FROTH ZONE MODELING OF AN INDUSTRIAL FLOTATION COLUMN

The mineral recovery in a flotation column is the result of the combin ed effect of two distinct zones: the collection zone, which acts like a first cleaning stage and the froth zone that allows for a secondary cleaning of the minerals entering the froth. In this paper an experime ntal study of the froth zone behaviour in an industrial flotation colu mn, is presented. The column is rectangular, 2x8 m(2) in cross-section and 14m height, and is part of the second copper cleaner circuit of t he Colon concentrator at El Teniente, Codelco-Chile. The column produc es 30 tph of 32% copper concentrate. A critical dependence of the frot h zone recovery withthe air rate and to a minor extent with the wash w ater rate was observed. The average froth depth was about 1 m. The ave rage air holdup along the froth zone was 80 %, for a typical range of gas rate J(g)=1.2-1.8 cm/s. The plant water supply war limited and all owed for a superficial wash water rate J(w) varying from 0 to 0.1 cm/s , which causes positive and negative bias operation. A semi-empirical model of the froth zone recovery Rf was derived in terms of the operat ing variables: superficial gas rate J(g), superficial water rate J(w) and froth depth H-f, as shown in the following equation, Rf=95exp(-1.4 410(-2)Hf(1+3Kw)/Jg(3)) A good agreement was found between the froth model, based on operating variables, and experimentally estimated data of froth zone recovery. The range of the copper recovery in the froth zone observed in the industrial column was 20-70 %, from tests where the global column copper recovery was in the range 40-88 %, respective ly. (C) 1998 Elsevier Science Ltd. All rights reserved.