Grant: Discovery Grants Program - Individual

This proposal is part of the applicant's ongoing efforts to explore the potential uses and benefits of dissolved gas and ultrasound technologies, and to encourage and promote their implementation in the mineral processing industry. Dissolved gas and ultrasound have important roles to play in mineral processing, but much research and development work are needed before industry becomes convinced of their benefits and considers implementing them in industrial practice. ""Dissolved gas"" can be used as a source for generating gas bubbles for mineral flotation processes. It is known that bubbles derived from dissolved gas are much finer than mechanically produced conventional bubbles and are better suited to the flotation of fine and ultra-fine minerals. Dissolved gas bubbles are obtained by first dissolving a gas (usually air) in the flotation pulp under pressure and then releasing the pressure. Depressurization causes the dissolved gas to come out of solution in the form of fine bubbles, but what is perhaps more interesting is that bubbles nucleate on mineral surfaces as they form and this further enhances the recovery of fine particles by eliminating the need for bubble-particle collision that would otherwise be necessary for bubble attachment to occur. With respect to the use of ultrasound, two areas of application will be considered: (a) mineral flotation, and (b) gold extraction by cyanidation. The benefits of ultrasound in these applications are derived from the unique phenomenon known as ""acoustic cavitation"" which occurs when ultrasonic waves are passed through a liquid. The main effect of this process in flotation is the cleaning of mineral particles to enhance or modify their surface properties. In the cyanidation process for gold extraction, ultrasound can significantly increase the gold dissolution rate which is otherwise a very slow process.