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From Particle Size Analysis (PSA 1970) to Particulate Systems Analysis (PSA 2003)

Dodds, J.; Rasteiro, G.; Scarlett, B.; Weichert, R.; Williams, R.
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
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It is now fully accepted that industrial processes involving particulate systems are in the mainstream of chemical engineering practice, research and education. A scientific approach to particle processing implies the study and development of means for characterizing particles, the primary characteristic being particle size and distribution. This paper, by members of the EFCE working party on Characterisation of Particulate Solids is intended to give an overview of the evolution of the subject and some ideas on future developments. Comparison is made of the content of the Particle Size Analysis Conference of 1970 (PSA 1970) with that of the Particulate Systems Analysis Conference held in 2003 (PSA 2003). This shows the move away from absolute methods to more rapid secondary methods such as light scattering. Further modern developments are the application of in-line measurement for understanding industrial processes and their modelling, and the growth of image-based systems and tomography applied to industrial processing. Finally there is renewed interest in methods for sub-micron particle sizing for nanotechnology.; http://www.sciencedirect.com/science/article/B8JGF-4RV2MKT-3/1/ed91686b8b819f1d8423d61541543d16

Effect of the relationship between particle size, inter-particle distance, and metal loading of carbon supported fuel cell catalysts on their catalytic activity

Corradini, Patricia Gon; Pires, Felipe Ibanhi; Paganin, Valdecir Antonio; Perez, Joelma; Antolini, Ermete
Fonte: SPRINGER; DORDRECHT Publicador: SPRINGER; DORDRECHT
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
67.130034%
The effect of the relationship between particle size (d), inter-particle distance (x(i)), and metal loading (y) of carbon supported fuel cell Pt or PtRu catalysts on their catalytic activity, based on the optimum d (2.5-3 nm) and x(i)/d (>5) values, was evaluated. It was found that for y < 30 wt%, the optimum values of both d and x(i)/d can be always obtained. For y >= 30 wt%, instead, the positive effect of a thinner catalyst layer of the fuel cell electrode than that using catalysts with y < 30 wt% is concomitant to a decrease of the effective catalyst surface area due to an increase of d and/or a decrease of x(i)/d compared to their optimum values, with in turns gives rise to a decrease in the catalytic activity. The effect of the x(i)/d ratio has been successfully verified by experimental results on ethanol oxidation on PtRu/C catalysts with same particle size and same degree of alloying but different metal loading. Tests in direct ethanol fuel cells showed that, compared to 20 wt% PtRu/C, the negative effect of the lower x(i)/d on the catalytic activity of 30 and 40 wt% PtRu/C catalysts was superior to the positive effect of the thinner catalyst layer.; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [Proc: 2010/20045-0]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [Proc. 131469/2011-8...

Influência da distribuição granulométrica no empacotamento de matérias-primas na formulação de porcelânicos.; Influence of particle size distribution in the packaging of raw materials for porcelain formulation.

Conceição, Edilene de Souza
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/07/2011 PT
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Materiais complexos como porcelanas e porcelanatos tem suas propriedades maximizadas quando atingem altas densidades finais após a sinterização. Contudo, a sua formulação contém no mínimo quatro matérias- primas diferentes, sendo o caulim a maior parte, mas também contendo quartzo e feldspatos. A granulometria final da mistura é controlada por uma única etapa de moagem de todos os materiais misturados. O objetivo deste trabalho foi obter combinações de diferentes granulometrias de ortoclásio, albita e quartzo com uma única granulometria de caulim através de cálculos de máximo empacotamento com o objetivo de alcançar a máxima densidade a cru, mantendo-se uma única composição química final. Os resultados mostraram que utilizando o conceito de empacotamento de partículas e otimizando a distribuição granulométrica foi possível obter corpos de prova com maiores densidades finais, menor retração final, além de reduzir a temperatura de queima, o que impacta diretamente no custo de produção.; Complex materials such as porcelain and porcelain stoneware have maximized their properties when they reach high final densities after sintering. However, formulations contain at least four different raw materials...

Effect of the calcium level and limestone particle size on the performance of semi-heavy layers in the second cycle of egg production

Pizzolante, CC; Garcia, Edivaldo Antônio; Laganá, C; Saldanha, ESPB; Deodato, AP; Faitarone, ABG; Scherer, MR; Batista, L
Fonte: Fundação APINCO de Ciência e Tecnologia Avícolas Publicador: Fundação APINCO de Ciência e Tecnologia Avícolas
Tipo: Artigo de Revista Científica Formato: 173-176
ENG
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An experiment was carried out at the Research and Development Unit of Brotas aiming at evaluating dietary calcium level and limestone particle size on the production performance of commercial (Hy-Line Brown) layers in the second lay cycle. Experiment duration was 112 days. A total number of 288 hens, with 83 weeks of age in the beginning of the experiment, were used in a completely randomized experimental design in a factorial arrangement of 2x3, with two calcium levels (3.5 and 4.0%) and three limestone particle size compositions: 100% fine limestone (FL), 30% coarse limestone (CL) + 70% fine limestone (FL), and 50% (CL) + 50% (FL), with six replicates of eight birds each. Egg weight (g), egg production (%), egg mass (%), feed intake (g), feed conversion ratio (kg/dz and kg/kg), mortality (%), and egg loss (%) were evaluated. The analysis of variance did not detect significant differences (p>0.05) among treatments on any of the evaluated performance parameters. It was concluded that the tested calcium levels and limestone particle composition did not influence the performance of semi-heavy layers in second production cycle.

Corn texture and particle size in broiler diets

Benedetti, MP; Sartori, JR; Carvalho, FB; Pereira, LA; Fascina, VB; Stradiotti, AC; Pezzato, AC; Costa, C; Ferreira, JG
Fonte: Fundação APINCO de Ciência e Tecnologia Avícolas Publicador: Fundação APINCO de Ciência e Tecnologia Avícolas
Tipo: Artigo de Revista Científica Formato: 227-234
ENG
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The objective of this study was to evaluate the effect of corn texture and the particle size on broiler performance, carcass yield, nutrient digestibility, and digestive organ morphometrics. In Experiment I, 720 male Cobb chicks were distributed in a completely randomized experimental design with a 2 x 3 factorial arrangement, consisting two corn textures (dented and hard) and three corn particle sizes, was applied, with four replicates of 30 birds each. Corn particle size was classified according to geometric mean diameter (GMD) as fine - 0.46 mm; medium - 0.73 mm, and coarse - 0.87 mm. In Experiment II, 120 broiler chicks were used to evaluate corn digestibility during the periods of 16 to 22 days and 35 to 41 days of age, using the method of total excreta collection. In Experiment I, corn particle size influenced body weight, average weight gain, feed intake and feed conversion ratio of 21-day-old birds. Corn texture and particle size did not affect the performance of 42-day-old broilers or carcass traits. In Experiment II, there was no influence of corn texture and particle size on digestive organ weights. Dented corn increased nitrogen excretion in the first trial, and hard corn improved dry matter digestibility in the second metabolic trial. Corn with fine particle size promotes better performance of broilers at 21 days of age. Hard corn results in higher dry matter digestibility and lower nitrogen excretion...

Different particle size silicas from water glass.

Martines, MAU; Davolos, M. R.; Junior, M. J.
Fonte: Soc Brasileira Quimica Publicador: Soc Brasileira Quimica
Tipo: Artigo de Revista Científica Formato: 469-472
POR
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Non-crystalline silica was obtained with different particle sizes. Samples were prepared from soluble sodium silicate (water glass) and sulfuric acid solutions. Dialysis was performed for sodium sulfate elimination. Products were dried in a microwave oven, milled and characterized by X-ray powder diffraction, infrared spectrum and sedigraphic analysis. Products milled for more than 120 minutes showed uniform particle size distribution with average silica particle size of 4.5 mu m.

Multifractal characterization of saprolite particle-size distributions after topsoil removal

Miranda, J. G. V.; Montero, E.; Alves, M. C.; Gonzalez, A. Paz; Vazquez, E. Vidal
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 373-385
ENG
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Multifractal analysis is now increasingly used to characterize soil properties as it may provide more information than a single fractal model. During the building of a large reservoir on the Parana River (Brazil), a highly weathered soil profile was excavated to a depth between 5 and 8 m. Excavation resulted in an abandoned area with saprolite materials and, in this area, an experimental field was established to assess the effectiveness of different soil rehabilitation treatments. The experimental design consisted of randomized blocks. The aim of this work was to characterize particle-size distributions of the saprolite material and use the information obtained to assess between-block variability. Particle-size distributions of the experimental plots were characterized by multifractal techniques. Ninety-six soil samples were analyzed routinely for particle-size distribution by laser diffractometry in a range of scales, varying from 0.390 to 2000 mu m. Six different textural classes (USDA) were identified with a clay content ranging from 16.9% to 58.4%. Multifractal models described reasonably well the scaling properties of particle-size distributions of the saprolite material. This material exhibits a high entropy dimension, D-1. Parameters derived from the left side (q > 0) of the f(alpha) spectra...

Influence of the particle size and animal slurry type on the potential of nitrogen mineralization after soil incorporation

Fangueiro, D.; Gusmão, M.; Grilo, J.; Vasconcelos, E.; Cabral, F.
Fonte: Cordovil, C. e Ferreira, L. Publicador: Cordovil, C. e Ferreira, L.
Tipo: Conferência ou Objeto de Conferência
Publicado em /09/2010 ENG
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RAMIRAN International Conference; Animal manures are rich in organic matter and nutrients, namely nitrogen (N) and, consequently, widely applied to soil as organic fertilizers. However, a large part of the nitrogen contained in animal manures is in the organic form and so not directly available for plants. Indeed, organic N has to be mineralized prior to plant uptake (Rees and Castle, 2002). Several manure characteristics as the C:N ratio (Chadwick et al., 2000), the lignin content (Kristensen, 1996) and the NH4 +/organic N ratio (Beauchamp and Paul, 1989) have been suggested as indicators of the plant-available N. More recently, Fangueiro et al. (2008) showed that the potential of N mineralization (PNM) of cattle slurry is inversely correlated with slurry particle size: finest fractions are the particle-size fractions from which N mineralization occurs in slurries whereas coarser fractions are associated with immobilization. Furthermore, Moller et al. (2002) reported that animal diet and anaerobic decomposition during storage in slurry channels and stores affect the slurry particle size distribution. Such information is of great interest since the finest slurry particle size should infiltrate the soil more easily and quickly relative to the coarser slurry particle size that should remain close to soil surface. Furthermore...

Effects of binary particle size distribution on the fluid dynamic behavior of fluidized, vibrated and vibrofluidized beds

Daleffe,R. V.; Ferreira,M. C.; Freire,J. T.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2008 EN
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In this work the effects of particle size distribution on the dynamics and segregation patterns in fluidized, vibrated and vibrofluidized beds were investigated. A binary particle size distribution and a reference one composed of glass spheres with a mean Sauter diameter of 2.18×10-3 m were tested. The experimental setup consisted basically of a circular glass chamber with a height of 0.50 m and a diameter of 0.114 m, operated in the fluidized bed mode (gamma = 0.00), in either vibrated or vibrofluidized bed modes (gamma = 2.00). The pressure drops in the fluidized and vibrofluidized beds were not significantly affected by the binary particle size distribution. Well-defined segregation patterns occurred in fluidized and vibrated beds with small particles concentrating at the top and large particles at the bottom in the first situation and the reverse in the second one. Segregation patterns in vibrofluidized beds depended on the values of vibration parameters. Segregation in vibrofluidized and vibrated beds was minimized by operating at a high amplitude of vibration.

Effect of the calcium level and limestone particle size on the performance of semi-heavy layers in the second cycle of egg production

Pizzolante,CC; Garcia,EA; Laganá,C; Saldanha,ESPB; Deodato,AP; Faitarone,ABG; Scherer,MR; Batista,L
Fonte: Fundação APINCO de Ciência e Tecnologia Avícolas Publicador: Fundação APINCO de Ciência e Tecnologia Avícolas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2006 EN
Relevância na Pesquisa
67.06295%
An experiment was carried out at the Research and Development Unit of Brotas aiming at evaluating dietary calcium level and limestone particle size on the production performance of commercial (Hy-Line Brown) layers in the second lay cycle. Experiment duration was 112 days. A total number of 288 hens, with 83 weeks of age in the beginning of the experiment, were used in a completely randomized experimental design in a factorial arrangement of 2x3, with two calcium levels (3.5 and 4.0%) and three limestone particle size compositions: 100% fine limestone (FL), 30% coarse limestone (CL) + 70% fine limestone (FL), and 50% (CL) + 50% (FL), with six replicates of eight birds each. Egg weight (g), egg production (%), egg mass (%), feed intake (g), feed conversion ratio (kg/dz and kg/kg), mortality (%), and egg loss (%) were evaluated. The analysis of variance did not detect significant differences (p>0.05) among treatments on any of the evaluated performance parameters. It was concluded that the tested calcium levels and limestone particle composition did not influence the performance of semi-heavy layers in second production cycle.

Corn texture and particle size in broiler diets

Benedetti,MP; Sartori,JR; Carvalho,FB; Pereira,LA; Fascina,VB; Stradiotti,AC; Pezzato,AC; Costa,C; Ferreira,JG
Fonte: Fundação APINCO de Ciência e Tecnologia Avícolas Publicador: Fundação APINCO de Ciência e Tecnologia Avícolas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2011 EN
Relevância na Pesquisa
67.290415%
The objective of this study was to evaluate the effect of corn texture and the particle size on broiler performance, carcass yield, nutrient digestibility, and digestive organ morphometrics. In Experiment I, 720 male Cobb chicks were distributed in a completely randomized experimental design with a 2 x 3 factorial arrangement, consisting two corn textures (dented and hard) and three corn particle sizes, was applied, with four replicates of 30 birds each. Corn particle size was classified according to geometric mean diameter (GMD) as fine - 0.46 mm; medium - 0.73 mm, and coarse - 0.87 mm. In Experiment II, 120 broiler chicks were used to evaluate corn digestibility during the periods of 16 to 22 days and 35 to 41 days of age, using the method of total excreta collection. In Experiment I, corn particle size influenced body weight, average weight gain, feed intake and feed conversion ratio of 21-day-old birds. Corn texture and particle size did not affect the performance of 42-day-old broilers or carcass traits. In Experiment II, there was no influence of corn texture and particle size on digestive organ weights. Dented corn increased nitrogen excretion in the first trial, and hard corn improved dry matter digestibility in the second metabolic trial. Corn with fine particle size promotes better performance of broilers at 21 days of age. Hard corn results in higher dry matter digestibility and lower nitrogen excretion...

Granulometria de grãos em rações para frangos Label Rouge; Particle size in Label Rouge broiler

GODOY, Heloisa Baleroni Rodrigues de
Fonte: Universidade Federal de Goiás; BR; UFG; Doutorado em Ciência Animal; Ciências Agrárias Publicador: Universidade Federal de Goiás; BR; UFG; Doutorado em Ciência Animal; Ciências Agrárias
Tipo: Tese de Doutorado Formato: application/pdf
POR
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To determine the nutritional value of corn, millet and sorghum in different sizes for broiler chickens, Label Rouge, animal performance and development of the digestive organs, experiments were performed in the areas of Poultry, Federal University of Goiás (UFG) and the Federal University of Tocantins (UFT). We evaluated the values of apparent metabolizable energy (AME) and apparent metabolizable energy corrected for nitrogen balance (AME) in the dry and natural, the coefficients metabolism of nutrients, animal performance up to 28 days and the biometrics of the digestive organs of broiler type rustic Red Label line with diets based on corn, millet and sorghum in different sizes For the determination of AME and AME of grains, we used the method of excreta collection of chickens 14 days old were distributed in a completely randomized in two experimental trials, using 60% reference diet and 40% of food test. The AME values of dry matter of coarsely ground corn, finely ground corn, millet grain, finely ground millet, sorghum grain, sorghum grain sorghum thick and finely ground, were 3530, 3445, 3617, 3586, 3295, 3156 and 3024 kcal / kg, respectively and the values of the AME 3273, 3200, 3352, 3372, 3137, 3147 and 2.967kcal/kg natural matter...

Effect of particle size on the flow properties of a South Australian coal-water slurry

Nguyen, Q.; Logos, C.
Fonte: Elsevier Science Publicador: Elsevier Science
Tipo: Artigo de Revista Científica
Publicado em //1996 EN
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The rheological behaviour of a low-rank coal-water slurry from Lochiel, South Australia, has been studied as a function of solids concentration, particle size and size distribution. Coal slurries consisting of particles finer than 45 μm suspended in water were found to exhibit a wide spectrum of flow behaviour ranging from Newtonian as low solids concentrations to shear-thinning and viscoplastic with a yield stress at higher concentrations. By adding a narrow-sized coarse coal fraction (208–279 μm) to the fine coal slurry, the flow characteristic of the slurry, at a fixed total solids concentrations, could be changed significantly with a substantial reduction in the slurry viscosity. An optimum coarse-to-fine particle ratio of 40:60 exists at which the slurry is Newtonian with a minimum viscosity of a about 5 times lower than the viscosity of a slurry containing only fine particles at the same solids concentration. A further reduction in the slurry viscosity of 50% was achieved by adding a second coarse coal particle (279–325 μm) to the bimodal slurry. The significant improvement in the rheological behaviour with changing the particle size distribution may be explained in terms of spatial rearrangement of the particles, and an apparent dilution effect. The results obtained in this study indicate that...

Bioflotation of apatite and quartz: Particle size effect on the rate constant

Merma,Antonio G.; Torem,Maurício Leonardo
Fonte: Escola de Minas Publicador: Escola de Minas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2015 EN
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This work deals with the fundamental aspects of apatite and quartz bioflotation using R. opacus bacteria as a bioreagent. It was observed that the flotability of both minerals depends on the pH value and the mineral particle size. The maximum flotability of both minerals was presented at a pH value of 5, achieving values of 90% and 14% for apatite and quartz, respectively, after seven minutes of flotation. The kinetics analysis showed that the smaller the apatite particle size, the lower its bioflotation rate value. On the other hand, the smaller the quartz particle size, the higher its bioflotation rate value. The first-order kinetic model better fitted the experimental data of both minerals, and a logarithmic relationship between particle size and kinetic rate constant was observed.

Effect of particle size in the TL response of natural quartz sensitized by high dose of gamma radiation and heat-treatments

Carvalho Jr,Álvaro Barbosa de; Guzzo,Pedro Luiz; Sullasi,Henry Lavalle; Khoury,Helen Jamil
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2010 EN
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67.18256%
This work investigates the effect of particle size in the thermoluminescence (TL) response of a quartz crystal that was initially crushed and classified into ten size fractions between 38 μm and 5 mm. Aliquots of each size fraction were sensitized with a dose of 25 kGy of γ rays and heat-treatments at 400 °C. TL glow curves of sensitized and non-sensitized samples were recorded as a function of different test-doses of γ rays. For the non-sensitized samples, the TL peak near 325 °C increases with the decrease in particle size. In the case of sensitized samples, a strong TL peak near 300 °C increases with the increase in particle size up to mean grain size equal to 304 μm. Above 304 μm, an abrupt reduction in the TL intensity is noticed for the sensitized peak. These effects are discussed in relation to the specific surface area of quartz particles and the intensity of the electron paramagnetic resonance signal of the E'1 center induced by the sensitization process.

Estudio del tamaño de las partículas en suspensión en relación con el caudal y la concentración de sedimento en una cuenca de montaña; Study of suspended particle size in relation with discharge and sediment concentration in a mountain catchment

Gallart Gallego, Francesc; Regüés, D.; Soler, M.
Fonte: Asociación Española para el Estudio del Cuaternario; Sociedad Española de Geomorfología Publicador: Asociación Española para el Estudio del Cuaternario; Sociedad Española de Geomorfología
Tipo: Artículo Formato: 184524 bytes; application/pdf
SPA
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67.27224%
[ES] Se presentan los resultados del muestreo automático del sedimento transportado en suspensión en tres estaciones de aforo instaladas en las cuencas experimentales de Vallcebre (Pirineo Oriental). Este trabajo analiza el tamaño de las partículas de sedimento recogidas por los muestreadores en tres de las estaciones del año (primavera, verano y otoño). Las máximas concentraciones de sedimento observadas han llegado a superar los 100 g l- 1. Los sedimentos transportados son mayoritariamente limo fino, con porcentajes bajos de arcilla y muy bajos de arena fina. Se han encontrado correlaciones positivas entre el tamaño de las partículas y el caudal en los respectivos aforadores mientras que la relación entre el tamaño de las partículas y la concentración de sedimentos sólo es significativa en la cuenca principal. En esta zona de cabecera, la fuente del material de origen es la que determina el tamaño de las partículas transportadas, aunque los procesos de transporte, sedimentación y re-erosión producen su desgaste y fraccionamiento.; [EN] This study shows presents the dynamics of suspended sediment transport at the the results of suspended sediment sampling at three gauging stations in the Vallcebre experimental basins (Eastern Pyrenees). The paper analyses particle size distribution of the automatically collected sediment samples during three seasons: The work analyses particle size characteristics of sediments collected by three automatic samplers in different seasons (spring...

Effect of Y-211 particle size on the growth of single grain Y?Ba?Cu?O bulk superconductors

Thoma, Max; Shi, Yunhua; Dennis, Tony; Durrell, John; Cardwell, David
Fonte: Elsevier Publicador: Elsevier
Tipo: Article; published version
EN
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This is the final published version. It first appeared at http://www.sciencedirect.com/science/article/pii/S0022024814008045#.; The engineering of fine Y2Ba1Cu1O5 (Y-211) inclusions of average particle size 1?2 ?m within the continuous, superconducting YBa2Cu3O7?? (Y-123) phase matrix of single-grain, bulk high temperature Y?Ba?Cu?O (YBCO) superconductors is fundamental to achieving high critical current density in these materials. However, bulk samples fabricated using fine Y-211 precursor powders generally suffer from incomplete growth of the Y-123 phase compared to samples fabricated with coarser Y-211 particles of average particle size >5 ?m in the precursor powder. In this study, the effects of Y-211 particle size on processing parameters during growth of large single YBCO grains are reported. Chemical analysis using EDX of cross-sections of single YBCO grains indicates that the loss of liquid phase during melt processing is greater when finer Y-211 precursor powder is employed, which accounts for the observed growth limitations and low sample yield. Specific modifications to the single grain growth process have been made based on the results of this investigation to reduce liquid loss and to enable the use of fine Y-211 precursor powder without compromising complete single grain growth or yield.; Yunhua Shi would thank the financial support from EPSRC (grant ref. EP/K02910X/1)...

Maximizing haematite recovery within a fine and wide particle-size distribution using wet high-intensity magnetic separation

Dworzanowski,M
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2014 EN
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The physical beneficiation of iron ore that has a wide particle-size distribution is problematic, regardless of the process applied, whether dense medium separation, gravity concentration, magnetic separation, or flotation. The problem of particle size is further compounded when there is a significant -10 µm fraction. Generally the approach to a wide particle-size distribution is to split into narrower size ranges and treat each separately. More often than not the -10 µm fraction is not treated but discarded. This approach results in a more complicated and expensive flow sheet and the loss of any potential value in the -10 µm fraction. Wet high-intensity magnetic separation (WHIMS) bench-scale test work was conducted on a haematite-rich material with a particle size of -200 µm What made this material different was that it contained a 60% -10 µm fraction, hence discarding the -10 µm material was not an option. The objective of the test work was to determine how to maximize the recovery of the haematite across the full particle size range. Given the unusual particle size distribution, it was concluded that WHIMS would be the only practical beneficiation route. The -200 +10 µm and -10 µm fractions were treated separately and together under varying WHIMS conditions. For a given concentrate grade...

A study on the effect of coke particle size on the thermal profile of the sinters produced in Esfahan Steel Company (ESCO)

Dabbagh,A.; Heidary Moghadam,A.; Naderi,S.; Hamdi,M.
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 EN
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The aim of this research was to investigate the effect of coke particle size on the thermal profile of the charge bed in the sintering process of iron ore. Six different ranges of coke particle size that could be used in practice in the sintering line of Esfahan Steel Company (ESCO) were used while parameters such as ratios and particle sizes of other ingredients, ignition temperature, and suction power were kept constant. Thermal profiles were obtained by measuring the temperature changes at three points in the sintering bed. The influence of coke particle size on rate of temperature rise, maximum temperature of the sintering bed, and the flame front velocity of the sintering bed was determined by analysing the thermal profiles. Moreover, the cold strengths of the sinters were measured using the Tumbler method. The results indicated that the coke particle size has a significant impact on the thermal properties of the sintering bed. Based on the results, a coke particle size between 0.212 mm and 3.350 mm was determined as the optimal range for the specific conditions in the sintering line of ESCO.

Relationship between particle size and manufacturing processing and sintered characteristics of iron powders

Sánchez,F.; Bolarín,A. M.; Molera,P.; Mendoza,J. E.; Ocampo,M.
Fonte: Universidad Simón Bolívar; ; Publicador: Universidad Simón Bolívar; ;
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2003 EN
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Abstract The effect of particle size distribution on physical properties of powder mixtures, of green compacts and of sintered samples has been studied. In the case of powder mixtures, the evaluated properties were flowability, apparent density, specific surface and compressibility. In green compacts porosity, roughness and green strength were evaluated, and in sintered samples grain size and transverse rupture strength were measured. In order to obtain samples with different average particle size, water atomized iron powders were sieved and separating it with sieves ranging from +44 to -150 m m. Flowability and compressibility decrease as average particle size does. On the opposite side, green strength and transverse rupture strength (TRS) increase as particle size diminishes. These effects were associated with changes in morphology and specific surface of the studied powder mixtures. Mathematical expressions relating average particle size with green strength, roughness and ultimate tensile strength were deduced from the experimental results. The results show that an appropriate selection of average particle size for the preparation of the powder mixture is useful in order to obtain samples with suitable physical properties.