Processamento da grafite de nipepe usando o óleo de fritura como colector

Abstract

The main objective of this study is the beneficiation of graphite ore from Nipepe (Niassa), focusing on the flotation process using non-ionic collectors, namely diesel oil and kerosene, as well as ionic collectors. The use of residual frying oil as an ionic collector is proposed due to the presence of free fatty acid radicals in it. To achieve this objective, the raw graphite sample was classified granulometrically and mineralogically in order to determine the particle size, the amount of graphite carbon, and the impurities present. The results of the granulometric classification reveal that the graphite ore under study is predominantly composed of coarse particles, with 90.32% of its mass retained in a fraction with a mean diameter of 1.5 mm. Its carbon content, determined by the loss on ignition test, is only 14%, and it contains impurities detected in high concentrations by X-ray fluorescence, such as Fe2O3, K2O, TiO₂ and SiO2 . Concentration was carried out in a single-stage flotation cell, preceded by comminution using a wooden roller. The results of the granulometric classification of the concentrates show that the alteration of characteristics or compositions in this process is the result of the use of different collectors. Thus, the residual frying oil proved to be economically and environmentally viable compared to the use of liquid hydrocarbons or non-ionic collectors, showing higher mineralogical yield under the same processing conditions. Flotation with kerosene and diesel oil resulted in 72% and 56% graphite recovery, respectively. In contrast, the residual frying oil, for soybean oil and sunflower oil residues, showed recoveries of 89% and 99%, respectively. The behavior of this residual oil, when varying its dosage during the process, reveals that its increase also promotes an increase in mass recovery at the expense of higher purity of the concentrates.