Papers by Keyword: Column Flotation

Abstract: Flotation is a complex process in which is present physicochemical and hydrodynamic phenomena. The flotation performance is related to the probability of bubble-particle collisions and stability of aggregate formed. The collision efficiency is a function of particle and bubble diameters. Currently one of the biggest challenges of the mining industry is the flotation of fine and ultrafine particles and a possible solution to increase the recovery of these fine particles is the use of bubbles with intermediate size (100-1000μm). Therefore, determining and controlling the bubble size is very important for further recoveries in the flotation of fine particles. It is known that the bubble size and air holdup are influenced by variations on the superficial gas velocity and by addition of surfactants. Thus this work aimed to study the effect of adding surfactants on bubbles formation. The results showed that the addition of surfactant was a good alternative to decrease bubble size and increase the air holdup in a bubble column. Three different surfactants had similar behavior on bubble size and holdup. It was possible to define the range of concentration values which are sufficient for forming bubbles with intermediate size and holdup within the range recommended for mineral flotation.

Abstract: Today, the phosphate rock processed in the world represents around some 20 billion dollars per year. Some exploitable deposits are characterizing by low grade phosphate rocks, composed of the apatite group in association with a wide assortment of accessory minerals. Usually a combination of beneficiation techniques is used to process a phosphate rock since run of mine, and then a flotation is applied to recovery apatite. This work proposes an evaluation of particle size for apatite recovery by column flotation in bench-scale. The variables collector dosage and depressant dosage were investigated experimentally applying a factorial design. According to the experimental results, the particle size range between 37&m and 105&m is an optimum size used to obtain simultaneously a product with the industry demand grade (at least 33%) and phosphorus recovery, upper than 60%.

Abstract: Performing of the flotation process in columns started in the year 1981. Since then, this new flotation technique became usual in many countries, including Brazil, where nowadays flotation columns are installed in plants for iron and phosphate ore concentration. Sees the need of a rational use of the phosphate of Barreiro, Araxá (MG), whose medium useful life is esteemed in 30 years, Federal University of Uberlândia in partnership with Bunge Fertilizers looks for in this work to develop conditions for use of the rejects of the flotation process. A laboratory flotation column was operated in discontinuous mode in order to examine the mixture of two different types of collectors, ore conditioning time and reagents dosages. Contents between 22 and 29 % P2O5 were obtained and Apatite recovery varied in the range of 18 to 58 wt %. The results shows that the use of mixture of the synthetic reagent KE and the rice oil soap provided an increase considerable in the selectivity of the concentrate.