Abstract: The reverse flotation for desiliconization form bauxite is better than direct flotation, and the grinding before flotation affects the flotation indexes to some extend. The grinding dynamic equation of bauxite based on the data of grinding experiment of diasporic bauxite was derived. The calculated value of the equation is identical with the experiment value. Further the grinding dynamic equation of intermediate grain size range suitable for reversal flotation has also been derived. The grinding time required could be calculated when the mass fraction of intermediate size grain is maximum. The formulation of grinding dynamic equation considerably simplified the grinding experiment, optimized the grinding process.

Key words:  bauxite； grinding dynamics； optimization