http://repositorio.ufc.br/handle/riufc/16300 2026-04-13T00:29:23Z http://repositorio.ufc.br/handle/riufc/45002 Título: Flotação de metafosforito silicatado de Lagamar/MG Autor(es): Ramos, Kennedy da Silva Abstract: The concentration via froth flotation of the metaphosphorite ore, mined at Lagamar/MG, requires careful studies considering that it consists of a complex material from the bottom of the pit. The present bench scale flotation study aimed at investigating the effects of reagents (depressant/dispersant, collector and booster) and pH capable to adequate the concentrate to the targets of P2O5 26% grade and 80% recovery. As preliminary steps, the ore was characterized and dispersion degree determinations were conducted. The P2O5 bearing mineral is fluorapatite and the silicatic gangue contains predominantly quartz, kaolinite, and mica. The natural slimes fraction, material passing 0,038 mm, represents 49% in weight. The silicates are finely disseminated in the apatite grains impairing the concentration due to the lack of liberation. The isoelectric point of the fluorapatite was determined at pH = 2.27. The dispersion degrees of quartz and apatite were low in the presence of sodium metasilicate and sodium tripolyphosphate. In the exploratory step, consisting of rougher flotation at pH = 9, reagents used in direct flotation were sodium oleate as collector and sodium metasilicate as depressant and those employed in reverse flotation were dodecyl amine chloride as collector and sodium tripolyphosphate as depressant, soluble starch and sodium carbonate as depressants. The affinity of the sodium oleate collector with apatite was satisfactory and dodecylamine chloride was selective regarding silicates but the required dosage was high. Concerning the reverse flotation, the decreasing sequence of apatite depression was achieved with sodium carbonate, starch, and sodium tripoliphosphate. Nevertheless, the last acted as gangue depressant, negatively affecting the concentrate grade and recovery. The next stages were planned according to the factorial design of experiments method: (1st) direct flotation (collector sodium oleate, depressant sodium metasilicate); (2nd) direct flotation (same reagents of 1st stage plus booster: emulsion of fuel oil and ethoxylated nonyilphenol); (3rd) reverse flotation (collector dodecylamine chloride, depressant sodium tripolyphosphate); (4th) reverse flotation same reagents of (3rd) stage plus booster: emulsion of fuel oil and ethoxylated nonyilphenol). The performance of the sodium oleate collector used in the rougher flotation was better than that of the dodecylamine chloride employed in the cleaner flotation. The target parameters for the concentrate were achieved with sodium metasilicate as depressant. On the other hand, results obtained with sodium tripolyphosphate were not satisfactory. The emulsion was effective only when added in conjunction with sodium oleate, condition under which the target parameters for the concentrate were achieved and leading to decrease in collector consumption. Tipo: Dissertação 2018-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/44988 Título: Uma arquitetura utilizando algoritmo genético interativo e aprendizado de máquina aplicado ao problema do próximo release Autor(es): Araújo, Allysson Allex de Paula Abstract: The Next Release Problem consists in selecting which requirements will be implemented in the next software release. For many Search Based Software Engineering approaches to the Next Release Problem, there is still a lack of ability to efficiently include the human opinion and its peculiarities in the search process. Thus, in this work it is proposed an architecture to solve the Next Release Problem where the human preferences can be incorporated and, through a learning model, is able to minimize the problem of human fatigue. Experimental results are able to show that an Interactive Genetic Algorithm can successfully incorporate the user preferences in the final solution with a small loss in objectives terms. Tipo: Dissertação 2015-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/44982 Título: Tratamento aeróbio de efluente sintético de laticínio usando reatores inoculados com fungos aspergilus niger an 400 Autor(es): Costa e Silva, Luana Viana Abstract: The dairy effluents are characterized by high concentration of organic matter in the form of carbohydrates, proteins and fats, which, if not removed properly, can cause serious environmental problems. To this end, this paper studied the removal of organic matter and nutrients from synthetic wastewater dairy provisions in the first phase in batch reactors and in the second phase, in continuous flow reactor and up. In the batch phase, the system was composed of two control reactors, two only inoculated with Aspergillus niger AN 400 and two inoculated with the same species and with the addition of sucrose, being PET and polyurethane the support for immobilization, in each type assembly. This step was performed in four periods of 7 days, totaling 28 days of operation. The reactor operated continuously for 106 days, inoculated with the fungus and filled with crushed PET as material support. The results of the batch showed efficiency on COD reduction, reaching a maximum of 71.7% and 64.8% for the RFe and RFP, respectively, in the 4th cycle, and a minimum of 23.4% and 20.4% for the RFP and RFSp the 2nd cycle. Removals achieved satisfactory as nitrate and orthophosphate, but in relation to ammonia, there was an increase in effluent concentrations of this variable. The treatment presented in streaming global removal of 75% for the COD at HRT of 8 h, some promising results regarding the removal of orthophosphate and ammonia, however, for nitrate, achieved average removal of 68%. Tipo: Dissertação 2010-01-01T00:00:00Z