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By F. K. Letowski

Leaching in froth is a particular case of a three phase (liquid-solid-gaseous) process which combines flotation with leaching by using a reactive gaseous reagent as a flotation carrier and a leaching solution as the reactive liquid medium to fonn the foam (froth) in' which the solid particles are suspended. Some physico-chemical and engineering aspects of leaching in froth are discussed and illustrated by its application for cleaning the mineral graphite. Leaching of the graphite concentrate containing 4L4% of the elemental carbon and 3.16% of the sulphidic 'sulphur was canied out in the froth fonned by: (a) a concentrated chloride solution, with a small addition of nitric acid, in the foam state; (b) a mixture of gaseous O2, NO., and H20 encapsulated in the foam; and (c) notable particles of graphite suspended in the foam. The laboratory experiments werecanied out in a "flotation column"-type reactor ala temperature from 80 to !08°C and under total pressure of 100 to 200kPa. In the 3-stage leaching-flotation process, the non-flotable fraction of particles was separated three times from the notable fraction. The concentration of carbon and elemental sulphur in the final flotable fraction was 96% C and 0.38% S respectively. The expected advantages and possible application in hydrometallurgy are suggested.

Jan 1, 1995

By T. Shibasaki, S. Kamio, K. Kanamori

"Mitsubishi Process has been proven through fifteen years operation to be highly productive, cost efficient and easy to abate environmental requirements. However, in order the process to remain competitive from now on, it should also be adaptable to a variety of varying conditions. Various test works have been conducted from such a stand point of view and some of the new concepts have been implemented to the actual operation.The paper discusses the adaptability of the process to the change of concentrate grade with respect to copper and also impurities, acceptability of the secondary materials and the potential to increase unit capacity. IntroductionThe first commercial plant of Mitsubishi Process with 48,000 mt copper annual capacity started its operation at Naoshima Smelter of Mitsubishi Metal Corporation in 1974, and the second plant with 65,000 st annual capacity started in 1981, at Kidd Smelter, Timmins, Ontario, now Kidd Creek Division of Falconbridge Limited 2. These plants have increased their capacities to 90,000 mtpa respectively by adding oxygen and acid plant capacities while maintaining the original furnace design uncharged. Thereby both smelters have established more cost efficient operations. (3), (4)Mitsubishi Process applies so-called multi-furnace continuous system. Figure 1 shows conceptual flowsheet. Backgrounds that required and justified the development of such system are as follows:"

Jan 1, 1988

By LeRoy C. Prichard

The scrap based steel producers in the United States generate an estimated 650,000 tons of electric arc furnace (EAF) dust annually which is classified as hazardous waste, K061. These scrap based producers commonly referred to as mini-mills represented 39% of the steel produced in 1994. Based upon the EAF plants being installed or planned today, it is a reasonable projection to anticipate 50% of the steel produced in the United States will be by EAF's. Using a straight line projection of percent of steel produced to tonnage of EAF dust generated, this will result in 833,000 tons of dust being generated upon the completion of these new EAF producing plants, presumably by the year 2000. Because the United States is a capitalistic economy, a steel producer is in business to make a profit therefore dust management becomes a very important variable in the cost of making steel. An EAF mini-mill dust management program must consider at least three components. First the handling of the dust must be in accordance with the law; i.e., the Environmental Protection Agency rules and state and local municipalities guidelines governing K061. Second, it must be an economical solution that allows a company to manage its dust processing costs, a component of its total steel production costs while producing steel at a profit. Third, the dust management program should be one that is environmentally responsible; viz., the program should reclaim or recycle the dust constituents, as feedstock materials or saleable products. The first component, obedience of the law seems to be a relatively straight forward, common sense objective; however, as nearly every mini-mill operation will testify it has been a area of changing laws with confusing variations when it comes to K061. Even more frustrating is the fact that obedience or compliance today does not mean that the company will be considered law abiding in the future.The liabilities associated with

Jan 1, 1995

By Himaki Nakano, Kenji Hara, Toshiaki Tsuru, Shunsuke Kawano, Takeshi Ohgai, Hisaaki Fukushima, Shigeo Kobayashi, Tetsuya Akiyama

"Electrodeposition of Fe-Ni and Zn-Ni alloys from aqueous solutions is one of the well-known examples of anomalous codeposition in which less noble metal deposits preferentially. In this paper, the electrodeposition behavior of these alloy systems was compared between the methanol and aqueous baths. In Fe-Ni system, the significant suppression of the deposition rate of more noble Ni was observed over a wide range of electrolysis conditions in both methanol and aqueous baths. However, the electrodeposition of Zn-Ni alloys showed the typical feature of normal type codeposition in the methanol baths, which was completely different from that in aqueous sulfate baths. The difference in the electrodeposition mechanism between Fe-Ni and Zn-Ni alloys was discussed on the basis of the alloy deposition behavior in the baths in which the activity of water was varied:INTRODUCTION'It has been well known that Fe-Ni alloys show an excellent soft magnetic property. Therefore, thin films of this alloy have been used to fabricate the'-various magnetic devices. For the production of Fe-Ni thin films, dry processes such as sputtering, PVD and CVD are 'employed frequently and the resulting films showed a preferable property as a magnetic material. Electrolyses as a production technique of thin films, on the other hand, has the advantage over other processes in its cheaper production cost due to the simplicity of the production unit The Zn-iron-group metal alloys such as Zn-Ni and Zn-Fe electrodeposited on a steel sheet ale known to exhibit excellent corrosion resistance and therefore the electrodeposition of these, alloys has been applied to the production of surface treated steel sheets mainly for automotive body panels.According to Brenner (1), the electrodeposition behavior of Fe-Ni and Zn-Ni alloys was' classified into the' 'anomalous type. In this type of codeposition, less noble metal, i.e. Fe for Fe-Ni and Zn for Zn-Ni system, deposits preferentially and the change in -the alloy composition- with the variation of electrolysis conditions was unpredictable because of their obscure deposition mechanism. Since most properties of the alloys mainly depend on their composition, the composition of the deposited' alloys must be controlled strictly. Therefore, it is neces5al)' to clarify the mechanism of anomalous codepasition in Fe-Ni and Zn-Ni systems: Several mechanisms have been proposed so fur, and among them the hydroxide .suppression mechanism (2), (3) has been regarded most plauslble depend on their composition, the composition of the deposited' alloys must be controlled strictly. Therefore, it is necessary to clarify the mechanism of anomalous codeposition in Fe-Ni and Zn-Ni systems: Several mechanisms have been proposed so far, and among them the hydroxide suppression mechanism (2), (3) has been regarded most plausible. According to this mechanism, it can be predicted that the codeposition behavior depends greatly on the characteristic of water solvent in this study, using methanol as a solvent, the electrodeposition behavior of the anomalous codeposition was investigated to discuss the validity of the hydroxide suppression mechanism."

Jan 1, 2000

By Hiroshi Maeta, Takao Kino, Hirota Osono, Kikuo Matsusaka, Azusa Shida

"Prior to refine an ultra-high purity material, it is necessary to estimate the surface cleanness of a base material. In this report, the cleaning method of a surface for refining of an ultra-high purity aluminum has been studied. Aluminum sample of 99.999% purity was p9lished mechanically and electrically and washed with various solvents. Surface composition and a depth profile near the surface were examined. Based on the experimental results, surface structure of an ultra-high purity aluminum was discussed.IntroductionRecently, studies on high purity metals have become of interest, and we have reported .various properties of an ultra- high purity aluminum1- 2)In order to purify a metal, it is necessary to clean a work area and to make vacuous as possible. So, we are studying the purification of aluminum by an ultra-high vacuum refining system and a zone refining system set up in a clean room with cleanliness class of 1000.Now, in order to avoid a mixing of impurities into the refining metal, a surface cleanness of a base metal is very important factor. The purity of the base aluminum used our work is 99.999%, but the surface state of the base aluminum is not clear. Aims in this work .are to investigate the surface state and to obtain the cleaning method of the base aluminum.Experimental procedureSamples used in this work were 99.9% (3N), 99.99%(4N) and 99.999% (SN) aluminum produced industrially and 99.9999% (6N) aluminum purified by us."

Jan 1, 2000

By G. C. Amstutz

The topic of the industrial applications of mineralogy is a vast field which can be adequately covered only in a large book or by a two or three semester course. This paper recalls experiences of the writer in this field, a task requested by the Process Mineralogy Committee. Therefore, this paper is largely an account of the industrial mineralogy problems I was involved with, since my student years, Although I will treat each application only briefly, it is hoped that they will illustrate to the students in the field how varied are the applications of mineralogical methods. In this respect, I want to emphasize that it is important for mineralogy teachers to point out the usefulness of mineralogical methods much more often in their courses. Not only does that help prepare young individuals for industrial careers, but also it arouses their feeling of consciousness of public responsibility which is an important attribute for the world's scientists. When professors utilize the varied applications in their teaching of mineralogical methods students then understand better the significance of learning those methods and appreciate the many years of necessary university preparation. The first time I was involved in an application of mineralogical methods was about 1944 as a student of Professor Paul Niggli. He was asked to study the problems of ice crystallization on wings of airplanes. The ice formed at high altitudes and during the winter. This was not outside his realm of expertise because he was the main initiator of the Snow Research Institute on the Weissfluhjoch in Switzerland. I believe that the work of this Institute was an important factor in stimulating much of the snow research subsequently carried out at the United States Army Snow Research Center, which was located at that time in Willmette near Chicago. Dr. Bader, one of Paul Niggli's former students, was the Director of Research at Wilmette at that time and for quite a number of years thereafter. A mineralogist-crystallographer can make important contributions to a better understanding of the problems of snow and ice formation, avalanche hazards, and the prevention of hail. The habits of snow crystals are essentially a function of the temperature and the humidity,

Jan 1, 1982

By H. Virtanen

Outokumpu copper refining operations have a long history of expansions and application of new technologies. Outokumpu is a name known around the world for technological excellence in the field of base metals, and part of the policy of operations is continuous investment and investigation in new technologies. The results of this hard work sometimes are immediate and sometimes take years. The work done during the last years at the Outokumpu Harjavalta Metals copper refinery, together with a sister technology group Outokumpu Wenmec, has started to bear fruit in terms of the following radical developments and advances that are and will be applied to assure Outokumpu's position as the technology leader and a low cost and safe producer. Some of the developments discussed include the new anode and cathode design, mechanised electrode handling, cell design incorporating features facilitating full automation, automated short circuit detection and removal, automated on line anode slime removal, and high efficiency and intensity refining.

Jan 1, 1999

By G. Cifuentes

It's know that the cathodic purity and the electrolyte treatment is affect for the solid present in the electrolyte. Anodic slimes properties (f.e.: chemical composition, crystalline composition, sedimentation) was studied in copper electrorefining, this properties were modify through by anodic composition and current density. In this paper will be present only the preliminary anodic slimes relationship at different lead anodic composition. The anodic material was doped during the poured process with lead at different composition. It's confirm the apparition of the (Bindheimitte) SMbz07. The specific gravity of this specie is approximately 7.3 - 7.5, with this values is biggest the probability of sedimentation and smaller the slimes not sedimentabel.

Jan 1, 1999

By Kenji Morinaga, Hiromichi Takebe

"Ge-S binary glasses in the range 57 to 90 at %S at 0.5 to 3 at %S intervals were prepared by a conventional melting technique using fused quartz ampoules as melting containers. Impurities contaminated during preparation process are evaluated by IR spectroscopy. The causes of impurity contaminations are discussed. Density data in a systematic series of Ge-S glasses is demonstrated. IntroductionSulfide glasses are of particular interest for new laser and nonlinear optical materials in the near-infrared and infrared regions [1]. Sulfide glasses have the features of low-phonon-energy and high refractive index with moderate rare-earth ion solubility. The low-phonon-energy is favorable for the reduction of nonradiative rate for the emission of rare-earth ions. The high refractive index results in a high radiative-rate and in a high third-order nonlinearity. However, impurities may degrade the superior optical properties of sulfide glasses.In this work Ge-S glasses were prepared by a conventional melting technique. Impurities contaminated during the preparation process are evaluated and their causes are discussed for future improvements. The measured densities of Ge-S glass samples were compared with the results of previous studies [2], [3]. Ge-S glasses have some favorable properties for practical .applications including non-toxicity, good thermal and chemical stabilities."

Jan 1, 2000

By Keizo Uematsu, Satoshi Tanaka, Zenji Kato, Nozomu Uchida

"A novel technique is developed and applied to evaluate the binder segregated at the· surface of granule. Compressive strength of each granule was measured directly with a micro-compressive instrument. The relation between compressive characteristics and the amount of binder was discussed quantitatively.IntroductionCharacterization of granules is essential in the production of ceramics, since they govern the structure of green compact and thus the structures and properties of ceramics. However, there is no research to clarify the relation between the strength of granules and structure of granules, especially of binder segregation at granule surface. We develop a novel technique to determine the binder concentration in the granules by the iodine method. In this study, we measure yield strength of granules directly and discuss the relevance between compressive characteristics and the concentration of binder.ExperimentalGranules were prepared by spray-drying of aqueous slurry of commercial alumina (AL160-SG1. Showa Denko, Tokyo, Japan) and PVA (PVA 105 Kurare, Japan). PVA. concentration in granules was 1.1, 1.5 and 2.3 wt%. The inlet and outer air temperatures were 200 and 95 °C , respectively. Iodine-potassium iodide solution was prepared by dissolving iodine (0.15mol) and potassium iodide (0.15mol) in diluted water (50ml). A saturated boric acid solution was prepared by mixing boric acid powder with a diluted water."

Jan 1, 2000

By Pedro Morales

At present the Codelco´s smelter & refinery business have growing complexities, concentrates with lower copper grades, higher impurities contents, and environmental restrictions which have lead to refocus the Codelco business, not only by considering the isolated developments for each of the Codelco´s Smelt & Ref complexes, but also as an integrated corporative complex scheme which improve the economy of scale, optimize the synergies, and include new technologies for higher productivity and lower operational costs. Accordingly, for the 2008-2012 period, Codelco have prepared a Development Plan integrated to the smelters and refineries business units that improve its single potentialities of and include the advances for the Teniente Converter [1] and Continuous Converting [2] Technologies, and also include the concept of uncoupling the smelting process from the converting process allowing a higher operational flexibility, and a better control of its contaminants. Thus, processing the white metal generated in the Teniente Converter unit of the smelter A into the smelter B has comparative advantages. These changes in the business concept allow an overall increment of the smelting capacity by processing only white metal as a final product through a very marginal investment in this way the total or partial conversion of the white metal into blister copper is eliminated allowing to use the available gas capture-treating capacity, and available acid plants for increase smelting capacity as well.

Jan 1, 2006

By C. O. Bounds

The magnetic properties of (NdDy)15Fe78B6 sintered magnets have been evaluated using powder prepared by Inert gas atomization. The atomized powder had a particle size distribution from 1 to approximate 1000 microns. The as atomized powders have been sieved into, coarse, intermediate, and fine fractions; magnetic properties were evaluated for the as produced powder and each fraction. A B, of 11.7 kG, a Hci of 11.0 kOe and a BHmax of 32.5 MGOe was -obtained on a sintered magnet made from the as-atomized powder. The magnet made from coarse powder exhibited a slightly higher B, of 12.1 kG, while that from fine powder showed a decrease in B, to 11.2 kG. Hydrogen decrepitation has been utilized to study its effect on the magnetic properties. Finally, cast ingots with a definite columnar structure have also been used to compare the magnetic properties of magnets of the same nominal, composition but of different alloy preparation process. Hydrogen decrepitation does not appear to improve the magnetic properties of magnets made from thin cast ingots. However, it does show a significant improvement in the Hci of magnets made from the atomized powders. Possible causes for the differences in the magnetic properties on magnets made from each process have been discussed in the paper.

Jan 1, 1992

By Kaixi Jiang, Lei Zhang, Sanping Liu, Yufang Wang, Xiaoping Zou

"Molybdenite concentrates are usually treated by roasting, but low concentration SO2 pollution is a problem. Extraction of molybdenum and rhenium from molybdenite concentrates with a pressure oxidative leaching (POX) and solvent extraction (SX) process was studied. A series of POX-SX laboratory and pilot tests were carried out on the molybdenite concentrate. In the POX stage, more than 95% rhenium and 15-20% molybdenum were leached into solution. Solvent extraction recovered the rhenium and molybdenum from the POX solution. The extraction rates of Re and Mo were above 98%. The loaded organic reagent is stripped with ammonia. The stripping ratio of Mo is more than 98%. Compared to the roasting process, the total recovery of Mo increased from 93% to 97%, and Re from 60% to 90%. In the coming five years, POX-SX technology will be competitive in China.IntroductionMolybdenite is the main resource for the production of molybdenum, and about 99% of the total molybdenum was extracted from molybdenite. Rhenium is one of the important new materials in national defense, space flights, nuclear energy and electronics, because of its high melting point, high strength, plastic properties and significant creep resistance. There are no single rhenium ores in the world; rhenium mainly co-exists with molybdenum. Consequently, molybdenite is also the main resource for the extraction of rhenium."

Jan 1, 2012

By Andreas Ludwig, Abdellah Kharicha, Menghuai Wu

"In order to demonstrate how CFD can help scientists and engineers to better understand the fundamentals of engineering processes, a number of examples are shown and discussed. The paper will cover (i) special aspects of continuous casting of steel including turbulence, motion and entrapment of non-metallic inclusions, and impact of softreduction; (ii) multiple flow phenomena and multiscale aspects during casting of large ingots including flow induced columnar-toequiaxed transition and 3D formation of channel segregation; (iii) multiphase magneto hydrodynamics during electro-slag remelting; and (iv) melt flow and solidification of thin but large centrifugal castings.IntroductionSince the Bronze and the Iron Ages, material processing, and here especially metallurgy, has got a global importance for the economic well-being of the societies. It is thus understandable that metallurgy has changed from arts and crafts into an engineering specialty, where the knowledge of centuries has lead to an enormous commercial and technical efficiency. However, increasing competition and the necessitation of energy and CO2 reduced manufacturing methods requires the improvement of existing techniques and even the development of new, alternative production technologies. On the other hand, the opacity of liquid and solid materials and the involved high temperatures makes the experimental penetration of metallurgical processes and with that the attainment of detailed process knowledge quite difficult."

Jan 1, 2012

By Fernando Guevara

Many smelting and slag-cleaning furnaces operate with cooling systems designed to freeze a slag layer over the refractory to protect it. The fluid flow and heat transfer conditions associated with the freeze layer and mushy zones are poorly understood. These phenomena were simulated with a small-scale room temperature, 2-dimensional model, using an aqueous solution of calcium chloride to simulate the slag. Reasonable similarity with conditions encountered with copper and nickel smelting systems was achieved (Pr 50 and Ra 108, in the laminar-turbulent transition). Measurements of the freeze layer development and velocities were made with the Particle Image Velocimetry (PIV) technique. Direct Numerical Simulations (DNS) were also made of the unsteady fluid flow and heat transfer problem. It was found that the solidification process is well described using an improved model for high molecular viscosity in the mushy zone. Solid front growth, isothermal profiles, velocity profiles and heat transfer through the walls showed good agreement between the PIV and DNS results. Experimental and numerical velocity profiles close to the freeze layer show a parabolic behaviour in the vertical velocity profile which is completely different from the calculation of heat transfer using a sharp interface model. The reason for this is attributed to the effects of the mushy zone with a high viscosity and high shear stresses acting on that area.

Jan 1, 2006

By Dachun Liu, Wenlong Jiang, Baoqiang Xu, Yongnian Dai, Bin Yang

"In the traditional method for refining of indium, glycerin-KI and glycerin-NH4Cl are used as electrolytes to remove Cd and Tl by electrolytic refining, which produces In with a purity of 99.995%. Large quantities of polluted industrial waste water are the result. It is calculated that the saturated vapor pressure of Cd and Tl are between 1-200 Pa, which is much larger than the vapor pressure of In. Thus, the study of removing Cd and Tl was carried out over the temperature range between 700-950 °C and pressures between 1-15 Pa. After vacuum distillation the contents of Cd and Tl in crude indium could sharply fall below 1 ppm..IntroductionIndium is a is a pale blue and silver white metal, and has high ductility [1-2]. Pure indium is generally used as a raw material to produce semiconductor compounds, fluorescent material and ITO targets [3]. Sublimation, zone melting and electrolytic refining are major methods to produce pure indium from crude indium. Electrolytic refining is the main method to product pure indium at present. High productive efficiency, simplicity of operation and short cycle of production are major advantages. However, glycerin-KI and glycerin-NH4Cl are used to remove Cd and Tl in electrolysis method. Large quantities of polluted industrial waste water are the result[4]."

Jan 1, 2012

By Pierre-François Bareel

EU legislation imposes ambitious recycling targets for various consumer goods. End-of-Life Vehicles (ELVs), scrap iron and various proportions of Waste Electrical and Electronic Equipment (WEEE) are processed by shredding plants which recover most of the metals but produce Shredder Residues (SR) which are landfilled. They represent 20 to 25 wt.% of the shredder input. Energy issues for the coarse fraction of SR are now largely studied. However, below 2 mm, the calorific value falls off drastically. These Fine Shredder Residues (FSR) represent up to 55 wt.% of the total SR. To meet European objectives other alternatives to landfilling must be considered for the FSR. The present paper describes a study carried out to characterise the FSR and investigates ways to process them and produce marketable products. Applying Gy's theory, a sampling procedure was conducted over two years to statistically quantify the variability of the physical and chemical properties of FSR produced by a Belgian post-shredding treatment plant. Macroscopic characterisation has led to the identification of four material categories which could be separated according to their physical properties: ferrous metals (more or less oxidised), non-ferrous metals, an organic fraction (plastics, rubber, textiles, foams, wood) and a minerals fraction (glass, ceramic, concrete). The entrainment of small metallic particles within the pores of organic fragments will affect the quality of the separations.

Jan 1, 2006

By S. N. Ashrafizadeh

Nowadays, hard carbides have found various industrial application in the manufacture of cutting and drilling tools as well as metal forming devices. About 60% of the world tungsten production is consumed in the manufacture of hard carbide pieces. Regarding the high economic value of hard carbide components, i.e., Ni, Co, TaC, TiC, and WC, their recovery from scrap species is attracting much interest. In the current research, the cobalt and tungsten content were recovered from scrap cemented carbide pieces through the application of high voltage electrolysis in nitric acid media. By this method, cobalt and tungsten were initially recovered as cobalt nitrate and tungstic acid, respectively. The precipitate of tungstic acid was calcined at 800ºC after being washed twice with distilled water. A pure tungstic oxide was obtained. The effects of current density, electrolyte concentration, speed of agitation, and the surface area of the anode on the efficiency of the electrolysis process were investigated. The optimum conditions of current density of 1500 A/m2, an acid concentration of 1.5 M, and a cell temperature in the vicinity of 60 to 80ºC were obtained. At the optimum conditions, an acceptable rate of collapse for the anodic carbide pieces of about 3.1 g/h was achieved, which remained constant up to the completion of the recovery process without any passivation .

Jan 1, 2003

By R. Parada

In January 1995, Disputada Mining Company Ltd. (Compañia Minera Disputada de Las Condes) started up the Expansion Project for the Chagres Smelter, following an investment of US$M 2 15. The new smelter replaced the 44,000 tomes per year revervatory furnace with an Outokumpu Flash Smelting Furnace (FSF) designed to produce 118,000 tonnes per year of copper. Nowadays, this smelting unit has achieved a 40% over design performance. The landmarks of this modernization project are described. The start up period in 1995-1996 was characterized by the impacts of several restrictions that prevented the smelter from reach design production. The design performance was reached in 1997-1998 through the implementation of solutions designed to eliminate, or at least mitigate, the restrictions found early on. The smelter has been further optimized in the 1999-2000 period, leading to a new record anode copper production rate of 148,000 tonnes in 2000 while obtaining 98% approval for our different anode shapes. The objective of this paper is to discuss the consecutive processes of start-up, achievement of design capacity, and operational improvements to go well beyond the design capacity. These processes took place between early 1995 and late 2000, under the principles of Continuous Improvement that promotes the effective participation of the workers in the technology innovation and Enterprise Management.

Jan 1, 2002

By Takashi Nakamura, Kenji Oosumi, Kazuhisa Fujisawa, Takayuki Kogishi

"Recycling of used aluminum beverage cans(UBCs) is one of the important issues for aluminum manufacturer presently. The direct re-melting of UBCs shows two problems. One is a reduction in molten aluminum recovery and the other is a contamination of other metals such as Ti and Fe from paints. Both problems are caused by paints coated on the surfaces of aluminum cans. Removal technique of the paints, therefore, has been required. Although roasting and shot blast techniques have been developed, both were not successful in removing the paints effectively. A swell-peeling method has been applied to remove them using a methylene chloride solution with acids and it works very well. Small laboratory scale tests have been carried out to develop the commercial process and clarify the mechanism of the swell-peeling method in the present study.When the surface area of UBC is more than 10 cm2, peeling time is independent of the surface area, about 60 seconds, because swelling phenomenon is controlled by the penetration of the liquid through the fine pits on the surface of the paint. This is good for a commercial process. Peeling takes place when the swelling force generated by methylene chloride exceeds the adhesion force between the film and the surface of aluminum, that is weakened by the coexisting acid, especially halogenated acetic acid."

Jan 1, 2000