| 摘要 |
A method for bleaching lignocellulosic material (pulp), in which heavy metals are removed before bleaching comprises treatment of the pulp with an inorganic and an organic compound. Preferably chloride and/or sulphate ions (e.g. calcium chloride) are used as the inorganic compound, whilst the organic compound is an acid (e.g. malonic acid, tartaric acid or citric acid) or even a nitrogen-containing chelating agent. Pulp is treated with the inorganic compound in a first step separate from the second step for treatment with the organic compound. |
