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By Hideyuki Itou

Municipal wastes are mainly incinerated in Japan. Both bottom ash and fly ash from the incineration treatment are smelted recently to decrease the volume. Direct smelting of municipal wastes is also becoming popular. The smelting treatment generates fly ash which contains concentrated heavy metals such as Zn, Pb and Cu, and the harmfulness is causing concern. The smelter fly ash is mainly landfilled after stabilization. An effective treatment process of the smelter fly ash is required to recover the metals. For the treatment process, an application of chloridizing volatilization technique is considered. Chloridizing volatilization experiments were carried out to determine the effects of various factors on the volatilization behaviors in this study. A pretreated ash was mixed with a main raw material which mainly consists of hematite. Calcium chloride water solution was added into the mixture. The mixture was pelletized, dried and used as samples for the volatilization experiments. The sample was placed in the reaction tube heated in an electric resistance furnace. 5%02-95%N2 gas with controlled humidity was introduced into the reaction tube. Effects of humidity in the carrier gas, addition of calcium chloride and mixed ratio of the ash to the main raw material were investigated on the volatilization of Zn, Cu and Pb. To determine the volatilization behavior, samples were taken from the furnace at specified temperatures on the heating stage. In addition, experiments at specified holding temperatures for 15 minutes with shortened heating time were conducted. The two series of experiments revealed the effect of heating temperature on the volatilization behavior of Zn, Cu, Pb and Cl.

Jan 1, 2006

By Andrey Dmitriev

The solution of set of equations for the bottom zone presented by a condition of a thermodynamic equilibrium, namely, an equilibrium constant of wustite reduction by carbon oxide, material and thermal the balances, supplemented by the equation of the heat balance for the top zone, allows to calculate the base indices of blast furnace smelting. The calculated indices are extreme accessible at the given parameters of charge and blast. Application of actual degrees of the use of gas instead of equilibrium allows the calculations of actual indices of the blast furnace smelting process.

Jan 1, 2006

By Min Chen, Lei Xu, Liang-yu Jin, Xue-liang Yin

For the purpose to reduce the high cost and heat storage loss of Al2O3-MgO bricks used as ladle linings, Al2O3-MgO-CaO bricks with lower theoretical density were fabricated and the densification behavior as well as mechanical property of this refractory was investigated. With addition of CaO, the initial sintering temperature of Al2O3-MgO refractory was decreased from 1300 to 1100°C associated with the expansive formation of CA2, and the compressive strength was also enhanced owing to the formation of bond linkage between CA6 and spinel. At high temperature, brick with 4% CaO content showed poor sinterability with high porosity because of the formation of platelet structure of CA6 grains, whereas brick with 8% CaO content was well sintered with higher relative density but lower bulk density than Al2O3-MgO brick, indicating that the densification as well as lightweight of Al2O3-MgO refractory was effectively promoted.

Jan 1, 2015

By Qingzhu Li

The adsorption process of Pb2+ from aqueous solutions by spent grains modified with Imol/L NaCI solution was investigated. The effects of solution pH, contact time, adsorbent concentration, initial Pb2+ concentration, particle size on Pb2+removal were also studied. The initial adsorption process was rapid and 90.35% of Pb2+ adsorption occurred within 30 min. The absorption equilibrium was obtained at 4h. When pH was 5.5, Pb2+ concentration in aqueous solutions decreased from the initial content of 20 mg/L to 0.0 I mg/L after 5 hours by application of IOg/L adsorbent at 25?C, Pb2+ removal efficiency reached up to 99.95% and the Pb2+ remaining in aqueous solutions was under China Sanitary Standard for Drinking Water (GB5749-85). Adsorption data fitted well with Lanf+muir and Freundlich models. However,Langmuir isotherm model was better to descnbe Pb- adsorplion than Freundhch model, mdlcatmg that the applicability of monolayer coverage of Pb2+ on the surface of adsorbent.

Jan 1, 2008

By D. R. Spink

A partial desulfurization roasting (PDR) technique has been developed for use on zinc concentrates whereby the sulfide sulfur associated with the iron content is selectively removed over a very short residence ?time in the roaster. The resulting PDR product is then leached for the selective removal of the iron. The resulting leach restdite is an upgraded zinc sulfide concentrate which has a very low iron content. The up-graded zinc concentrate can be subjected to a conventional dead roast without formation of deleterious zinc ferrite so that hot acid leaching and jarosite (or other) iron precipitation steps are obviated. Examples are presented for the treatment of three very different types of zinc concentrates.

Jan 1, 1990

By C. Dresen

This paper discussed the reaction kinetics of the reduction of industrial phosphate pellets for P4 production. In the reduction process of various phosphate ores, the following parameters were investigated: Diffusion of the phosphorus oxide and other gaseous products from the reaction mixture after having been reduced on the reductant (coke) surface. Influence of silica on reaction kinetics. Temperature influence. Influence of mineralogy and morphology (different ores). Particle size influence of silica and coke. Experiments were carried out in a vertical tube furnace with 2 ores, 2 types of silica and one type of coke. Selected experimental conditions simulated furnace conditions. The following conclusions could be made: Reaction rate increases with the addition of SiO2 into the pellet. The reaction rate increases above 1350°C (melting temperature of the slag). Mixing different ore types in the pellets leads to differences in reduction kinetics. Particle size of the coke particles influence reduction kinetics. The amount of slag formation is influenced by silica addition, coke size and temperature.

Jan 1, 2002

By D. W. Hoey

Eight years use of the ISA Process is reviewed and current design and operations described. Nodern Technology used for impurity control and disposal as well as the use of mechanised electrode handling equipment, cell voltage monitoring, cell insulation and an efficient contact bar system are described. Improvements achieved in terms of energy usage and plant productivity are detailed.

Jan 1, 1987

By W. Drummond

The cooling of smelter gases by air dilution, adiabatic evaporative cooling and indirect heat exchange is discussed with reference to the ,process, to the subsequent cleaning of the gas and to the use of the heat extracted from the gas. The method of reducing the effect of acidic ,sulphide formation on the corrosive properties of the gas and the dust and the development of surface cleaning mechanisms are discussed. The development of indirect recuperators using air, water or steam cooling, made 'possible by the control of surface fouling is traced. The application of the modern Waste Heat Boiler to the new sulphide smelting processes is discussed with respect to the natural and forced circulation concepts. Case histories are presented to illustrate mistakes made with respect to designs produced without recourse to sensitivity analysis and without an appreciation of "worst process conditions".

Jan 1, 1992

By Santo Ranieri

We will briefly review the nickel market in 2003 and look forward to the supply demand balance for the next few years focusing in on the key factors influencing future price dynamics. On the supply side we will examine slated brownfield and greenfield expansions including the Norilsk factor and the small to mid-range 'supply creep'. We will also review the cost side of the industry and what to expect going forward. On the demand side, we will discuss the stainless steel and non-stainless demand, the China factor and the stainless steel scrap supply cycle. We will conclude by pinpinting where the market is on the current price cycle, and where we believe the mid-term direction is headed.

Jan 1, 2004

By Yun Li

In 1999 Yunnan Copper Corporation (YCC) decided to modernise their copper smelter and change the existing sinter plant I electric furnace process to a combination of ISASMEL T and electric slag cleaning furnace. The main aim of the project was to improve the environmental performance and decrease the energy consumption. Generally the project has been successful, partly attributable to the selection of a reliable and fully demonstrated technology. The design capacity for the ISASMEL T furnace is 600,000 tonnes of dry copper concentrate per year. The furnace has been running smoothly since heat up in May 2002. YCC expended considerable effort in the preparation for plant operation. An extensive training program for key YCC personnel at the Mount Isa Copper Smelter improved their understanding of the process significantly and ensured successful hand-over of the technology. This paper describes the project history and summarizes initial operating results.

Jan 1, 2003

By Jie Ma, Shun-Li Zhao, Jian Zhao, Jie-Yu Zhang

"Microstructural morphology evolution of Ni-45wt.%Mo droplets during rapid solidification process was investigated using an advanced modified 3D cellular automaton-finite element(CAFE) model by CALCOSOFT software. The model was modified by User-defined functions (UDFs) and validated with experimental solidification microstructural morphology of Ni-45wt.%Mo droplets available in the literature. Then, the influences of convection heat transfer coefficient, superheat of the alloy droplets and droplets size were investigated during the rapid solidification process. The predictions show that microstructural morphology is obviously sensitive to convection heat transfer coefficient and droplet size. With the decrease of convection heat transfer coefficient, the grain density decreases. In addition, the decrease of the droplet size could obtain refined microstructure. However, decrease the superheat ofNi-45wt.%Mo droplets has little effect on microstructural morphology.IntroductionFor several decades, much attention has been paid to undercooled alloy droplets of rapid solidification process for which can obtain refined microstructure, decreased microsegregation and extended solubility of alloying elements [1-3]. Extensive prior work shows that solidification of droplets plays an essential role in advanced material properties [ 4]. Consequently, it is very important to investigate the microstructural morphology evolution, especially for dendrite growth during non-equilibrium solidification process, for dendrite growth reflected the kinetics of the crystal growth process."

Jan 1, 2013

By W. Drummond

The cooling of smelter gases by air dilution, adiabatic evaporative cooling and indirect heat exchange is discussed with reference to the process, to the subsequent cleaning of the gas. and to the use of the heat extracted from the gas. The method of reducing the effect of acidic sulphide formation on the corrosive properties of the gas and the dust and the development of surface cleaning mechanisms?are discussed. The development of indirect recuperators using air, water or steam cooling, made possible by the control of surface fouling is traced. The application of the modern Waste Heat Boiler to the new sulphide smelting processes is discussed with respect to the natural and forced circulation concepts. Case histories are presented to illustrate mistakes made with respect to designs produced without recourse to sensitivity analysis and without an appreciation of "worst process? conditions".

Jan 1, 1992

By Abhishek Lahiri

Titanium dioxide is extracted from titaniferous ores by chloride and sulfate processes. These two processes produce wastes in the forms of iron chloride, iron sulfate and rare earth oxides gangue, each of which has to go through a further treatment before it can be disposed safely, which may be expensive. The shortage of high-grade ores is also making the two conventional processes less efficient. In view of the above mentioned problems, an alternate beneficiation process of roasting titaniferous ores with soda ash is discussed. The advantage of this process is that, there is no production of wastes. The impurities present in the ore can be selectively separated after the roasting process. The roasting of titaniferous ores with soda ash was carried out between temperatures of 873K and1173K for several hours. The roasting process resulted in the formation of complex alkali compounds and various sodium titanate compounds, depending on the Na2CO3to ore ratio. The phases formed after roasting were characterized using the X-ray powder diffraction (XRD), X-ray florescence (XRF) and scanning electron microscopy (SEM) techniques. The phase equilibria in the Na-Ti-O system are evaluated and compared with the phases obtained after the roasting process. The effects of temperature and the proportion of sodium carbonate on titaniferous ores are also discussed. From the experimental data, the overall reaction kinetics and phases formed were analyzed to ascertain the mechanism of overall reaction and the rate-limiting steps.

Jan 1, 2006

By Ruhi Bux, Akshay Verma, Mohini Saxena, P. Asokan

"Due to the colossal increment in the industrialization, the generation of wastes gathered as a result of different extraction, benefaction and generation processes is having an alarming problem for waste disposal. The best and most acceptable way is to use the waste in accordance to its potential for the generation of high value lucrative composite goods. The study in this paper elucidates the potential of several industrial wastes like fly ash, red mud and marble slurry dust for the production of different wood substitute products like doors, windows, roofing sheets and instant houses for the rehabilitation on the sites of catastrophes. Wastes were initially characterized for the physical, chemical and mineralogical properties and then used in different formulations with binder like Polymer along with natural fiber like Jute to intensify the physical as well as mechanical properties of the resultant composite. The study also reveals that these composites have better mechanical properties than the available ones like teak, medium density board, Rice husk board etc. Also, the fly ash and red mud composites have better mechanical properties than marble slurry based composites. The results fosters the implementation of natural fiber with the industrial waste in the generation of eco-friendly and non-hazardous composites.IntroductionOver the last few decades, there has been a tremendous increase in the generation of industrial wastes gathered as a result of various extractions, benefaction and generation processes. The condition worsens even, when it comes to high quantum generated wastes like Fly ash, Red mud and Marble slurry dust. The primordial motif behind the incorporation of industrial wastes as filler in the development of composites is primarily composed of two main objectives; Firstly waste management, the colossal waste dissemination in the environment has disturbed the ecological balance by polluting land, surface water, ground water, air, natural resources and even disturbing the public health [1]. Secondly, to act as a perfect substitute for the conventionally existing building materials, this will aid in dwelling places to many with the least incorporation of exhaustive natural resources as woods quid pro quo."

Jan 1, 2008

By Tracy Morris, Weldon Read, Luis Navarro

"Bismuth is a recognized contaminant in the electrolytic refining of copper that can render many cathodes to be outside ASTM standards and unsuitable for copper rod and other downstream products if not carefully controlled. This paper portrays the performance of Molecular Recognition Technology (MRT) for bismuth removal at the Amarillo Copper Refinery (ACR) and describes how the highly selectivity gel has been successfully used to achieve good bismuth removal and how many pit falls and draw backs have been overcome.IntroductionASARCO operates one of the largest copper refineries in the world at Amarillo, Texas. The main feed for this refinery is produced at the Hayden smelter in Arizona. During the operation of this smelter a variety of metals are carried as impurities in the copper anodes because of the diversity of concentrates and residue products used as raw materials in the smelter feed mix. Even though the impurities are concentrated enough to be detected at the smelter, it is difficult to remove them completely. A simple way to control impurities at the smelter is to minimize the addition of material with a high concentration of impurities to the charge in order to reduce the output of this metal species. All this leads us to have a ""refinery problem"" [1,2,3]."

Jan 1, 2012

By Kandipati Sreenivasarao

A promising method for removing heavy metal ions from dilute effluents is ion- or precipitate- flotation, in which a suitable collector is added to form hydrophobic metal-collector complexes or compounds that can be collected as foams. We have successfully removed Cu(II), Cd(II), and Pb(ll) from dilute solutions using sodium dodecylsulfate and ethanol as collector and frother respectively. However the process would not be economically viable unless the collector could be recycled, and the heavy metals recovered in a concentrated, preferably marketable, form from the foams. We investigated four different methods to decompose heavy metal-dodecylsulfate complexes, namely precipitation of hydroxides, precipitation of sulfides, chemical stripping, and electrolysis. We compare the performance of these methods. In each case the observed behavior is related to known thermodynamic data, and potential applications are discussed.

Jan 1, 1995

By Tracy Morris, Weldon Read, Luis Navarro

"During the leaching of anodic slimes, tellurium dissolves into the leach liquor together with copper and must be removed before the solution is sent to liberator cells for copper recovery. Prior to the installation of autoclaves, tellurium was precipitated using raw slimes that caused a recirculation of tellurium in the leaching circuit. After autoclaves were installed the old leach tanks were converted into tellurium reactors utilizing copper chips, steam and agitation to form a copper telluride precipitate. Tellurium levels of less than 10 rng/L are achieved in a timely manner.IntroductionThe electrolytic refining of copper consists of an electrolytic cell provided with an anode of impure copper, a cathode of substantially pure copper (starter sheet) and an electrolyte made of copper sulfate and sulfuric acid [1]. When a direct electrical current is passed between the anode and cathode inside the cell, the impure copper anode dissolves in the electrolyte and pure copper is plated onto the cathode. During this operation, many of the impurities are deposited on the bottom of the cell as an anodic slime residue composed of insoluble chemical compounds. Slimes are a major source of rare and precious metals in the copper industry [2-5],In the Amarillo Copper Refinery (ACR), the anodic copper slimes are sent to the Precious Metals department in order to extract and then refine the gold, silver, platinum and palladium from them. The remaining impurities, in the form of a soda slag or copper slag are sent to the Hayden smelter for further processing. Copper telluride is sent to the Selenium/Tellurium department inside the plant for selenium and tellurium recovery. During the leaching process of the anodic slimes, copper, tellurium, and other metal species in the slimes are dissolved into leach liquor that cannot be returned to the tankhouse unless the tellurium concentration is below 10 mg/L."

Jan 1, 2012

By B. Q. Li, S. P. Song

"This paper describes an on-going research on developing coupled boundary element and finite element algorithms for the solution of thermal and electrodynamic problems relating to materials processing. The coupled methods are uniquely suitable for field problems involving composite regions, in which detailed information on field distributions within one particular region is of more interest and yet the solution can be obtained only if the effects of other regions are all considered. Problems of this type include heat transfer in multiple regions and also magnetic induction involving an infinite boundary. The hybrid boundary and finite element formulation, algorithm development and the applications are discussed. Two examples are given to demonstrate the capability and accuracy of the coupled algorithm for heat transfer problems. Various treatments of corner discontinuity are discussed. It is found that the double flux treatment is an ideal choice amongst those tested as it is easy to implement and also gives the most accurate solution. 1. INTRODUCTIONElectrodynamic and transport problems occur frequently in materials processing systems. Accurate solution of these problems is of great importance not only for our fundamental understanding of physical principles governing these phenomena in the processing systems but also for optimization of the existing processes as well as development of new processes. For this purpose, many numerical algorithms have been developed. These computational schemes in general can be classified into three categories, that is, the finite element and finite difference schemes and the boundary element scheme. The former two are domain based numerical algorithms while the latter the boundary-based algorithm.The finite element method, which is based on the variational calculus, is a very useful and yet popular engineering numerical method for boundary value problems defined over irregular boundaries. The use of the method requires the discretization of the entire domain. It can be applied to solve both linear and nonlinear problems, but is particularly powerful for nonlinear problems that involve the field variables defined within the computational domain. On the other hand, the boundary element method, with its root in the Green's function method, is very efficient for linear boundary value problems or nonlinear problems that involve field variables only along the boundaries. The primary advantage of the boundary element method lies in the fact that only the boundaries of the computational domain need to be discretized, and hence the dimension of the problem is reduced by one, compared with the finite element method."

Jan 1, 1994

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 John C. Taylor

With growing emphasis on energy conservation and increased concern over the presence of heavy metals in the environment, it is fortunate that most metals are readily recycled. In this respect, metals have a significant advantage over plastics and similar materials used as metal substitutes. For many years a secondary industry has processed scrap copper, nickel, lead and zinc to produce refined metal which has, to varying degrees, influenced the price and displaced the production of primary metal. This paper reviews some of the challenges the industry will face and the changes in process technology which will be required as pressure mounts to increase the amount of metal recycled. In the case of most base metals, this will have an impact on primary metal production; as the tonnage of metal recycled increases, the requirement for primary production, or new metal, will depend more and more on the growth in consumption.

Jan 1, 1993