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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Estudo de viabilidade t?cnica do uso de res?duos oriundos do beneficiamento de scheelita na composi??o de concretos asf?lticos / Technical feasibility study of using waste from scheelite processing in composition of asphaltic

Costa Filho, Francisco das Chagas da 03 February 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-20T23:06:42Z No. of bitstreams: 1 FranciscoDasChagasDaCostaFilho_DISSERT.pdf: 6168357 bytes, checksum: c578fb868ea385c90fbc6817fbe806b9 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-24T21:28:11Z (GMT) No. of bitstreams: 1 FranciscoDasChagasDaCostaFilho_DISSERT.pdf: 6168357 bytes, checksum: c578fb868ea385c90fbc6817fbe806b9 (MD5) / Made available in DSpace on 2017-03-24T21:28:11Z (GMT). No. of bitstreams: 1 FranciscoDasChagasDaCostaFilho_DISSERT.pdf: 6168357 bytes, checksum: c578fb868ea385c90fbc6817fbe806b9 (MD5) Previous issue date: 2017-02-03 / A produ??o mineral brasileira ? uma atividade de suma import?ncia para a economia do pa?s, visto que al?m de contribuir para o produto interno bruto - PIB, ? respons?vel pela gera??o de muitos empregos diretos e indiretos. Neste cen?rio, a minera??o Tomaz Salustino S/A (Mina Breju?) ? uma grande representante nordestina deste setor. Dados de 2012 demonstram que a produ??o da Mina Breju? era em torno de 20 toneladas mensais (MACHADO 2012), representando mais de 300 empregos gerados, al?m do desenvolvimento do munic?pio de Currais Novos, onde a empresa est? situada. Entretanto, devido ao beneficiamento do min?rio (scheelita), desde 1943, foram geradas toneladas de res?duos, e, atualmente, estima-se que no entorno da minera??o existe cerca de 7 milh?es de toneladas (4,5 milh?es de fra??o grossa e 2,5 milh?es de fra??o fina), dispostos em pilhas e bacias de res?duos, gerando diversos impactos ambientais, como a modifica??o da paisagem local. Em vista deste grande estoque de res?duo, aliado a necessidade de extra??o de mat?ria prima natural para compor as camadas usuais de um pavimento, o presente estudo avaliou a viabilidade t?cnica dos res?duos provenientes da Mina Breju? na composi??o de concretos asf?lticos, em substitui??o ao agregado mi?do natural, pela fra??o grossa do res?duo, e, do f?ler convencional, pela fra??o fina do res?duo. Para isto, realizaram-se ensaios de caracteriza??o f?sica, qu?mica e mineral?gica das fra??es do res?duo e dos agregados naturais utilizados na pesquisa, al?m de dosagens Marshall em composi??es de concretos asf?lticos para analisar os par?metros volum?tricos e a estabilidade dos materiais quanto a utiliza??o em obras vi?rias. A partir do programa experimental proposto, pode-se verificar que a fra??o grossa do res?duo do beneficiamento da scheelita apresentou um potencial elevado para ser utilizado in natura como agregado mi?do, pois os corpos de prova analisados demonstraram bom desempenho com rela??o aos par?metros volum?tricos e a estabilidade Marshall. A fra??o fina tamb?m se mostrou vi?vel para ser utilizada como f?ler artificial, por?m, para tal aplica??o, se faz necess?rio processos de melhoramento de qualidade para que a fra??o do res?duo se enquadre como material de enchimento de misturas asf?lticas, visto que in natura, a mesma n?o apresentou os 65% de material passante na peneira de 0,075 mm requisitado pela norma DNER - EM 367/97 (DNER, 1997a). / The Brazilian mineral production is an extremely important activity for the country's economy, since in addition to contributing to gross national product - PIB, it is responsible for the generation of many direct and indirect jobs. Therefore, the Tomaz Salustino Corporation Mining (Breju? Mine) is a important northeastern representative of this sector. Data for 2012 show that the production of the Breju? Mine was around 20 tons per month (MACHADO 2012), representing more than 300 jobs generated, in addition to the development of the municipality of Currais Novos. However, due to the ore (scheelite) processing, since 1943, tons of waste have been generated, and it is currently estimated around 7 million tons (4.5 million thick fractions and 2.5 million fine fractions), disposed in piles and waste basins, generating several environmental impacts, such as the modification of the local landscape. Due of this large stock of waste, jointly with the need for extraction of natural raw material to compose the usual layers of a pavement, the present study evaluated the technical feasibility of the residues from the Breju? Mine in the composition of asphaltic concretes, replacing the natural small aggregate by the thick fractions of the residue, and the conventional filler by the fine fractions of the residue. For this, chemical and mineralogical characterization of fractions of the residue and of the natural aggregates used in the research, besides Marshall dosages in compositions of asphaltic concretes was carried out to analyze the volumetric parameters and the stability of the materials as for the use in road works. From the proposed experimental program, it can be verified that the thick fractions of the scheelite processing residue presented a high potential to be used in natura as a small aggregate, because the analyzed specimens showed good performance in relation to the volumetric parameters and the Marshall stability. The fine fraction has also proved feasible to be used as an artificial filler, however, for this application, it is necessary to improve the quality for that the fraction of the residue fits as asphalt mixtures filling material since, in natura, it did not present the 65% passing material in the 0.075 mm sieve required by DNER - EM 367/97 (DNER, 1997a).
2

Perdas de qualidade e contamina??o do solo em mina de sheelita no semi?rido tropical

Andrade, Jo?o Manoel Dantas de 31 July 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-10-04T19:24:48Z No. of bitstreams: 1 JoaoManoelDantasDeAndrade_DISSERT.pdf: 1799678 bytes, checksum: 52edc7fdf918d5dc0c069ed539c834d6 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-10-09T22:24:00Z (GMT) No. of bitstreams: 1 JoaoManoelDantasDeAndrade_DISSERT.pdf: 1799678 bytes, checksum: 52edc7fdf918d5dc0c069ed539c834d6 (MD5) / Made available in DSpace on 2017-10-09T22:24:00Z (GMT). No. of bitstreams: 1 JoaoManoelDantasDeAndrade_DISSERT.pdf: 1799678 bytes, checksum: 52edc7fdf918d5dc0c069ed539c834d6 (MD5) Previous issue date: 2017-07-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A disposi??o irregular de pilhas de rejeito e est?ril causa degrada??o ambiental. Pilhas de rejeito e est?ril s?o fontes de contamina??o continua do ambiente, impactando principalmente o solo, reduzindo sua qualidade a partir de altera??es nos seus atributos f?sicos e qu?micos e na disposi??o de metais pesados. O presente trabalho teve como objetivo avaliar os atributos f?sicos e qu?micos e teores de metais pesados dispon?veis do solo da Mina Breju?. Foram coletadas amostras de solo em nove locais da minera??o e um em mata nativa que serviu de refer?ncia de qualidade. Foi feita an?lise dos atributos f?sicos (densidade do solo, de part?cula, porosidade total e granulomentria), qu?micos (pH, condutividade el?trica, Ca??, Mg??, Na,K?, H?+Al??, Al??, soma de bases, capacidade de troca de c?tions potencial, satura??o por bases e por alum?nio e mat?ria org?nica) e teores de metais pesados dispon?veis (Fe, Mn, Cd, Cr, Cu, Ni, Pb e Zn). A minera??o de scheelita provoca perdas de qualidade do solo. Os atributos f?sicos e qu?micos, mais sens?veis na distin??o entre as ?reas mineradas e a mata nativa s?o Ds, MO, Ca??, CE, pH e acidez potencial, os quais podem ser utilizados em programas de monitoramento ambiental da ?rea. Os processos de degrada??o do solo mais evidentes nas ?reas mineradas s?o a compacta??o, saliniza??o, redu??o dos teores de mat?ria org?nica e contamina??o por metais pesados. Os metais Cd, Ni e Pb est?o sendo disponibilizados a partir das pilhas de res?duos da minara??o de scheelita ultrapassando os Valores de Refer?ncia de Qualidade do Solo do estado do Rio Grande Norte. ? necess?rio a elabora??o de um plano de gest?o e recupera??o da ?rea minerada visando a disposi??o adequada dos res?duos, com ?nfase a pilha de rejeitos ferrosos, e a mitiga??o dos processos de degrada??o evidenciados no presente estudo. / The irregular disposition of amounts of tailings causes environmental degradation. Piles of tailings are regular sources of contamination in the environment, impacting, mainly, in the soil, reducing its quality by changes in its physical and chemical attributes and also by the deposition of heavy metals. The main objective of this study was the evaluation of physical and chemical attributes, and also evaluate the heavy metals content in the soil of Breju? Mine. It was collected soil samples in nine mining places and also it was collected soil samples from a native forest place, the last one it was used as quality reference. It was analyzed physical attributes (soil particle density, total porosity and granulometry), chemicals (pH, electric conductivity, Ca??, Mg??, Na?,K?, H?+Al??, Al??, sum of bases, potential cation exchange capacity, saturation by bases and by aluminum, organic matter) and available metals contents (Fe, Mn, Cd, Cr, Cu, Ni, Pb e Zn). The scheelite mining causes losses in the soil quality. Physical and Chemicals attributes more affected when compared to native forest areas are Ds, MO, Ca??, CE, pH and potential acidity, those attributes can be used in programs of environmental monitoring of the area. The most evident degradation processes in the mining area are compaction, salinization, depletion in the organic matter contents and contamination by heavy metals. Metals like Cd, Ni e Pb are been available by piles of mining waste of scheelite exceeding reference values of soil quality for Rio Grande do Norte state. It is necessary the elaboration a plan to manage and recover the mining area aiming adequate disposition of wastes, with emphasis on the pile of ferrous tailings, and the mitigation of degradation processes evidenced in the present study.

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