| 摘要 |
<p>When pulp is manufactured by so-called modified cooking methods, spent liquor is formed containing large amounts of calcium bound to the dissolved material. During evaporation calcium is liberated and precipitates on the heat transfer surfaces of the evaporating plant. By means of the method according to the invention the precipitation of calcium is either moved to a stage in the evaporating process where it co-precipitates with sodium salts, whereby the precipitate is easily dissolved, or the calcium is deactivated prior to the evaporating plant by allowing it to precipitate at a stage where no scaling can be formed on heat transfer surfaces.</p> |
