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By Mojtaba Ahmadiantehrani

A previous study showed that up to 80% gold extraction could be obtained with 160 lbs/ton hypochlorite consumption at ambient temperature from a low grade Carlin-type carbonaceous ore. Crushing the ore to a finer size and agglomerating with cement decreases hypochlorite consumption by 60%; while, agglomeration and curing the cement-ore mixture with hypochlorite solution has no significant effect on total gold extraction. The high hypochlorite consumption is due to oxygen depletion as the solution percolates through the column, i.e., oxidation of gangue materials. These side reactions are reduced at sub-ambient temperatures resulting in a substantial further decrease in hypochlorite consumption. The optimum temperature range and additional reduction of hypochlorite consumption by introducing the reagent into the column at different elevations will be discussed.

Jan 1, 1992

By Liyuan Chai, Bing Peng, Ji Peng, Di Yu

"Electric arc furnace (EAF) stainless steel dust has been classified as a hazardous waste by various government regulatory agencies as it releases heavy metals to environment. The solidification of EAF dust is to stabilize the hazardous components to the amorphous silica-alumina-based clays. The process of solidification is investigated and the softening temperatures of dust and additive clay mixtures are measured for economical thermal treatment. The results indicate that the mixture of dust and local clay with the ratio of 1:1 has the lowest softening temperature 1100 °C and it could pass the toxicity characteristics leaching procedure (TCLP) test for the environmental regulatory limits after thermally treated at softening temperature for 15 min. Major phases of thermal solidification product clinker are CaAl2Si2O8, (Fe, Cr)2O3, (Fe, Mg)(Cr, Al)2O4 and Al6Si2O13.IntroductionThe yield of stainless steels in China arrived to 10 million tons in 2006 and more than 0.2 million tons of stainless steel dust are produced annually. Approximately 1-2 wt.% of scrap charged to an electric arc furnace (EAF) enters the off-gases and then is converted into the dust and reported to the bag-house. The disposal or landfill of the dust becomes a serious environmental problem in China due to the increased production of stainless steels in recent years. The dust contains elements such as chromium (Cr), nickel (Ni), lead (Pb), zinc (Zn), cadmium (Cd) and their solubility in leaching media exceeds the environmental regulatory limits [1]. Even though easily feasible for low-grade MgO, it is not appropriate to stabilize the heavy metals from the heavily contaminated soils after the dust landfill [2]. Several dust treatment technologies have been developed and they can be divided into two types. One is to recover the metals from the dust [3, 4] and another is to stabilize hazardous components present in the dust [5, 6]. Recycling of the dust generated in EAF is a remediation option for cleaner production. Direct recycling of EAF stainless steel dust was developed to recover the metal value from the dust and protect the environment [7], but it was only suitable for the dust with high contents of Ni, Cr and Fe. As for the dust with low valuable metal content, thermal solidification is an appropriate choice for the dust treatment."

Jan 1, 2012

By Stefan Mutl

By the term sorting one understands the separation of a material mixture into two or several products according to different material characteristics in the preparation technology. The oldest sorting procedure, the handpicking, is less and less used to separate different material mixtures because of the considerable personnel expenditure and the strict hygienic regulations at the workplaces in Europe. In general, the manual assortment is able to solve separation tasks, which could not be solved by machines so far. The picking is one of the most selective processing methods. However, the progress in the computer and sensor engineering today makes the creation of automatic picking devices possible, whose efficiency goes far beyond the possibilities of handpicking. Therefore in the future automatic picking will not only be applied to already common applications like the waste glass assortment by colour, but also to the assortment of complex composed material mixtures e.g. old shreddered cars. Thus, the automatic picking, supported by high performance computer systems and new sensor technology, gains more and more significance within many applications of waste processing. However, in order to apply automatic sorting procedures for different material streams within recycling processes, a substantial research and development need still is existing. The desire of the users is to sort more extensively in order to achieve products with bigger material varieties, In addition, the requirement of the accuracy of recognizing and sorting out of single grains rises, This lecture illustrates the procedure of the hand picking before it was employed in waste processing. Thus, a renaissance of a long forgotten method is happening in terms of today's state of the art procedure "automatic picking". Possible technologies, fields of application and future potentials of this technology are pointed out.

Jan 1, 2003

By Jiang Diao, Yong Qiao, Xuan Liu, Tao Zhang, Bing Xie

Adding CaO into the vanadium extraction converter is an effective way to decrease the dephosphorization burden in subsequent steelmaking process. The crystallisation process of spinel is one of the most decisive factors in the subsequent extraction. The theoretical calculation results show that the temperature of the peak total crystallization rate will decrease 5K with basicity increasing 0.1. The relation between cooling conditions and grain size of spinels is also discussed. It is found that low cooling rate and high basicity benefit spinel crystal growth. And the non-isothermal crystallization kinetics results indicated that the restriction factors of spinel growth is that solid crystals accept new components from liquid-solid interfacial. While the sample was cooled down to 1250 (1523K) at cooling rate of 5K/min, the crystal growth is consistent with Ostwald coarsening grew up law, and controlled by diffusion of particle.

Jan 1, 2016

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 David G. Dixon

Although the kinetics of leaching processes are of paramount importance in the design and analysis of nearly all hydrometallurgical flowsheets, these concepts remain poorly understood and, as a result, are only rarely applied to mass and heat balance models. In this second of two papers, we demonstrate how simple yet powerful models of leaching kinetics and other rate processes may be added to mass and heat balance models, and apply these concepts using a spreadsheet model of a simplified pyrite autoclaving flowsheet. In particular, we focus on the interpretation and scale-up of batch leaching data, and on simple means for modeling other phenomena commonly associated with leaching, such as reagent depletion, gas-liquid mixing, and the precipitation of oxides and basic salts.

Jan 1, 2002

By Harrison Hodge

In the Bayer process for alumina production, between 2–35% Al2O3 is lost with bauxite residue due primarily to incomplete dissolution of aluminiumbearing minerals during caustic leaching or the precipitation of sodium alumino-silicate solids. The recovery of sodium and aluminium from the residue, and particularly from the contained sodium alumino-silicates, is becoming an increasingly critical issue from both an environmental and economic standpoint. Lime-soda residue sintering followed by selective leaching has been proposed as a method to recover sodium and alumina. The factors influencing the sintering mechanisms and kinetics, and the subsequent leaching have not been well described to date. In this study, the physical and chemical changes taking place during isothermal sintering of bauxite residue in air, particularly at short reaction times are investigated using scanning electron microscope (SEM) and X-ray diffraction (XRD). The impacts of these changes on the recovery of valuable materials are reported.

By Krzyszof Borowiec

With the aim of determining the thermodynamic conditions for sulfation of impurity elements, in particular magnesium, in titaniferous slags the equilibrium gas composition for the sulfation reaction: MO + so2 + 1/2 02 = MS04 has been studied by an EMF technique with a solid zro2 + Cao electrolyte. Here M denotes the impurity elements: Mg, Ca and Mn, and the following _oxide systems have been studied: Ti02-MgO-Fe2 o 3 , Ti02-MnO-Mn2 o 3 , and Ti02 -CaO-Si02 , all in the . temperature range 700-1000ºc. Reproducible EMF values were obtained by adding small amounts of -Na2so4 to the oxide-sulfate mixture. From the observed results the Gibbs energy of formation of the phases Mg 2Ti04 , MgTi03 , MgTi 2o 5 , MnTi03 , CaTi03 , and CaTiSio5 , as well as the activity of MgTi05 in the solid solution with Fe2Ti05 have been calculated. The results show that, from a thermodynamic viewpoint, sulfation of these impurities in titaniferous stags i:s favorable- at around and below 800ºC.

Jan 1, 1985

By Armin D. Ebner

A hetero-f1occulation model is developed to calculate the net force exerted on a paramagnetic nanoparticle that is moving in the proximity of a magnetite particle that is fixed or supported within an open flow and magnetically energized packed bed. Important variables investigated include the size and surface charge of the particles, the magnetic field, the ,flow velocity, the electrolyte concentration and the magnetic susceptibility of ,the nanoparticle. The ?influence: of other naturally occurring forces, such as hydrodynamic and DLVO(Le., van der Waals and electrostatic) forces on the magnetic attractive forces between the magnetite particle and the nanoparticle are also examined. This model reveals the feasibility of using magnetite particles instead, of stainless steel as the energizable element for high gradient magnetic separation.

Jan 1, 1999

By R. H. Rubisov

Sulphuric acid pressure leaching of nickeliferous laterites has attracted considerable attention from the nickel industry during the past five years. The process is especially advantageous for limonitic laterites that mostly contain goethite, because iron precipitates releasing acid and thus rendering low acid consumption. It is also applicable to mixtures of limonites and saprolites, although at higher acid consumption due to magnesium. Effective process design requires the solubility of metals that precipitate during the process to be known. In the present work, determination of metal solubilities is based on a simple speciation program that assumes the presence of only one dominant complex for each metal. The thermodynamic data for the precipitation reactions are extracted from high-temperature experiments with monometallic systems published previously. The validity of the approach is then tested against mixed bimetallic systems, and finally applied to calculate the solubility of aluminium, iron and magnesium in laterite leaching effluents "at temperature". In both cases of limonitic feed and limoniticfsaprolitic blends, the prediction closely follows metal solubilities measured experimentally at temperatures from 230 to 270°C and at terminal he acidities ranging from 10 to 75 g/L.

Jan 1, 1999

By Jinxing Ji

Several fundamental aspects related to the nickel electrowinning from chloride electrolytes have been addressed in this paper. The thermodynamic study includes the activity coefficient of the hydrogen ion and the speciation diagram of NiCI2 solutions. The activity coefficient of the hydrogen ion (YH+) was calculated and estimated experimentally using a combination glass pH electrode. It was found that YH+ was greater than one in concentrated NiCl2 solutions and increased significantly with increasing NiCl2 concentration. The speciation diagram for NiCl2 solutions was plotted with YH+ and the effect of the ionic strength on the equilibrium constants being taken into account. It was discovered that the predominant nickel species in the acidic region were Ni2+ and NiCI+ in 0.937 M NiCl2 solution at 25°C. Electrodeposition tests demonstrated that higher Nit' concentration in the electrolyte improved the current efficiency of nickel electrodeposition (CENi). The additions of H3BO3, and NH4Cl increased very little the current efficiency of nickel electrodeposition at pH 1.5 and temperature 60°C. However, the addition of sulfate decreased the current efficiency of nickel electrodeposition. Nickel electrodeposition was also found to be a steady-state process since the amount of acid added to the electrolyte at a constant pH increased linearly with time during galvanostatic electrodeposition. The cathode surface pH during nickel electrodeposition was measured using a flat-bottom combination glass pH electrode and a 500-mesh gold gauze as cathode. The cathode surface pH was found always to be higher than the pH in the bulk electrolyte, and if the current density was sufficiently large, it would eventually reach a level causing precipitation of insoluble Ni(OH)2(s) on the cathode surface. Rotating disc electrode studies revealed that the rate of nickel electrodeposition was first order with respect to the activity of nickel ion and zero order with respect to the activities of chloride and hydrogen ions. The rate of hydrogen evolution was found to be first order with respect to the activity of hydrogen ion and to be zero order with respect to the activities of nickel and chloride ions. These findings indicate that nickel deposition and hydrogen evolution proceed independently.

Jan 1, 1995

By Run Huang, Xuewei Lv, Songli Liu, Chenguang Bai

"Titanium alloy was prepared from titania-bearing blast furnace slag (Ti-BF slag) by aluminothermic process in an induction furnace. The effects of aluminum amount on the titanium silicon yield and titanium recovery ratio were studied. The phase transformation and chemical composition of the prepared alloy were investigated by X-ray diffractometry (XRD) and X-ray fluorescence (XRF) respectively. It was found that the mass fraction of silicon and aluminum increased with increasing the aluminum amount, however, the mass fraction of titanium increased first and then decreased with increasing the aluminum amount. Furthermore, both the titanium alloy yield and titanium recovery ratio increased with the increase of aluminum amount. The main phases of the alloy were TixSiy and AlTi3. The titanium alloy samples prepared in various conditions had a composition (wt.%): 38–50% Ti, 29-34% Si, 4-11 Al%, 1.6-2.2 Mn%.IntroductionPanzhihua and Xichang regions in the southwest of China are rich in vanadium-titanium magnetite containing iron, vanadium, titanium and gangue. According to the characteristics of the resource, iron and vanadium are successfully recovered with a blast furnace process and a converter process. However, most content of titanium are entered in the blast furnace slag with TiO2 22% -26% and metallic Fe 2%–6% called Ti-BF slag. Due to the dispersed distribution of Ti in various fine grained mineral phases with a complex combination between Ca, Al and Si, it is difficult to recover the Ti components[1]. This slag is generated at a current rate of 3.6 million tons per year, which adds to the existing 70 million tons of slag produced so far[2]. The slag has had to be piled as large as the mountains, which not only waste of resources but also cause a pollution of the environment. Therefore, the study of integrated utilizing Ti-BF slag has become very significant."

Jan 1, 2012

By Desmond Cook, Cynthia P. Dogan, Dale Govier, Gary Korth, James C. Rawers

"The microstructural and mechanical properties of iron powders processed in an attrition mill are highly dependent upon the processing environment. Extended high-energy ball milling in argon resulted in nanocrystalline bcc-Fe microstructure, while processing in nitrogen or alloying with carbon resulted in both nanocrystalline bcc-Fe and bct-Fe microstructures. In this U.S. Bureau of Mines study, both X-ray diffraction and Mössbauer analysis were used to show that the infused carbon and nitrogen concentrations were predominantly on the grain boundaries. Explosive consolidation resulted in a fully dense product with microstructure similar to the microstructure of the mechanically processed powder. Hardness values of the compacts correlated highly with grain size, independent of the processing conditions.IntroductionNanocrystalline materials have been theorized and shown to have unique properties that make them interesting for material scientists and promising for material engineering applications. Several conferences have been devoted solely to the techniques of preparing nanostructured materials have been held(l,2,3.). To date, most techniques used to generate nanocrystalline materials produce only a few grams of particles(1). High-energy ball-milling, however, is an efficient and effective technique that can produce substantial quantities of nanocrystalline materials with homogenous chemical composition that cannot be produced by conventional processing techniques(3).Applications and material evaluations of nanocrystalline materials require several grams of solid samples. Because nanocrystalline microstructures' are thermodynamically unstable, producing consolidated macro structures of nanocrystalline material has proved to be very difficult(2,3). In particular, retention of the nanocrystalline microstructure during consolidation of nanocrystalline particles has proven to be a problem. In contrast to many consolidation techniques that require elevated temperatures, explosive compaction uses a shock wave for consolidation( 4,5)."

Jan 1, 1994

By Y. A. Chang, J. Woodford, C. R. Kao

Reactive diffusion studies between NbC and Si were carried out at 1300 °C under a vacuum of 10-5 torr and a uniaxial pressure of 1 MPa. The annealing time ranged from 8 to 100 hours. The Si used was single crystal silicon; the NbC was hot-pressed powder compact. A NbSi2+SiC two-phase reaction layer formed with NbSi2 as the matrix and SiC as discontinuous particles. The microstructure of the reaction product is homogeneous, dense, and fine. The NbSi2 grain size and SiC particle size are in the micron range. The growth of the reaction products follows parabolic kinetics. Extrapolation of the data to zero thickness suggests an apparent incubation time of 3.5 hours. However, for short annealing time «60 hours), the thickness data can be approximated by linear kinetics with an initial growth rate of about 2 11m/hr. Based on these experimental observations, a growth mechanism for the reactive diffusion between Si single crystal and NbC powder compact is proposed. We propose that the nucleation sites for the SiC particles are at the voids of the NbC powder compact. This proposed nucleation mechanism offers a potential way of controlling the SiC particle size by changing the void size and void density of the NbC powder compact. This hypothesis, if proven to be true, will allow us to control mechanical properties of the composites by tailoring the SiC particles formed. It is also pointed out that the microstructure requires Si to be the dominant diffusing species and to diffuse through the reaction layer, while Nb and Conly have to undergo local rearrangement.

Jan 1, 1996

By Deyou Yin, Kongfang Feng, Bo Wang, Jieyu Zhang, Xin Hong, Shaobo Zheng, Jinyin Xie

"The flow patterns and mixing characteristics in a water model of C-H2 smelting reduction furnace are experimentally studied in this paper. Water modeling is employed to investigate the features of gas jet stirring and the fluid flow patterns in the bath of a smelting reduction furnace during the top, bottom, and side combined blowing process. The influence of the gas flow rate for top, bottom and side nozzles, angle, submerged depth of each side nozzles and the height of the top nozzle has been examined. It showed that the gas flow rate of side nozzles and bottom nozzle had a key role on the fluid flow and mixing characteristics. The gas jet from the top nozzle could change the agitation and fluid flow pattern caused by the gas jets from the side nozzles in the bath.IntroductionFacing the current natural resources decrease and the environmental degradation, smelting reduction iron-making technique is believed to be the most representative at present. Mid last century, the concept of producing liquid iron or semi-steel directly from ore fines and inexpensive fuel was the subject of considerable pilot plant development activity. Among these projects, the direct smelting process, which is the reduction and melting of iron-bearing materials by carbon and other hydrocarbons in the vessel containing a molten bath, is the most popular one. A number of direct smelting processes have been developed around the world, e.g. COREX, DIOS, HIsmelt, AISI, ROMELT, etc.These studies put forward a new technology, which through bottom nozzle blowing rich hydrogen, top nozzle blowing rich oxygen and provide preheating ore and solvent, side nozzles blowing oxygen-coal to realize smelting reduction iron-making process. Owing to the metallurgy reactions always in high temperature, which is above 1600 °C, it is difficult to visualize the mixing behavior and measure the desired phenomena in the reduction vessel. With water modeling, the primary advantages are that it is relatively easy to observe and measure the flow phenomena in the bath."

Jan 1, 2011

By L. Yin, R. B. Haber, N. Sobh, D. A. Tortorelli, R. W. Hyland Jr.

"We optimize continuous quench process parameters to produce a desired precipitate distribution in aluminum alloy extrudates. To perform this task, an optimization problem is defined and solved using a standard nonlinear programming algorithm. Ingredients of this algorithm include a cost function, constraint functions and their sensitivities with respect to the process parameters. These functions are dependent on the temperature and precipitate size which are obtained by balancing energy to determine the temperature distribution and by using a reaction-rate theory to determine a discrete precipitate particle size distribution. Both the temperature and the precipitate models are solved via the finite element method. Since we use a discrete particle size model, there are as many as 105 degrees-of-freedom per finite element node. After we compute the temperature and precipitate size distributions, we must also compute their sensitivities. This seemingly intractable computational task is resolved by using an element-by-element discontinuous Galerkin finite element formulation and a direct differentiation sensitivity analysis which allows us to perform all of the computations on a PC.1 IntroductionThis work addresses the need for an integrated design capability that links microstructure evolution to the process parameters. It is motivated by the manufacture of lightweight aluminum-alloy extrusions for use in automotive structures. Aluminum alloys offer obvious benefits, however, care must be taken to manufacture favorable microstructures that ensure acceptable structural performance. For example, the manufacturing process for 6000-series components involves hot extrusion of cast aluminum billets followed by either an air or water quench process. The bill~t's initial grain structure is dramatically altered during extrusion by massive mechanical deformations and recrystallization processes. The microstructure continues to evolve during the quench, as complex chemical processes determine the formation of precipitates. The control of the precipit'ate size distribution is vital. Indeed, large precipitates located on grain boundaries serve as crack initiation sites which adversely effect structural crash· worthiness."

Jan 1, 2000

By D. V. Hughes, J. R. Nyberg

"Since 1985, a comprehensive automation system has been installed at the Outokumpu Oy Zinc Plant, Kokkola, Finland. In leaching and solution purification special sample handling equipment, on-line analyzers and instruments, and a computer-based control system with duplicated supervisory stations have been installed. The system has enabled closer control of the process and more efficient use of labor. Since its installation recovery of zinc has improved, and use of zinc dust, steam, and water have decreased. The system has performed reliably. It includes optimizing programs and process study tools, which facilitate improving process performance. An expert system has been built-up to prompt process personnel to take appropriate action on the basis of process data. In electrolysis a similar system, based on extensive monitoring of the process and of production of zinc cathodes, is used to maximize- current efficiency by maintaining optimum conditions in the process. It is planned that in the future the control systems will be integrated and extended to cover the roasting plant and effluent control.IntroductionThe Zinc PlantThe Zinc Plant of Outokumpu Oy Metallurgical Division at Kokkola, on the West Coast of Finland, has grown from a 90,000 t/a plant founded in 1969 to become, with its present capacity of 170,000 t/a, one of the world's ten largest zinc plants. Especially since the completion in 1988 of a thorough modernization programme, it is also among the world's most modern.The Kokkola plant takes its raw materials from Outokumpu's own mines, Vihanti and Pyhasalmi in Finland, and Tara in Ireland, and from outside sources. Concentrates are roasted in two Lurgi fluid-bed furnaces, and the calcine is leached and iron removed by the Conversion process. Following this copper, cobalt, and cadmium are removed, and zinc is refined by electrowinning. The leaching and purification, and the cell-house are automated under computer-based control, and anode and cathode handling in the cell-house are mechanized and fully automatic."

Jan 1, 1989

By R. P. King

The linear intercept distributions provide unambiguous and accurate characterizations of the texture of mineralogical materials. The relation between the measured linear intercept distributions and the spatial correlation function is shown to be given by: in the Laplace Transform domain. The linear intercept distributions of the two phases in a low- grade chromite-serpentinite ore were measured. and the spatial correlation functions for both phases were evaluated using the above relation. The correlation functions are the primary relations for integral geometric models of mineralogical texture and this work demonstrates the relation between the 10 stereological model and the 3D integral geometry model for mineral liberation.

Jan 1, 1991

By Jie E. Zhou, Yu U. Wang

"Development of crystallographic texture in polycrystals during templated grain growth process is studied by phase field modeling and computer simulation. To characterize the grain texture development, X-ray diffraction peak intensities are computed for the evolving grain structures as simulated by the phase field model, based on which Lotgering factor is further calculated as a quantitative measurement of uniaxial texturing. While the phase field modeling allows direct comparison between simulated grain structures and experimental microscopy observations, the computational diffraction allows convenient correlation between computer simulation and experimental X-ray diffraction characterization. The latter feature is especially desirable, since microscopy experiments normally require more efforts than X-ray diffraction, and diffraction is usually the preferred choice for material characterization.IntroductionThe properties of individual grains in polycrystals are generally anisotropic, while untextured polycrystalline materials with random grain orientations exhibit isotropic macroscopic properties that are independent of directions. In order to achieve anisotropic response in polycrystals, crystallographic texturing of grains is required [1]. Texture refers to the collective distribution of grain orientations towards preferred orientation in a polycrystal. To develop texture, special processing routes are needed, such as templated grain growth (TGG) for uniaxial texture [2]. TGG has been shown to provide uniaxial texture in wide variety of materials. For example, [001]-textured ferroelectric polycrystalline ceramics have been fabricated by TGG process, which exhibit enhanced piezoelectric properties [3]. Such highly textured polycrystalline materials offer better cost-performance ratio than single crystals. Thus, texture development in polycrystals is of technological importance for material applications.In this computational work, grain texture development in polycrystals during TGG process is studied. Grain structure evolution is simulated by phase field model, X-ray diffraction peak intensities for the evolving grain structures are computed, and Lotgering factor is calculated to quantitatively measure the development of uniaxial texturing. The phase field modeling allows direct comparison between simulated grain structures and experimental microscopy observations using imaging techniques such as scanning electron microscopy or optical microscopy. The computational diffraction allows convenient correlation between computer simulation and experimental X-ray diffraction characterization. The latter feature is especially desirable, because microscopy experiments normally require more efforts than X-ray diffraction, thus diffraction is usually the preferred choice for material characterization."

Jan 1, 2014

An iridium oxide coated titanium electrode was tested as anode in copper electrowinning. Initial results confmed that the DSA-type anode was significantly more active for oxygen evolution than traditional lead anodes. However, during longer runs, the anode potential was observed to increase linearly at a rate of 220 mV/year. Scanning elecuon microscopy (SEM) and energy dispersive spectroscopy (EDS) showed that the anode passivation could be attributed to elecuochemical dissolution of the coating. The effect on the anode potential of organic additives (glue and thiourea) and lead in solution was also examined. A preliminary economic evaluation of the anodes is given.

Jan 1, 1992