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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 S. K. Utimurd, D. C. R. Espinosa, J. A. S. Tenório

"Waste Electrical and Electronic Equipment (WEEE) has become an environmental issue due to technological advance and waste plastic is one of the main polluters. The excessive discard of these plastics result in a difficult to dispose it to landfill and need further separation with technique in order to produce high added value plastics. There are many kinds of plastics in extensive use at the present time and the co=on are the acrylonitrile-butadiene-styrene (ABS) and high impact polystyrene (HIPS) used in the production of electric appliances. These plastics are difficult to separate because they have similar densities. Flotation of plastics is one possible separation technique and using selective wetting agents. The separation may be possible given close control at particle size and the concentration of the reagent. The process was able to produce a concentrate of HIPS with at least of 93% purity and a concentrate of ABS with 99% purity.IntroductionThe current situation of municipal solid waste (MSW) management especially in emerging economies like Brazil, the growing population and economic activity will result in a significant increase in the generation of waste in the coming decades. It is worthwhile to review and update the sources, amounts and recovery technologies of specific materials from waste, particularly from municipal solid waste (MSW).The growing impact of the current waste management practices stresses the need for a change in how waste is handled. The 2012 survey and the Brazilian Association of Public Cleaning and Special Waste Disposal Companies (ABRELPE) reports the generation of 62 Mt urban MSW in that year, which is an increase of 13% compared to 2011. It has been reported that in Brazil about 90.17% of the generated MSW is currently collected, which indicates an increase in the coverage of collection services compared to 2011 [ l]."

Jan 1, 2014

By Youn-Bae Kang

Evaporation mechanism of S from liquid Fe–C–S alloys at 1873 K was proposed by analyzing available experimental data. It has been known that increasing C content in liquid alloy increases activity coefficient of S ðfSÞ, and it could raise driving force for the evaporation reaction S = S(g). However, experimental data of the evaporation of S in the Fe–C–S alloys could not be accounted for only by considering the increases of fS. In the present study, formation of carbosulfides, CS(g) and CS2(g), was additionally taken into account in order to explain role of C for the accelerated S evaporation. Surface adsorption of S was also taken into account, which retards the evaporation rate of S. An evaporation model equation was formulated. It can be applied to calculate the evaporation rate of S over wider C content (from zero to its saturation to liquid alloy).

By K. S. V. L. Narasimhan

Recently developed high energy permanent magnets SmCo5, Sm2Co17, Nd2Fe14B offer an interesting study of magnetic phenomenon. This publication discusses briefly the evolution of these magnets and the origin of the coercive force. Atomized SmCo5 coarse particles (150 to 300 microns) exhibit unusually large coercive force contrary to the experience in cast alloys. A brief discussion of utilization of these magnets into devices is also presented.

Jan 1, 1992

By Christina Viklund-White

Life Cycle Assessment has been used to compare the environmental performance of landfilling versus recycling of the zinc used for galvanizing steel. Hypothetical process routes were com-posed involving four different EAF dust treatment processes; Waelz kiln, DC-furnace, EZINEX and slag fuming, as well as scrap dezincing. The study shows that recycling of zinc used for galvanizing steel has environmental benefits in that it saves zinc resources. However, zinc recovery does not necessarily decrease the potential impact on global warming and acidification. The magnitude of these two impact categories is tightly correlated with the amount and type of primary energy consumed in a process. Due to the high electricity consumption in the dezincing process, this route has the highest impact on Global Warming Potential as well as Acidification Potential. The major part of the energy requirement for the production of zinc from primary and secondary sources is consumed in the reduction of ZnO to Zn. The consequence is that the theoretically possible savings in primary energy by recycling zinc-containing materials are relatively minor. The impact categories "land use" and "waste generation" are not considered in this study, but most likely the evaluation of such impacts would further increase the potential environmental impact of the landfill alternative. The results also show that the location of an electricity-intensive process highly affects the potential environmental impact. Comparing process and material alternatives in LCA studies where branch average data is used, is considerably more complex than when LCA is used within a company.

Jan 1, 2000

By F. L. Marley

Small and medium-sized flotation plants with no assaying instrumentation still depend much upon the art of the operator to produce acceptable and consistent results. Improved performance can be accomplished by the use of the simple microscope set up as a control device. The visual recognition of products in the circuit does much to eliminate uncertain shift operating decisions and is an easy technique to acquire. Mineral staining methods further assist in the determination of components within the mill products. Simple mounting upon scotch tape and other adhesives is rapid and convenient. The microscope also has a practical role for the plant metallurgist or laboratory technician when evaluating middling products, and their routing within the circuit. Examples are reviewed where the microscope has been used for operational control in both sulfide and nonmetallic mineral flotation plants.

Jan 1, 1981

By Florian Kongoli

Slags and fluxes are important interchangeable dimensions of pyrometallurgical processes. They can increase the efficiency of the smelting, converting and refining processes and improve the quality of the final products. A good slag should have appropriate physicochemical properties such as low liquidus temperature, optimal viscosity, maximum ability to attract undesirable elements, minimum potential of attracting valuable elements, etc .. A good flux, on the other hand, when properly used, can considerably improve the physicochemical properties of the slag since by modifying its chemical composition it could decrease the liquidus temperature, improve viscosity etc.. Consequently, the choice of a good slag and the corresponding fluxing strategies has become indispensable in most of industrial processes. However, the properties of multicomponent slags as well as the effect of several fluxes are known only empirically and confusion exists in the literature and in the industrial practice. In today's reality of frequent changes in the composition of raw materials and that of the fluxes themselves, in the existing or new developing technologies, the quantification of the thermophysicochemical properties of multicomponent slags and the effect of fluxes becomes indispensable. This paper reviews some of the work carried out by the author's group during the last ten years on the quantification of the thermophysicochemical properties of multicomponent slags and on the effect of fluxes in several smelting and converting processes in close relation to their individual characteristics. Several examples have been given in order to demonstrate the fact that when taken outside the context some fluxes can become in fact anti-fluxes.

Jan 1, 2003

By Z. R. Llanos

This paper presents a review of industrial and experimental processes for the recovery of molybdenum, vanadium, nickel, cobalt and aluminum from spent hydrotreating or hydrodesulfurization catalysts. Numerous processes have been developed in a laboratory and pilot scale. However, worldwide, there are only four well established commercial facilities currently in operation. The installed capacity of these facilities exceeds the availability of spent catalysts and may be sufficient to assimilate future increases of spent catalysts. Despite liability risks; significant quantities of spent catalysts are still being landfilled. Changing regulations that may affect the future handling and disposal of spent catalysts are also reviewed.

Jan 1, 1995

By Wang Zhi

High-Mg-content concentrates are usually treated in Jinchuan flash smelting Furnace. Because the viscosities of high-Mg-content slag is very high, the operation of flash smelting becomes very difficult. To solve this problem, the viscosities of the semi-synthesized FeO-MgO-SiO2 slag of different compositions were measured. The results showed that when in the slag the weight percentage of MgO [w(MgO)] is 6-10%, the ratio of the weight percentage of iron to that of Si02, w(Fe)/w(Si02) is 1.1-1.4 and the temperatures are within 1473-1773K, the slag viscosities increased with the increase of W(MgO) and w(Fe)/w(SiO,). When w(Mgo)<6%, the smelting temperature should be controlled at I 300°C in order to to keep the smooth operation. When w(MgO)>10%, the temperature should be kept above I 633K. When the content of MgO is higher, a lower viscosity slag can be produced by decreasing the ratio of w(Fe)/w(SiO,). The appropriate ratio of w(Fe)/w(SiO,) for Jinchuan flash smelting furnace is about 1.2.

Jan 1, 2003

By Florian Kongoli

Slags and fluxes are important interchangeable dimensions of pyrometallurgical processes. They can increase the efficiency of the smelting, converting and refining processes and improve the quality of the final products. A good slag should have appropriate physicochemical properties such as low liquidus temperature, optimal viscosity, maximum ability to attract undesirable elements, minimum potential of attracting valuable elements, etc .. A good flux, on the other hand, when properly used, can considerably improve the physicochemical properties of the slag since by modifYing its chemical composition it could decrease the liquidus temperature, improve viscosity etc.. Consequently, the choice of a good slag and the corresponding fluxing strategies has become indispensable in most of industrial processes. However, the properties of multi component slags as well as the effect of several fluxes are known only empirically and confusion exists in the literature and in the industrial practice. In today&apos;s reality of frequent changes in the composition of raw materials and that of the fluxes themselves, in the existing or new developing technologies, the quantification of the thermophysicochemical properties of multicomponent slags and the effect of fluxes becomes indispensable. This paper reviews some of the work carried out by the author&apos;s group during the last ten years on the quantification of the thermophysicochemical properties of multicomponent slags and on the effect of fluxes in several smelting and converting processes in close relation to their individual characteristics. Several examples have been given in order to demonstrate the fact that when taken outside the context some fluxes can become in fact anti-fluxes.

Jan 1, 2003

By R. E. Johnson

The No. 3 reverberatory furnace at Phelps Dodge. Corporation&apos;s Morenci, Arizona copper smelter first received oxygen from a new oxygen plant during October 1982 and began operation with oxygen-fuel and oxygen sprinkle smelting burners which burn concentrate with oxygen. The furnace was completely converted to roof-mounted oxygen-fuel firing in October 1982. All conventional air-fuel bridge wall burners were extinguished at that time. The novel arch-mounted oxygen sprinkle smelting system began continuous operation April 1983. Since startup, unit fuel requirements decreased and furnace throughput significantly increased. Furnace off gas SO2 strength increased from an average of 1.5% SO2 to an average of 20% using only oxy-fuel burners. Oxygen sprinkle burner operation also has given excellent results, with the furnace off gas strength increasing to 35%-60% S02. There has been a reduction in overall arch temperatures, an increase in matte and slag temperatures, and a lowering of furnace bottom buildup with oxygen smelting. Furnace off gas is blended with converter off gas and treated in a sulfuric acid plant.

Jan 1, 1983

By Jinhui Li

Silver is a very important metal used in a wide range of applications. It is necessary to recovery of Ag from electronic wastes for increasing of Ag price and circumstance protection. For separating and recycling Ag from Ag-Cu composite materials, thermodynamic data of reaction is calculated and some experiments have been proceeded with Ag-Cu composite material scraps, time, temperature, nitric-sulfuric mixed acid volume ratio and the volume ration of mixed acid vs. water have been discussed. The results show that the optimization conditions is that nitric-sulfuric mixed acid volume ratio 5:95, volume ratio of mixed acid vs. water 10:1, temperature 55?, time 25min. In the conditions, Ag can be selectively leached from Cu-based composite material, Cu base is not eroded nearly.

Jan 1, 2009

By S. W. Marcuson

Smelting of nickel-copper sulfide ores at Vale Inco’s Sudbury operations commenced in 1888 and the first converting plant went into operation in 1892. As the demand for nickel grew, the smelting operations expanded and by the 1960’s the Copper Cliff Smelter featured the longest converter aisle in the world with space for nineteen Peirce-Smith converters. During this long period, different converting techniques and vessels were employed. The evolution of converting is reviewed with special emphasis on the modifications made to the Peirce-Smith vessel to accommodate the metallurgical and process needs of the changing times.

Jan 1, 2009

By George J. Karcas

"Non-ferrous metals such as copper, nickel, lead, zinc and precious metals are produced via the electrorefining and electrowinning processes. Apart from controlling electro-chemical conditions for the production of these metals, there has always existed the challenge of controlling the corrosive effect of the electrolyte environment which serves as the medium for non-ferrous metal production.The practice of acid containment in electrometallurgical operations has entered the world of high technology with the advent of advanced acid resistant materials such as vinyl ester resin which is either combined with aggregate to form polymer concrete or used to line various acid containment vessels and ·surfaces. ill comparison to some Asian, European, and African copper refineries, the North and South American copper industry has recently embraced quite heavily in the use of polymer concrete electrolytic cells and process vessels, such as electrolyte storage tanks, and in the use of vinyl ester resin for corrosion protective surface sealing 'systems in lieu of epoxy, acrylic and other materials because of its combination of higher corrosion resistance and superior flexibility.Electrolytic cell construction has undergone a transformation from a multiple part configuration to a single piece moulded/cast unit. ·The one piece moulded polymer concrete cell, which has been patented by Corrosion Technology International, with the overflow, decant, inlet, fast fill and segregation systems integrally designed is now the industry standard.. The combination of a wood, steel, or concrete frame with a lining made of lead, asphalt, rubber or plastic has been historically successful in providing limited protection from chemical and mechanical attack in electrolytic cells and electrolyte storage tanks all over the world. These combinations have now become obsolete as materials such as polymer concrete provide exceptional corrosion and mechanical protection with greatly reduced maintenance requirements and improved efficiency and productivity for the tankhouse. ill addition, polymer concrete can be disposed of in a regular land fIll which is much less costly than disposing of contaminated concrete that is normally associated with conventional lined concrete cells."

Jan 1, 1997

By Luiz A. Teixeira

A process is described whereby worn, deffective or crystallized photoconductive Se-As layers can be stripped off from aluminium photocopier drums, using hydrogen peroxide solutions in conditions such that the aluminium substrate is preserved from chemical attack. The process allows the stripped drum to be recoated with a new photoconductive layer, and to be put again in use.

Jan 1, 1990

A novel, low-pressure adaptation of Praxair?s coherent jet technology utilizing CoJet lances was developed for application at Inco&apos;s Copper Cliff Smelter where oxygen is available in large tonnage quantities but only at relatively low supply pressures (< 193 kPa header pressure). The project objectives were to evaluate the effect of coherent jet technology on controlling oxygen lance accretion (?horn?) formation and to increase oxygen efficiency in the Inco Oxygen Top-Blowing Nitrogen Bottom Stirring (TBBS) MK Reactor used for converting nickel- contaminated chalcocite to semi-blister copper. This paper describes the development and subsequent implementation and testing of two CoJet lances in this application.

Jan 1, 2005

By A. K. Riihimäki

The description deals with duplex stainless cast steels and austenitic high molybdenum steels used in pumps for severe condition service. The main modem nitrogen alloyed duplex cast steels are presented in the ASTM standard A-890. Two grades of high molybdenum austenitic stainless steels there are presented in ASTM A-744 (-96) standard i.e. CN-3MN and CK-3MCuN. The latest and most corrosion- resistant stainless steel grade is AVESTA 654 SMO?. Avesta Sheffield the trademark owner has granted Ahlstrom Pumps license to produce the material. This new stainless steel as pump material for severe service has improved properties in the hydrometallurgy and electrorefining processes of metal and especially in the copper industry compared to duplex stainless steels. The paper deals briefly with the foundry process to manufacture high alloy stainless steel pump castings. The AOD-method (AOD= Argon Oxygen Decarburization) is an important prerequisite for the melting of low carbon, high chromium and molybdenum alloyed nitrogen steels. The properties of these steels are included. The main topic is the corrosion resistance of the above-mentioned pump materials in severe service. Results of short-time erosion and corrosion tests are discussed and compared with the results of plant tests. Practical results of pump materials performance in severe service for the copper industry are given. The new high alloyed cast stainless steel (main elements; Cr-24%, Ni-22%, Mo-7,3% and N-0,5%) has shown improved corrosion and erosion properties as process pump material in several severe service applications e.g. in the metal industry.

Jan 1, 1999

By Rashmi Ramesh

Zinc oxide nanoparticles and nanostructures form an active area of research in the recent years. It can be doped to modify electronic, optical and other properties. Synthesis and characterization of zinc oxide is of extreme importance in order to understand the structure property relationship in this material which is now being considered of importance next to carbon nanotubes. Microstructure of zinc oxide nanomaterial is extremely sensitive to the preparation conditions. Nanocrystalline pure and Mn and Mg doped zinc oxide samples were prepared by wet-chemical method under different growth conditions. The samples were investigated for crystalline phase, microstructure, morphology and luminescence characteristics. The effect of Mn and Mg doping on the characteristics of ZnO have been discussed.

Jan 1, 2010

By Evgueni Jak

Recent advances in analytical, experimental techniques, and computer-based theoretical modelling of fundamental properties and elemental processes, provide new opportunities to develop the next level of whole-of-reactor pyrometallurgical furnace models. These models have the potential to significantly improve the prediction of, and adding value to, industrial operations. In non-ferrous smelting, the starting point of these models is the development of multicomponent thermodynamic databases for gas-slag-matte-speiss-metal-solids phases supported by systematic experimental research. The whole-of-reactor-models additionally should take into account kinetic processes taking place at micro- and macro- scales, and other key factors. Examples of applications of the latest research tools and modelling approaches to analysis of industrial flash and top submerged lance (TSL) sulphide smelting processes are presented. Different levels of industrial modelling are discussed from elemental local reactions, through general and more detailed whole-of-reactor-models, to plant sections and further to whole plant operation models. Some principles for development of pyrometallurgical reactor models are discussed.

By Richard D. Hagni

Microscopic examination of selected, representative, unweathered samples of Birmingham, Alabama, Silurian, sedimentary iron ores has fully revealed the nature of the phosphorous-bearing mineral grains. The grains are composed of carbonate-fluorapatite (collophane), range in size from 1 um to 2.25 mm, and exhibit varied types of intergrowth with hematite. Modal analyses conducted under cathodolumi-nescence have provided quantitative data on the a3undance of each of 15 types of phosphorous-bearing mineral grains and made it possible to assess the potential phosphorous liberation from four types of iron ore. The results indicate that 27% of the total phosphorous contained in the iron ores in the western part of the Birmingham district can be expected to be liberated by fine grinding; 60% for ores in the eastern part of the district.

Jan 1, 1982