| 摘要 |
<p>A method for producing chemithermomechanical pulp from lignocellulosic material, by preheating and refining the material at an elevated temperature of 160-180 °C, subsequent to pre-impregnating the chips with an impregnating liquid that contains borohydride, at least one compound chosen from the group sodium sulphite, sodium hydrosulphite and sodium disulphite, and optionally one or more sequestering agents. The impregnating liquid preferably has a neutral, near neutral or slightly acid pH. The inventive method enables pulp discoloration to be avoided and/or a reduction in pulp brightness to be counteracted in the preheating and refining processes. The invention also relates to an impregnating liquid for impregnating lignocellulosic material in the production of chemithermomechanical pulps.</p> |
