Method of bleaching pulp


(57) Abstract:

The inventive when bleaching pulp with hydrogen peroxide in alkaline medium as organic additives used ortho-phenantroline in an amount of 0.01 to 1.0% by weight of the absolutely dry fiber. Then the pulp is subjected to alkaline treatment and kislovka. table 1.

The invention relates to a process of bleaching cellulose and can be used in the production of fibrous materials for various purposes.

Known methods of bleaching pulp by multi-processing unbleached fibrous mass of chlorine, alkali, sodium hypochlorite, chlorine dioxide, alkali, again by chlorine dioxide and kislovka [1] the Disadvantage of these methods is the multistage process of bleaching and the use of toxic chlorine-containing reagents.

Closest to the proposed to the technical essence and the achieved effect is a method of bleaching lignocellulosic material, which consists in the treatment of pulp with oxygen and peroxides in the presence of cyclic catasetinae and/or amines in alkaline medium [2]

However, the use of gaseous oxygen in the bleaching requires special equipment delakorda most effectively at temperatures above 100aboutC.

The purpose of the invention to simplify the process of bleaching, increased white fibrous material.

This task is solved by the bleaching of cellulosic materials by hydrogen peroxide in alkaline medium at 60-90aboutIn the presence of organic additives catalytic type, which use ortho-phenantroline as 0.01 to 1% by weight of the absolutely dry. C.) fiber.

The use of the additive ortho-phenanthroline allows to exclude the use of gaseous oxygen and at the same time to achieve the same white indices at lower times peroxide bleaching, carry out the process at lower temperatures and at lower temperatures and with lower consumption of hydrogen peroxide than without the additive, indicating that the increase of the efficiency of bleaching.

According to the proposed method subjected to bleaching of unbleached sulphate pulp hardwood rigidity 16% Kappa (white 35%). Cook the pulp suspension to a concentration of 10% in the solution containing 2-6% hydrogen peroxide (by weight and. C. fiber), sodium hydroxide in the amount of 2-3% by weight of the fiber (pH 10.5-11.5) and a portion of the proposed additions ortho-penetralia (0,01-1% ). Together controI 60-90aboutFor 15-240 minutes Then spend the bucking weight within 5-10 min, a solution of NaOH (pH 12) and kislovka solution SO2(pH 3-5) for 5-10 min, after which the fiber is washed with water and prepare a standard casting to determine white leucometer according to GOST 7690-66.

P R I m e R 1. 1, and. C. unbleached pulp is poured 10 ml of alkaline hydrogen peroxide solution containing 2% of hydrogen peroxide, 3% sodium hydroxide and 0.5% ortho-phenanthroline. The mass is well stirred, placed in a thermostat heated to 85aboutC, and incubated for 60 minutes after the mass bleaching leach, then kislovka and washed with water, and then prepare a standard casting to define whiteness. The whiteness index of the sample bleached thus cellulose 64.0% Parallel conduct Supervisory experience without the addition of ortho-phenanthroline. White control sample 61.5%

P R I m m e R 2. The order of conducting the process of pulp bleaching is the same as in example 1. The differences are: the consumption of hydrogen peroxide 4% by weight. C. cellulose, ortho-phenanthroline 0,01% process temperature bleaching 75aboutWith time bleaching 120 minutes White sample is 67.5% of the control sample has a white 66.5%

P R I m e R the temperature conditions, the duration of the bleaching, the concentrations of reagents, flow additives (as proposed and known in the prototype), presented in the table.

The bleaching results show that the addition of ortho-phenanthroline has a strong catalytic effect on the process of peroxide bleaching. Analysis of the results carried out in the table shows that the same indicators of white fibrous material can be achieved in the control experiments, i.e., without the proposed additions, varying the time and temperature of the bleaching process, the concentration of whitening reagent (examples 5 and 11, 8 and 14, 9 and 15).

The use of the additive ortho-phenanthroline allows to reduce the time of bleaching, to reduce the process temperature or the flow rate of hydrogen peroxide (examples 5 and 7, 5 and 12, 13 and 15), to improve the performance of the white pulp with the same control parameters of the process.

The table below shows results on the influence of flow additives on white fibrous material (examples 2, 17-24, 27) show that the optimal consumption is ortho-phenanthroline 0.05 to 0.1% by weight. C. fiber. A further increase of the flow rate of the additive to 1.0% reduces the whiteness of the sample, giving it a slightly reddish tint (from 72.5 to 69.0% at 60

Thus, the application of the proposed method of bleaching can simplify the apparatus bleaching process, to improve the efficiency of the process and the white fibrous material.

METHOD of BLEACHING CELLULOSE by treatment with hydrogen peroxide in alkaline medium in the presence of organic additives with subsequent alkali treatment and kislovka, characterized in that the organic additives used ortho-phenantroline in an amount of 0.01 to 1.0% by weight of the absolutely dry fiber.


Same patents:

The invention relates to pulp and paper production and can be used to improve ergonometry - ical properties of pulp and paper respectively

FIELD: pulp-and-paper industry, in particular method for PULP whitening.

SUBSTANCE: craft pulp mass with concentration of 2.5-5.0 % after oxygen-alkaline treatment is treated with potassium permanganate in consumption of 0.01-0.1 % based on dry cellulose at 40-80°C and pH 1.6-3.0 or with sulfuric acid solution in consumption of 1.0-1.5 % at 90°C for 30 min. In steps II and IV cellulose with concentration of 10 % is treated with hydrogen peroxide in consumption of 2 % based on mass of dry cellulose for 120 min at 80-90°C and pH 9.5-10.5 wherein consumption of sodium alkali and sodium silicate is 1.3 % and 2.5 %, respectively. In step III cellulose is treated with potassium permanganate in consumption of 0.01-0.4 % under step I conditions.

EFFECT: reduced consumption of whitening agents.

1 tbl, 9 ex

FIELD: pulp-and-paper industry, in particular method for pulp whitening.

SUBSTANCE: pulp mass with concentration of 5-10 % after oxygen-alkaline treatment in step I is treated with sulfuric acid in consumption of 5 % based on dry cellulose mass and pH 2.6-3.0. In step II peroxide treatment is carried out in alkali consumption of 1.0-1.3 % based on dry cellulose mass, and in step III pulp is treated with chlorine dioxide in consumption of 1.0-1.6 % based on dry cellulose mass at 70°C.

EFFECT: pulp with increased whiteness.

1 tbl, 17 ex

FIELD: pulp-and-paper industry.

SUBSTANCE: unbleached sulfate cellulose obtained from hardwood is subjected oxygen-alkali delignification, after which treated with chlorine dioxide in presence of oxyethylidenediphosphonic acid and then consecutively hydrogen peroxide and chlorine dioxide solutions. Process may be used in production of bleached fibrous intermediates.

EFFECT: increased whiteness and strength characteristics of cellulose and improved environmental safety of bleaching process.

2 cl, 1 tbl

FIELD: paper-and-pulp industry.

SUBSTANCE: cellulose delignification process comprises alkali treatment, delignification with hydrogen peroxide with sodium hydroxide and sodium silicate additive, and acid treatment. Alkali treatment consumes 0.5% hydrogen peroxide and 2.0% sodium hydroxide based on the weight of absolutely dry cellulose and is conducted for 2.0-2.5 h at 60-90°C. Acid treatment of delignified product is accomplished with aqueous hydrochloric acid, which is consumed in amount 1.0% based on the weight of absolutely dry fibers, while treatment is conducted for 30-60 min at ambient temperature.

EFFECT: enhanced economical efficiency without loss cellulose characteristics.

2 tbl, 11 ex

FIELD: textile, paper.

SUBSTANCE: method is referred to bleached wood pulp production from hardwood chips for their further use in different compositions for paper and cardboard production. Chipped wood is impregnated with alkali solution of sodium sulfite. Spent impregnating solution is then removed. Chipped wood is milled in two stages. In between components are treated by alkali solution of hydrogen peroxide at weight concentration 14-18% and final pH=9.5-10.0. Following the second stage of milling, pulp is dissolved to concentration 3.0-5.0% and cured during 30-60 minutes to pH=7.5-8.0. Pulp is chemically treated by alkali solution of hydrogen peroxide between milling stages at 75-85°C during 15-20 minutes.

EFFECT: decrease of chemicals consumption for impregnation and improvement of mechanical and optical properties of target product.

2 cl, 1 tbl, 4 ex

FIELD: paper industry.

SUBSTANCE: cellulose containing material from herbaceous plants is soaked in alkaline solution, washed, bleached, again washed, squeezed and dried. After soaking thermal-mechanical-chemical treatment is carried out in double-auger device, which consists of heated working chamber with impermeable wall and two parallel joined shafts arranged in it. Alternating injection auger and grinding cam tips are installed on shafts. At the same time prior to washing they additionally execute thermal-mechanical-chemical treatment in double-auger device, on shafts of which there are alternating injection and braking auger tips.

EFFECT: invention provides for cost-efficient method of cellulose making.

2 cl, 1 tbl

FIELD: chemistry.

SUBSTANCE: absorbent material is made by treating lignin-cellulose material in the presence of a catalyst from a transition metal with oxidation. The oxidising agent is selected from a group consisting of hydrogen peroxide, hypochlorite, hypochloric acid or any combination thereof. The lignin-cellulose material is treated at pH from approximately 2 to approximately 6. The treated lignin-cellulose material has viscosity equal to or less than approximately 17 cP. The treated lignin-cellulose material is subjected to dry grinding. The dry ground lignin-cellulose treated material is used as an absorbent intermediate layer for making absorbents.

EFFECT: improved bacteria inhibition properties.

2 cl, 17 ex, 16 tbl

FIELD: textile, paper.

SUBSTANCE: method relates to production of mechanical or chemical-mechanical wood pulp applied as raw material for manufacturing of paper or cardboard, and may be used and pulp and paper industry. According to this method wood pulp is exposed to fibrillation. Produced wood pulp is screened to separate wastes from acceptable materials. At the same time wastes are removed in amount of maximum 60% of overall amount of wood pulp. Wastes and acceptable material are bleached separately. Wastes are bleached with the help of peroxide or peroxy acid. After that bleached wastes are mixed with bleached acceptable material. After combination they are exposed to finishing grinding, at the same time amount of consumed energy makes approximately 10-1000 kW-hr/ton. Finishing grinding is carried out at low concentration. Then wood pulp is batched into paper- or cardboard-making machine. Wastes are bleached in alkaline medium.

EFFECT: improved strength of wood pulp and reduction of energy consumed for grinding.

12 cl, 1 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: method involves treating cellulose with sulphuric acid at the first step after oxygen-alkaline treatment. At the second step, peroxide bleaching is carried out in an alkaline medium in the presence of a stabiliser - magnesium sulphate. The third step involves treating cellulose with chlorine dioxide with its consumption not more than 0.5% for hardwood pulp and with chlorine dioxide consumption of 0.5-0.7% of the weight of absolutely dry cellulose for soft wood pulp. At the fourth step, cellulose is treated with hydrogen peroxide in an alkaline medium.

EFFECT: reduced consumption of chlorine dioxide, reduced corrosion of equipment and high environmental safety of the process.

1 tbl, 7 ex

FIELD: textile, paper.

SUBSTANCE: method is carried out by means of subsequent soaking of cellulose-containing herbal raw materials in alkaline solution, thermomechanical treatment, squeezing, washing, bleaching, squeezing, washing, squeezing and drying, besides, squeezing and washing are done in pulsating centrifuge.

EFFECT: higher yield of cellulose, reduced norms of consumption of initial reagents and water and reduced power inputs.

1 tbl, 3 ex