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In the design of a solvent extraction plant for metals it is necessary to treat the equilibrium data either graphically or analytically. This enables stagewise calculations to be performed to explore solvent usage and feed conditions and so optimise on the cost of recovery of the metal. The present study reviews the methods of presenting and correlating equilibrium data for solvent extraction systems involving metals; the limitations of each approach are highlighted. The most important example of metal extraction which has been studied falls into that class involving a metal species, in acid aqueous media, which displaces protons from the organic extractant during the mass transfer process. In the typical case of copper extracted by hydroxyoximes the equilibrium problem reduces to one of modelling a surface. The concentration of copper in the organic phase is a function of the concentrations of copper and sulphuric acid in the aqueous phase. Empirical models seem to be as satisfactory to the engineer as chemical ones provided the model is used between restricted regions of data. Practical work has involved the measurement of equilibrium data for the extraction of zinc and copper by di- (2-ethylhexyl) phosphoric acid (D2EHPA) in a kerosene diluent. Both the single and binary metal systems have been studied. The data reported are for feeds between 2-40 g/l zinc, 2-60 g/l copper and 20% V/v D2EHPA. A limited number of results are also presented for 10% V/v D2EHPA. Specific chemical and empirical models have been developed to correlate these data. Because the extractant has a high affinity for zinc in the presence of copper the binary data can be modelled making the assumption that the interaction of copper on zinc is negligible. However the effect of zinc on the limited extraction of copper is significant, the zinc reducing the copper loading markedly. In this way zinc can be decontaminated of copper. The methods for presentation of equilibrium data are discussed and a computer program is given which displays three dimensional equilibrium surfaces. Classical design procedures for stagewise. calculations are used against these three dimensional data plots. Computer programs which allow the investigation of a variety of operating conditions have also been written.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-08-11T13:11:52Z No. of bitstreams: 1 Juliana Loureiro de Almeida Campos.pdf: 3540601 bytes, checksum: 50a88a661838079c462a2ae532ddf5bd (MD5) / Made available in DSpace on 2016-08-11T13:11:52Z (GMT). No. of bitstreams: 1 Juliana Loureiro de Almeida Campos.pdf: 3540601 bytes, checksum: 50a88a661838079c462a2ae532ddf5bd (MD5) Previous issue date: 2013-07-29 / We aimed to analyze the fruit extraction of Attalea speciosa Mart. ex Spreng (babaçu palm) in the Araripe Environmental Protection Area (APA-Araripe), northeastern Brazil, seeking to understand local knowledge and the process of exploitation of this resource, and to investigate the implications of different ways of land-use on natural populations of the species and on the rate of fruit production. Semi-structured interviews were conducted with 49 extractivists of this palm (43 women and 6 men) through the "snowball" methodology. To understand the ecological implications of different forms of land use on babaçu palms populations, 150 plots of 10x10 meters were randomly demarcated in three areas with high incidence of A. speciosa subjected to different land uses, being 50 plots established in a pasture area (Area 1), 50 plots in an area of shifting cultivation (Area 2) and 50 plots in an area of seasonal forest (Area 3). Within each plot, all individuals of A. speciosa were counted, classified in seedlings, young and adults, being measured for height and diameter at breast height (DBH). To calculate the annual amount of fruit produced by the species, 20 individuals of babaçu were marked in each study area and for 12 months, they were monitored to estimate the productivity of fruits per bunch and number of bunches produced by individual. We obtained 352 citations and 50 different uses in eight different categories of use, receiving attention the categories crafts, construction and food. The total monthly income of the extractive had significant and positive influence on knowledge, suggesting that the informants explore babaçu to complementary monthly income. There was no significant relationship between knowledge and current practices of A. speciosa. The fruits and leaves are the only parts extracted by the informants, showing greater "use pressure" on these non-timber forest products. Access to technology can replace some of the traditional uses of babaçu, besides inducing a selection on the type of use that is practiced in the community. All babaçu populations had their vertical structure in a "J-inverted", indicating good recruitment of the species. The grazing and shifting cultivation showed up as the most favorable to the establishment of populations of A. speciosa, and the factor that appears to contribute to this is the highest rate of light incidence present in these locations. With respect to fruiting, grazing and shifting cultivation areas were more favorable, with the average number of fruits / individual significantly larger than the area of semideciduous forest. It was possible to verify that the babaçu palm is considered highly important commercial resource for residents of Sítio Macaúba, and subsistence uses are uncommon. The palm A. speciosa grows well in anthropogenic environments, and agricultural and pastures areas may contribute to the rapid establishment and growth of this species as well as higher rates of fruiting. / Essa pesquisa teve como pretensão analisar a extração do fruto de Attalea speciosa Mart. ex Spreng (palmeira babaçu) na região da Área de Proteção Ambiental do Araripe (APA- Araripe), nordeste do Brasil, buscando-se compreender o conhecimento local e o processo de exploração desse recurso, bem como investigar as implicações das diferentes formas de uso da terra sobre populações naturais da espécie e sobre a taxa de produção de frutos. Foram realizadas entrevistas semiestruturadas com 49 extrativistas dessa palmeira (43 mulheres e 6 homens), selecionados por meio da técnica “bola de neve”. Para compreender as implicações ecológicas das diferentes formas de uso da terra sobre as populações da espécie, foram demarcadas aleatoriamente 150 parcelas de 10x10 metros em três áreas com elevada incidência de A. speciosa submetidas à diferentes usos da terra, sendo 50 parcelas estabelecidas em uma área de pastagem (Área 1), 50 parcelas em uma área de agricultura itinerante (Área 2) e 50 parcelas em uma área de floresta estacional semidecidual (Área 3). Dentro de cada parcela, todos os indivíduos de A. speciosa encontrados foram contados, classificados em plântulas, jovens e adultos, sendo medidos quanto à altura e diâmetro à altura do peito (DAP). Para calcular a quantidade anual de frutos produzida pela espécie, foram marcados 20 indivíduos adultos de babaçu em cada área de estudo e durante 12 meses, os mesmos foram monitorados para estimar a produtividade de frutos por cacho e o número de cachos produzidos por indivíduo. Foram obtidas 352 citações e 50 usos diferentes, distribuídos em oito categorias de uso, recebendo destaque as categorias artesanato, construção e alimentação humana. A renda mensal total dos extrativistas teve influência significativa e positiva sobre o conhecimento. Não houve relação significativa entre o conhecimento e as práticas atuais de A. speciosa. Os frutos e as folhas são as únicas partes extraídas pelos informantes, evidenciando maior “pressão de uso” sobre estes produtos florestais não madeireiros. O acesso a tecnologias pode substituir alguns dos usos tradicionais do babaçu, além de induzir uma seleção no tipo de uso que é praticado na comunidade. Todas as populações de babaçu tiveram sua estrutura vertical em formato “J-invertido”, evidenciando bom recrutamento da espécie. A pastagem e a agricultura itinerante mostraramse como as áreas mais favoráveis ao estabelecimento de populações de A. speciosa, e o fator que mais parece contribuir para isso é o maior índice de incidência luminosa presente nesses locais. Com relação à frutificação, as áreas que se mostraram mais favoráveis foram a pastagem e a agricultura itinerante, apresentando número médio de frutos/indivíduo significativamente maior que a área de floresta estacional semidecidual. Foi possível verificar que a palmeira babaçu é considerada um recurso de elevada importância comercial para os moradores do Sítio Macaúba, sendo os usos de subsistência pouco frequentes. A palmeira A. speciosa se desenvolve bem em ambientes antropizados, uma vez que áreas de cultivo e de pastagens podem contribuir para a rápida expansão e estabelecimento dessa espécie, assim como para as maiores taxas de frutificação da mesma.

In the design of a solvent extraction plant for metals it is necessary to treat the equilibrium data either graphically or analytically. This enables stagewise calculations to be performed to explore solvent usage and feed conditions and so optimise on the cost of recovery of the metal. The present study reviews the methods of presenting and correlating equilibrium data for solvent extraction systems involving metals; the limitations of each approach are highlighted. The most important example of metal extraction which has been studied falls into that class involving a metal species, in acid aqueous media, which displaces protons from the organic extractant during the mass transfer process. In the typical case of copper extracted by hydroxyoximes the equilibrium problem reduces to one of modelling a surface. The concentration of copper in the organic phase is a function of the concentrations of copper and sulphuric acid in the aqueous phase. Empirical models seem to be as satisfactory to the engineer as chemical ones provided the model is used between restricted regions of data. Practical work has involved the measurement of equilibrium data for the extraction of zinc and copper by di- (2-ethylhexyl) phosphoric acid (D2EHPA) in a kerosene diluent. Both the single and binary metal systems have been studied. The data reported are for feeds between 2-40 g/l zinc, 2-60 g/l copper and 20% V/v D2EHPA. A limited number of results are also presented for 10% V/v D2EHPA. Specific chemical and empirical models have been developed to correlate these data. Because the extractant has a high affinity for zinc in the presence of copper the binary data can be modelled making the assumption that the interaction of copper on zinc is negligible. However the effect of zinc on the limited extraction of copper is significant, the zinc reducing the copper loading markedly. In this way zinc can be decontaminated of copper. The methods for presentation of equilibrium data are discussed and a computer program is given which displays three dimensional equilibrium surfaces. Classical design procedures for stagewise. calculations are used against these three dimensional data plots. Computer programs which allow the investigation of a variety of operating conditions have also been written.

Made available in DSpace on 2015-05-14T12:17:01Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 8007914 bytes, checksum: d09668ced21570359a017ceb049cd63b (MD5) Previous issue date: 2012-06-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / According to the UN, desertification is a type of degradation that occurs in areas, arid, semiarid and dry sub-humid, resulting from climate change and human activities. In Brazil, the Northeast semiarid region has primacy in the development of this phenomenon. Thereby was carried out in this work a review of the historical processes of occupation of the region, analysis of the secular public policies to combat drought and times (cycles) developed in economic Cariri. Trying to understand desertification as a result of the relationships that historically [re]produce this space. The methodology relied on the research literature, consultations with government statistical data on the extraction activities and field work in order to conduct investigations and collect soil samples that have suffered various types of use to know whether there were changes in normal patterns of fertility originally found. The results show that since the arrival of the colonizer caririseiras landscapes have been greatly altered. Highlighting the historical and cultural importance of using vegetation as an alternative economic and energy by the population. In private in the cities studied (São João do Tigre, São Sebastião do Umbuzeiro e Camalaú), the trade of wood earns state and interstate boundary, especially for large quantities of wood that are exported to the city of Pernambuco constituting the Polo Geseiro. Since the experimental part of the research showed that intensive deforestation, affect the vegetation, also causes changes in this feature, especially in the chemical elements phosphorus (P), potassium (K) and stuff organic which are the main elements present in soils of the Brazilian semiarid region. In summary form, this type of economic practice that occurs in the cities studied and in all that occurs in semiarid northeastern shaky foundations. In this case, the increase endangers the whole area, which by natural conditions prevailing tendency to exhibit the phenomenon of desertification in the medium term that may further aggravate thesituation in the region of land. / Segundo a ONU, a desertificação é um tipo de degradação que ocorre nas áreas, áridas, semiáridas e subúmidas secas, resultante das mudanças climáticas e das atividades humanas. No Brasil, a região semiárida nordestina apresenta a primazia no desenvolvimento desse fenômeno. Desse modo, realizou-se nesse trabalho uma revisão dos processos históricos de ocupação da região, análise sobre as seculares politicas públicas de combate à seca e dos momentos (ciclos) econômicos desenvolvidos no Cariri, buscando compreender a desertificação como fruto das relações que historicamente se reproduzem nesse espaço. A metodologia utilizada contou com a realização de pesquisa bibliográfica, consultas aos dados estatísticos dos órgãos governamentais sobre as atividades extrativistas e de trabalhos de campo com o objetivo de realizar investigações e coletar amostras de solo que sofreram diversos tipos de uso para sabermos se houve alterações nos padrões normais de fertilidade natural encontrado originalmente. Os resultados apontam que desde a chegada do colonizador as paisagens caririseiras vêm sendo fortemente alteradas, evidenciando a importância histórica e cultural do uso vegetação como alternativa energética e econômica por parte da população. Em particular nos municípios estudados (São João do Tigre, São Sebastião do Umbuzeiro e Camalaú), o comércio da lenha ganha contorno estadual e interestadual, com destaque para as grandes quantidades de lenha que são exportadas para os municípios pernambucanos que constituem o Polo Gesseiro. Já a parte experimental da pesquisa, mostrou que o desmatamento intensivo, ao afetar a vegetação, provoca também alterações nesse recurso, principalmente nos elementos químicos fósforo (P), potássio (K) e matéria orgânica (M.O), que são os principais elementos presentes em solos da região semiárida brasileira. De forma sintética, esse tipo de prática econômica que ocorre nos municípios estudados e em todo o semiárido nordestino ocorre em bases pouco sustentáveis. Nesse caso, o seu aumento coloca em risco toda essa área, que pelas condições naturais dominantes apresentam tendência ao fenômeno da desertificação, o que em médio prazo pode agravar ainda mais a situação das terras da região.