Made available in DSpace on 2017-07-10T19:25:19Z (GMT). No. of bitstreams: 1 Claudio.pdf: 8512630 bytes, checksum: ab5b2087ffb29cad05f9d8e20d22b7fd (MD5) Previous issue date: 2011-12-12 / Water and soil conservation is essential for water resources management. Thus, conservationist actions are developed and applied in order to make part of a set of measures which enable the supply management, based on an appropriate recharge of the aquifers as well as the improvement of their quality, from the reduction of erosive processes and volume of effluents discharged in lakes and rivers. Some of these actions are associated to the precision agriculture, which aims at improving yield, reducing costs as well as the environmental impact by a site-specific management in an agricultural area. Thus, the main goal of this research is the development of software to determine the management zones, using empirical and grouping methods to be applied for soil and water conservation. This software tool, multiplatform, provides the ability to input and output data through specific standards, draws thematic maps according to well-known methods of interpolation (inverse of distance, moving average and the nearest neighbor) As well as evaluates management zones, generated by methods of relative efficiency and comparison test of averages. The software was tested according to physical and chemical data and soybean yield, so that management zones were generated and evaluated. Water leaching data were analyzed if the management zones can be used to identify the places with the greatest potential for leaching. The use of software allowed the generation of management zones in an easier way, as well as their analyses. Therefore, it identified that the generated management zones could be used as a source of recommendation and analysis of most of the studied attributes. Except nitrogen, the other attributes had the same potential for leaching, according to the comparison test of straight lines / A conservação da água e do solo é de fundamental importância para a gestão dos recursos hídricos. Para isso, são desenvolvidas e aplicadas ações conservacionistas que compreendem um conjunto de medidas que possibilitam a gestão da oferta, por meio da adequada recarga dos aquíferos e da melhoria de sua qualidade, a partir da redução dos processos erosivos e do volume de efluentes lançados nos lagos e rios. Algumas dessas ações estão relacionadas à agricultura de precisão, a qual visa, além do aumento da produtividade, diminuir tanto os custos como o impacto ambiental a partir do gerenciamento localizado da lavoura. Neste contexto, esta pesquisa teve como objetivo principal a elaboração de um software para definição de unidades de manejo, com métodos empíricos e de agrupamento para auxiliar na conservação do solo e da água. A ferramenta computacional, multiplataforma, fornece a possibilidade de entrada e saída de dados a partir de padrões específicos, realiza a geração de mapas temáticos por métodos conhecidos de interpolação (Inverso da distância elevado à determinada potência, média móvel e vizinho mais próximo) e permite avaliar unidades de manejo, geradas utilizando métodos de eficiência relativa e teste de comparação de médias. O software foi testado a partir dos dados físicos, químicos e da produtividade da soja, sendo geradas e avaliadas as unidades de manejo. Dados provenientes de água lixiviada foram analisados, visando identificar se unidades de manejo podem ser utilizadas para identificar locais com maior potencial à lixiviação. O uso do software possibilitou a geração de unidades de manejo de forma facilitada, bem como a realização de análises sobre as mesmas. Logo, permitiu identificar que as unidades de manejo geradas podem ser utilizadas como fonte de recomendação e análise da maior parte dos atributos estudados. Com exceção do nitrogênio, os demais atributos apresentaram-se com o mesmo potencial de lixiviação, conforme teste de comparação de retas

A presença da pirita (FeS2) em depósitos de rejeitos de carvão mineral pode causar danos ambientais. A pirita oxida e proporciona a geração da drenagem ácida de minas (DAM). Uma possível maneira de se evitar tal problema é separando a pirita e empregando-a para algum fim. Assim, o objetivo do presente trabalho foi desenvolver uma rota para sintetizar óxidos magnéticos a partir de um concentrado de pirita oriundo de rejeito de carvão. Experimentalmente, utilizou-se 300 kg de um concentrado com 73,2% de pirita em escala piloto. Realizou-se uma etapa de lixiviação aeróbica com água, em circuito fechado, com o intuito de se obter um extrato aquoso rico em íons férricos. A seguir, procederam-se mudanças no sistema de forma a estabelecer uma condição anaeróbia e redutora ao meio para obterem-se íons ferrosos. O lixiviado, rico em íons Fe2+ e SO4 2-, foi misturado com etanol para a precipitação do ferro como melanterita. Duas rotas para a produção de óxidos ferromagnéticos foram avaliadas. Primeiro, para a síntese de ferritas, utilizou-se o direto ajuste de pH da solução lixiviada reduzida até 10,5 durante 4 dias e posterior precipitação do material magnético. Segundo, para a síntese da magnetita, os cristais de melanterita, obtidos pela precipitação com etanol, foram dissolvidos em água deionizada e procedeu-se o mesmo ajuste de pH e tempo reacional para a cristalização do ferro na forma de óxido. Os cristais foram separados por precipitação, lavados com água deionizada, secos e caracterizados em relação à composição elementar, cristalinidade, distribuição granulométrica, forma, termodecomposição e magnetização. Pode-se concluir que os procedimentos empregados resultaram na obtenção de ferritas e cristais de magnetita na faixa granulométrica entre 0,1 e 10,0 μm. As ferritas apresentaram medidas de magnetização de saturação e coercividade de 29 emu/g e 33,4 Oe e a magnetita de 86,6 emu/g e 75,2 Oe. Os rendimentos em relação ao Fe presentes no lixiviado reduzido (síntese da ferrita de zinco) e melanterita (síntese da magnetita) foram de 34,9% e 93,2%, respectivamente. A produção de reagentes e materiais com valor agregado a partir de concentrados de pirita, oriundo de um rejeito mineral é tecnologicamente viável. O custo estimado para a produção de nano e microgrãos de magnetita foi calculado em R$ 136,29/kg. O processo reduz o desperdício de materiais, minimiza impactos de descarte de resíduos ao meio ambiente e pode tornar-se uma fonte de recursos alternativa dentro da cadeia de produção de carvão. Deve-se ressaltar que os óxidos magnéticos encontram aplicações como pigmentos, em suspensões de meio denso, suporte magnético, agente de contraste em medicina e como material adsorvente. / The presence of pyrite (FeS2) in coal tailings deposits can cause environmental damage. Pyrite oxidizes and generates acid mine drainage (AMD). One possible way to avoid such a problem is by separating the pyrite and employing it for some purpose. Thus, the aim of the present work was to develop a route to synthesize magnetic oxides from a pyrite concentrated from coal rejects. Experimentally, it was carried out in a pilot leaching unit with 300 kg of a pyrite concentrate with of 73.2% FeS2. A step of aerobic leaching with closed circuit water was carried out in order to obtain an aqueous extract rich in ferric ions. Next, changes were made in order to establish an anaerobic and reductive condition in the medium to obtain ferrous ions. The leachate, rich in Fe2+ and SO4 2- ions, was mixtured with different proportions of ethanol to precipitate the iron as melanterite. Two procedures to produce ferromagnetic oxides were investigated. First, for ferrite synthesis, the reduced leachate had the pH adjusted to 10.5 and this condition was kept for a period of 4 days for crystallization of the magnetic material. Second, for magnetite synthesis, melanterite crystals obtained by the precipitation with ethanol (A.P) were dissolved in deionized water and the same pH adjustment and reaction time for the crystallization of the iron as ferrites was carried out. The crystals were separated by precipitation, washed with deionized water, dried, and characterized in relation to elemental composition, crystallinity, particles size distribution, shape, thermo-decomposition, and magnetization. The procedures applied resulted in ferrites and magnetite particles in particle size between 0.1 and 10.0 μm. Ferrite particles presented magnetization saturation and magnetization coercivity of 29 emu/g and 33,4 Oe and magnetite particles of 86.6 emu/g e 75.2 Oe. The yields, from the reduced leachate, were 34.9% for ferrites and 93.2% for magnetite. The production of reagent and materials with aggregate values from pyrite concentrates is viable. The estimated cost for nano and micro particles of magnetite synthesis was estimated in R$ 136.29/kg. The process reduces the waste of materials, minimize the discharge of wastes in the environment and could be source of resource in coal production chain. It should be noted that magnetic oxides find applications as pigments, in dense media suspensions, magnetic support, contrast agent in medicine, and as adsorbent material.

CNPq / Faced with the need to implement a sustainable development, and seeking solutions for protecting the environment, the management of residues has undergone marked changes. Companies are increasingly involved in the optimization of residues produced in their production processes. The oil industry participates in this search by funding research and development of environmentally sound technologies. This study aimed to evaluate the development of barley plants (Hordeum vulgare L.) in soils incubated with drill waste from oil well treated by washing to eliminate the influence of sodium. Two residues generated during drilling of the well 7-SMC-50D-AL were selected to be used in two assays: one in pots planted with barley, and one with leaching columns. For the pots testing the residues were washed with water, using a ratio of 1:5, aiming to reduce the effects of the sodium. Thus, the washing treatment defined two other conditions: residue washed and unwashed. The quantity of residue added to the soil was defined in order to obtain the barium concentrations of 300 mg kg-1, 600 mg kg-1 and 1200 mg kg-1. The soil moisture was maintained at 70% of field capacity. The experimental units were kept incubated for 30 days, and covered with plastic bags to prevent water loss by evaporation. The plants sowing was made using 10 seeds in each pot, and after the thinning with 30 days there was left 4 plants per pot. After the harvesting, the plants were separated into root, shoot and grain; and it was evaluated the absorption of the elements barium, iron, manganese, calcium, sodium, zinc and potassium. The results showed that the residues of the centrifugal and the dryer promoted an increased production of plant dry matter, especially in the treatment with the residue washing. For the test columns, there was no washing of the residues. The same doses were tested with two conditions of humidity (70% of field capacity and reduced condition, simulating the presence of a ground water table). During the incubation the pH and the redox potential (Eh) were monitored until, in the reduction condition, values close to ? 200 mV were obtained, and then, waiting for 30 days to ensure the occurrence of the reduction reactions. After that, the leaching test proceeded, simulating rainfall and collecting the extract leachate to evaluate the barium content. The geochemical fractionation of barium was done using a modification of the BCR method. The fractionation results showed that the reduction condition provided greater availability of barium, increasing the bioavailable fraction for both cuttings. In the leaching test, there was an increase in barium level in the reduction condition, due to the reduction of sulfate to sulfide. / Diante da necessidade de implementar o desenvolvimento sustent?vel, buscando solu??es para a prote??o do meio ambiente, a gest?o de res?duos tem passado por mudan?as marcantes. As empresas est?o cada vez mais envolvidas na otimiza??o de res?duos produzidos em seus processos produtivos. A ind?stria petrol?fera participa dessa busca por solu??es atrav?s do financiamento de pesquisas e do desenvolvimento de tecnologias ambientalmente seguras. Este trabalho teve como objetivo avaliar o desenvolvimento de plantas de cevada (Hordeum vulgare L.) em solos incubados com res?duos de perfura??o de po?o de petr?leo tratados com lavagem para eliminar a influ?ncia do s?dio. Foram selecionados dois res?duos gerados durante a perfura??o do Po?o7-SMC-50D-AL para serem utilizados em dois ensaios: um com vasos cultivados com cevada e outro com colunas de lixivia??o. Para o ensaio com vasos foi feita a lavagem dos res?duos em ?gua, na propor??o 1:5, visando diminuir os efeitos do s?dio. Dessa forma, o tratamento de lavagem definiu duas condi??es: res?duo lavado e res?duo n?o lavado. A quantidade de res?duo adicionada ao solo foi definida de modo a atingir as concentra??es de b?rio de 300 mg kg-1, 600 mg kg-1 e 1200 mg kg-1. A umidade do solo foi mantida a 70% da capacidade de campo. As unidades experimentais permaneceram incubadas por 30 dias, cobertas com sacos pl?sticos para evitar a perda de ?gua por evapora??o. Em seguida foi feita a semeadura, utilizando 10 sementes em cada vaso, e com o desbaste ap?s 30 dias restaram apenas 4 plantas por vaso. Ap?s a coleta as plantas foram separadas em raiz, parte a?rea e gr?os e foi avaliada a absor??o dos elementos b?rio, ferro, mangan?s, c?lcio, s?dio, zinco e pot?ssio. Os resultados obtidos demonstraram que os res?duos do secador e da centr?fuga promoveram aumento da produ??o de mat?ria seca pelas plantas, principalmente no tratamento lavado. Para o ensaio com colunas n?o houve lavagem dos res?duos. Foram testadas as mesmas doses em duas condi??es de umidade (70% da capacidade de campo e ambiente reduzido com presen?a de l?mina de ?gua). Durante a incuba??o foi feito o monitoramento de pH e potencial redox (Eh) at? que, na condi??o de redu??o, fossem atingidos valores pr?ximos de -200 mV, aguardando por 30 dias para assegurar a ocorr?ncia das rea??es de redu??o. Em seguida foi feito o ensaio de lixivia??o, simulando uma precipita??o e coletando o extrato lixiviado para avalia??o quanto ao teor de b?rio. Foi feito o fracionamento geoqu?mico do elemento b?rio utilizando-se o m?todo BCR com algumas modifica??es. Os resultados mostraram que no fracionamento as fra??es biodispon?vel para ambos os res?duos na condi??o de redu??o proporcionou uma maior disponibilidade do b?rio. Na lixivia??o houve um aumento dos teores de b?rio na condi??o de redu??o proporcionado pela redu??o de sulfato a sulfeto.

Made available in DSpace on 2017-05-12T14:47:44Z (GMT). No. of bitstreams: 1 Tatiane Cristina Dal Bosco.pdf: 2407688 bytes, checksum: dc7f310a6c6d81768cdc17673481b44b (MD5) Previous issue date: 2007-12-12 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / West of Paraná presents as outstanding economical activity the swine activity. The effluent of swine generated in the agricultural properties are known by its high pollutant potential. Usually the effluents are treated and later applied to the soil as manuring form and reuse of water. However, these applications happen without a defined rate that considers the soil conditions, climate and cultures cultivated in the area. As a consequence, it can cause problems related to the diffuse pollution due to the runoff and the ions movement in the profile of the soil. So, the objective of this work was to evaluate the diffuse pollution, in terms of total nitrogen, nitrate, nitrite, phosphorus, copper and zinc, due to the application of swine wastewater (ARS) in soil cultivated with soybean, under simulated rain condition. The experiment was installed in November of 2006, in the experimental farm of PUCPR, campus of Toledo where five rates of ARS were applied to the soil (0, 50, 100, 150 and 200 m3 ha-1 in the cycle), in three repetitions for treatment, divided in six applications along the cycle of the soybean. Gutters to collect the runoff material were installed and it was made six rain simulations during the experiment, resulting in six collections of the runoff material that was analyzed pH, total nitrogen, nitrate, nitrite, phosphorus, copper and zinc. At the end of the cycle of the soybean soil samples were collected of each one of the experimental parcels. It was analyzed pH, total nitrogen, nitrate, phosphorus, cation exchangeable capacity, organic matter, copper and zinc of the soil. It was observed that the phosphorus, the total nitrogen, the copper and the zinc were the elements that represented larger concern in terms of pollutant potential of the superficial waters by the runoff. The largest copper, zinc and nitrite concentrations were observed in the initials collections, while the largest concentrations of nitrate and phosphorus were verified in the final collections. In the soil, the effect of ARS was just verified for the cation exchangeable capacity and nitrate. / A região Oeste do Paraná apresenta como atividade econômica marcante, a suinocultura. Os dejetos suínos gerados nas propriedades agrícolas são conhecidos pelo seu alto potencial poluidor. Normalmente os dejetos são tratados e posteriormente aplicados ao solo como forma de adubação e reúso de água. Entretanto, estas aplicações ocorrem sem que se tenha uma taxa definida que considere as condições de solo, clima e culturas cultivadas na região. Como conseqüência, pode-se ter problemas relacionados à poluição difusa decorrente do escoamento superficial e da movimentação de íons no perfil do solo. Deste modo, o objetivo deste trabalho foi avaliar a poluição difusa, em termos de nitrogênio total, nitrato, nitrito, fósforo, cobre e zinco, em função da aplicação de água residuária de suinocultura (ARS) em solo cultivado com soja, sob condição de chuva simulada. O experimento foi instalado no mês de novembro de 2006, na fazenda experimental da PUCPR, campus de Toledo onde foram aplicadas ao solo cinco taxas de ARS (0, 50, 100, 150 e 200 m3 ha-1 no ciclo), em três repetições por tratamento, divididas em seis aplicações ao longo do ciclo da soja. Foram instaladas calhas coletoras do material escoado e fez-se seis simulações de chuva durante o experimento, resultando em seis coletas do material escoado, no qual foi determinado pH, nitrogênio total, nitrato, nitrito, fósforo, cobre e zinco. Ao final do ciclo da soja foram coletadas amostras de solo em cada uma das parcelas experimentais. Determinou-se o pH, nitrogênio total, nitrato, fósforo, capacidade de troca de cátions, matéria orgânica, cobre e zinco do solo. Observou-se que o fósforo, o nitrogênio total, o cobre e o zinco foram os elementos que representaram maior preocupação em termos de potencial poluidor das águas superficiais via escoamento superficial. As maiores concentrações de cobre, zinco e nitrito no material escoado foram observadas nas coletas iniciais, enquanto que as maiores concentrações de nitrato e fósforo foram verificadas nas coletas finais. No solo, o efeito da ARS foi verificado apenas para a capacidade de troca de cátions e o nitrato.

Made available in DSpace on 2017-05-12T14:48:42Z (GMT). No. of bitstreams: 1 Claudio.pdf: 8512630 bytes, checksum: ab5b2087ffb29cad05f9d8e20d22b7fd (MD5) Previous issue date: 2011-12-12 / Water and soil conservation is essential for water resources management. Thus, conservationist actions are developed and applied in order to make part of a set of measures which enable the supply management, based on an appropriate recharge of the aquifers as well as the improvement of their quality, from the reduction of erosive processes and volume of effluents discharged in lakes and rivers. Some of these actions are associated to the precision agriculture, which aims at improving yield, reducing costs as well as the environmental impact by a site-specific management in an agricultural area. Thus, the main goal of this research is the development of software to determine the management zones, using empirical and grouping methods to be applied for soil and water conservation. This software tool, multiplatform, provides the ability to input and output data through specific standards, draws thematic maps according to well-known methods of interpolation (inverse of distance, moving average and the nearest neighbor) As well as evaluates management zones, generated by methods of relative efficiency and comparison test of averages. The software was tested according to physical and chemical data and soybean yield, so that management zones were generated and evaluated. Water leaching data were analyzed if the management zones can be used to identify the places with the greatest potential for leaching. The use of software allowed the generation of management zones in an easier way, as well as their analyses. Therefore, it identified that the generated management zones could be used as a source of recommendation and analysis of most of the studied attributes. Except nitrogen, the other attributes had the same potential for leaching, according to the comparison test of straight lines / A conservação da água e do solo é de fundamental importância para a gestão dos recursos hídricos. Para isso, são desenvolvidas e aplicadas ações conservacionistas que compreendem um conjunto de medidas que possibilitam a gestão da oferta, por meio da adequada recarga dos aquíferos e da melhoria de sua qualidade, a partir da redução dos processos erosivos e do volume de efluentes lançados nos lagos e rios. Algumas dessas ações estão relacionadas à agricultura de precisão, a qual visa, além do aumento da produtividade, diminuir tanto os custos como o impacto ambiental a partir do gerenciamento localizado da lavoura. Neste contexto, esta pesquisa teve como objetivo principal a elaboração de um software para definição de unidades de manejo, com métodos empíricos e de agrupamento para auxiliar na conservação do solo e da água. A ferramenta computacional, multiplataforma, fornece a possibilidade de entrada e saída de dados a partir de padrões específicos, realiza a geração de mapas temáticos por métodos conhecidos de interpolação (Inverso da distância elevado à determinada potência, média móvel e vizinho mais próximo) e permite avaliar unidades de manejo, geradas utilizando métodos de eficiência relativa e teste de comparação de médias. O software foi testado a partir dos dados físicos, químicos e da produtividade da soja, sendo geradas e avaliadas as unidades de manejo. Dados provenientes de água lixiviada foram analisados, visando identificar se unidades de manejo podem ser utilizadas para identificar locais com maior potencial à lixiviação. O uso do software possibilitou a geração de unidades de manejo de forma facilitada, bem como a realização de análises sobre as mesmas. Logo, permitiu identificar que as unidades de manejo geradas podem ser utilizadas como fonte de recomendação e análise da maior parte dos atributos estudados. Com exceção do nitrogênio, os demais atributos apresentaram-se com o mesmo potencial de lixiviação, conforme teste de comparação de retas

Made available in DSpace on 2017-07-10T14:38:19Z (GMT). No. of bitstreams: 1 Daniela Herrmann.pdf: 621996 bytes, checksum: 8bfc3d047c704a58a12b63a71c9d3c9b (MD5) Previous issue date: 2013-08-16 / Swine wastewater (SWW) has high organic load becoming an important source of macro and micronutrients to plants, promoting the improvement of soil quality and development in several tilth. however when done without agronomic and environmental standard, can cause problems in soil, leaching of nutrients, prejudice to water resources and toxicity to plants. The objective of this work, was to evaluate the chemical in soil and leachat regarding association of swine wastewater and mineral fertilization(MF) in farming black oat. Conducted an experiment using applications of SWW associated or not with MF, the treatments consisted of rates 0, 100, 200 and 300 m3ha-1 in the absence or presence MF, under field conditions. Were collected and analysis of soil and leachate in two seasons. It was observed effect associated with the wastewater and mineral fertilization on phosphorus in soil, isolated effect of mineral fertilization on the magnesium, potassium and electrical conductivity in soil and isolated effect of wastewater in the levels of pH, calcium, sodium, copper, zinc, nitrite + nitrate in soil and effect on sodium content in leachate / A água residuária da suinocultura (ARS) possui carga orgânica elevada se tornando fonte importante de macro e micronutrientes às plantas, promovendo a melhoria da qualidade do solo e do desenvolvimento em diversas culturas. Porém quando feita sem critérios agronômicos e ambientais, pode causar problemas no solo, lixiviação de nutrientes, prejuízos aos recursos hídricos e toxicidade às plantas. O objetivo deste trabalho foi avaliar os atributos químicos em solo e lixiviado frente a associação de água residuária da suinocultura e adubação mineral (AM) no cultivo de aveia-preta. Realizou-se um experimento em lisímetros de drenagem usando aplicações de ARS associadas ou não a AM, os tratamentos consistiram em doses de 0, 100, 200 e 300 m3ha-1 com ausência ou presença de AM, em condições de campo. Foram realizadas coletas e análises de solo e lixiviado em duas épocas. Observou-se efeito associado da água residuária e adubação mineral no teor de fósforo no solo, efeito isolado da adubação mineral nos teores de magnésio, potássio e condutividade elétrica no solo e efeito isolado da água residuária nos teores de pH, cálcio, sódio, cobre, zinco, nitrito + nitrato no solo e efeito no teor de sódio no lixiviado

A \"Região dos Lagos\" de Santa Gertrudes é um exemplo das muitas áreas contaminadas com metais pesados existentes no Estado de São Paulo e no Brasil. O pólo de Revestimentos Cerâmicos de Santa Gertrudes dispôs inadequadamente seus resíduos sólidos e águas residuárias diretamente no solo por mais de três décadas, contaminando uma área de 1,5 km2. A despeito das incertezas que cercam e que prejudicam a plena compreensão de um processo de bioremediação de um solo contaminado, esta pesquisa avalia a influência do pH inicial e da adição de inoculo e nutrientes sobre a eficiência de remoção de chumbo (Pb) e zinco (Zn) de um latossolo vermelho, submetido à biolixiviação com Acidithiobacillus ferrooxidans e Acidithiobacillus thiooxidans. Este solo apresenta elevados teores de óxidos de ferro (8,3 %) e alumínio (16,8 %), argila (57 %), chumbo (717 mg/kg) e zinco (181 mg/kg). Os experimentos foram conduzidos em reatores em batelada, monitorados durante 30 dias e resultaram na solubilização de até 3,6 mgPb/L e 50,0 mgZn/L. Constatou-se que para este solo e sob as condições experimentais utilizadas, não foi necessária a redução inicial do pH; a solubilização do chumbo foi inexpressiva, provavelmente, devido à sua precipitação na forma de PbSO4; a do zinco decorreu, principalmente, da liberação de íons H+, produzidos durante a dissociação dos nutrientes, em particular o FeSO4, que promoveram a acidificação do meio. Embora a lixiviação química tenha sido o principal mecanismo de solubilização do zinco, a biolixiviação devido a Acidithiobacillus ferrooxidans indígenas foi registrada e incrementou em até 17 % a lixiviação deste elemento, a partir do décimo dia de experimentação. / The \"Lake Region\" of Santa Gertrudes is one of several contaminated sites with heavy metals in São Paulo State, Brazil. As in other regions of this country, in the 1970\'s the ceramic industries of Santa Gertrudes disposed their solid wastes and wastewaters directly in soil and contaminated an area of 1.5 km2. Biological solubilization of lead (Pb) and zinc (Zn) from soil of the Lake Region was tested in batch reactors. The biological process used the leaching capacity of Acidithiobacillus ferroxidans and Acidithiobacillus thiooxidans. Tests were performed to determine the influence of initial pH, the percentage of inoculum and the addition of nutrients on the efficiency of removal of these metals. The soil contained high concentration of iron oxides (8.3 %) and aluminum (16.8 %), clay (57 %), lead (717 mg/kg) and zinc (181 mg/kg). It was not necessary to reduce the initial pH of soil. Solubilization of lead (up to 3.6 mg/L) and zinc (up to 50 mg/L) was obtained, but the solubilization of Pb was low, probably because the element was precipitated as PbSO4. The solubilization of zinc was strongly correlated with the release of H+ ions produced from nutrient dissociation, particularly FeSO4, which promoted the acidification of solution. Although chemical solubilization was the main mechanism of Zn removal, biological solubilization by indigenous Acidithiobacillus ferroxidans was detected, reaching up to 17 % of the total element leached after 10 days of testing.

Este trabalho enfocou o levantamento de informações químicas e mineralógicas de detalhe em amostras de depósitos alcalinos e alcalino carbonatíticos brasileiros contento terras raras, de modo a fornecer subsídios para o desenvolvimento de processos de aproveitamento. Estes depósitos apresentam elevados volumes de recursos, baixos teores de elementos de terras raras (essencialmente terras raras leves) e elevada complexidade mineralógica. As amostras estudadas são provenientes de depósitos lateríticos, com teor total de óxidos de terras raras entre 1,27 e 6,45%, sendo a monazita o principal mineral portador desses elementos, exceto em uma das amostras, onde é predominante a bastnaesita; como minerais traços estão presentes cerianita, xenotima e um fosfato de escândio. Os minerais de terras raras tendem a concentrar-se em direção às frações granulométricas mais finas, mostram d50 de 15 µm nas frações acima de 0,008 mm e chegam a valores inferiores a 0,1 µm abaixo da mesma. Esses minerais ocorrem preferencialmente em íntimas associações com a ganga, sendo que valores superiores a 60% de liberação (em área) são observados apenas nas frações menores que 0,020 mm. O potencial de concentração desses minerais foi avaliado por separações físicas e extração hidrometalúrgica. Separações físicas em líquidos densos e magnéticas não possibilitaram a obtenção de produtos enriquecidos em terras raras. O resultado mais promissor refere-se à possibilidade de remoção de um produto contaminante magnético nas frações retidas em 0,020 mm e que responde por 30% do total de Fe2O3 contido nas amostras (em média), sem perdas significativas das terras raras. A condição experimental otimizada para a dissolução seletiva dos minerais de terras raras em meio ácido foi estabelecida a partir de um planejamento experimental baseado em princípios estatísticos. Para o material cominuído abaixo de 0,30 mm, a solubilização dos óxidos de terra raras é de 77%, considerando-se ácido sulfúrico concentrado, reduzida porcentagem de sólidos, temperatura ambiente e tempo de 4 horas. Maiores níveis de solubilização das terras raras podem ser alcançados, mas juntamente com elevação da solubilização da ganga. / This work focused on the acquisition of chemical and mineralogical detailed information in samples from Brazilian alkaline and alkaline-carbonatitic deposits containing rare earths, in order to provide subsidies for process development. These deposits present high volumes of resources, low contents of rare earth elements (essentially light rare earths) and high mineralogical complexity. The studied samples are lateritic materials, with a total content of rare earth oxides between 1.27 and 6.45%, being monazite the main rare earth bearing mineral, except in one of the samples, where bastnaesite is predominant; cerianite, xenotime and a scandium-phosphate occur as trace. Rare earth minerals tend to enrich toward the finest sieve fractions with an medium grain size of 15 µm in the fractions greater than 0.008 mm and decreasing below 0.1 µm in finer fractions. These minerals occur preferentially in intimate associations with the gangue; liberation greater than 60% (in area) are observed under 0.020 mm fractions. The concentration potential of these minerals was evaluated through physical separation and hydrometallurgical extraction. Physical separations (heavy liquid and magnetic) did not succeed in obtaining products enriched in rare earths. The most promising result were the possibility of removing magnetic phases above 0.020 mm (responsible for 30%, on average, of the total Fe2O3 contained in the samples) without significant losses of rare earths. The rare earths acid leaching protocols and conditions were established by statistical experimental design. For samples comminuted below 0.30 mm, the best rare earths solubilization (77%) and with minimum gangue leaching was obtained in concentrate sulfuric acid, low solids concentration, environmental temperature and four hours of reaction. Higher levels of rare earths solubilization can be achieved, however accompanied by higher gangue solubilization.

The demand for rare earth elements (REEs) has increased over the last decade due to applications in high technology devices including those in the defense industry. The recovery of REEs from primary sources such as rare earth minerals are viable using physical separations followed by chemical processing. However, weak market values and environmental concerns have limited the viability of such operations. On the other hand, REE recovery from secondary sources such as apatite ore, bauxite waste, and waste recycling, provides an opportunity to take advantage of a resource that does not require mining costs as well as other associated costs given that these expenses are covered by the revenue generated from the production of the primary material. Coal-based materials represent a potential source for REEs which may be extracted and concentrated by the use of physical and/or chemical processes. The current study focused on developing a leaching process to extract REEs from the pre-combustion coal sources including coarse and fine refuse and low-valued material obtained from coal preparation plants. Materials collected for leaching characteristic studies were found to have average total REE concentrations in the range of 200-350 ppm on a whole sample basis. Mineralogy studies performed on Fire Clay seam coal refuse using SEM-EDS detected micro-dispersed rare earth phosphate mineral particles which are generally difficult to dissolve in strong acid solutions. On the other hand, XRD analysis results from a high REE content segment of the West Kentucky No. 13 coal seam indicated the presence of fluorapatite which is soluble in weak acid solutions. The mineral associations of REEs were studied by extracting REEs using different types of acids under various pH conditions. Differential extraction of the REEs was examined along with the associated impurity elements such as iron, aluminum, and calcium among others. The findings showed that the light REEs were primarily associated in a phosphate mineral form, whereas the heavy REEs were mostly present in an ion substitution form associated with clay minerals. Relatively high concentrations of REEs were discovered in mixed-phase particles consisting of both coal and mineral matter. By reducing the particle size, more leachable forms of REEs were liberated and recovered along with the associated mineral matter embedded in the coal structure. The type of lixiviant played an important role during the initial stage of leaching but was found to be insignificant as the system reached equilibrium. Solids concentration in the leaching medium has an important role in establishing the throughput capacity of the leaching system. Test results found that an increase in solids concentration had a significant negative effect on rare earth recovery. This finding may be explained by higher concentrations of soluble calcium-based minerals such as calcite which provided localized pH increases near and within the pores of the solids. The result was precipitation of CaSO4 within the pores which blocked access for the lixiviants. This hypothesis was supported by the findings from BET and XPS analyses which found lower pore volume in high solid concentration systems and the existence of CaSO4 on the surface of the solids. Leaching test results obtained using sulfuric acid over a range of temperatures showed that the leaching process was mainly driven by a diffusion control process. The activation energy determined for an Illinois No. 6 coal source was 14.6 kJ/mol at the beginning of the reaction and 35.9 kJ/mol for the rest of the leaching process up to 2 hours. For material collected from the Fire Clay coal seam, the apparent activation energy was 36 kJ/mol at the start of the leaching reaction and decreased to 27 kJ/mol over the remaining period of the test. The activation energy values were nearly equivalent to the upper-level values that generally define a diffusion control process and the lower values of a chemical reaction control process. The lack of clarity in defining a clear control mechanism is likely associated with the variability in associated mineralogy, various modes of occurrence of the REEs and the interfacial transfer of product through the porous structure of the coal-based particles which requires relatively high activation energy. As such, both diffusion control and chemical reaction control mechanisms are likely occurring simultaneously during the leaching process with diffusion control being more dominant.

The contamination of ground water resources represents a serious problem and a prominent threat to the health of our society. This study focuses on the leaching of inorganic anions as a function of agricultural practices under natural field conditions. In order to enhance the understanding of such leaching processes, this thesis evaluates the spatial variability of the leaching characteristics of a site, the factors controlling percolation, and the use of a cereal rye cover crop to reduce nitrate leaching. Thirty-two Passive Capillary Wick Samplers (PCAPS) and 32 suction cups were installed at a depth of 120 cm under row crop produced in a Woodburn Variant loam (fine-loamy mixed mesic Aquultic Argixeroll). Significant correlation for the water flux was seen at the 2.0 m distance, beyond which values were uncorrelated. No spatial correlation was seen in hydrodynamic dispersion coefficients. Percolation was independent of field saturated hydraulic conductivity, while the quantity of incident water was strongly correlated with percolation. The occurrence of preferential flow affected the leaching process as documented by solute breakthrough ahead of the main solute peak. Rates of nitrogen fertilizer application were proportional to observed nitrate leaching losses. The cover crop significantly reduced the amount of nitrate leaching at all N fertilizer application rates. At the recommended rate, nitrate-N concentrations were lowered on average from 22.2 to 9.9 mg/l; cumulative N mass losses were cut by 62% due to plant uptake by the cover crop. The study demonstrated the importance of conducting long-term field experiments under natural conditions to accurately assess leaching processes. / Graduation date: 1996