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Estudo de recuperação de chumbo de escória metalúrgica por flotaçãoNUNES, João Alberto de Souza 07 October 2015 (has links)
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Tese de Doutorado - João Nunes - Recuperação de Pb de Escória Metalúrgica por Flotação.pdf: 3142676 bytes, checksum: 24077634f2b469c913c04a7ae58a9678 (MD5) / Made available in DSpace on 2016-04-19T13:12:37Z (GMT). No. of bitstreams: 2
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Tese de Doutorado - João Nunes - Recuperação de Pb de Escória Metalúrgica por Flotação.pdf: 3142676 bytes, checksum: 24077634f2b469c913c04a7ae58a9678 (MD5)
Previous issue date: 2015-10-07 / As empresas produtoras de baterias chumbo-ácido são obrigadas, por lei, a
reciclar as sucatas de baterias usadas. Em Pernambuco, a reciclagem é feita por
processo pirometalúrgico que gera um resíduo denominado de escória, tendo como
principais elementos o chumbo e o ferro. Assim, o presente trabalho teve como objetivo
estudar a possibilidade de reaproveitar o chumbo contido nesta escória, através do
método de flotação. Este reaproveitamento trará um ganho ambiental e econômico a
empresa, devido a redução do seu passivo e o alto valor agregado do chumbo no
mercado internacional, respectivamente.
A fim de caracterização minerológica e química da escória, foram realizadas
análises por difração de raios X (DRX), fluorescência de raios X (FRX) e microscopia
eletrônica de varredura (MEV), o que possibilitou a escolha de uma rota ideal de
tratamento deste resíduo. Os testes de flotação foram realizados em uma célula
mecânica de bancada, estudando-se a influência do tipo de coletor, concentração do
coletor, tempo de condicionamento, pH da polpa, tempo de flotação, tipos de
espumantes de flotação (o metil-isobutil-carbinol - MIBIC e eter-poliglicólico - F650) e
ação de agentes modificadores (amido, o sulfeto de sódio e o querosene) com diferentes
funções, tais como depressores de ferro, ativadores de chumbo e extensor de cadeia
carbônica para aumentar a recuperação do chumbo, respectivamente.
Os resultados mostraram que é possível uma recuperação de 54,4 % do chumbo
da escória com as partículas na faixa granulométrica de 150 – 400 mesh, com o coletor
mercaptobenzotiazol, a uma dosagem de 1.000 g/t, pH 9,0 e tempo de flotação de 20
min. As análises de MEV detectaram a presença de chumbo no interior de partículas de
ferro, o que limita a possibilidade de melhorar a sua recuperação. Por sua vez, o xantato
etílico de sódio foi bastante seletivo, proporcionando um concentrado com apenas 0,4 %
do ferro contido na alimentação, com teor de chumbo de 22,9 %. O teor de chumbo
apresentou um valor inferior a 40,0 %, meta proposta pela empresa, devido a presença
de carbono no concentrado de flotação, o que não foi considerado um problema, pois os
testes piloto mostraram que é possível a sua reutilização na metalurgia do chumbo. / Factories of lead-acid batteries are required by law to recycle battery waste. In
Pernambuco, the waste is recycled by a pyrometallurgical process, which produces a
residue called slag, that has as main elements lead and iron. Therefore, this work had as
a target to study the possibility of reusing the lead of the slag of battery scrap, through
the flotation method. This waste recycling will give the company an environmental and
economic value, due to the reduction of the quantity of slag and due to a greater
recuperation of the lead, especially since its price has been increasing in the
international market.
For the purpose of minerológica and chemical characterization of the slag, it
was performed an analysis by X-ray diffraction (XRD), X-ray fluorescence (XRF) and
scanning electron microscopy (SEM), which allowed the choice of an ideal treating for
this residue. Flotation tests were carried out in a laboratory cell to study the influence of
the type of reactants, the reactant concentration, the adaptation time of the reactants, pH
of the pulp, the flotation time, sparkling types of flotation (methyl-isobutyl- carbinol -
MIBIC and ether polyglycol - F650) and types of modifying agents (starch, sodium
sulfide and kerosene) with different functions, such as iron depressants, carbon chain
extender to increase the lead recovery respectively.
The results showed that it is possible to arrive at a recovery of 54.4% of the
lead with the particles in the size range of 150 - 400 mesh, when we use
mercaptobenzothiazole as reactants of flotation, at a dosage of 1000 g/ton, pH 9.0 and
flotation time of 20 min. The SEM analysis detected the presence of lead inside the iron
particles, which limits the possibility of improving and increasing its recovery. In turn,
the sodium ethyl xanthate was quite selective, providing a concentrate with only 0.4%
of the iron contained, in relation to the initial mass, and with lead concentration of
22.9%. The lead content showed a value less than 40.0%, of the target proposed by the
company, due to the presence of carbon in the form of coke on flotation concentrate,
which was not considered a problem since pilot tests showed that it is possible to reuse
it in the metallurgical process.
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The attenuation of cosmic radiation in lead.Forbes, Vivienne Mary. January 1958 (has links)
No description available.
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Lead Distribution in Urban Soils: Relationship Between Lead Sources and Children's Blood Lead LevelsMorrison-Ibrahim, Deborah E. 14 June 2011 (has links)
Indiana University-Purdue University Indianapolis (IUPUI)
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Low Level Lead Exposure and Postural Balance in ChildrenHemingway, Jennifer M. January 2012 (has links)
No description available.
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Iodine's Crucial Contribution to the Breakdown of Hybrid Tin-Lead Perovskite: Unveiling the Mechanism of DeteriorationAlsulami, Asayil 04 June 2023 (has links)
In developing photovoltaic technology for commercial use, it is essential to prioritize low cost, high efficiency, and long-term stability, along with low toxicity and quick energy payback time. Organic-inorganic metal halide perovskites are among the most promising photovoltaic materials due to their exceptional efficiency and cost-effectiveness. However, their practical significance remains unclear due to their notoriously short device operation duration. Mixed-metal tin-lead perovskites are a class of perovskites that have captured researchers' attention due to their unique optoelectronic features, including a small bandgap, making them useful for various applications (tandems, NIR light detection, and imaging e.g.). Still, the low ambient stability of tin-lead perovskites obstructs their commercialization, necessitating extensive research into their underlying breakdown mechanisms. This study aims to better understand these mechanisms and the involvement of halide chemistry, specifically emphasizing the significant role of iodine in perovskite deterioration. Our findings reveal that tin-lead-based perovskites experience cyclic degradation, with iodine and SnI4 as key degradation products that harm the stability of the perovskite. Investigating the impact of iodine is critical because it is a common component of the perovskite material, and its presence has been shown to play a crucial role in the optoelectronic properties of the perovskite. However, the presence of iodine can also lead to the degradation of the perovskite material over time, reducing the efficiency and lifespan of the perovskite solar cells. Therefore, understanding the role of iodine in perovskite deterioration is essential to improve the stability and durability of tin-lead perovskites and bring them closer to commercialization. By gaining insight into the degradation mechanisms of tin-lead perovskites, we can develop effective strategies to mitigate their degradation, enhance their stability and lifespan, and unlock their full potential for use in various photovoltaic applications, contributing to a more sustainable and environmentally conscious future.
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In-Situ Lead Immobilization Using Phosphate Based BindersDarnell, Jason Ellis 07 August 2004 (has links)
The purpose of this study was to determine the optimum phosphate treatment method to stabilize lead contaminated soil from a firing range. Seven different phosphate sources at five different concentrations were added to soil collected from a firing range on a military base. A series of tests were performed to determine a generic phosphate treatment method. The selected generic phosphate treatment was compared to an untreated control soil sample and to four commercially available treatments provided by invited vendors selected from industry. The four vendors processes, control, and generic treatments were subjected to a series of physical and chemical tests at 0, 14, and 28 days of curing time to determine the effectiveness of each treatment. The generic treatment using Hydroxyapatite developed in the MSU laboratory was competitive with three vendors? treatments. The fourth vendor?s treatment was more effective at reducing the lead leachability of the contaminated soil.
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BODY FLUID DIAGNOSTICS IN MICROLITER SAMPLESShetty, Gautam N. 10 March 2006 (has links)
No description available.
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Evaluation of Bioaerosol Components, Generation Factors, and Airborne Transport Associated with Lime Treatment of Lead-Contaminated Sediment for Beneficial Use PurposesBarth, Edwin F., III 28 September 2006 (has links)
No description available.
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Ferroelectric field effect radiation detector studies utilizing oxygen depleted lead zirconate titanate surface layers /Miller, D. W. January 1971 (has links)
No description available.
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Chronic lead poisoning : time course of hematologic and metabolic changes in rats /Cardona, Edward January 1971 (has links)
No description available.
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