SU1650834A1 - Method of producing cellulose - Google Patents

Abstract

The invention relates to the technology of producing pulp from coniferous wood and allows to improve the physico-mechanical characteristics of cellulose and reduce the content of resins and fats in it. Wood chips are treated with an aqueous solution of ammonia with a concentration of 8-25 g / l 60-100 ° C for 20-40 minutes, followed by removal of the spent solution, after which the pre-treated chips with a bisulfite solution on a magnesium base are boiled at 155-165 & ° C 1 tab.

Description

This invention relates to the pulp and paper industry and can be used in the production of softwood pulp for paper and cardboard.

The purpose of the invention is to improve the physico-mechanical properties of cellulose and reduce the content of resins and fats in it.

According to the proposed method before. Cooking softwood with a bisulfite solution on a magnesium base chips are treated with an aqueous solution of ammonia with a concentration of 8-25 g / l at 60-100 ° C for 20-40 minutes, followed by removal of the spent solution.

Processing chips with an aqueous solution of ammonia improves the stability of hemicelluloses at the stage of bisulfite cooking, which improves the physico-mechanical properties of cellulose.

At the ammonia treatment stage, the pH of the solution is 10-12, which is sufficient for saponification and dissolution of resinous and fatty acids and reduces their content in the fiber semi-finished product after cooking.

The proposed method is carried out as follows.

Chips are steamed for 15 minutes at 100-105 ° C, then treated with an aqueous solution of ammonia with a concentration of 8-25 g / l at 60-100 ° C for 20-40 minutes. After treatment, the spent solution is removed and the cooking bisulfite O is poured.

ate about

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Nye solution containing 4.7% S02 (of which 3.1% free), 1% MDO and having a pH of 3.5.

The cooking is carried out according to the mode: the temperature rise to the final one is 1 hour, the time of standing at the maximum temperature is determined by achieving a concentration of 802 total 0.4-0.6%.

In parallel, receive cellulose by a known method.

Chipping is carried out for 15 minutes at 100-105 ° C. Cooking mode: temperature rise time up to 110 ° C for 2 hours, intermediate stand time at 110 ° C for 1 hour, temperature rise to 1 ° C for 1.5 hours, cooking at 163 ° C for 3 hours and 10 minutes with the same bisulfite cooking solution as in the proposed method. Quality indicators of cellulose, obtained by the proposed and known methods are shown in the table.

The table shows that the proposed method allows to increase the strength indicators of cellulose by 5-10% and reduce the content of resins and fats to 0.22-0.75%. In addition, the boiler turnover is reduced by 1-2 hours.

Claims (1)

Invention Formula The method of producing cellulose by boiling coniferous wood with a bisulfite solution on a magnesium base, characterized in that, in order to improve the physicomechanical performance of cellulose and reduce its resin and fat content, before cooking, wood is treated with an aqueous ammonia solution of 8-25 g / l at 60-100 ° C for 20-40 minutes, followed by removal waste solution.  Examples 1 to 9 - by the proposed method, examples 10 to 12 - control, example 13 - by a known method. Unit Kappa.