Flotation column scale-up and modelling

CIM Bulletin, Vol. 79, No. 891, 1986

G.S. DOBBY, Department of Metallurgy and Materials Science, University of Toronto, Toronto, Ontario, and J.A. FINCH, Department of Mining and Metallurgical Engineering McGill University Montreal, Quebec

A significant development in froth flotation technology has been the emerging industrial acceptance of column flotation during the past few years. Flotation columns are being employed now in several Canadian base metal concentrators and they are being considered for a wide range of flotation applications throughout North and South America. Since the operating principles of a column differ markedly from those of conventional flotation machines, and have been poorly understood, scale-up of columns has been difficult. This paper describes a methodology for translating laboratory column data to industrial operation. The scale-up model utilizes kinetic data that is obtained from a series of laboratory column experiments; the laboratory column can be as short as 2 m. For modelling purposes the column is considered to consist of two zones: the collection zone, where particle recovery occurs, and the cleaning zone, a packed bubble bed generated by downward flowing wash water. Mixing conditions in the collection zone have been characterized using the results of tracer experiments on plant columns at Mines Gaspe. The same experiments demonstrated the nearly complete suppression of entrained gangue minerals that is attained in the cleaning zone. The model explicitly accounts for both the collection zone and cleaning zone recoveries and allows for the effects of bubble overloading. Results of column scale-up experiments at Gibraltar Mines are presented.

Keywords: Flotation, Flotation columns, Modelling, Mineral processing, Concentrators, Copper cleaning.