Recycling is the Norm - But Where Does the Ink Go?

These days we're very good at collecting and recycling paper to remake into new paper - but where does the ink go? A good question, and one we have an answer to if you read on

Removing Ink From Paper - Demystified

When all the paper we collect goes for recycling how exactly is the ink removed?

Paper sent for recycling is de-inked by either washing or flotation - or a combination of both methods:

1. Washing - As the paper is pulped, soaps are added which separate the ink from the paper and allow it to be washed away in water, which is then cleaned and re-used.

2. Flotation - Air is passed through the pulp, producing a foam which captures at least half of the ink and can be skimmed off.

After de-inking , the pulp may also be bleached using hydrogen peroxide, which breaks down into water and oxygen on disposal.  Although the de-inking process uses water and chemicals it is still less harmful to the environment than the manufacturing process of making new paper.

IWhat happens to that ink slurry depends on the recycling facility:

• Used in cement manufacturing: Some mills send the deinking residue to cement plants, where it can be used as an alternative raw material or fuel.
• Energy recovery: In some cases, the sludge is dried and burned in waste-to-energy facilities to generate heat or electricity.
• Landfill disposal: Where reuse or energy recovery is not practical, some deinking sludge still ends up in landfill.
• Recovery of minerals and fillers: Certain advanced recycling operations recover useful materials such as calcium carbonate and other fillers from the sludge for reuse in industrial applications.

The sludge itself typically contains a mixture of:

• Ink particles
• Paper fibres too short for further recycling
• Clay and calcium carbonate fillers
• Coatings and adhesives
• Residual deinking chemicals

So, in modern paper recycling, the goal is to divert as much ink slurry as possible into beneficial reuse applications rather than sending it to landfill.