SU597767A1 - Composition for bleaching cellulose-containing fibrous semifinished products - Google Patents

Description

(54) COMPOSITION FOR BLEACHING OF 1CHELLULOSE-CONTAINING OVERHEAD SEMI-FINISHED PRODUCTS of the group containing barbituric acid, ammonia, ammonium sulphate, 1N sodium nitrate in the following ratio of components, weight. %: Peroxide O, O1-O, 5 Caustic soda, RZ-OD5 Nitrogen-containing compound O, O23-0.11 WaterEstal. Nitrogen compounds are good interrupters for free-radical reactions occurring during bleaching with E – hydrogen peroxide. These compounds are also complexing agents, i.e., e. ions of some metals metal of iron, copper, etc., are accelerated to catalytic decomposition of hydrogen peroxide into oxygen and water and contribute to obtaining a white semi-finished product of reduced materiality, Compound, nitrogen also contribute to the acceleration of diffusion into the solution of fibrous cellulose-containing inlays during the bleaching process peroxide voororoda in Vols low-grade semi-finished products. The preparation of a solution of each of the whitening components is carried out separately, after which they are fed into the pulp. The calculated amount of concentrated hydrogen peroxide is diluted with water and stirred. The concentration of hydrogen peroxide in the solution should be alkaline reagent — all sodium is prepared separately, its concentration in aqueous jpacTBOfje should be 4 O-6 O g / l. The preparation of a solution of the stabilizer by the products in a similar way is a negligible concentration in an aqueous solution of 5-10%. Example. Unbleached sulphite ae LCI103U with a whiteness of 6O% (determined according to GOST 769O-66) is removed with a solution containing: hydrogen peroxide, W To sodium-barbourse acid at a ratio (% of components, wt.%: Leak hydrogen, 25 Caustic soda .0.15 Barbituric Acid, O23 WaterOstal, Comparison Day, the same cellulose was bleached with a known composition containing hydrogen peroxide, caustic soda, or sodium silicate at a ratio of components, weight, Pfericum O, 25 Caustic Soda, 5 Sodium silicate O, 3 WaterOther, The same bleaching : Temperaure 55-6О ° С; continuation 3 hours, mass concentration of 1O%, pH - 1O, 5. The main indicators of the quality of bleached elulose are whiteness, at 1, C% of its ammonia solution, PC number (whiteness stability) are given in Table I, Table I Suggested 73 , 0652 Known71,452 O The number of PCs is determined by (1аа.А) „.Jj QQ-Ai Prc m 3 p 2. From the bottom of the line (the chlorine stage - neck checks - hypochlorite bleaching, having a whiteness of 83 D%, is whitened peroxide peroxide in an alkaline solution, using barbituric acid as a stabilizer with a ratio of components, weight. %: Hydrogen peroxide, 1 Caustic soda, 1 Barbituric acid, 115 WaterEverything. For comparison, the same cellulose is added with hydrogen peroxide in an alkaline solution using sodium silicate as a stabilizer. %: Hydrogen peroxide Caustic soda Sodium silicate Saline Water Condition bleaching in both the same: temperature, duration of 3 h, concentration; mass 10%, pH 1O, 5. The main indications of bleached teli-3bv are represented by the E tabl;; /, Table Primerz. Sulphite cellulose, which went through chlorination-alkali steps, lochlorite bleaching, and whiteness 68, is treated with hydrogen peroxide in an alkaline solution, using an aqueous ammonia solution as a stabilizer with a ratio of components, wt. %: Hydrogen peroxide Hydroxide sodium hydroxide, O Ammonia (stabilizer) O, O5 Water Else For comparison, the same cellulose is added with the ratio of components, weight. %; Hydrogen peroxide, 1 Caustic soda, OT Silicate, sodium, R. O2, WaterEvalue

The bleaching conditions in both cases are the same: the temperature is 7p ° C, it lasts for 3 hours, the pH is 1.6, the concentration of the mass is 10%.

The main indicators of the quality of bleached pulp are presented in table 3,

Table3

The whiteness on the blue filter,% white rubber

Viscosity 1% honey: Trif. Sulphite cellulose, the past stages of chlorination, the hypochlorite bleaching and bleaching and having a whiteness of 85.5% (determined according to GOST 769O-66), were made with a known composition with a ratio of components, weight. %:

Hydrogen peroxide Caustic soda Sodium nitrate Water

For comparison, the same cellulose was made with hydrogen peroxide in an alkaline medium using sodium silicate (a known solution) with cdbTKCtoeHHH component as a stabilizer, wt. %; Example 4. Su.shifit cellulose, which passed through chlorinated stages, hypochlorite bleaching and whitening whiteness of 85.4%, was added with hydrogen peroxide in an alkaline medium, using as a stabilizer ammonium sulphate at a ratio of components, wt. %: Hydrogen peroxide, 1 Sodium hydroxide, 7 Ammonium sulphate, 0.05 Water, Other comparison CPUs compare the same cellulose with a known composition with a ratio of components, weight. %: Hydrogen peroxide, sodium hydroxide, O7, silicate, sodium, 2, water, remaining. The conditions of bleaching in both cases are the same: temperature 7 ° C, duration 3 hours, mass concentration 1O%, H 1 O.5. Essential {quality indicators of cellulose quality in table. 4. Table 4

Hydrogen peroxide akim natr Silicate sodium Water

The bleaching conditions in both cases are galvanized: temperature 7 °, production 3 hours, pH 1 °, 5, concentration by mass 10%. Indicators of the quality of bleached pulp are presented in table. five,

Table 5

The proposed 86.4 462O, 82

Known 86.6 4440.94

As a slurry from the examples above, bleaching of cells with the use of iipeo lagged composition makes it possible to obtain cellulose with quality additives higher than when using a known composition.

Improving the quality indicators allows obtaining a higher brand cellulose. The waste solution obtained after bleaching with the proposed composition allows the wastewater treatment to be carried out in a rational way and to increase the degree of their purification.

Form5gla Invention

Cellulose-containing bleaching composition | -. fiber prefabs | 1katov, including KHi waterborne peroxide, caustic soda, stabilaat and water, differing gvm, that, with a chain of improving the quality of the target product and increasing the degree of purification. as a stabilizer, he will use a nitrogen-containing compound,

H) One of the groups from the group containing barbituric acid ammonia, ammonium sulphate and nitrate sodium with a barely correlated component®, weight. %: Peroxide peroxide, Ot-6.5

Caustic 03-0; i5

Nitrogen-containing compound O ,, 11

WaterEverything,

Sources 1shpi AI (AI)) are the first in the manva during the examination:

1, Monograph TAPPI Bleaching of cellulose, 1968, from 140-141,