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By Harovel G. Wheat

It has been shown that the incorporation of fly ash into concrete as a replacement for part of the cement can be beneficial. In some cases, the strength of the concrete can be increased and the permeability can be decreased. This latter property can lead to a reduction in the migration and/or penetration of aggressive species into reinforced concrete. Some of these species, such as chlorides from deicing salts or marine environments, can subsequently result in accelerated corrosion of the steel reinforcement, a loss of the protection provided by the passive film on steel, and a loss of structural integrity of the concrete. Care has to be taken so that the appropriate compositions of the components of the fly ash are utilized in order to ensure maximum benefit to the concrete structures. This will be discussed as it relates to fly ash generation and treatment.

Jan 1, 2002

By Ana P. Paiva, Marc F. Comella, Sandra S. Reis, Joao N. Reis, M. Soledade Santos

"In this work, the influence of the malonamide structure, acidity of the aqueous phase and diluent on the equilibrium interfacial tension (IT) of N,N'-dimethyl-N,N'-diphenylmalonamide (DMDPHMA) and N,N'-dimethyl-N,N'-dicyclohexylmalonamide (DMDCHMA) in 1,2- dichloroethane (1,2-DCE), and DMDCHMA in toluene, with aqueous HCl, were investigated. IT isotherms were determined using the Du N ouy ring method. Densities of the organic phases were determined, and used to screen solute-diluent interactions. Formation of third phases was never observed; furthermore, ITs increase with the phase separation period, constant values being obtained for separation periods larger than 1000 seconds. Each malonamide interfacial efficiency at the oil/water interface is interpreted in terms of malonamide basicity, diluent polarity and malonamide - hydrochloric acid- diluent interfacial interactions.IntroductionFor several years now, N,N'-tetrasubstituted malonamide derivatives have been extensively investigated as liquid-liquid extraction agents since they were first proposed as the organic components of the DIAMEX process, with the aim of advantageously replacing tributylphosphate in PUREX [1]. Therefore, a significant part of research studies with malonamides appearing in the literature deal with the extraction of major and minor actinides in real or simulated spent nuclear fuels in nitric acid solutions [2]. Under typical experimental process conditions, the tendency shown by some N,N'-tetrasubstituted malonamide derivatives to aggregate in the organic phase, leading in a few cases to the formation of undesirable third phases, has been remarked and consequently thoroughly investigated [3, 4]. The increasing use of chloride streams as hydrometallurgical aqueous feeds is becoming a reality, and this fact is obviously deeply founded on an extensive research carried out to recover value-adding metals from these media. Following this trend, a number of N,N'-tetrasubstituted malonamides have already been screened for the recovery of iron(III) [5, 6] and platinum-group metals [7] from hydrochloric acid solutions. The results obtained are quite promising either in terms of total metal ion recoveries or selectivity patterns achieved. The formation of a third phase when iron(III) was extracted by the tested N,N'-tetrasubstituted malonamide derivatives has never been observed under the adopted experimental conditions, and the extraction data collected would need to be reinterpreted accordingly if any aggregation phenomena involving the considered extraction systems were to take place."

Jan 1, 2011

By James Cornwell, John A. Elton

"Thermionic induced reactions and radiation resonance catalysis of aluminum and aluminum oxide materials exposed to microwaves and triboemissions will be described and explained from both a fundamental and practical level. Magnetron operation at distinct operating conditions that generates both plasmon and triboemissive radiation will be explained and the resulting tribochemical and radiation resonance catalytic reactions between aluminum, aluminum oxide, water and graphite will be delineated. The generation of hydrogen from these materials using triboemissive radiation and microwaves will be described, and the application of this methodology for hydrogen based technologies will be discussed.IntroductionProtective Systems Directed Energy RadiationProtective Systems, Inc, has developed a new radiation device called the EMR (Electromagnetic Resonator) that has unique characteristics that separates it from traditional microwave and rf radiation devices. The radiation from the EMR device is generated using a modified electronresonance magnetron with proprietary filters and operating characteristics.Electronic Device Shutoff. When electronic devices such as cell phones, computers, and other IC based electronics are placed within the EMR radiation, these devices become non-functional as long as the EMR beam is active. Upon removal of the EMR radiation the devices either become operational again or become operational after a cold start. The devices are not damaged by the irradiation.Faraday Cage Interaction Effect. When any of the above electronic devices are placed in a Faraday cage and activated within the Faraday cage without EMR radiation, they operate normally. However, these devices will still be rendered inoperative when an EMR beam generated outside the Faraday cage is directed at the electronic."

Jan 1, 2010

By E. S. Peterson

The selective separations of trace metals- and organics from water are processes of importance to industry. The application of a new metals capture technology coupled with polymer membrane technology has proven to be one avenue to accomplish such selective separations. The polymers used in these studies are polyphosphazenes. Polyphosphazene polymers consist of an alternating backbone of nitrogen and phosphorus atoms. The polymers have high thermal and chemical stabilities. Experiments at the Idaho National Engineering Laboratory demonstrate that polyphosphazene membranes coupled with Chromato Chem,"Chelation Chromatography" process are capable of removing both chlorinated hydrocarbons and metal ions from process streams. These results point to a wide range of potential industrial and environmental applications for such systems. Data will be presented which show the efficiency and selectivity of separations, postulated separation mechanisms, and the initial designs of industrial demonstration units which are currently under construction. Parts of this work have been performed under a Cooperative Research and Development Agreement (CRADA) between ChromatoChem, Inc. and Idaho National Engineering Laboratory (INEL). The work at INEL was been sponsored by the United States Department of Energy's Office of Industrial Technologies

Jan 1, 1995

By Robert Vidal

A model of the homogeneous chemistry and transport processes within the separator of a chrome-alum electrowinning cell is introduced, discussed, and compared to experiment. The influence of diffusion, electromigration, and convection are included; it is found that convection was the dominant mode of transport for the experimental conditions. Simulation results explain experimental observations concerning an apparent disappearance of dichromate ions produced at the cell anode. The relation between potential drop across the diaphragm and the current and fluid flow is also illustrated. The model is used to recommend future experimental and theoretical work.

Jan 1, 1994

By S. J. Buckler

Many chemical and metallurgical processes use submerged gas injection to increase contact area between gas and liquid phases in order to promote faster overall reaction or refining rates. The total interfacial area produced by gas injection through lances, nozzles or tuyeres is both an important design parameter for new vessels and a measurement for estimating the maximum processing capacity of existing equipment. Estimating total interfacial area from submerged injection into industrial pyrometallurgical vessels from existing knowledge is a problem with two aspects. The first difficulty is the difference in behaviour of cold (aqueous) and hot (molten metal) systems, implying that existing models and correlations of gas-liquid behaviour developed in low temperature systems are not necessarily appropriate for estimation of high temperature behaviour. The second difficulty is the issue of scale-up of correlations from laboratory to industrial sized vessels. The work presented in this paper is part of an ongoing experimental investigation, at the GK Williams CRC for Extractive Metallurgy, to quantify the total gas-liquid interfacial area available in pyrometallurgical vessels using chemical measurement methods. The effects of three operating variables, injected gas flow rate, nozzle diameter and nozzle submergence, on total interfacial area are quantified in a IOOL aqueous system - the first stage of a three stage process in examining the implications for scale-up of high temperature, medium-scale results are discussed. The results of work at high, injected gas flow rates (up to 500/min) show that the submerged Froude number is not sufficient for use as the sole variable in a predictive model of total interfacial area. Further work is being undertaken to identify other dimensionless variables that will better represent the gas-liquid characteristics in submerged injection that influence the formation of total interfacial area. The second and third stages of the experimental investigation involve measuring the total interfacial area in a large-scale (1000L) aqueous sodium sulphite and small-medium scale molten metal baths.

Jan 1, 2002

By Amy Anderson

The Silica (SME) Technology has been utilized on three separate projects focusing upon the stabilization of mercury-contaminated materials: at the Mother Lode Mine in Oregon, the Sulfur Bank Mercury Mine in California and at a former chloralkali plant in British Columbia. Each of the projects relied primarily on the results collected via EPA Method 1311 TCLP, with additional tests such as SPLP, humidity cell tests and other supporting tests employed as well. Both technical and economic performance of the silica-based technology was evaluated as well as that of competing technologies in some cases. Results established that in each of the three projects an SME chemical dosage rate of 3% chemical by weight of soil/sludge was the optimal ratio required to achieve project treatment objectives, TCLP test results exhibited a reduction in the leachable mercury from the treated materials ranging between 75% and 99% as compared to untreated material, satisfying the technical objectives for each project, Project costs ranged from $l5.00 - $18.26 per metric ton.

Jan 1, 2003

By L. L. Sutter

Fly ash is a by-product produced from the combustion of most hels including municipal solid waste. Currently, most combustion residuals are disposed of in landfills at a continually increasing cost and with questionable impact on the environment. Due to the presence of heavy metal compounds, municipal waste combustor (MWC) fly ash has the potential to leach these metals (e.g., lead and cadmium) above regulatory limits. The heterogeneous nature of MWC fly ash makes detailed characterization difficult. This research focuses on the identification of lead compounds in MWC fly ash. Samples obtained from the Olmsted Waste-to-Energy Facility in Rochester, Minnesota were examined in this study. The fly ash was fractionated into six size ranges and prepared as geological thin sections for analysis. The worked discussed in this paper involves using an electron microprobe analyzer to determine phase composition in MWC fly ash. In addition, backscattered electron imaging, digital image processing, and mineral liberation analysis software were used to determine phase distributions and phase associations as a function of particle size. Several lead containing compounds in several forms are identified. The results of this study show that lead can be identified in small sectioned particles which would not be apparent using normal backscattered electron imaging.

Jan 1, 1994

By Y. Zhoa

The surface morphology of materials is of fundamental importance to many surface related applications, such as wetting, friction, reflection, drag, and adhesion. Various approaches for micro/nano patterning atop polymer surfaces have been proposed in recent years. However, a cost effective technique is still highly in demand. In this paper, we demonstrate a novel but rather simple and generic approach for surface micro/nano patterning using shape memory polymers (SMPs). Different types of novel patterns are realized and their 3-D surface features are quantitatively analyzed by a PLµ Confocal imaging profiler.

Jan 1, 2010

By Regina Krachler, Herbert Ipser

"The principles of the derivation of statistical-thermodynamic models to interpret the compositional variation of thermodynamic properties in non-stoichiometric intermetallic compounds are discussed. Two types of models are distinguished: the Bragg-Williams type, where the total energy of the crystal is taken as the sum of the interaction energies of all nearest-neighbor pairs of atoms, and the Wagner-Schottky type, where the internal energy, the volume, and the vibrational entropy of the crystal are assumed to be linear functions of the numbers of atoms or vacancies on the different sublattices.A Wagner-Schottky type model is used for the description of two examples with different crystal structures:For B'-FeAl (with B2-structure) defect concentrations and their variation with composition are derived from the results of measurements of the aluminum vapor pressure; the resulting values are compared with results of other independent experimental methods.For Rh3~ (with an NiAs-derivative structure) the defect mechanism responsible for nonstoichiometry is worked out by application of a theoretical model to the results of tellurium vapor pressure measurements. In addition it is shown that the shape of the activity curve indicates a certain sequence of superstructures.In principle, there are no limitations to the application of statistical thermodynamics to experimental thermodynamic data as long as these are available with sufficient accuracy, and as long as it is ensured that the distribution of the point defects is truly random, i.e. that there are no aggregates of defects."

Jan 1, 1996

By John Snowberger III, J. Brent Hiskey

The electrochemical dissolution of super alloys containing different amounts of rhenium was investigated. The initial part of the investigation focused on the anodic dissolution of rhenium from second-generation (3% Re) and third-generation (6% Re) nickel based alloys. Exploratory electrochemical tests were conducted to evaluate solution chemistries and to establish fundamental dissolution behavior of the alloys. These included rotating disc electrode (RDE) cyclic voltammetry, linear sweep voltammetry, and chronoamperometry tests. Electrolytes comprising sulfuric acid, hydrochloric acid, and ammonium sulfate were examined. Of these, a 0.1 M HCl solution proved to be extremely effective for electrochemical dissolution of samples of CMSX-4, CMSX-10, and SC-180 alloys. This paper discusses in detail the electrochemical behavior of these alloys.

Jan 1, 2014

By Kwong. Kyei-Sing

Gasification is a process that converts a carbon feedstock into synthesis gas (CO+H2). Slagging gasifiers operate at high temperature and pressure and in a corrosive-wear environment from the slag. Cr2O3-based refractory linings are used to protect the steel vessel that comprises the gasifier from the aggressive gasification environment. Increasing service life of the gasifier is one of the keys for wide spread development of this technology. In support of the goals, research on the gasifier atmosphere, the slag chemistry, the interaction of Cr2O3 refractory with different feedstock mixtures (e.g., coal and petcoke) were characterized by post mortem analysis of bricks from service in gasifiers and thermodynamics simulation of the environment. Examples demonstrating how thermodynamic calculations can explain the post mortem results and make predictions of material interactions will be given. Attention is placed on the possibility of Cr+6 in different feedstock mixtures and operating conditions.

Jan 1, 2010

By J. Etay, S. Daugan, Y. Fautrelle

"New type of electromagnetic parametric instabilities arising at the free surface of liquid metal in the presence of a low frequency magnetic field are presented. First, the mechanism of the instability is analysed in an idealised case. Then, the experimental device working with mercury is described. Various shapes, both regular and irregular, of free surface are found. A experimental stability diagram is obtained. Measurements of the deformation performed on photographs are compared with physical orders of magnitude.IntroductionWhen a liquid metal pool of electroconductivity a is submitted to an A.C. magnetic field B = B0 cos mt, electrical currents j are induced in the liquid metal and interact with the applied magnetic field to create electromagnetic body forces F = j x B. Those Lorentz forces comprise both a mean value (time average) and an oscillating part. Those forces are widely used in many metallurgical processes to stirr a liquid metal or to control its free surface, e. g., in aluminium continuous casting or electromagnetic levitation problems (1-3). When liquid metal free surfaces are submitted to AC. magnetic fields, the shape of those interfaces may interact with the applied field and leads to a various instabilities. A review of these instabilities may be found in Fautrelle (4). That instabilities may be a problem for the control of processing as electromagnetic levitation or quasi-levitation."

Jan 1, 1999

By Filippos Patsiogiannis

Laboratory size (4.5 kg) low carbon steel melts were deoxidized using Al and FeAl (33% Al), with and without synthetic fluxes, in alumina and zirconia crucibles. The dissolved oxygen, total oxygen, soluble aluminum, insoluble aluminum, silicon and carbon contents in the melt were determined as a function of refining time and temperature. It was observed that the reaction between aluminum and oxygen in solution closely follows thermodynamic equilibrium. Silica present in the alumina crucibles was found to be a source of oxygen for the melt, while this was not the case for zirconia crucibles. Reoxidation of the melt occurred through oxygen pick-up from the atmosphere. The extent of this reoxidation was found to be a function of oxygen content of the bath and the slag cover on the surface of the melt. The effectiveness of calcium-aluminate based fluxes in protecting the melt from the reoxidation and in increasing the rate of removal of inclusions was evaluated.

Jan 1, 1992

By S. N. Lekakh

Phosphorous segregated at grain boundaries during solidification and heat treatment dramatically decreases low temperature toughness of precipitation hardened Fe-Mn-Al-C austenitic steel. A thermodynamic analysis was performed to evaluate the possibility of decreasing P and subsequent segregation by Ca- and Ce-additives in the melt. It was shown that the predicted probability of forming a P containing compounds depends on melt composition and treatment sequence. Experimental heats were performed and several micro- and macro-structural effects of Ca- and Ce-additives were recognized by using an automated inclusion analysis technique.

Jan 1, 2010

By Xue Sun, Dengfu Chen, Yuting Chen, Mujun Long, Song Xu, Helin Fan

In order to seek an effective extraction process for vanadium, the recovery of vanadium from a high Ca/V ratio vanadium slag was studied by sodium roasting and ammonia leaching. In the present paper, the oxidation and leaching process of vanadium slag was investigated by X-ray diffraction (XRD), scanning electron microscopy and energy dispersive X-ray spectrometry (SEM/EDS) techniques. The effects of ammonium carbonate concentration, leaching temperature and leaching time on the leaching ratio of vanadium were discussed. As indicated in the experimental result, the optimal (NH4)2CO3 concentration was 120g/L, leaching temperature was 60°C and leaching time was 20 min. Approximately 92% of the vanadium was recovered under the optimal conditions. Furthermore, by means of X-ray diffraction analysis, the phase transformations of the vanadium slag during roasting and leaching processes were analyzed and discussed.

Jan 1, 2014

By Wen-Ming Chien

Low temperature X-ray diffraction and thermal property studies of the solid-solid state phase transition for the polyalcohols (pentaerythritol (PE), pentaglycerine (PG) and neopentylglycol (NPG)) thermal energy storage solid solutions have been investigated by using X-ray diffractometry and differential scanning calorimetry (DSC) methods. X-ray diffraction studies on polyalcohols solid solutions, PE-NPG and PG-NPG, are from ?10oC to 50oC. XRD results shows the + mixed phase at the related low temperature (?10oC) for both PE-NPG and PG-NPG solid solutions. At high temperature range, XRD results show phase for PG-NPG solid solution and + mixed phase for PE-NPG solid solution. There are only two Bragg peaks, (111) and (200), shown in phase XRD patterns. The polyalcohols solid solutions have been cycled 5 times between -20oC to 100oC at different DSC scan rates to study the phase transition properties. DSC results of both PE-NPG and PG-NPG solid solutions show that the solid-solid state phase transition is near room temperature. Details of low temperature phase transition XRD and DSC results of PE-NPG and PG-NPG solid solutions will be presented

Jan 1, 2006

By F. M. Doyle, K. Sreenivasarao

Copper and cadmium metal has been recovered from dilute (3 X 10-4 mol/dm3 ) chloride solutions by ion flotation with dodecysulfate, followed by electrolysis. This approach should facilitate treatment of effluents too dilute for effective direct electrolysis. . The adsorption density of metal dodecylsulfate complexes on bubble surfaces was estimated from surface, tension data, and compared well with experimentally-observed metal removal kinetics, and ultimate recoveries. Copper and cadmium were recovered by electrolyzing the foamate, using steel wool cathodes and a graphite anode. The stability constants of the copper and cadmium dodecysulfate complexes are estimated, and used to analyze the thermodynamics of electrolysis. Dodecysulfate was unaffected by the electrolysis process, and hence could be recycled to ion flotation. A conceptual flowsheet for an overall effluent-treatment process is presented.

Jan 1, 1997

By Rajashekhar Marthi

Lithium is a key component for future electric vehicle batteries and energy storage. The future availability of lithium to meet the growing demands remains in question. Around 60% of lithium resources exist in the form of continental brines. Traditional methods to recover lithium from brines use solar concentration with precipitation and have found limitations in lithium extraction due to interference of Mg in high Mg/Li brines. Thus, there is a need for highly selective adsorbents. Recently, spinel structured delithiated lithium manganese oxides have demonstrated promising results. However, due to the small particle sizes, it is economically difficult to recover the adsorbents and thereby limits industrial applications. In our work, LiMn2O4 ion sieve was synthesized and immobilized on diatomaceous earth. Fundamental adsorption studies were carried out in lithium buffer solutions to understand the nature of adsorption and kinetics. The adsorbents were also tested for recycle stability, as well as recovery of lithium from Great Salt Lake water samples.

By Richard J. Abitz

Thennodynamic geochemical models have been applied to assess the relative effectiveness of a variety of reagents added to aqueous waste streams for the removal of radioactive elements. Two aqueous waste streams were examined: effluent derived from the processing of uranium ore and irradiated uranium fuel rods. Simulations of the treatment train were performed to estimate the mass of reagents needed per kilogram of solution, identify pH regions corresponding to solubility minimums, and predict the identity and quantity of precipitated solids. Results generated by the simulations include figures that chart the chemical evolution of the waste stream as reagents are added and summary tables that list mass balances for all reagents and radioactive elements of concern. Model results were used to set initial reagent levels for the treatment trains, minimizing the number of bench-scale tests required to bring the treatment train up to full-scale operation. Additionally, presentation of modeling results at public meetings helps to establish good faith between the federal government, industry, concerned citizens, and media groups.

Jan 1, 1996