Deinking/Flotation Flashcards
(7 cards)
1
Q
What are 4 main tasks of flotation
A
Ink/dirt speck removal
Sticky removal
Brightness increase
Ash removal
2
Q
What is the principle of deinking
A
Selective flotation (based on bubble size and chemical)
3
Q
What is deinking soap used for?
A
To increase surface activity and collect ink+stickies
4
Q
What is caustic soda used for in deinking
A
Fibre swelling
Saponification of fatty acids
5
Q
What is hydrogen peroxide used for in deinking line pulper
A
this is to reduce yellowing tendency caused by caustic soda
6
Q
What is sodium silicate (waterglass) used for in deinking
A
To stabilise hydrogen peroxide from decomposition caused by heavy metal ions
7
Q
What is calcium chloride used for in deinking
A
Only needed if the water isn’t hard (5 degrees German hardness)
