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Search Results: 1 - 10 of 38411 matches for " Peres Ant?nio Eduardo Clark "
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Aproveitamento econ?mico das lamas de ferro
Rocha, Luciano;Peres, Antnio Eduardo Clark;
Rem: Revista Escola de Minas , 2009, DOI: 10.1590/S0370-44672009000300006
Abstract: high grade deposits were mined in the early stages of the activity. no attention was paid to maximizing the use of the deposits. even nowadays, millions of tons of useful minerals are discarded every year into tailings ponds. this study investigated the possibility of economically retrieving ultrafine tailings (slimes) from an iron ore concentrator via reverse cationic flotation. the promising results of the bench scale tests led to carrying out pilot-scale tests. it was observed that a reverse cationic column flotation process, using high depressant dosage was selective, yielding high levels of iron recovery, approximately 60% mass recovery and 80 % metallic recovery in the flotation stage, from 9 to 12 % of fe in the tailing and from 0,55 % to 0,90 % of sio2 in the concentrate (sio2+al2o3 < 2,00 %). the ultrafines flotation is an economic alternative for increasing the recovery in mineral processing operations. the flotation of ultrafines may also be evaluated for decreasing or treating effluents disposed to the environment.
Caracteriza??o de minérios: uso do Magstream-Model 100, suas vantagens e limita??es
Salum, Maria José Gazzi;Peres, Antnio Eduardo Clark;
Rem: Revista Escola de Minas , 2002, DOI: 10.1590/S0370-44672002000100011
Abstract: this paper discusses the importance of mineral characterization as a support to understand their behavior in mineral processing and in the control of the processes and quality of the products obtained. also presented is a brief review on the main techniques used in minerals characterization, including the procedures for minerals separation from an ore. special attention was given to the technique of mineral separation from an ore according to their specific gravities using a device called magstream-model 100. it is shown that the magstream process, which involves the use of a magnetic fluid as a medium for mineral separation, a magnetic field and a rotation speed system, offers advantages compared to the heavy liquids technique. however, the magstream process leads to changes on mineral surface properties, imparting to them different flotation behaviors. this fact is considered a limitation for its use when further studies with the minerals involve surface properties.
Flotabilidade da apatita e minerais de ganga provenientes de minério sílico-carbonatado com oleato de sódio
Oliveira, Michelly dos Santos;Peres, Antnio Eduardo Clark;
Rem: Revista Escola de Minas , 2010, DOI: 10.1590/S0370-44672010000300019
Abstract: the processing of phosphate ores containing silicates and carbonates in the gangue is strictly necessary to increase phosphate rock production to meet the brazilian demand for fertilizers. aiming at the processing of these ores, this investigation addressed, via microfl otation and zeta potential determinations, the effect of sodium oleate, corn starch and carboxymethylcellulose (cmc) on the surfaces of pure minerals from the catal?o/go silicate-carbonate deposit. the results suggested the possibility of selective apatite concentration via direct fl otation at ph = 9, using sodium oleate as collector, in the absence of depressants; a route that would be industrially unfeasible. both, cmc and starch, act as dolomite depressants, but the action is not selective, for apatite is also depressed by these reagents. starch is a stronger apatite depressant than cmc.
Interferência de cátions Ca2+ nas etapas de deslamagem e flota??o de minério de ferro
Carvalho, Mauro Rodrigues de;Peres, Antnio Eduardo Clark;
Rem: Revista Escola de Minas , 2004, DOI: 10.1590/S0370-44672004000200005
Abstract: aiming at the evaluation of the possibility to change the point of addition of hydrated lime, from the slurry stocking tanks of the pipeline to the feed of the concentrate thickeners, a sample of the feed material of samarco's concentrator was collected. laboratory experiments, involving grinding, dispersion, desliming and flotation, were carried out by varying the addition of hydrated lime as a function of the slurry's ph, to check out the interference generated by the ca2+ cations present in the recovered water over the desliming and flotation processes. the ph targeted level was chosen to better comply with the slurry rheology control during the pumping process (ph=11,4). the results appointed the change as possible, given the performance of the desliming process receives a continuous control. if the increase in the level of the hydrated lime added is enough to increase the pulp ph level to values above 10,5, the ca2+ cations start to act as coagulants, therefore promoting a negative effect over its own performance, affecting the flotation process and making it difficult to obtain the specified sio2 levels in the concentrate.
Caracteriza o de minérios: uso do Magstream-Model 100, suas vantagens e limita es
Salum Maria José Gazzi,Peres Antnio Eduardo Clark
Rem: Revista Escola de Minas , 2002,
Abstract: O presente trabalho discute a importancia da caracteriza o de minérios como suporte para o entendimento do comportamento de seus minerais frente a processos de tratamento de minérios, controle de processos e controle da qualidade dos produtos obtidos. é, também, apresentada uma breve revis o da literatura sobre as principais técnicas de caracteriza o, incluindo aquelas utilizadas para a separa o de minerais de um minério. Especial aten o foi dada à técnica de separa o de minerais de um minério, utilizando um equipamento chamado Magstream-Model 100. O trabalho mostra que o processo Magstream, que envolve o uso de fluido magnético como meio separador, campo magnético e um sistema de rota o, oferece vantagens em rela o a outras técnicas, como, por exemplo, a de líquidos densos. Entretanto o processo utilizado pelo Magstream leva a mudan as em propriedades de superfície dos minerais, modificando seus comportamentos frente à flota o. Esse fato foi considerado como uma limita o de seu uso, quando estudos posteriores com os minerais processados no Magstream envolvem propriedades de superfície.
Caracteriza??o tecnológica de rejeito de minério de ferro
Gomes, Marcos Antnio;Pereira, Carlos Alberto;Peres, Antnio Eduardo Clark;
Rem: Revista Escola de Minas , 2011, DOI: 10.1590/S0370-44672011000200016
Abstract: this paper addresses the characterization of fines stocked in a pond as tailings from an iron ore concentrator. the characterization consisted of size analyses by wet screening, chemical analyses by icp, and mineralogical analyses by x-ray diffraction. the next stage consisted of technological tests. two concentration routes were evaluated at bench scale: the first (route i) consisting of classification (0.15mm), magnetic separation (-1.0+0.15mm), desliming and flotation (-0.15mm); and the second (route ii) consisting of magnetic separation (-1.0mm global), aiming at achieving a concentrate adequate for use in the metallurgical industry. the size distribution of the iron ore fines indicated 8.21% above 0.150mm and 58.81% passing 0.045mm. the calculated average chemical composition of the sample is 48.08% fe, 20.58% sio2, and 3.16% al2o3. the iron minerals identified by x-ray diffraction were: hematite, martite, magnetite, and goethite; and the detected gangue minerals were: quartz, gibbsite, and kaolinite. the best performance came from route ii, magnetic separation only: weight recovery 68.00%, metallurgical recovery 90.81%, 67.54% fe, 1.50% sio2, 0.49% al2o3.
Reologia de suspens?es minerais: uma revis?o
Ferreira, Eliomar Evaristo;Brand?o, Paulo Roberto Gomes;Klein, Bernhard;Peres, Antnio Eduardo Clark;
Rem: Revista Escola de Minas , 2005, DOI: 10.1590/S0370-44672005000100014
Abstract: mineral processing is often carried out on suspensions (usually a mixture of solid particles and liquid). the process is influenced by the resistance to flow resulting from a shear stress or pressure applied in the fluid (suspension). therefore, the viscosity of suspensions will affect the mineral process. this paper reviews the applications of rheology in mineral processing. this review focuses on conceptual aspects such as fluid classification, variable of rheology and measurements with concentric viscometer.
Adsor??o de coletores ani?nicos em silicatos
Viana, Paulo Roberto de Magalh?es;Araujo, Armando Corrêa de;Peres, Antnio Eduardo Clark;
Rem: Revista Escola de Minas , 2005, DOI: 10.1590/S0370-44672005000300005
Abstract: the understanding of the adsorption mechanisms of collectors is of primary importance for the optimization and, eventually, the feasibility of the flotation process. although anionic collectors are included in the main reagents used in various flotation systems, only a few studies of adsorption of these reagents in silicate flotation systems have been carried out when compared with the large number of studies developed with sparingly soluble minerals and oxides. the present work makes a concise revision of the adsorption mechanisms for the main anionic silicate collectors, carboxylic and sulfonic acids and sulfates. carboxylic acids are emphasized due to their ability to form insoluble salts with metallic cations.
Metodologia para estima??o de parametros físico-químicos de espumas
Luz, José Aurélio Medeiros da;Peres, Antnio Eduardo Clark;
Rem: Revista Escola de Minas , 2001, DOI: 10.1590/S0370-44672001000400006
Abstract: the calculation of flow splitting in froths and foams is needy in several instances in the industrial field. the liquid splitting can be calculated in terms of viscosity, surface tension, and the syneresis specific rate of the interstitial pulp, considering that, under equilibrium and during air sparging, the drainage flow rate of liquid matches the upward liquid flow rate caused by the air bubbles rising. this works treats on the determination of these properties, using very simple experimental setup.
Avalia??o da produ??o de um super-concentrado de minério de ferro
Ferreira, Vinícius Mendes;Donda, Joaquim Donizetti;Peres, Antnio Eduardo Clark;
Rem: Revista Escola de Minas , 2003, DOI: 10.1590/S0370-44672003000300008
Abstract: aiming at producing a concentrate with a silica content lower than 1.00%, laboratory experiments were conducted using a sample of the concentrate from samarco's mechanical flotation, which presented 3.08% silica content. this sample was split in two size ranges: +105mm and -105mm. the -105mm fraction, representing 76.69% of the initial mass, was submitted to another flotation, generating 0.61% silica content. the fraction +105mm, representing 23.31% of the initial mass, was ground 100% -105mm, deslimed, and submitted to flotation. concentrates with 0.90% silica content were obtained. considering the mass proportions of the two size fractions, the calculated silica content of the concentrate is 0.68%, which is considered satisfactory for the objective of this investigation. the major reasons for the 0.90% silica content are the presence of silicon in the lattice of goethites and the presence of residual slimes in the pores of porous hematite.
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