Simulation of industrial flotation tanks : a CFD approach

• Main Author: Zietara, Rafal
• Published: University of Manchester 2009
• Subjects: 622.752
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498783

Froth flotation is a separation process widely used to concentrate valuable minerals. It is based on differences in the surface properties of the valuable minerals and the waste (known as gangue). Separation takes place primarily in the underlying pulp phase but minerals are further cleaned in the froth phase. Although there has been a considerable amount of research on froth flotation, the process is still poorly understood. The interaction of many parameters (e.g. the particle size of the ore), operational conditions and chemical interactions, influence the process performance and make it difficult to investigate. The effect of changing operating variables on concentrate grade and mineral recovery has been previously linked with performance changes only by experimental measurements. This thesis attempts to build a mathematical description of the influence of operational conditions on gas, liquid and solid ow behaviour in a flotation tank. Detailed models of pulp and froth were built and implemented in a custom written three dimensional, finite volume framework. The pulp phase model consists turbulent gas-liquid interactions, solid dispersion and selective gas-solid attachment. The froth model includes froth motion, liquid drainage and solid particle dispersion in Plateau borders of froth. Both models were validated separately on a series of test data samples. Finally models were linked in one framework with a pulp-froth interface common for both domains. It was found that pulp phase significantly influences froth phase. The non-uniform distributions of parameters on the pulp-froth interface resulting from computation of pulp phase may change significantly distribution profiles in froth This can possibly affect yield and purity of final product.