efficiency of this system is high and its internal exergy loss rate is about 11%. This method can bring huge economic and environmental benefits which are important to the survival and sustainable development of iron-steel enterprises. The molten BF slag acts as not only thermal media but also good catalyst. The kinetic parameters on gasification reaction with different types of coal used differ from each other.IntroductionEnergy consumption in the iron-making process is about 50%~60% of the total energy input. The blast furnace is very important in the iron & steel process. So energy conservation and emission reduction about blast furnace is very important. In recent years, in order to recovery energy, many new technologies such as TRT (Top gas pressure Recovery Turbine) and CCPP (Combined Cycle Power Plant) were used in iron-making. But the energy of molten blast furnace (BF) slag has only been used limitedly so far.Molten BF (Blast Furnace) slag is the byproduct of iron-making at the high temperatures range from 1723 to 1923K, and has a large amount of sensible heat remaining. The yield of molten BF slag is about 300 kg per ton of pig iron. In conventional processes, molten BF slag is quenched rapidly using a large amount of water to produce a glassy-granulated slag. The quenching slag must be dried before it can be used in cement manufacture. During the process, a large amount of water was consumed and the energy of molten slag can not be recovered. At the same time, it causes environmental pollution problems. So the critical problems of the process are not only energy recovery of molten slag and reducing emission of H2S and SO2, but also guaranteeing the subsequent use value of slag. For this propose, many new technologies were investigated to recover the thermal energy of molten slag. The promising methods are dry granulation [1-4] and reforming of methane [5-9]. The method, utilization of reaction heat instead of latent heat and sensible heat, is quite attractive from viewpoints of energy storage without heat loss, and makes a connection to other industry. But both of them are in laboratory. In this paper, coal gasification in molten BF slag was used to recover the energy of molten BF slag. The gasification technological parameter in molten BF was calculated and the exergy of the system was analyzed. The gasification reactions were studied kinetically by the isothermal thermogravimetry using STA409PC thermal analyzer."

Jan 1, 2011

By B. A. Paponetti

The following report discusses the bioleaching of chalcopyrite of italian origin catalyzed by Thiobacillus ferrooxidans. The developments vcr.ius time of the main .biochemical and chemical reactions involved in the production of soiuble and insoluble species were investigated focusing on the times at which they begin and bow long they last. The precipitates were characterized both in quantity and in quality relating the rate of the process to the precipitates fonnatiom. A material. balance has been made to verify the proposed mechanism.

Jan 1, 1991

By Pekka Hanniala

The Outokumpu Flash Smelting process today is the most feasible method for copper matte smelting. The economic feasibility of the process has always been one of the main decision making criteria in smelter projects. Thus, today about 50 % of the world primary copper production utilizes Outokumpu Flash Smelting Technology. However, in the future, environmental criteria will have stronger and stronger impact on decision making. Flash Smelting technology offers the best pollution control features of any process. today. It is foreseen that, in the near future, the global trend will be that all the smelters must decrease their emissions at an accelerating rate, compelling the smelters to make increasingly larger investments on environmental protection. In most of smelters ?today, Peirce-Smith converting and transfer of the molten material in ladles are the number one pollution source. The key today for copper converting and minimizing emissions is the Kennecott-Outokumpu Flash Converting process, which has proven to be the most effective converting method in terms of pollution control and, production efficiency including capital and operational costs. Outokumpu Flash Smelting technology is applicable also for small to medium scale smelters but the most interesting area is the upper capacity limit for smelting in one line, which has not yet been reached. We predict that by the year 2000 to 2005, there will be at least one smelter which produces 500,000 tonnes of Cu per year based on one Flash Smelting and Flash. Converting unit. The current state-of-the-art of the Outokumpu Flash Smelting - Flash Converting process is presented in this paper as well as some new options for copper production to be utilized in the near future but which are available already today.

Jan 1, 1998

By Adolfo Pillihuaman Zambrano

Fe-Cr-C production is a very high electrical energy consuming process. Decrease up to 10% of this electrical energy is expected when self-reducing agglomerates are used. This research aims to understand how the synergetic effects are when stronger reductant, like Fe-Si, is substituted for coke in self reducing pellets. Brazilian chromites containing 41.2%Cr2O3 were mixed with petroleum coke and agglomerated with cement as the binder. Small amounts of 1%, 2% and 4% of Fe-75%Si were substituted for the equivalent petroleum coke, and pure silica plus hydrated lime were added for adjusting the slag composition. The mixture was pelletized, dried and submitted at 1773K up to complete the reactions. The results showed that the reduction reactions were 1.4 and 2 times faster with 1% and 2%Fe-Si addition, respectively, than with no addition. The microscopic analysis showed that it was formed a liquid phase, but the pellet did not collapse what indicates that the coalescence of the metallic phase depends on the dissolution of the pre-reduced particles of the chromites into slag.

Jan 1, 2008

By Satu Strömberg

Four different nickel concentrates were oxidized in a laboratory scale laminar flow furnace in simulated flash smelting conditions. The major nickel- and iron-bearing minerals in the con- centrates were pentlandite, violarite, gersdorffite, and pyrite and pyrrhotite, respectively. Thermal decomposition, ignition and oxidation behavior of nickel and iron sulfides were examined by using optical and scanning electron microscopy. General reactivity of the concentrates was monitored with sulfur removal which was most effective in violarite-based concentrate. Pentlandite-concentrates needed higher experimental temperatures for complete desulfurization and gersdorffite-based concentrate contained 5 - 10 % of the original sulfur even in the most oxidizing conditions studied (1 100°C, 50 vol-% 02). The reactivity of the iron minerals was found to depend on the other minerals present in the concentrate. In this paper, the observed re- action products and mineralogical changes are presented and preliminary conclusions of possible reaction mechanisms of nickel-bearing minerals are discussed.

Jan 1, 1997

By Hiroyuki Sano

A closed recycling process for the low-grade scrap of Al-based composite materials was developed. In this process flux treatment with water-soluble halide is a key technique. In the present work, flux treatment conditions were discussed from the viewpoint of the separation and the recovery of the base material, reinforcement and flux. Optimum separation condition was obtained for the NaCl-KCI-KF flux treatment. The recovered aluminum alloy can be recycled for various usages. The recovered SiC particles cannot be reused as reinforcement because of the coexistence of the contamination, therefore it is necessary to eliminate these contaminates or to find another use. The recovered flux is reusable with supplemental addition of fluoride.

Jan 1, 2003

By J. S. Pitsillos

A new furnace tapping technique involving the simulation of a control valve at the exit to a furnace is being investigated. The purpose of this new tapping technique is to regulate the flowrate of liquid furnace products( slags, metals and mattes). Numerical modelling and experimental work has been carried out on tapping of slags leaving a SIROSMELT reactor and the results found to be in good agreement. Numerical modelling has also enabled prediction of the important industrial conditions for the onset of blockage from the shape of the pressure versus flowrate curves. Slag launder experiments have been carried out and a one-dimensional heat transfer model was used to evaluate the effectiveness of launder covers and different coolants. From the experimental results and mathematical model some launder design guidelines such as inclination angle, covers and coolants have been developed.

Jan 1, 1991

By XUEWEN WANG, Xingming Wang, Xuehui Liu, Mingyu Wang

The Panzhihua titanium concentrate contains high contents impurity of Mg and Al, and it is difficult to prepare high grade titanium slag. To solve this problem, a sodium salt roasting-acid leaching process was proposed for removing the impurities in titanium concentrate. Na2CO3 and titanium concentrate were mixed with the proportion of 1:4, and then the mixture was roasted at 700 for 2h. After roasting, the calcine was leached with HCl solution. The experimental results showed that the removal rate of silicon and aluminum can reach more than 85% and 80%, respectively, at leaching temperature of 70 , leaching time of 4h, HCl addition of 5ml and liquid-solid ratio of 4:1.

Jan 1, 2016

By Hector M. Henao

To provide thermodynamic data for converting nickel matte to liquid nickel at high temperature, an experimental study was conducted on the phase equilibrium between the Ni-S alloy and the FeOX-SiO2, FeOx-CaO, and CaO-A12O3 base slag in a magnesia crucible and the CaO-Al2O3-MgO slag in an alumina crucible. All experiments were carried out at 1773 K under controlled pso2 of 0.1 atm and po2 in a range between 5x10- and 10-5 atm by using CO-CO2-SO2 gas mixtures. The dissolution of nickel in the slag was found to be minimum for the CaO-Al203¬-MgO slag with a molar ratio of NCaO/NA1203=1.7. The solubility of nickel in this slag at p02 of 6x10 atm (just before the precipitation of solid NiO) was 4 mass%. This result suggests that a CaO-A12O3 base slag could be used in converting Ni-S melt to nickel while minimizing nickel losses to the slag.

Jan 1, 2002

The results of laboratory, large-scale laboratory and commercial scale investigations regarding the process of slag melts cleaning by oxidizing-reduction gas mixtures with a wide range of Po2 and the use of matte of various compositions as an extracting phase are presented. The copper, nickel and cobalt behavior during the cleaning process has been studied based on SEM and x-ray Microprobe of the quenched slag melts. The general cleaning mechanisms have been found. On the basis of the obtained data the most efficient cleaning methods have been proposed.

Jan 1, 2003

By Rolf R. von Oppenfeld

Onsite hazardous waste processors often find obtaining a Treatment Storage and Disposal (TSD) permit one of their first major challenges. Some processors may spend the time and money required by the permitting process, only to find out later that a permit was not necessary. This paper will present and analyze four strategies that processors may use to avoid obtaining a TSD permit. Some facilities will be able to remove their waste streams from RCRA's oversight by ensuring the material is not "hazardous" waste. Parties that treat waste while it is in process may be able to avoid generating "waste" altogether. Certain treatment facilities have been specifically exempted by EPA. Finally, treatment of waste while it is in generator storage tanks may be allowed without a RCRA TSD permit. Hazardous waste point of generation, an important determination relating to these strategies, will also be discussed. Generators and processors will find this paper useful when evaluating their permit exemption potential

Jan 1, 1996