Memoria del XVI Congreso Internacional de Metalurgia Extractiva Abril 26-28 de 2006 Dr. Manuel Méndez Nonell, in Memoriam Saltillo, Coah., México 195 ASSESSMENT OF REAGENT AND REGRINDING IN A FLOTATION CIRCUIT J.L. Reyes Bahena 1 , J.P. Franzidis 2 , E.V. Manglapig 2 , A. López Valdivieso 3 , M.C. Ojeda Escamilla 3 1 Facultad de Ingeniería / Instituto de Metalurgia, Universidad Autónoma de San Luis Potosí Av. Sierra Leona 550, Lomas 2a Sección San Luis Potosí, S.L.P. México 78210 2 Julius Kruttschnitt Mineral Research Center, The University of Queensland, Island Road, Indooroopilly, Brisbane, Australia. 3 Instituto de Metalurgia, Universidad Autónoma de San Luis Potosí Av. Sierra Leona 550, Lomas 2a Sección San Luis Potosí, S.L.P. México 78210 jlreyes@uaslp.mx ABSTRACT Laboratory flotation tests using a bottom driven cell are reproduced with a high level of confidence. These types of laboratory data are used to investigate the effect of reagent and regrinding of coarse particles in an industrial flotation circuit. The addition of collector (BX) has a significant effect on the flotation response of chalcopyrite in the scavenger bank. The reconstructed recovery-time curve (combine products) is greater than that of the rougher tailings (scavenger feed) prior to reagent addition. By adding collector (BX) in the scavenger feed, the ultimate recovery of chalcopyrite increases 20% which means an increase of 1.7% of chalcopyrite recovery in the scavenger feed. Meanwhile, the reagrinding of coarse particles shows a detrimental effect on the collectorless flotation of an initially hydrophobic chalcopyrite sample. Cyclone underflow, 80% recovery at pH 7.7, was decreased to 40% after regrinding at the same range of pH. The chalcopyrite flotation response immediately after regrinding is severely retarded. It is assumed that the centrifugal action of the cyclone is another important factor restoring the chalcopyrite hydrophobic flotation due to the oxygenation of the slurry. Therefore, additional pre- conditioning time after a regrinding stage should have a positive change in the recovery of chalcopyrite. The overall flotation response before and after the regrinding stage showed that the cyclone underflow response is slightly slower compared with the combine feed in the first four minutes of flotation. This behavior is related to changes on surface chemistry because of the regrinding of coarse particles. INTRODUCTION Evaluation and optimization of flotation circuits has been the focus on most metallurgists since the first plant started hundreds of years ago. In the late 60’s, computer based techniques were developed to evaluate flotation process performance and to develop mathematics model which describe behavior of minerals across a flotation cell/bank or circuit. Such mathematical