Chemistry of Flotation and Washing for Deinking Newsprint Part II: Particle Interactions and Systems, 1991 Papermakers Conference Proceedings
This is the second of a series of papers on the deinking of newsprint. Two major types of surfactants are used in deinking. The chemical behavior of soap/calcium is easier to understand than the behavior of nonionics. Soap will be used to illustrate how the chemistry of flotation and washing work. Included is an explanation of the role of inorganic minerals in flotation. Nonionics will be discussed in the next paper.
The key to washing is making ink vehicle particles hydrophilic. The key to flotation is making them hydrophobic. The following chemistry model is offered as a tool to help clear up the role that chemistry plays in commercial deinking to improve the operation of existing plants and the design of new ones.
Most of the mills using soap/calcium chemistry, if they have washing, put it before flotation, rather than after. So this discussion will be based on a wash-float system with the reverse order discussed at the end.
Chemistry of Flotation and Washing for Deinking Newsprint Part II: Particle Interactions and Systems