text: Froth flotation is one of the processes used to recover recycled paper. In the paper industry this step is called deinking or just flotation. The target is to release and remove the hydrophobic contaminants from the recycled paper. The contaminants are mostly printing ink and stickies. Normally the setup is a two-stage system with 3,4 or 5 flotation cells in series.
  * pH control: sodium silicate and sodium hydroxide
  * Calcium ion source: hard water, lime or calcium chloride
  * Collector: fatty acid, fatty acid emulsion, fatty acid soap and/or organo-modified siloxane