| 摘要 |
<p>PURPOSE: To obtain a deinked pulp having high whiteness and a remaining only slight residual ink from waste paper as a raw material under saving a bleaching agent at a high yield. CONSTITUTION: In deinking of waste paper ass a raw material, at least one kind of a nonionic surfactant selected from a product obtained by adding an alkylene oxide to a mixture of oil and fat with an alcohol or a compound of the formula: RCOO(AO)m R' (R is a 7-23C alkyl or alkenyl; R' is H, a 1-22C alkyl or a 2-22C alkenyl or acyl; AO is a 2-4C oxyalkylene; (m) is an integer of >=1) is used for peeling off ink from the raw material waste paper. Ion concentrations of Ca and Al in a flotation system are kept respectively at 10-400ppm and 0-40ppm and pH is adjusted at 4-9, and an amine or an acid salt of an amine expressed by formulae I-III, etc., (R1 is an alkyl, an alkenyl or a hydroxyalkyl; R2 and R3 are each an alkyl or an alkenyl; HA is an inorganic acid or an organic acid; AO is an oxyalkylene, etc.), formula IV< formula V, etc., (R1 is an alkyl or an alkenyl; R2 and R3 and each H, an alkyl or an alkenyl, etc.) is added to the system in an amount of 0.01-1.0wt.% based on the waste paper, and treated.</p> |
