The optimisation and control of mineral separation by froth flotation remains one of the great challenges in mineral processing. Variable feed characteristics and throughput, together with a lack of predictive physical models, present a barrier to advanced optimisation techniques. The solution to this is Peak Air Recovery (PAR), a simple concept in which a single target (air recovery) is maximised by varying physical operating parameters such as air rate. Although the importance of air recovery was discovered in early froth physics models, its real value has been demonstrated through numerous plant surveys.

Over the last ten years, we have shown that mineral recovery can be maximised, often at higher concentrate grade, when operating flotation cells and circuits at their optimal air recovery. This is linked to the trade-off between bubble stability and froth mobility. In this talk, I will give an overview of developments in froth stability optimisation, and look at what the future holds for implementation of flotation control systems based on PAR.

Dr Kathryn Hadler
Lecturer in Mineral Processing, Imperial College London

Kathryn graduated from the University of Manchester with a MEng in Chemical Engineering with French, followed by a PhD focusing on froth stability and flotation performance in 2006. She continued with her research in flotation with a postdoc position at Imperial College London, becoming a lecturer in 2011. After an 18 month period in industry working at a mineral processing consultancy (GSL), she returned to Imperial in 2016, and now works part-time between academia and consultancy.


Sustainable Minerals Institute
Sir James Foots Building #47A
Level 4 Seminar room