Avaliação Do Tamanho De Bolha Produzido Por Aeradores Tipo Tubo Poroso E Micro-Venturi Em Coluna De Flotação Minipiloto

Abstract

RESUMOO tipo de aerador (sparger), assim como a dosagem de espumante, possuem um papel fundamental no controle do tamanho de bolha em colunas de flotação, com influências na cinética de flotação e no desempenho metalúrgico (recuperação e teor). Este trabalho apresenta estudos de avaliação online da distribuição de tamanho de bolhas geradas por um sparger tipo tubo poroso e um micro-venturi acoplados em uma coluna de flotação minipiloto automatizada. EVALUATION OF THE BUBBLE SIZE PRODUCED BY A POROUS TUBE AND A MICRO-VENTURI IN A MINI PILOT COLUMN FLOTATION ABSTRACTThe sparger type as well as the frother dosage have a fundamental role on the bubble size control with influences on the kinetic flotation and metallurgical performance (recovery and grade). This work shows online evaluation studies of the the bubble size distribution generated by a porous tube sparger and a micro-venturi coupled in an automatized mini pilot flotation column. The effects of the frother (DF250 -propylene glycol methyl ether) dosage and the air flow rate on the bubble size and holdup were evaluated. The mean bubble diameter was strongly influenced by the frother dosage for both spargers; nevertheless, the micro-venturi was more efficient than the porous tube, because it was able to disperse the air more finely and with smaller dosages of frother. The smaller mean diameters obtained, according to the applied experimental conditions, were of 1.25 mm (154.8 mg/L of DF250) for the porous tube and 0.45 mm (44.2 mg/L of DF250) for the micro-venturi.