A new non-wood pulping process for high silicon content raw materials. Application to rice straw

The cooking of rice straw is carried out at atmospheric pressure using a mixture of formic acid/acetic acid/water. The chemical and mechanical properties of the pulp obtained are similar to pulp obtained with a mixture of caustic soda/anthraquinone. The majority of the silica derivatives are retained in the pulp because of the acid cooking conditions. However the cooking chemicals are easily recyclable, because of the absence of mineral reagents, without the need for combustion of the black liquor.