| 摘要 |
<p>1458056 Reclaiming paper; bleaching DEUTSCHE GOLDUND SILBER-SCHEIDEANSTALT 5 Feb 1974 [9 March 1973] 5188/74 Headings D1P, D2A and D2W A process for reclaiming paper from waste paper comprises beating a waste paper stock to a stock density of 1-8% in pulper 1, optionally with a complexing agent dewatering the stock in filter 3 to a stock density of 12-30%, mixing the stock in mixer with a deinking agent and a complexing agent, if not added previously, bleaching the stock in tower 6 at a stock density of 12-30% for 1-3 hours 'at 10-50‹C, diluting the bleached stock to a stock density of 2-6%, passing it through a cleaner 8 to separate staples, a deshiver 9 to remove bunches of fibres, and a flotation unit 10 to remove priting ink particles, concentrating the deinked stock to a stock density of 3-30%, the water removed during concentration being at least partly returned to the flotation unit and optionally at least partly returned to the pulper. Specified complexing agents are salts of ethylene diaminotetraacetic acid. The deinking agent may be sodium or hydrogen peroxide and alkali, and may include water glass, an emulsifier (e.g. a fatty alcohol or fatty acid polyglycol ether, and/or an aliphatic carboxylic acid of the formula where n = 10-24, m = 21-49, and x = 0-4.</p> |
