A Tool for Optimal Deinking - The New Multi-Stage Flotation Technology, 2002 Fall Technical Conference

The new multi-stage flotation technology was launched year 2001 when the first mill scale system was started successfully. This multi-stage flotation cell technology combines well proven aeration technology and new ideas of cell structure. Aeration is based on dispersion of low-pressure air in the turbulence field generated by a plate rotor specially designed for the deinking purposes. The advanced feature of this aeration system compared to the existing flotation technologies is, that for the first time in mill scale operation the flotation system can be equipped with tools to fully control all important parameters affecting flotation.

The cell structure utilises natural occurring flow dynamics inside the cell. The utilisation of density difference in different functional parts of the cell eliminates the external pumps from the flotation cell. An additional advance of this approach is that the flows inside the cell can be optimised regarding the raw material rheological properties and process consistency.

This paper describes the operating principle of this new multi-stage flotation technology and summarises the experiences from the first mill scale system. Also some examples from mill scale trials are shown to give an idea about the potential of the tools featuring this technology which yields the optimised flotation performance regarding brightness gain and reject properties.