As there is seldom enough ground available on which the tailing of a flotation plant can be run to waste without being stacked, it is usual to impound it in some form of dam where the solids can be deposited and the water decanted off for return to the plant. It is generally advisable to recover as much of the water as possible in order not only to save the expense of obtaining a fresh supply but also to return to the flotation circuit any reagents that it still contains in solution. Assuming that it is necessary to return the water to the plant, it is best to dispose of the tailing pulp in two stages, dewatering it in a thickener close to the plant before sending it to the dam, which can seldom be near and often has to be a considerable distance away. This method keeps at a minimum the cost of pumping, which is the heaviest item of expenditure.
In modern practice the first stage of dewatering is generally carried out in a Traction Thickener, which is of the same ….Read more