Recycled paper as raw material

Question 1

1. What is the definition of the term utilization rate?

Answer 1

Recovered paper (t)/production of paper (t) = utilisation rate

Question 2

2. What is the definition of the term recovery rate?

Answer 2

Recovery rate = collected paper (t)/consumption of paper (t)

Question 3

What are the five main groups of recovered paper and board according to the
European list EN643?

Answer 3

Group 1 – ordinary grades – mixed paper and board, supermarket corrugated, magazines etc
Group 2 – Medium grades – newspapers, office paper coloured letters
Group 3 – High grades – White newsprint, white printouts
Group 4 – Kraft grades – Used corrugated kraft, new kraft
Group 5 – Special grades – mixed recovered paper and board, liquid board packaging, wet labels

Question 4

If you vary the proportion of old magazines and old newsprint, what would be the
influence on brightness, ash, dirt specks and stickies?

Answer 4

Newspapers are much harder to deink than standard magazines. This is because newspapers do not have coating. It is much easier to remove ink that is attached to a coating/filler rather than when it is attached to fibre, this makes it much easier to remove ink from newspaper. Therefore the brightness may be much lower is more newspapers are added.

Question 5

Which methods for determining the moisture control do you know – explain the
different principles

Answer 5

Moisture measurement for bales
- Opening bale taking out sample and drying in oven at 105C.
- Taking a sample out of the bale using core drilling device then same as before
- Technical instrument. Eg NIR probe
Moisture measurement for loose material
- Visual inspection.
- La testing – oven 105C. No standard method but each mill should have a standard.

Question 6

Explain the CEPI guidelines for the moisture control procedure.

Answer 6

Systematic measurement – eg having a daily measurement routine, taking random bales to test as well as visual inspections. Measurements can be done by opening or core drilling bales to perform gravimetric analysis or using a technical instrument. Using the data it is possible to see whether the moisture content is within tolerance. With this information the bale can be accept, refused, or accepted with conditions.

Question 7

What does cleaning efficiency mean?

Answer 7

Cleaning efficiency is the ratio of actual separation to the theoretical separation.