A comparative study on the removal of methyl isobutyl carbinol from froth flotation circuits by chemical treatment

Abstract

Residual frother accumulation is a growing problem in coal and mineral processing plants due to the increased need for water recycling to meet environmental regulations and cost management. The presence of accumulated frother downstream from flotation circuits promotes foam generation in process units such as pumps and cyclones causing cavitation and in severe cases can lead to plant froth out and shut down. It is therefore highly desirable to determine an appropriate method to remove the frother from the process water downstream of the flotation circuit to prevent accumulation of residual frother and avoid the associated problems. This project aimed to identify and evaluate methods of controlling the level of one of the most commonly used surfactants for frothing applications, methyl isobutyl carbinol (MIBC). Performance was assessed by comparing the steady-state foam heights before and after chemical treatment using Bikerman's method to generate foam. Three reagents that are readily available in industry were examined; ozone, sodium hydroxide and sulfuric acid. Although all three reagents successfully reduced the foam height and hence frother concentration, ozone was found to be up to 200 times more effective than either sodium hydroxide or sulfuric acid. Furthermore, both sodium hydroxide and sulfuric acid were rejected as feasible industrial solutions due to the large quantities required. Therefore, an industrial solution using ozone could be a viable solution with minimal capital and operating costs involved in implementation.