LONG TERM POTENTIATION AS A MECHANISM FOR LEARNING AND MEMORY

The invention concerns the recycling of waste paper in a deinking process with flotation with at least one other cleaning stage downstream. According to the invention, selective flotation is performed in multiple stages. After no more than a third flotation stage, the flotation foam collected up to that point is removed and purified by means of flash flotation, which produces sludge, clear water and separated foam that contains the contaminants from the waste paper feed. Subsequently, the sludge is removed from the paper recycling process. Large impurities are removed from the sludge (foam) (except for the foam from up to the three last stages) in up to two washing units (including thickeners) or screen units. The fibers are then separated from the relatively fine contaminants, and these contaminants are primarily removed as sludge from the resulting low-fiber fractions by flash flotation. The fiber-containing fraction and the clear water from flash flotation is recycled to a point prior to the selective flotation system.