Process and apparatus for removing contaminants by flotation from an aqueous fibrous suspension

摘要

In a paper recycling process, ink and other impurities are removed by selective floatation in a series of linked modular upright chambers (4) in which there is a downward flow of liquid fibre suspension intermingled with an upward flow of bubbles. The chambers are of rectangular cross section. The length L of each chamber is at least 1.5 times the width (B). The flow-path hydraulic cross sectional diameter is not greater than 2.7 m. The incoming suspended matter is distributed over at least 80 % of the module cross-sectional area as seen in planform. Also claimed is a commensurate assembly.