| 摘要 |
Method of reducing the amt. of complexed ions of manganese, copper or iron in liqs. produced during the prepn. of lignocellulose-contg. materials, comprises adding an alkaline earth metal cpd. to the liq. to form a ppte. or flock, the liq. being maintained at a combination of pH, temp. and standing time so that when the ppte. or flock is sepd. off then the amt. of metal ions is reduced by at least ca. 30%. In an example 10 g/l calcium oxide were added to liq. obtd. from a step where birchwood sulphate pulp was treated with EDTA prior to bleaching with hydrogen peroxide, contg. 2.5 mg/l Mn, 0.4 Fe and 0.06 Cu, then the mixt. was heated for 60 mins. at 80 deg C, pH 12.8 and the ppte. sepd. to give a liq. contg. 0.13 Mn, 0.10 Fe and 0.02 Cu, corresponding to a reduction of 95, 75 and 67% respectively. |
