| 摘要 |
<p>Waste paper is deinked by treating it in a solution containing a sodium sulphite deinking agent and a soluble polymer that is a polyampholyte or has a lactam or substituted lactam structure. The polymer may be casein, animal glue, collagen or polyvinylpyrrolidone. The deinking agent may also include sodium tripolyphosphate or a surface-active agent, e.g. soap or an alkyl aryl polyether alcohol, or both. A sequestering agent such as the sodium salt of diethylenetriamine-pentacetic acid may also be present. The waste paper may be treated with the solution in a pulping stage, which is followed by an ink-separation stage. The treatment may be followed by bleaching, e.g. with sodium hydrosulphite and sodium tripolyphosphate.</p> |
