If it is recycled, the paper will go through a lengthy process of disintegration and renewal. When paper first reaches the recycling center, it must be returned to the state of pulp by using many different chemicals, such as sodium hydroxide, hydrogen peroxide, and sodium silicate. These chemicals will bleach and disperse the pulp fibers. The fibers are then run through cleaning and screening sequences which remove any contaminants. The pulp must then be washed with clean water to remove ink particles that were removed from the paper by the chemical process.
Flotation is a widely-used method of removing the ink.
The pulp is submerged in water, and heated. The ink attaches to air bubbles, which must then be removed before they break and let the ink float back to the pulp. This is a tedious process, involving a watchful eye and careful timing. Most recycling centers will treat the water they used, and remove any contaminants. Screens and mechanical cleaners are the most common, which may let chemicals slip through.