Method of regulating a flotation system with a primary and secondary stage

A method of regulating a flotation system having an inflow quantity of suspension flow dependent on production demands, said flotation system including a primary flotation stage having a plurality of primary flotation cells, and a froth chute in communication with each of said primary flotation cells, each said primary flotation cell having a froth overflow device;

• and a secondary flotation stage having a plurality of secondary flotation cells, and a froth chute in communication with each of said secondary flotation cells;
• said method comprising the steps of:
• feeding said inflow quantity of suspension to said primary flotation stage and forming a froth in said primary froth chute;
• determining an overflow level of the suspension flow to the froth chute in the primary flotation stage;
• dependent on said overflow level, adjusting a back-up level of the froth in the froth chute of the primary flotation stage;
• dependent on said back-up level, controlling accepts from an outlet of said primary flotation stage to provide a substantially constant back-up level of the froth in the froth chute of the primary flotation stage;
• de-aereating the froth from the froth chute of the primary flotation stage;
• transporting the de-aereated froth to a collection vessel which is in fluid communication with an inlet to the secondary flotation stage;
• recycling suspension flow from the secondary flotation cells of the secondary flotation stage in part to an inlet of the primary flotation stage, and in part to the inlet of the secondary flotation stage;
• regulating the level of de-aereated froth in the collection vessel by controlling the amount of suspension flow recycled from said secondary flotation stage to the inlet of the secondary flotation stage;
• measuring a height of the froth in the froth chute of the secondary flotation stage before an outflow weir associated therewith;
• and
• regulating the ratio of the amount of said suspension flow from the secondary flotation cells which is transported to the inlet of the primary flotation stage relative to the amount of said suspension flow which is transported to the inlet of the secondary flotation stage, dependent on said measuring step.