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By Marcela C. Santini, Luiz A. Teixeira

"Surface conditioning (also referred as etching) of plastics prior to metallization is generally conducted with sulfuric I chromic acid solutions. Although these baths perform well technically, the presence of Cr (VI) imposes serious operating problems of an environmental nature. The present work reports ·the results of a study of surface conditioning o(ABS using solutions based. on sulfuric acid, with hydrogen peroxide and/or nitric acid, replacing chromic acid, as oxidants. Process performance was evaluated by SEM and by the uniformity and adherence of electroless nickel coatings applied on selected conditioned samples. The results showed that the evaluated types of solutions could be optimized to perform as well as the chromic-based baths, with a much superior environmental quality.IntroductionMetallization of plastics is normally undertaken for either decorative or functional purposes. Through metallization, the specific properties of plastics such as light weight, design flexibility, and low-cost of manufacturing are enhanced by the addition of properties usually associated with metals. These include reflectiveness, abrasion resistance, electrical conductivity, and a variety of decorative effects (1).The available processes that can be used for metallization of plastics are vacuum metallization or vapoµr deposition; indirect metallization and plating (1). Plating can be sub-divided into electroless plating and electroplating. In electroless plating, metal ions in aqueous solution are deposited on the .activated plastic surface by oxi-reduction reactions without the aid of an external electric potential, forming a thin metallic layer. This electroless deposited film has two functions: (a) it provides an electrically conductive substrate that allows further coating by electroplating; and (b) provides a secure bond between the plastic substrate and the electroplated layer (1,2). In case the electroless metallic part requires an additional layer for finishing purposes, or just an increase in thickness, the part can be additionally electroplated with a· variety of metals - in most cases those are copper, nickel or chromium (3)."

Jan 1, 2000

By Selim Coskun

In this study, tungsten matrix composites reinforced with 2 wt% TiC particles were mechanically alloyed (MA?d) for 3h, 6h, 12h and 24h. 1 wt% Ni is used as sintering aid which is added before and after mechanical alloying. Microstructural and phase characterizations of composite powders and sintered samples were carried out via SEM and XRD analyses. Furthermore, density and hardness measurements of as-consolidated and sintered samples were carried out. Additionally, DSC experiments were conducted to investigate the sintering behavior of the MA?d powders.

Jan 1, 2009

By F. Tanaka

In April 1999, a two-year campaign of the Mitsubishi furnaces was achieved at Naoshima Smelter; the present one is expected to be extended much longer. An overview of basic technology for decreasing refractory wear in the Mitsubishi Process is presented. One of the main features of the process is the use of top blowing lance technology which has a different effect on the furnace refractory than other conventional processes. The refractory wear of concern is hearth wear caused by top blown powder injection, wear of the side wall caused by splashing droplets, and wear of the bath level refractories caused by surface waves of melts in the furnace. These have been systematically investigated for many years. This paper describes the results of various model tests and their application to practical furnace design and operation.

Jan 1, 1999

By Viviane Tavares

The liquid crystal display (LCD) are currently known by its vast application in electro ? electronic devices, amongst them can be detached the devices of TV, laptops, electronic date, calculators and even though the mobile telephones (mobiles). The mobiles are changed more frequent of the TV for example, this happens due to the technology advance. With the constantly mobile exchange, the batteries, printed circuit board and liquid crystal display accumulation its become an environmental problem. To minimize the environmental impacts caused by mobile telephones residues are considered the segregation process of the LCDs main components, to goal to recover the recycle material. This process involves the use of treatment ore techniques with disc, hammers and balls mills. The process with best efficiency (about 98%) of LCD glass release was the hammers mill. The glass recovered can be used in the glass recycling and the sand substitution in the production of concrete blocks.

Jan 1, 2009

Gas flow and heat transfer phenomena in two industrial-scale waste-heat boilers of the Outokumpu copper flash smelting process were analyzed with a commercial computational fluid-dynamics (CFD) package Phoenics. Various operating conditions were simulated for the first boiler and particularly for the second boiler. The gas flow pattern was compared qualitatively with the physical laboratory models, and the general flow pattern was consistent with the laboratory visualization. The heat transfer simulation was validated with, temperature measurements for both boilers, and good agreement was reached between the computed temperature profiles and the measured data. The computational results indicate that gas flow in both boilers is of three-dimensional and recirculating nature. The numerical tracer experiments indicate that some dead volume is present in both boilers, and the boiler modification reduced the dead volume from 38% to 15% under basic operating conditions. Radiative heat transfer accounts for 65-90% of the total 'heat transported in the radiation sections of both boilers under different operating conditions. The modified boiler is very efficient for cooling the off-gases at almost doubled volume flow rate. The CFD modeling proved to be a useful tool for numerical experiments and analysis of boiler performance for process: optimization.

Jan 1, 1998

By Shaohua Ju, Jin-hui Peng, Ya-jian Wang, Shuai-dan Lu, Li-bo Zhang, Lei Guo

"The granulation of a red mud is of great importance for recycling this material as an adsorbent for waste water or gas. A new granulating process was developed and its effect was evaluated. To reduce the cost of the granulation process, the wet filter cake (containing 25% water) was directly mixed with different cement contents (4%, 6%, 8% and 10% based on wet material). The mixtures were placed in a moist environment for 4 days, and then were washed with deionized water until the pH values of leachants were lower than 9.0. The efflorescence ratio, surface area and particle size of the aged mixture were determined, respectively, by bottle shaking experiments, N2 adsorption and screening. The results showed that the best addition of cement is 2%, and this yielded granulated material with a particle size of less than 2 mm, an efflorescence ratio of 4.83% and a specific surface area of 17.42 m2/g.IntroductionRed mud is a residue of the aluminium industry that is produced during the alkaline extraction of alumina from bauxite by the Bayer process. For every ton of alumina that is produced, the amount of red mud generated can vary from 0.3 to 2.5 tons, depending on the characteristics of the bauxite. In its typical form, red mud is brick red in colour, caustic, about three times as dense as water and, when un-neutralised, has a high pH, typically around pH 13 [1]. It is primarily composed of iron oxide, silica and alumina, along with traces of heavy metals. Red mud particles are quite small; typically 99% will pass through a 0.6 mm sieve and 87% through a 0.038 mm sieve [2],"

Jan 1, 2012

By R. P. King

The essential features of an image analysis system for the measurement of mineral liberation are described. Good procedures for image acquisition and image processing prior to image analysis are defined. The basic stereological methods for the measurement of volume fraction, surface area per unit volume, particle size distribution and liberation spectra are given. The appropriate methods for fractal correction when measuring perimeters of irregular features and for frame correction when measuring linear intercepts are developed. Practically useful and accurate procedures for the stereological correction of particle size and liberation distribution methods are given.

Jan 1, 1995

By Pinakin Chaubal

An analysis of the blast furnace and the low-pressure shaft DR furnace is carried out by redefining the reaction zones. The concept of a characteristic reaction gas temperature (CRGT) is introduced and the two reactors are compared and contrasted using some recent process developments with an aim to develop a platform for further synergistic innovations.

Jan 1, 2006

By R. K. Mehta

Microorganisms have been increasingly used in applications such as-metal solubillzation, precipitation and recently being used as flocculants. Optimal control and on-line monitoring of these processes occurring in microbial reactors are of extensive interest but often difficult because of the unavailability of a mechanistic model of the process and on-line direct sensors. In this paper a dynamic populatlon balance model of microbial desulfurization will be presented. The influence of certain physical and biological parameters on the leaching rate will be illustrated via computer simulations and an extended continuous-discrete Kalman filter will be Implemented for estimation of unknown states.

Jan 1, 1991

By Alim Ullah

Process, quality and management control are necessary in order to produce DRI of required quality and at minimum cost. Although the characteristics of the two (2) principal inputs, that is, iron oxide feed and natural gas (for gas-based DRI plants) can affect the operation of a DRI plant significantly, they are outside the control of plant operators, at least in the short run. The quantity of reduction gas, its composition and reduction gas temperature are some of the key process variables. Statistical Process Control (SPC) can be used in a DRI plant to minimize the production of off-grade material and costs, as well as to improve the overall operation of the plant. One of the key quality variables to be measured and controlled is percent metallization, defined as FeM/FeT*100 where, FeM and FeT respectively are metallic iron and total iron in DRI. Control charts are used to monitor the quality of DRI produced and, when necessary, corrective actions are taken to bring the product back within the control limits. Management control can consist of essentially following how well the plant performs against some pre-established standards of parameters like daily production, downtime, consumption of material and energy, etc. In this respect, it is suggested that yield, defined as theoretical consumption/actual consumption of iron oxide feed, be used to monitor the consumption of feed material. Similarly, instead of using natural gas per ton of DRI produced, a better criterion would be efficiency, defined as theoretical natural gas consumption/actual natural gas consumption.

Jan 1, 2006

By Xuling Chen, Zhiyun Ji, Min Gan, Wenqi Li, Xiaohui Fan, Zhiyuan Yu

"Specularite and vanadium-titanomagnetite are difficult to granulate, and with the increase of their proportions, the permeability of sintering bed is deteriorated together with the combustion velocity of fuel for the shortage of air through the sintering bed, which can lower sintering speed and specific production capacity significantly. The biomass fuel has a higher combustion velocity than coke breeze, therefore the productivity of specularite and vanadium-titanomagnetite ore can be improved remarkably by replacing coke breeze partly with biomass fuel .The results showed that, when the proportion of biomass fuel replacing coke is 40%,the sintering speed and specific production capacity of 35% specularite were improved from 19.06mm/min, 1.33 t/(m2·h)to 21.45mm/min, 1.47 t/(m2·h),and that of 55% vanadium-titanomagnetite were improved from 17.23mm/min, 1.11 t/(m2·h)to 22.80mm/min, 1.44 t/(m2·h). As a conclusion, biomass fuel is effective to strengthen sintering of refractory iron ore.IntroductionThe iron and steel industry of our country has achieved significant development in the recent years. In 2010, the output of steel has reached to 0.627 billion tons. The increasing scale of iron and steel has led to rigorous domestic iron ore environment, and the reserves of hematite and magnetite that have superior sintering characteristics are on the decline with continually exploiting and utilizing [1]. Therefore, the RIO (refractory iron ores) SP (specularite) and VT (vanadium-titanomagnetite) have to be applied vastly. However, the quality of sinters can be deteriorated when utilizing RIO in high proportion due to their poor granulation and metallogenic performances [2, 3]. Generally, the ratio of SP is 3~5%,which should not exceed 10% in our country currently [4]. Though high rate of VT is adopted in PZH steel for a long time, the productivity is obviously low compared with normal sintering [5]."

Jan 1, 2012

By Nam-Il Um

Bottom ash contains several ferrous materials (ferrous metals, Fe3O4, Fe2O3, FeS, etc.). In particular, ferrous metals contain heavy metal because Ni and Cr are chemically attracted to iron. Likewise, Cu is used to coat Ni and Cr metals as polish or to prevent corrosion. In this study, an Fe3O4-Fe2O3 double layer (similar to pure Fe) was found to have been formed in ferrous metal during air-annealing in an incinerator (1000°C). A strong thermal shock such as one that occurs during the water-cooling of bottom ash results in the breakdown of this oxidation layer, facilitating the degradation of ferrous metals and formation of corrosion products. Therefore, Fe-ion (heavy metal) oxides may be formed on ferrous metals and may be separated from bottom ash via magnetic separation. This study sought to investigate the separation ratio of heavy metals as magnetic separation and mineralogical formation of Fe-ion (heavy metal).

Jan 1, 2006

By Dan Wang, Qian Xu, Guangshi Li, Xionggang Lu, Xingli Zou, Zhongfu Zhou, Hongwei Cheng, Changyuan Lu

The preoxidation of the ore has a profound significance to the concentration, separation and purification of nickel and copper from the lean complex ore. In this paper, the natural Ni-Cu sulfide mineral samples under the elevated temperature condition in air were investigated, as well as under isothermal condition at 600 oC in air. The mineralogical characterization was studied using XRF, ICP and the Rietveld method. The oxidation behavior and the element migration of the Ni-Cu sulfide ore were studied by XRD, SEM-EDS and TG. The XRD Rietveld method was successfully developed in the phase identification and quantification of this complex ore powder sample. The oxidative intermediates (Cu/Ni-ferrite) were detected by XRD, and the process of the element migration was obviously revealed by the line scans using SEM-EDS. It is the preoxidation of this mineral that provides guidance for the extraction of valuable metals from low-grade Ni-Cu sulfide ores in the future.

Jan 1, 2015

By Liu Wei-feng

Base on the thermodynamic calculation of vapor pressure of lead, antimony and arsenic at high temperature, the possibility of separating lead, antimony and arsenic in different temperature was analyzed ,and the practice of producing qualified antimony white from lead-antimony alloy by direct blowing was introduced in detail in this paper. The blast furnace reduction smelting was brief introduced firstly, and then alkaline refining was applied to removing arsenic from lead-antimony alloy that contains As1%,Sb39%,Pb58%,the arsenic in the treated lead-antimony alloy could decrease to 0.009% by that method. The antimony white containing Sb2O3 99.5% could be produced by air blowing in the special furnace at 650? from the treated lead-antimony alloy. And the electrolytic lead could be achieved by electrolysis from the lead-rich alloy which contained 83% lead.With high-grade product being obtained the process was shortened. The technology has been applied successfully many years in Guangxi, China.

Jan 1, 2009

By Michael E. Stout

The recovery of the constituent components of spent lead acid batteries was pioneered in the early 1970's by M.A. Industries, Inc. MA's main reason for research and development in this area was to recover the polypropylene casings for use as feed stock in their injection molding plants. At that time spent and reject casings were either disposed of or being fed with the lead 'bearing materials into the ,smelting process. M.A. has since developed, built and operated plant for the conversion of scrap casing into reusable copolymer resins. The system is composed, of washing, .sizing, extrusion and pelletizing the polymer into a form which is ready to be injection molded into new products.

Jan 1, 1995

By A. J. Meir, Paul G. Schmidt

"We present a novel approach to the mathematical analysis and computational simulation of fully three-dimensional, nonlinear, viscous, incompressible MHD flow in complex configurations involving several liquid and solid conductors. Such configurations arise in numerous metallurgical processes. Employing the current density rather than the magnetic field as the primary electromagnetic variable, it is possible to avoid artificial or highly idealized boundary conditions for electric and magnetic fields and to account exactly for the electromagnetic interaction of the flow region with the surrounding space. In addition, the approach lends itself naturally to finite-element based discretization techniques. As an application, we simulate the stationary flow of an electrically conducting fluid around a solid spherical particle of arbitrary conductivity, in the presence of crossed uniform electric and magnetic fields, and compute the Lorentz, pressure, and viscous forces exerted on the particle. This problem arises in connection with the electromagnetic filtration (purification) of molten metals before the casting stage.IntroductionNumerous metallurgical processes are governed by MHD effects resulting from the macroscopic interaction of liquid metals with applied or induced currents, electric and magnetic fields. Frequently these effects are technologically exploited in order to drive or to control the flow of metallic melts. Typical examples include the electromagnetic stirring of molten metals before the casting stage [1]; electromagnetic turbulence control in induction furnaces [2]; electromagnetic damping of buoyancy-driven flow during solidification [3]; and the electromagnetic shaping of ingots in continuous casting [4]."

Jan 1, 1999

By J. Méndez-Nonell

The thermodynamic and chemical properties of SrSO4 and SrS in a gaseous flow of CO and CO2 at high temperature are discussed. The thermodynamic analysis of the system was made using data from the literature. The results obtained from the thermodynamic analysis were experimentally verified using the thermogravimetric technique. The experimental results suggest the formation of a complex compound between SrO and SrSO4. It was also found a change in the chemical mechanism of the process between SrSO4 and CO-CO2 and in the chemical mechanism of the process between SrS and pure CO2.

Jan 1, 1995

By Xiang-dong XING, Zhen-yang wang, Xing-le LIU, Jian-Liang Zhang

Experiments were carried out by adding CaF2 as catalyst in a Ar atmosphere to study the isothermal reduction kinetics of vanadium titano-magnetite carbon composite pellets under high temperature in the range from1473 to 1673K. By analyzing reduction mechanism, it was found that the rate controlling step was gas diffusion, and the activation energy was 178.39kJ•mol-1 without adding any catalysts. Adding CaF2 of 3% to vanadium titano-magnetite carbon composite pellets can decrease the apparent activation energy of reduction, and the decrease extent was 14.95kJ•mol-1. In addition, temperature is an important factor influencing on reaction rate.

Jan 1, 2015

By Richard D. Hagni

Process mineralogy has not been given adequate attention in years past, because geologists have not been sufficiently interested in applying mineralogical techniques to industrial processes, and most process engineers are not adequately trained to use them. Although some individuals and institutions have made efforts to improve the situation, it is only in the last few years that the significance of applying the methods of mineralogy to a wide variety of industrial processes has been fully appreciated. Presently, the formation and organization of several groups devoted to applied mineralogy have created a more amenable climate for the development of process mineralogy. As a result, the presentation, discussion, and publication of the results and case histories of process mineralogy have become fairly common. Short courses affording hands-on experience with applied techniques are now available to the many geologists and process engineers engaged in industrial mineralogical processes. The future role of the process mineralogist is viewed as an expanded one, which will increase in value.

Jan 1, 1982

By D. G. Mason

During the design of copper refinery tankhouses, there is a need to develop mass balance calculations for many process components, so that optimum physical plant configuration is achieved. Each mass balance is complex, possibly with over 120 interactive variables as basic input data. Recent developments in tankhouse design (e.g. permanent cathodes) have greatly increased the design options available for any project, multiplying even further the requirement for calculations. In the past these calculations were tedious and susceptible to human error. A comprehensive computer program can now simplify the task of the process metallurgist, enabling more sophisticated and sensitive plant designs to be produced. The paper describes the successful development of a flexible mass balance program that originallly was used in a feasibility study which had to be completed within a short time schedule. The program has been further developed and used for design and energy calculations; it can be usefully applied to existing plants to assess the impact of variations in operating parameters. The software takes account of staged liberation, electrolyte purification bleed and generates a reliable process inventory listing: it can also cope with stripper starting sheet options and disparate commercial circuits.

Jan 1, 1987