Water recycling poses a challenge to mineral concentrators. The quality of process water is often uncontrollable and varies across operations due to changes in the amount of total dissolved solids, the ionic strength and pH. A change in ionic strength could affect the flotation process by affecting the surface reactions occurring at the mineral surface and also the stability of the froth. This study investigated the effect of ionic strength on the water recovery, bubble size, foam height and foam collapse time in a 2-phase flotation system in an attempt to predict the overall foam stability behaviour which is believed to be directly proportional to froth stability. Batch flotation results showed a tremendous increase in water recovery with increasing ionic strength. The bubble size decreased quite significantly with an increase in ionic strength. Foam height and collapse time increased with increasing ionic strength. These findings suggest that the ionic strength of plant water plays an important role in froth stability. (C) 2012 Elsevier Ltd. All rights reserved.