| 摘要 |
PROBLEM TO BE SOLVED: To provide an industrially useful thioureadioxide bleaching method having a slight loss of chemicals, a low energy consumption and a highly bleaching effect as a bleaching method for various kinds of waste papers, mechanical pulp, kraft pulp, or the like. SOLUTION: (1) Thiourea, (2) a peroxide and (3) at least one kind selected from the group consisting of oxyacids of tungsten, molybdenum, vanadium, selenium and titanium and their salts are mixed with water and reacted to give a reaction solution, which is added to pulp to bleach papermaking pulp.
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