A method and apparatus are provided to control of a flotation separation process, including parameters of the flotation process and reagent addition to optimize mineral recovery. The apparatus includes a signal processor or processing module configured at least to receive signalling containing information about at least one acoustic characteristic of a froth layer in a flotation cell or tank of a flotation separation process; and determine a control characteristic related to the flotation separation process based at least partly on the signalling received. The signal processor or processing module may also be configured at least to: provide corresponding signalling containing information to control the flotation separation process based at least partly on the control characteristic determined.