Froth performance in commercial sized flotation columns

Abstract

This work aimed to investigate the performance of plant flotation column froths. It consisted of two sets of tests. The first were made at Cominco's Sullivan concentrator in Kimberley, B.C. The column produces final Zn product. The performance at various points in the froth was investigated, primarily as a function of radial distance and depth, and operating parameters such as gas rate and location of wash water pipes. A sampling technique was developed aiming to distinguish and quantify the amount of solids that are carried upwards either by flotation or by entrainment at any point in the froth. The second set of tests was conducted at the Strathcona concentrator of Falconbridge Ltd. in Sudbury. The initial procedure was redesigned to meet the objectives of that testwork. Grade profiles along the froth were obtained and the trends observed in the first set of tests were verified. Solids concentration profiles were also obtained throughout the depth of froth. Both tests indicated that the solids concentration dropped significantly with froth height, either because of bubble coalescence or by drainage. This indicates that froth recovery was low, especially in the second case. Slight upgrading was observed of bubble load with froth height, while the entrained material was rejected in the first 30 cm of froth.