DSpace Communidade:http://www.repositorio.ufop.br/jspui/handle/123456789/5052024-03-29T16:00:06Z2024-03-29T16:00:06ZLixiviação ácida de elementos terras raras presentes em resíduos de equipamentos elétricos e eletrônicos : uma breve revisão.Gomes, Rodrigo F.Pereira, Matheus MelloLeão, Versiane Albishttp://www.repositorio.ufop.br/jspui/handle/123456789/170162023-07-19T19:26:40Z2022-01-01T00:00:00ZTítulo: Lixiviação ácida de elementos terras raras presentes em resíduos de equipamentos elétricos e eletrônicos : uma breve revisão.
Autor(es): Gomes, Rodrigo F.; Pereira, Matheus Mello; Leão, Versiane Albis
Resumo: The accelerated expansion of the use of electronic products has generated large amounts of Waste
Electrical and Electronic Equipment (WEEE), which makes the use of management strategies based on
Circular Economy (CE) essential. In this sense, the recycling of these residues is of great interest due
to the presence of metals with high added value, such as Rare Earth Elements (REE). Given the above,
this review aims to elucidate issues related to the management and processing of WEEE and to evaluate
the main parameters that influence the leaching step of REE present in these wastes. From the critical
analysis of the bibliographic survey, it was noted that fluorescent lamps, cathode-ray tubes, NbFeB magnets
and NiMH batteries are widely studied, with the objective of recovering REE. However, considerable
variations were observed with regard to the content of metals present in each of these residues. In short,
it is important that the recovery of these metals is studied, not only due to economic aspects, but also
aiming at environmentally sustainable recycling.2022-01-01T00:00:00ZOn the cobalt content upgrade in nickeliferous laterites using iron (III) sulfate : a study based on thermodynamics simulations.Souza, Rodrigo Fernandes Magalhães deTavares, Mariana Aguiar de AzevedoCruz, Luiz Eduardo CarnevaleOliveira, Víctor de Andrade AlvarengaSantos, Iranildes Daniel dosMoura, Francisco JoséBrocchi, Eduardo de Albuquerquehttp://www.repositorio.ufop.br/jspui/handle/123456789/169232023-07-10T19:21:11Z2022-01-01T00:00:00ZTítulo: On the cobalt content upgrade in nickeliferous laterites using iron (III) sulfate : a study based on thermodynamics simulations.
Autor(es): Souza, Rodrigo Fernandes Magalhães de; Tavares, Mariana Aguiar de Azevedo; Cruz, Luiz Eduardo Carnevale; Oliveira, Víctor de Andrade Alvarenga; Santos, Iranildes Daniel dos; Moura, Francisco José; Brocchi, Eduardo de Albuquerque
Resumo: Nickel (Ni) and cobalt (Co) are relevant technological metals for the future of the lithium-ion
battery (LIB) industry. Based on the current and projected demand for these, an increased interest in
developing processing routes to exploit lateritic occurrences has been observed, as these are reported
as critical raw materials for future mineral–metallurgical industry. However, the content of Ni and Co
in such ores is minimal and requires impracticable mineral-processing operations for concentration
before metal extraction. It was identified that information regarding the sulfation roasting of this
material is scarce on what concerns the iron sulfates interaction as a function of the temperature. Based
on that context, the present work has its purposes associated with the proposition of an alternative
chemical pretreatment to upgrade the content of metals of technological interest in lateritic ores
through a simple roast–leach process. Thus, the chemical interactions between the mineral sample
and iron (III) sulfate (Fe2
(SO4
)3
) through thermodynamic simulations and experimental procedures
were explored. The latter included specific water leaching practices for the selective concentration of
metals. The equilibrium calculations indicate that Fe2
(SO4
)3 and FeSO4
tend to decompose at lower
temperatures, and considering the higher stability of other metal sulfates, it could be an interesting
reagent in this type of process. Regarding the experimental results, the characterization of materials
indicates a recovery of Co as high as 73.4 wt.% after sulfation roasting at 500 ◦C followed by water
leaching, with the full content of Iron (Fe) being reported in the insoluble phase. Based on these
findings, the present development could be an interesting alternative to consider within operations
for the chemical upgrade of cobalt in such types of mineralogical occurrences.2022-01-01T00:00:00ZDiversidade da comunidade de macroinvertebrados bentônicos no reservatório de Volta Grande, Bacia do Baixo Rio Grande.Camargo, Paulo Ricardo da SilvaBarbosa, Newton Pimentel de UlhôaCardoso, Antônio ValadãoAssis, Paulo SantosPelli, Afonsohttp://www.repositorio.ufop.br/jspui/handle/123456789/169222023-07-10T19:11:49Z2022-01-01T00:00:00ZTítulo: Diversidade da comunidade de macroinvertebrados bentônicos no reservatório de Volta Grande, Bacia do Baixo Rio Grande.
Autor(es): Camargo, Paulo Ricardo da Silva; Barbosa, Newton Pimentel de Ulhôa; Cardoso, Antônio Valadão; Assis, Paulo Santos; Pelli, Afonso
Resumo: A comunidade de macroinvertebrados bentônicos é composta por alguns organismos mais sensíveis e outros mais
resistentes as mudanças ambientais. Nesse sentido, são utilizados como bioindicador. O presente trabalho teve como
objetivo verificar a diversidade de espécies local (diversidade alfa) da comunidade de macroinvertebrados em dois
trechos da Bacia do Baixo Rio Grande com composição de substrato distintos. O estudo ocorreu em dois pontos da
Bacia do Baixo Rio Grande. No ponto 1 foram coletadas amostras de sedimentos ao longo de doze meses, onde foram
calculados o índice de diversidade dos parâmetros riqueza (S), abundância, dominância, diversidade de ShannonWiener (H'), diversidade de Simpson (D') e equitabilidade (J) e por meio da análise não paramétrica Kruskal-Wallis
foram comparados entre todos os meses do ano e também estação chuvosa e de estiagem. No ponto 2 foram coletados
substratos artificiais e foram calculados os índices de diversidade, compreendendo também as estações chuvosas e de
estiagem. No ponto 1 não houve diferença significa entre as estações chuvosas e de estiagem, mas apresentou
diferenças entre a abundância e equitabilidade entre todos os meses amostrados. No ponto 2 foi evidenciado que o
valores dos índices de diversidades se apresentaram maiores nos meses de estiagem. Em síntese, foi inferido que as
comunidades bentônicas podem estar sob o reflexo da homogeneização ambiental resultantes das atividades
antrópicas. Portanto, esses índices de diversidades podem ser uma ferramenta adequada para compreender o ambiente,
e assim fomentar decisões mitigadoras em prol da conservação das espécies mais assertivas.2022-01-01T00:00:00ZThe Bauschinger effect magnitude control in ultra-low carbon steel wires.David, Felipe FarageCordeiro, Rafael de OliveiraVasconcelos, Luan Marcel CostaBatista, Ben Dêivide de OliveiraLiberato, Frank de MelloCosta, Adilson Rodrigues dahttp://www.repositorio.ufop.br/jspui/handle/123456789/169212023-07-10T19:07:37Z2023-01-01T00:00:00ZTítulo: The Bauschinger effect magnitude control in ultra-low carbon steel wires.
Autor(es): David, Felipe Farage; Cordeiro, Rafael de Oliveira; Vasconcelos, Luan Marcel Costa; Batista, Ben Dêivide de Oliveira; Liberato, Frank de Mello; Costa, Adilson Rodrigues da
Resumo: The cold roller die process increases the tensile strength and decreases the ductility of steel wire.
Annealing heat treatment is applied to restore mechanical properties, but this is a costly process. This
research shows that it is possible to control the mechanical properties of ultra-low carbon steel wire
inducing the Bauschinger effect and relieving residual steel stresses. The present study uses several
pulleys to promote and control the Bauschinger effect magnitude through alternated cyclic bending. A
Completely Randomized Design, a regression study, and the Akaike Information Criterion were used
to understand the relationship between the quantity and diameter of pulleys and the influence on the
magnitude of the Bauschinger effect. Statistical models showed that it is possible to have a maximum
increase of 103% in uniform elongation and a maximum decrease of 14% in yield strength. An
interaction between the factors studied in controlling the Bauschinger effect magnitude was confirmed.2023-01-01T00:00:00Z