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By Mario H. Castro-Cedeno

"A design for a handheld MEMS chemical detector is proposed. The detector will be used to detect trace amounts of chemicals in air. It can detect drugs, toxic chemicals and/or explosives. The proposed detector will use ion mobility spectrometry (IMS), a technique that is well known for accuracy and has been used in the past in suitcase sized chemical detectors. The separation and detection of the chemicals occurs in the drift channel and the process was modeled using the finite element method and CoventorWare modeling software. A manufacturing process sequence for the drift channel is proposed and was demonstrated.IntroductionThe goal of this effort is to design, mode~ and prototype a MEMS chip that will be the key component in an ion mobility spectrometer (IMS). This technique uses and asymmetric potential to separate the various ion species in a stream of incoming air [1-4]. One advantage of IMS is its ability to separate chemical species from air at atmospheric pressure and temperature. This is a requirement for a simple to use handheld drug or chemical detector. IMS can be used to detect drugs, toxic chemicals and explosives and it is well known for accuracy in detecting very small amounts of chemicals. This chemical detection technique has been used in the past, but not in handheld detectors.One variant of IMS is the high-field asymmetric waveform ion mobility spectrometry or FAIMS [3]. The FAIMS process, shown in Figure l, works as follows: a gas sample is admitted into the instrument where gas molecules are ionized, typically by a weak radioactive isotope source, ultraviolet light source; and more recently through field emission. The ions move along the length of a channel while they are separated in the transverse direction by an asymmetric electrical potential. The potential, in the form of an asymmetric waveform, causes relative motion between the various chemical species. The species that hit the charged top and bottom plates are neutralized and only those ions that move along the center are detectable as charged chemical ions at the end of the channel."

Jan 1, 2004

By LuisW. Pommier

The industrial wastes generated by the plating industry, the circuit board manufacturing industries and other related industries normally contain high concentrations of metals, which make them hazardous. The extraction of the contained metals and their separation may be achieved by both pyro and hydro metallurgical processes. Some of the industrial wastes, those rich in some metals like nickel for instance, are being treated like mine ore concentrates and are being fed to smelting furnaces. The slags from these smelter operations are hazardous. They have, however, special environmental dispensations issued by the regulatory authorities. Hydro-metallurflcal processes have been reported. They also generate a residue which is hazardous because not all the valuable metals are leached out and also, because "non valuable" components, like chromium, are less readily leached. Residues from the plating industry, containing nickel, copper. zinc, iron and chromium as the major constituents and also sodium and calcium, together with cadmium, cobalt, lead. manganese, magnesium, molybdenum, and potassium, have been processed for the extraction of the valuable components. The generation of electrolytic nickel, copper and zinc and also of ferric chloride and chromium oxide is reported. The operation is achieved by a caustic leach for the extraction of zinc, followed by a sulfuric acid leach for the extraction of nickel and copper. This acid leach also extracts the iron and some chromium. The nickel copper and zinc are rendered pure by electrolysis, the iron is oxidized for the production of ferric chloride and the chromium is recovered as an oxide. The leaching operation is performed in two stages, first at a pH of 2.5 to generate an electrolyte for the partial recovery of the metals and then at a pH of 0.5 for the complete extraction of the metals. This leaching operation generates a residue, which although small in volume compared to the initial feed, still contains traces of the valuable metals and a portion of the chromium which makes it hazardous. Additional leaching with hydrochloric acid or nitric acid is required for its complete dissolution. The other minor constituents mentioned are present in concentrations each of less than 0.1% and are handled as impurities in the process. The metals which are soluble at a pH 0.5 and precipitate between 0.5 and 2.0 are bled off. Other impurities will concentrate on the raffinate from the solvent extraction operations from whence they are bled off. These bleeding streams are hazardous and the "impurity metals" are now present in concentrations which would make them valuable, however, the size of these streams is so small that they do not warrant their processing, however they could be marketed to specialized smelters. The extraction of the valuable metals, of the hazardous constituents, the generation of a marketable mixture of minor constituents and the production of a non-hazardous residue for declassification is profitably achieved.

Jan 1, 1998

Arsenic occurs naturally in rocks and soils, water, air, plants and animals. It can be further released into the environment through natural activities such as volcanic action, erosion of rocks and through human actions. Higher levels of arsenic tend to be found more in ground water sources than in surface water sources of drinking water. Compared to the rest of USA, western states have more systems with arsenic levels greater than 10 parts per billion (ppb). The US Environmental Protection Agency (EPA) has historically regulated arsenic in drinking water at 50 ppb, but the agency has lowered the maximum contaminant level (MCL) for arsenic to 10 ppb-to be in compliance by January 2006.This paper reviews briefly a) aqueous arsenic chemistry and removal mechanisms and b) the available treatment processes to attain the drinking water standard of 10 ppb by 2006. The combining of an appropriate removal method with an existing system depends on several factors such as nature of arsenic, the water source, existing plant equipment and processes site conditions etc. The paper also includes one or two case studies from the State of Arizona. Key words: Arsenic, Drinking water, Treatment Technologies

Jan 1, 2005

By Xianzhong Hu, Qingbo Yu, Qin Qin

"Oxy-fuel combustion is one promising option among different CO2 capture technologies. The object of this work is to show the effect of CO2 dilution on the laminar flame speed, flame structure and reaction pathway for methane oxidation at O2/CO2 atmosphere. In this paper, kinetic simulations were made using CHEMKIN with GRI-Mech 3.0 mechanism, which was validated by experimental data of laminar flame speeds. The reaction pathway of CH4/O2/CO2 mixture was derived from reaction flow analysis. Results showed that CO2 decreased the flame speeds, lowed concentration of major intermediates and increased flame thickness. The major chemical pathways of CH4 to CO2 have not changed at O2/CO2 atmosphere comparing with O2/N2 atmosphere, but contributions to major intermediates formation from each related elementary reaction have changed a lot. In addition, the secondary chemical pathways of CH3 oxidation became different at O2/CO2 atmosphere.IntroductionNowadays, as the global economy is developing fast and the pollutant levels (especially global warming gases) are increasing, a lot of researches are focusing on new technologies which can cut greenhouse gas emissions [1]. New technologies have been developed, such as high Mild combustion, flameless combustion and Integrated Gasification Combined Cycle (IGCC) technology. Oxy-fuel combustion using carbon dioxide as dilution of oxygen is considered as a promising approach for reducing CO2 emission. The properties of CO2 in flue gas are different from N2 in air. On one side, the transport, thermal and radiative properties of CO2 are different from N2 in air. On the other side, CO2 is not inert but directly participates in chemical reactions and recent researches [2-5] also present the chemical effects of CO2 on oxy-combustion. For these differences above, the characteristics of oxy-combustion are not alike with traditional combustion. It is necessary to develop the investigation of oxy-combustion.In all combustion processes, laminar flame speed is an important parameter, which links to combustion behavior. Analysis of this parameter can provide a better understanding of the effect of CO2 dilution in the process of oxy-combustion. Several investigations of laminar flame speeds of oxy-fuel flame have been improved, including experimental measurements and numerical computations. A.A.Konnov et al. measured the flame speeds of oxy-methane and oxy-ethane mixture using the heat flux method with a flat burner [6-8]. V. Ratna Kishore et al. used heat flux method to measure the adiabatic laminar flame speeds of hydrogen [9] and H2/CO mixture [10]. Adiabatic laminar flame speeds of hydrogen in O2/CO2 atmosphere are much smaller than in O2/N2 or in O2/Ar. The burning velocity of H2/CO mixture decreased with increase in CO2 content in mixture. Jeongseog Oh et al. [11] used Bunsen flame to measure the laminar flame speeds of premixed oxy-methane mixture with angle methods in atmospheric condition (300k, 1atm). The results were SL=29.1cm/s and SL=29.5cm/s respectively derived from oxy-methane from CH* images and Schlieren photos."

Jan 1, 2014

By G. R. Waters

NMR360 is developing a suite of chloride-based metals extraction processes, with the first commercial operation scheduled for commissioning late in 2018. It is critical, therefore, that with the introduction of any new technology, that the circuits do not suffer from mechanical failures which will compromise the operation. Although chloride leaching is at atmospheric pressure and relatively low temperature, the main challenge is preventing corrosion, since the high proton activity makes even a small amount of acid behaves as though it were concentrated. An additional challenge in concentrated chloride circuits is the potential for solids precipitation. In this context, therefore, correct valve selection is crucial, and NMR360 has partnered with CGIS to ensure that the Severe Service Valves (SSVs) needed will perform over and above the definitions of the Manufacturers Standardization Society (MSS) of the Valve and Fittings Industry. This paper outlines what the minimum requirements are for SSVs in chloride leaching applications, drawing on five decades of industry experience from one of Canada’s leading valve experts.

By Ryokichi Shimpo, Akio Fuwa

"In order to elucidate the present status of process-control technology, survey study has been made on the present process control schemes of representative copper smelting and converting processes in Japan. Conceptual control flow diagrams have been deduced and shown on respective functional reactors, i.e. drying, smelting, converting and fire-refining units, where the objective OUTPUT items are correlated to the INPUT variables through respective CAUSE-AND-EFFECT RELATIONSHIPSFuture view has been also discussed on several feasible and desirable improvement and refinement ~n measurements and control system for better copper smelting and converting operations.INTRODUCTIONIn other to seek for the better and efficient operation in copper smelting and converting process, survey study has been first conducted on the present process-control schemes of respective functional unit processes, i.e. drying, smelting, converting and refining unit processes, of representative copper production processes in Japan. Conceptual process flow chart of control scheme has been then deduced where output items are correlated to input items through the respective cause-and-effect relationships.After this survey study, future view has been discussed on the feasible and desirable improvement and refinement in the measurement and control system in these processes. Emphasis has been placed on the better and precise measurements of temperature, oxygen partial pressures in respective furnaces and end-point in converting and refining unit operations."

Jan 1, 1989

By A. Valenzuela

During the last years, Chile has been the largest copper producer, either as concentrates or cathodes. Copper obtained via pyrometallurgy is produced by seven smelters, which have carried out modernization plans to increase smelting capacity or to achieve environmental regulations established in the Chilean legislation. Thus, the present work updates technological innovations in smelters, environmental regulations and presents solutions for SO2 handling, particulate matter and arsenic. Also, the authors emphasize the important role of CODELCO Chile, the most important state-owned copper company, in developing technologies such as EI Teniente Converter and EI Teniente Slag Cleaning Furnace,

Jan 1, 2003

By Antonio Luraschi

The constituents iron, oxygen, silica and cop- per are of principal interest in slags utilized in pyrornetallurgical processes for producing copper. Accordingly, phase relationships in the.Cu-Fe-0-SiO2 system are important when one considers the physico- chemical behavior of slags. These phase relation- ships for the quaternary and constituent ternary systems are developed from available information. Isothermal composition and composition-oxygen potential diagrams, and oxygen potential-temperature diagrams are utilized to describe the' important relationships.

Jan 1, 1976

By A. Valenzuela

During the last years, Chile has been the largest copper producer, either as concentrates or cathodes. Copper obtained via pyrometallurgy is produced by seven smelters, which have carried out modernization plans to increase smelting capacity or to achieve environmental regulations established in the Chilean legislation. Thus, the present work updates technological innovations in smelters, environmental regulations and presents solutions for S02 handling, particulate matter and arsenic. Also, the authors emphasize the important role of CODELCO Chile, the most important state-owned copper company, in developing technologies such as El Teniente Converter and El Teniente Slag Cleaning Furnace.

Jan 1, 2003

By Kenji Monden

"In order to obtain basic data for the development of highly thermally conductive composite materials, the thermal conductivity of a resin composite material with an Aluminum Nitride filler was assessed. Several different measurement techniques such as the xenon flash and the temperature wave thermometric analysis method were employed to gather data on these composites. An excellent match between theoretical and experimental data was achieved by employing a predictive expression that takes into account the effect of percolation on thermal conductivity.IntroductionA thermal solution composite is made by incorporating dense inorganic fillers with high thermal conductivity into a resin. Because the composite materials have high thermal conductivities, they have been used in electrical products that generate excessive thermal energy during operation, such as inverters, amplifiers and motor drivers. They function as electrically insulating and thermally conducting parts of the electric modules. As the uses of thermal solutions are expanded, composites of higher thermal conductivities will be required. The aim of this work was to investigate, evaluate, and try to predict the influence of key parameters on thermal conductivity and diffusivity. This was achieved by analyzing the effect of both volume fraction and shape of Aluminum Nitride ceramic fillers and measuring the thermal conductivity. In addition, the influence of percolation on thermal conductivity is considered. The thermal conductivity of the composites is discussed by employing a predictive equation using literature data of thermal conductivities for both the filler and resin. As well as thermal conductivity measurements the effect of volume fraction of the filler was also explored.ExperimentalSpecimen PreparationThe composite samples were prepared from silicone resin and Aluminum Nitride (AlN) fillers. The AlN fillers with an average particle size of 20 µm are shown in Figure 1. The mean diameters of the AlN particles used are given in Table I. For comparison the AlN fillers with an average particle size of 5 µm are shown in Figure 2. A planetary centrifugal mixer was used for simultaneously dispersing the components uniformly and de-aerating the mixture. After mixing, these materials were placed in a silicone rubber case and cured at 150 °C for 1 hour."

Jan 1, 2013

By Shuo Wang, Yu Wang, Bing Xie, Rui Tang, Hong-Yi Li, Kun Wen

"During present converter vanadium extraction process, phosphorus could not be removed from hot metal due to absence of CaO in slag though it is an efficient way for vanadium extraction. In order to improve the phosphorus remove and produce CaO-containing vanadium slag, which could be directly used in subsequent roasting process, during the converter vanadium extraction process, lime dissolution in FeOx-Si02-V203-Ti02 slag was investigated by using a rotating cylinder technique and the slag-lime interface was characterized by SEM/EDS. Results showed that changes in the slag chemistry and phase compositions during the lime dissolution process were similar to that in CaO-Si02-FeOx based slag during the BOF process. The V and Ti in the slag were expected to diffuse into the lattice of2CaO·Si02 solid solution, which formed a rather thinner layer in thickness at the slag-lime interface than that in BOF process, leading to improvement of lime dissolution in the slag.IntroductionVanadium is important material that widely applied in industries. The traditional technique to extract vanadium was to leach vanadium after sodium salt roasting. However, the sodium salt roasting process has several problems including lower yielding rate[!] and environmental pollution[2]. Therefore, the more environment-friendly technique of calcium roasting[3-4] was proposed. In order to increase roasting efficiency of vanadium slag, it is essential to study the dissolution/reaction mechanism between lime and vanadium slag. Many investigations about the dissolution reaction of lime in molten slag have been carried out from the standpoints of rapid slagging to De-Pin steelmaking process[5-6]. However, their studies were focused on BOF slag and the reaction mechanism between solid lime and slag containing vanadium has not been reported yet. In present work, the dissolution process was studied with rotating cylinder technique and the reaction interfaces were observed and analyzed by SEM/EDS to elucidate the dissolution mechanism of lime in vanadium slag. This work was supported by National Natural Science Foundation of China No. 51090382."

Jan 1, 2013

By Jr. Brown, A. Calderara, A. L. Antozzi

"The result of extensive research into fundamental mixed metal oxide catalyst morphology has produced a next generation all titanium Dimensionally Stable Anode (DSA ®). This new DSA ® anode, patent pending, is tailored for electrowinning of non-ferrous metals (copper, nickel, cobalt, zinc) by means of this new coating technology.These DSA ® anodes are characterized by a hanger bar with vertical distributor bars, having primary titanium mesh attached by weldments. The active mesh is provided with noble-metal electrocatalytic coatings, consisting of iridium and/or ruthenium oxides, obtained by thermal decomposition of precursor solutions applied to the titanium substrates. The catalytic activity of state-of-the-art DSA ® anodes is increased by controlling the crystallite size of the noble-metals without decreasing the decomposition temperature. It is known that below a certain value (typically 400°C) the stability of these oxides, and associated lifetime, is seriously compromised. A highly active DSA ® anode, consisting of a quasi-amorphous phase, is obtained at high temperature (above 450°C), therefore not compromising lifetime performance. Through optimization of these design parameters, the manufacture of these novel anodes was identified.DSA ® anode performance advantages include: lead-free ' green' all titanium anodes, true leadfree cathode quality, energy savings of 0.3 to 0.55 V can be realized depending on the EW application when compared to industry standard lead-alloy anodes, eliminate need for cobalt sulphate addition required for lead anodes, sustainability designed into long-life recoatable anode structures, increase plant cathode output through increased current density operations, improve plant on-stream production, no sludge generated or removed, and improve current distribution producing smooth high efficiency cathode.Introduction of ProductThere are many factors to consider when engineering a high performance DSA ® electrowinning anode. Half of the anode's performance is derived from the physical attributes of the electrocatalyst and methods employed when applying this catalyst to the titanium anode structure. The other half of the performance benefits relate to the proper structural design of the anode. In this paper, we will highlight the anode development program in which De Nora has invested to provide the Electrowinning marketplace with a high performance anode product."

Jan 1, 2012

By Ruth Marlene Campomanes Santana, Michel Tieccher, Marcondes Mafacioli Pacheco, Juliano Urach

"IntroductionThe gaseous emissions of fuel burning by mobile sources are responsible for incidence and increase of many lung and cardiovascular diseases (Braga et al., 2007). These implications can watch in morbity as much as mortality, even when the levels of pollution are considerate restrained or lower. (Leite et al., 2002).Sample of mobile sources exhausts contain not only particles directly shaped by burning, but also secondary particles that results of reaction between other compounds (Burtscher, 2004).One of the principal pollutants produced by combustion process with major toxicity and raiser of adverse effects to health is the particulate material. In its constitution there are fine and ultrafine particles that can to extend deep portion of breath system, break epithelial barrier and reach the interstitial of lungs and then, to unleash inflammatory process (Arbex, 2004).The Particulate Material is employed to define a mixture of solid particles and liquid drops suspense in atmosphere. Queiroz et al. (2007) declare that this material can be divided in two types separated by size interval that together, represent the major class of disperse particles: the fine particles type of 2,5 µm de (breath particulate) and the type of earthliness particles, major than 2,5 µm to 10 µm (inhale particle). The difference of size between the particles influences on the physics and chemistry properties. They affirm that exist correlation between size of particle and heavy metals; how many lower was the dimension of particulate materials, major is the concentration of heavy metals.The inhale particulate (MP10) that is object of present study can exhibit in your composition sulfates, nitrates, amoniacal, marine salt (NaCl), soil elements (Al, Ca, Fe, Si, Ti), metals (Cd, Cr, Cu, Ni, Pb, V, Zn) and water (Queiroz et al., 2007).Recent studies have exhibit strong relation between daily levels of particulate material inhale (MP10) with diameter until 10 µm and others pollutants and one infinity of effects to health that go since total mortality of population, sicken for specific causes until congenital bad formation or even difficult win weight by the fern during gestation (Gouveia et al., 2006)."

Jan 1, 2008

By Aline Maria dos Santos Teixeira, Francisco Manoel dos Santos Garrido, Joao Alves Sampaio, Marta Eloisa Medeiros

"Rocks for crops is a natural practice for soils fertilization which consists on adding rocks to the soil while water decomposes the rock, through chemical weathering, and gradually releases nutrients to the soil solution. This practice can be considered an alternative to the low production of potassium fertilizers in Brazil. In this context, the phonolite rock was characterized in order to evaluate its application as an alternative source of nutrients to the Brazilian agriculture. The phonolite studied is an igneous, volcanic rock with alkaline character that is chemically composed of a high grade of potassium due to the presence of feldspar minerals. In order to quantify the minerals present in the sample, characterization was carried out using several techniques such as X-ray diffraction, X-ray fluorescence and scanning electron microscopy.IntroductionBrazilian soils are generally acidic and nutrient poor due to the tropical climate in which high temperatures and intense rainfall favor a rapid decomposition of the rocks that from the soil. And as agriculture is one of the main bases of the country's economy, large amounts of fertilizer are used to make the soil productive.Although Brazil has large reserves of potassium, the demand for potash fertilizer is higher than the national supply, which makes the country dependent on fertilizer imports, especially in the form of potassium chloride. Thus, we must look for economic alternatives to traditional fertilizer [1].Stonemeal is a natural practice for soil fertilization that consists in adding basic or ultrabasic rocks to the soil so that water, through chemical weathering, decomposes the rock while it gradually releases nutrients."

Jan 1, 2011

By Aïda Espinola

This work is part of a research program concerning the study of heavy metal removal and selective recovery from electroplating waste waters in the Guanabara Bay ecosystem, preventing the potential noxious retarded effect of landfill, specially in a country of heavy rainfall. A flow-throw cell was employed to adapt to the limits established by the local legislation for disposal in rivers and seas. The cell design is presented and preliminary results show that this cell may be applicable for the decontamination from copper.

Jan 1, 1994

By P. Louis

Gécamines is the world largest cobalt producer with about 60 % of the Western World production. During the last ten years, its annual production varied from 5,400 to 14,600 t/year. The actual cobalt production capacity of Gécarnines is 18,000 t/year and could be increased in the near future if necessary. Cobalt is presently produced at the Shituru plant by an old in-pulp electrolysis process and in Luilu, by electrolysis of a clear weakly acidic solution. The Shituru Cobalt quality is lower than the Luilu one. For that reason, part of the Shituru Cobalt is fire refined and cast into granules. Large efforts have been succesfully accomplished to improve the cobalt quality. This has been made possible by a better knowledge of the purification processes and of the electrolysis parameters.

Jan 1, 1988

By Fabio J. Esper, Wildor T. Hennies, Guillermo R. Martín-Cortés, Francisco R. Valenzuela-Díaz, Antonio J. Santana de Araujo, Maria G. Silva Valenzuela

Seeking to replace carbon-black as filler of rubber in the production of vulcanized goods, researchers from University of São Paulo have studied different materials types as minerals, vegetal or wastes agricultural and industry. Results of rubber composites filled with MA1 a waste of mineral treatment provided by Esper Industries are presented. MA1 was characterized through X-ray diffraction; Thermal analysis; Scanning Electronic Microscopy; and others laboratory methods. The composite and shaped masses were evaluated by these methods plus their mechanical properties such as tensile strength, elongation at break and hardness. Exceptional results were obtained in the mechanical properties evaluated, better than those obtained with the traditional carbon-black. Seeing the kind of material used as filler, it can conclude that the environmental benefit is present, as well as economic development, giving credibility to the use of these alternative material in replacement carbon black.

Jan 1, 2015

By Jacqueline JAlexander

Two of the most important phenomena which govern the continuous casting process and determine the quality of the product are the fluid flow and the heat transfer. Steel flows into the mold through the ports of a bifurcated submerged entry nozzle (SEN), which directs the jet to the mold narrow faces where the superheat contained is dissipated on the solidifying shell. Many important aspects of the fluid flow in the mold are transient and difficult to control. However, the time-averaged flow pattern in the mold is greatly influenced by the nozzle geometry, the submergence depth and the mold dimensions. The aim of this work is to analyze the relationship between the heat transfer and the fluid flow pattern inside the mold using the CFD technique at several operating conditions.

Jan 1, 2009

By J. M. Demarthe

The recovery of minor metals from zinc concentrates is dependent on the process used for their treatment. The behaviour of gennanium and indium in pyrometallurgical processes such as the Imperial Smelting furnace or the cupola furnace is of practical importance. The .Anaconda process for the treatment of zinc leach residues is not well suited to the recovery of valuable minor metals, and new technologies must be studied. In this regard, a solvent extraction process, using Kelex 100, developed by Minenet Recherche for the recovery of gennanium from dilute sulphate leach solutions is described. Also, new hydranetallurgical techniques in chloride media can be applied to the purification and concentration of minor metals depending on the stability of their chloro-complexes and the valency of associated inpurities. A synthesis of methods is proposed to address the problems related to the recovery of valuable minor metals in the zinc industry.

Jan 1, 1990

By N. G. Azeredo

This work dealt with the evaluation of engineering structural clay brick samples that were sintered at estimated temperatures of 700 and 800°C. They were collected in a red-brick plant in Campos dos Goytacazes, RJ, Brazil. From a lot, a sample already sintered in its kiln at 700°C were collected and also a sample from the same lot only dried by the air, which were then sintered at 800°C controlled temperature. The samples were subjected to Brazilian Standard tests (ABNT NBR 15270:2005) to determine their geometric, physical and mechanical properties. In order to be classified as structural clay brick it is required minimum 3.0 MPa for the characteristic compressive strength (fbk) to be suitable for up to five floors structural building applications. We also used the Weibull Probability Plot and Weibull Maximum Likelihood Estimation to evaluate distribution parameters in order to compare the results of compressive strength obtained in the tests.

Jan 1, 2015