Análise das principais variáveis na flotação industrial do complexo de mineração de Tapira - MG

Faced with an agribusiness expansion scenario and the increase in fertilizer consumption due to the exponential growth of the population, it is necessary to make better use of existing reserves, by obtaining products of better quality and in adequate quantities to meet demand national. In Tapira Mining Complex, Vale Fertilizantes, the phosphate concentrate is produced with content of 35.0% P2O5 from ore with content of about 8.0% P2O5, which are intended to supply Complex Industrial Uberaba and Araxá Minero Chemical Complex for the production of fertilizers. The industrial flotation step responsible for the recovery of P2O5 and hence the viability of the business is divided into the crumbly, grainy and ultrathin circuits, and, friable and granular concentrate comprise the conventional concentrated. Today only 14.7% of the mass which feeds the mill product becomes, the remainder being considered losses in the process, and the larger mass losses are located in the waste of flotation, representing 42.3%. From 2012 to 2014, the daily global mass recovery processing plants varied from 12.4 to 15.9% while the daily metallurgical recovery of P2O5 from 48.7 to 82.4%. By the degree of variability, it appears that the plant operated under different conditions. Seen this, this study aimed to analyze the influence of operational and process variables in P2O5 mass and metallurgical recoveries of industrial flotation circuits of grainy, crumbly and ultrathin. And besides was made an analysis of the effect of ore variables, as degrees, hardnesse and the ore front 02 percentage, in global recoveries of processing plant and the effect of dosages of reagents in the recoveries obtained from the bench flotation using the experimental design methodology. All work was performed using the historical database of Vale Fertilizantes of Tapira-MG, where all independent variables were dimensionless as the experimental range used. To make the statistical analysis it used the response surface technique and the values of the independent variables that maximize recoveries were found by canonical analysis. In the study of industrial flotation circuit crispy were obtained from 41.3% mass recovery and 91.3% metallurgical recovery P2O5, good values for the circuit, and the highest recoveries occur for solids concentration of the new flotation power between 45 and 50%, which values are assigned to the residence time of the pulp in cells and industrial flotation columns. The greater the number of ore heaps resumed on the higher the mass recovery, but in this scenario flotation becomes unstable because there is enormous weight variation in the feed. Higher recoveries are obtained for mass depressant dosage exceeding 120 g / t for synthetic collector dosage of 11.6%. In the study of industrial flotation circuit of the granulate were obtained 28.3% to 79.4% mass recovery and metallurgical recovery of P2O5 being considered good values for the circuit. Higher recoveries are obtained when the front ore 02 percentage is above 90%, because the ore of this front have more clear apatite. Likewise recoveries increase when the level of pulp rougher step is highest due to the high mass of circulating step receives loads. In the analysis of industrial flotation circuit of the ultrafine were obtained 23.95% of mass recovery, and the same is maximized to depressant dosage and the top collector 420 and 300 g / t, respectively. The analysis of the influence of variables ore, it was observed that higher recoveries are obtained for ores with P2O5 content above 8.0%, Fe2O3 content in the order of 28% forward and 02 of ore percentage of 83%. Hard ore percentage has strong influence on recoveries due to mass division in the circuit that is linked to this variable. However, the hard ore percentage that maximizes recoveries was very close to the design capacity of the processing plant, which is 20%. Finally, the study of the bench flotation, has noted that in friable and granular circuits the highest recoveries are achieved for a collector dosage exceeding 250 g / t and the simultaneous increase of collector dosage and synthetic collector percentage contributes to the increase recovery in the flotation, but this scenario is suitable to produce a concentrate poorer in terms of P2O5 content, showing that higher recovery is not always the ideal scenario. Thus, the results show the values of variables that provide higher recoveries in the flotation and hence lower losses in the waste.

Retificação plana tangencial dos ferros fundidos nodular, vermicular e cinzento em várias condições de corte

In a scenario of increasing competitiveness of the global industrial sector and with a consumer market increasingly demanding, there is an increased demand for new materials and, consequently, possibilities to explore new research and technological advances towards the development of new manufacturing methods or the improvement of existing technologies. In the case of cast irons, new grades of them have been developed so that their mechanical properties have been improved, making them more competitive with steel, expanding the applications and thus represents great economic gain for metallurgy and manufacturing sectors. This increases the interest and creates new opportunities to study these materials and identify how they respond in terms of the surface integrity, tool wear, cutting forces, among others, when machined by grinding operation. In this context, due to the lack of results from grinding of cast irons and studies comparing grindability among several grades of cast irons found in the literature, this work aims to generate scientific and technological contribution to the metallurgical and metal working sector through roughness results (Ra and Rz parameters) and evaluation and analysis of the subsurface integrity of three cast iron grades (gray, compacted graphite and nodular). The machining trials were performed on a surface grinding machine with silicon carbide grinding wheel at different cutting conditions. The input variables were the radial depth of cut (15 and 30 μm), worktable speed, vw (5 and 10 m/min) and the abrasive grain size of the grinding wheel. The results showed that surface roughness increased with the radial depth of cut for all materials tested; and the lowest values were obtained for gray cast iron. Also, roughness was sensitive to variation of worktable speed and the lowest values were obtained after machining with vw = 5 m/min. With respect to the abrasive grain size, as it decreased the roughness values increased to gray and nodular cast iron grades. Furthermore, grinding burns marks were observed on the surfaces of nodular cast iron and compacted graphite iron grades after grinding the smallest grain size, contrary to what is usually reported in literature. However, no evidence of severe thermal damages below the machined surfaces of all cast iron grades was observed after analyzing the results of hardness and the SEM micrograph images.

Dinâmica industrial, emprego e pobreza no Brasil, uma abordagem alternativa

Between 2003 and 2014 Brazil has increased exports by 52%, increased the formal employment and paid employment by 19% and reduced multidimensional poverty by 42%. The purpose of this work is to test the hypothesis that there is a Brazilian Growth Virtuous Circle where these three variables would be connected in order to increase exports and reduce poverty through the salaries transfer of funds. The construction of the hypothesis is made for Export Industry through ideas Verdoorn, Kaldor and Thirlwall presenting the export industry as an engine of economic growth. To present employment acting directly on economic growth is used Wage Led Rowthorn approach. The Capability Approach of Amartya Sen is used to understand the Multidimensional Poverty. The hypothesis was tested using data from the National Household Survey and Aliceweb between 2003 and 2014 with the use of the Generalized Method of Moments and the generation of elasticities between export and employment, employment and poverty, and export and poverty.

A pedagogia industrial da FIEMG: um estudo sobre o pensamento empresarial a partir da revista vida industrial (1961-1974)

The present research results of the studies and debates inherent in PhD in Education at the Graduate Program in Education at the Federal University of Uberlândia, belonging to the Research Line "Politics and Knowledge in Education." This thesis aims to analyze the contradictory meaning of education as training human history, specifically educational representative under the logic of the industrial business associated FIEMG (Federation of Industries of the State of Minas Gerais) in the context 1961-1974. This definition is justified by the historical fact that it was a period marked by the cyclical crises of capital and their impacts in the final phase of the industrialization process in Brazil: it starts with one of the apexes of economic growth in the country , driven by national developmental , continues with a severe political crisis in 1966 , also impacting the economic sphere, and finally, with the constant quest for economic stability even under high prices, hatch the factors that led to the Brazilian economy to the context of the "Economic Miracle". For this, it was necessary to link the debate between education and work from the perspective of historical materialism and dialectical their subsidies theoretical-methodological and epistemological. In the first chapter, we designed a "State of the art" category "human formation", conceived as a process of education and history, from the Marxist assumptions, aiming at the reconstruction of concepts and meanings of which is the formation of workers in contradictory logic, the bias of comprehensive training and the prospect of capital accumulation. Then, in the second chapter, we present a review about industrialization, the industrial business and its development perspective 1961-1974. The third chapter was established on a contextualization of the state and its peculiarities, the industrial business and its proposed development both nationally and at the state (Minas Gerais). Finally, in the fourth chapter, was organized dialogue with the sources, from a historical survey of the shares of the industrial business with an emphasis on education, which converged in a pedagogy industrial consolidation in line with the political and economic conditions specific period from 1961 to 1974. It has mailing bibliographic reference business thinking expressed in the concreteness of training workers and industry of Minas Gerais, in agreement with the demands of work and training of mining companies. The thesis of this study is the defense that the corporate actions which constituted pedagogy industrial concepts were articulated to political and economic development in Brazil, since the discipline to work imposed by such conceptions met the human worker training geared to the accumulation the general capital and industrial capital in particular. Establish, therefore, different logics, the state level, the scope of private foreign capital and domestic private capital, which came up the process of capital accumulation, loading, contradictorily, the possibilities of building the human beyond capital, or a teaching job.