Adequação da malha de uma peneira vibratória inclinada no circuito de beneficiamento de uma mina de calcário

Abstract

This research aims to analyze rejected material in the mesh of the last deck in a separation by size equipment. This loss causes arrest equipment and result in financial loss for lack of material in the supply segments of the production process. The focus of this work is an inclined vibrating screen Piacentini PVA model 1540 with three decks, which have openings of 6 inches (152,4 mm), 2 inches (50,8 mm) and 0,75 inches (19,05mm) in the first, second and third deck, respectively, have slope of 15 ° and an efficiency of 85%. The study was conducted in Caltins Calcário Tocantins LTDA Company, whose have like main product dolomitic limestone and crushed stone like byproduct. The production has a processing circuit which works with two production lines, 1 and 2. During the development of the survey, was observed in line 1 the disposal of material that could be reused in the production process, and that his recovery could help in solving the problem in analysis, improving production and increasing financial gains with the appropriate change. And that, after the implementation of the measures necessary, materials are not discarded. This work highlights the study of particle size separation. 5 screening assays using 10 kg of each sample were performed. The rejected material, which is around 25% of material is fed, found a percentage of 37.30% reusable material, which in this case is gravel 1 (grain size above 12,21 mm) and gravel 0 ( particle size above 6,35 millimeters), resulting in a decrease in tailing of 9.33% and an increase in usable cell material in the process with the same value. Noting that the last of suitable mesh screen deck for reusing the material is expected to be 0.25 inches (6.35 millimeters), which is the mesh where is retained the greatest amount of usable material in the process. For now, besides the gain of 9.33% in the pile of material supply, there will be a decrease of 39.58% in the cost of transport of rejected material, which costs in the year of this work (2014), R$ 0,86 (eighty-six real cents) per ton.