US 12,104,321 B2 · Oxygen bleaching method of pulp

Abstract

An oxygen bleaching method of pulp includes the steps of: adding a solution formulated by a magnesium salt and an activator to an unbleached chemical pulp, stirring to be mixed well, and bleaching by introducing oxygen. The activators are nano zero-valent metals that are conventional, low-cost, and recyclable. These activators can activate low-concentration oxygen at low-temperature in neutral aqueous solution to efficiently generate peroxide anion radicals, so as to promote the generation of hydroperoxide anions and peroxide ions, achieving high efficient delignification. The whole process does not generate waste water, the oxygen consumption is only 50-85% of the original process, the yield is increased by 1.5-2.8% compared with the original system, the pulp brightness is increased to 28-32° SR, and the magnesium salt can be recycled and reused.

Claims11

Dependent claims

An oxygen bleaching method of pulp comprising:

mixing an unbleached chemical pulp with a protective agent and an activator in a cooking tank;
and introducing high-purity oxygen and reacting under stirring;
wherein the protective agent is one or more selected from the group consisting of magnesium oxide, magnesium hydroxide and magnesium sulfate;
wherein the activator is one or more selected from the group consisting of nano zero-valent iron, nano zero-valent aluminum, nano zero-valent cobalt, nano zero-valent zinc and nano zero-valent nickel, and has a size of 100 nm to 500 nm;
and
wherein the reaction temperature is less than or equal to 40° C.

3 more elements

Dependencies are inferred from the claim text.

Oxygen bleaching method of pulp

Life of this patent

Oxygen bleaching method of pulp

Life of this patent

Abstract

Claims11