| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for deinking waste paper raw material, enabling to allow particles having hydrophobic interfaces to selectively adsorb an ink and efficiently discharge the ink outside the system by adding the particles to a flotation process for removing the ink released from the waste paper. SOLUTION: This method for deinking waste paper of raw material comprises charging the waste paper such as collected waste newspaper into a disintegrating machine, disintegrating the waste paper in the presence of sodium hydroxide, sodium silicate, hydrogen peroxide and a deinking agent, ageing the obtained pulp slurry, diluting the aged slurry into a prescribed concentration, adjusting the pH of the diluted slurry to 4-9, adding particles having hydrophobic interfaces having a contact angle of >=60 deg., such as calcium carbonate having an average particle diameter of 5-50μm, in an amount of 0.01-5wt.% based on the pulp, and at least one of an amine compound, an amino acid salt, a cationic compound and an amphoteric compound in an amount of 0.005-5wt.% based on the pulp to the pulp slurry, and subsequently subjecting the mixture to a flotation treatment.</p> |
