Investigation of nanobubble enhanced reverse anionic flotation of hematite and associated mechanisms

Abstract

Hematite is commonly upgraded in China using a reverse anionic flotation process with starch as depressant for hematite, Ca2+ as activator and fatty acids as collector for quartz. The Anshan type of hematite is well known for its low grade, fine dissemination, difficulty in upgrading, and huge reserve in China. To investigate effects of nanobubbles and different reagents on the flotation process of this particular hematite, batch flotation tests were conducted with a mechanical flotation cell integrated with a cavitation device that generates nanobubbles under different process parameters including corn starch dosage, lime (CaO) dosage, collector dosage, and air flow rate through the nanobubble generator. Significant improvements in hematite flotation performance was achieved in the presence of nanobubble. The nanobubble flotation results and associated mechanisms are discussed based on up-to-date chemistry of hematite flotation and unique nanobubble characteristics.