Polyacrylamides in reverse cationic iron ore flotation: bench scale study

Kelly Cristina Ferreira,Antonio Eduardo Clark Peres

doi:10.1590/0370-44672020740104

Abstract

A bench scale study was carried out to investigate the influence of polyacrylamides as co-depressant in a blend with starch depressant on the reverse cationic iron ore flotation. The results indicated that the use of polyacrylamides as dual function polymer should be an alternative to improve the flotation process. These polymers act as a depressant and flocculant reagent, decreasing the mechanical entrainment of hydrophilic iron minerals, forming hydrophobic aggregates. Also, the use of polymers as a co-depressant could prevent the possibility of clathrate formation caused by starch and amine overdose. The results obtained showed that cationic and non-ionic polyacrylamides improve the selectivity when applied at low dosages. Only the slightly charged anionic polyacrylamide yielded good results in flotation tests. The design of experiments carried out with non-ionic polyacrylamides showed that flotation results was were affected by the physico-chemical conditions of the system, such as pH, flocculant molecular weight and amine type.

Highlights

The iron content in the final tailings of industrial reverse cationic circuits is consistently high
Silica content in the final concentrate stayed at 2.1% and the iron content in the tailings dropped from 11.0% to 9.8%
The first report of the use of a dual polymer system acting as depressant in bench scale iron ore cationic flotation experiments came from Turrer et al (2007)

Summary

Introduction

The iron content in the final tailings of industrial reverse cationic circuits is consistently high. Polymers that play the dual function of depressant and flocculant can reduce the entrainment by particle aggregation, reduction of flotation retention time and decrease of water recovery in the froth as discussed in Liu et al (2006). The first report of the use of a dual polymer system acting as depressant in bench scale iron ore cationic flotation experiments came from Turrer et al (2007). Significant increases in the metallurgical recovery of 5.5% and 7.8% were achieved with cationic and non-ionic polymers, respectively It represents a wide field open for investigation. The objective of this investigation was to improve the flotation indexes by applying high molecular weight flocculants as co-depressant in the reverse cationic iron ore flotation

Materials and methods

Results and discussion

Conclusions