SK278679B6 - Method of deinking the collected paper with surface active substances - Google Patents

Abstract

This patent describes the procedure closed to the deinking the collected paper with the use of surface active substances, where the collected paper is defibred in water and the mixture of the above mentioned surface active substances, together with 3 up to 25 moles of ethylene oxide, in a quantity 0,08 up to 0,55 weight percent related to stock, or alkylester of saturated or unsaturated fat acid C18, or oxyethyl alkyl phenol is added to this suspension, in the ratio closed to the value of 30 up to 50 : 70 up to 50 weight parts before the defibering is provided, and the released parts of printing colour are removed, with the use of the flotation, after the homogenisation and dilution of the suspension was provided however these surface active substances are prepared based on the condensates closed to the fat alcohol C12 up to C18.

Description

Technical field

The invention relates to a method of lightening waste paper with surfactants.

BACKGROUND OF THE INVENTION

Basically, waste paper lightening is a separation process that uses chemicals, heat, and mechanical energy to remove ink particles and toners from secondary fibers. The choice of equipment and chemicals for the lightening process determines the type of ink and the way the waste paper is printed. Primarily, it controls the size of the ink particles to be removed from the fibers. Large ink particles are removed by sieve and centrifugal screeners and small particles by blackmail. Flotation removes those particles that are too small to remove by sorting and too large to drift (Shrinath A., Szewczak JT, Bowen IJ, Tappi 74: 7, 85-93, 1991). The particles are 10 to 150 µm in size. Chemicals are added to pulping, flotation and washing.

In the prior art methods of lightening waste paper containing wood-based paper, such as e.g. newsprint, during pulping, add 0.8 to 1.5% NaOH, 0.5 to 2.0% H ₂ O ₂ , 1.0 to 3.0% sodium silicate and 0.15 to 0.4% chelating reagents up to a 5 to 15% fiber suspension (% by weight per fiber) at a temperature of 45 to 55 ° C to release the ink particles and prevent them from being redeposited onto the fibers (Ferguson LD, Tappi 75, 7, 75-83), 1992). Each chemical has a specific function. In the subsequent flotation, 0.25 to 1.5% of a suitable surfactant should be added to release the ink particles entrained by air bubbles to the surface and to wipe away from the bleached pulp. These are generally fatty acid soaps and more recently also ethylene oxide etherified wood and phenol-formaldehyde resins as well as ethylene oxide-propylene oxide copolymers based on fatty acids and their diamines. Often it is a mixture of substances that can already be added to pulping. The disadvantage of these processes is that an optimum amount of individual chemicals and surfactants must be determined for each lighted fiber while respecting their interaction and their cost / effect relationship. For example, silicates greatly increase the efficiency of cost-intensive hydrogen peroxide, but their use raises problems with the formation of deposits and deposits on equipment, sieves and felts.

After the dilution of the waste paper and the pulped suspension, float after dilution.

The luminous effect of this process is higher than that of a pulping process with a mixture of chemicals such as NaOH, H ₂ O ₂ , sodium silicate, chelating agent and subsequent soap flotation, is achieved at room temperature using a small amount of substances readily biodegradable and without problems which causes the use of silicate.

The method of lightening waste paper is exemplified by examples not specifically covered by this method.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

A suspension of 50 g of newsprint and 50 g of magazine waste paper in 5 L of water is pulped for 30 minutes. 100 ml of an aqueous solution containing 0.1 g of synthetic C ₁₂ to C 1.5 fatty acid condensates, 4.5 alcohols with 4.5 to 13 moles of ethylene oxide and 0.05 g of isobutyl oleate are added to the pulped suspension and, after homogenization for 10 minutes, 5 l of water are added. the released ink particles are removed by flotation. The fiber is lightened by 8% ISO. In the lightening process of the same waste paper mixture with the addition of a mixture of 1% NaOH, 1% H ₂ O ₂ , 2% Na ₂ SiO ₃ and 0.3% chelating agent to pulping at 40 ° C and 0.5% addition of the soap (% by weight per pulp) in the subsequent flotation, the pulp is lightened by 7% ISO.

Example 2

To a mixture of 65 g magazine and 35 g newsprint is added 5 liters of water and 100 ml of an aqueous solution containing 0.065 g of C ₁₂ to C ₁₅ fatty alcohol condensates with 3 to 25 moles of ethylene oxide and 0.065 g of oxyethylated nonylphenol. 7 l of water and the released ink particles are removed by flotation. The fiber is lightened by 8% ISO.

SUMMARY OF THE INVENTION

The above-mentioned disadvantages are eliminated by the process according to the invention, which consists in the fact that the recovered paper is disintegrated in water and into a disintegrated suspension with a content of 1 to 15% by weight. The recovered paper in water is treated with a mixture of surfactants based on condensates of fatty C ₁₂ -C ₁₈ alcohols with 3 to 25 moles of ethylene oxide in an amount of 0.08 to 0.55% by weight. or a saturated or unsaturated C 1-6 alkyl ester is added to the mixture ₈ to 30 parts by weight or oxyethylated alkylphenol in a ratio of 30 to 50: 70 to 50 parts by weight and the released ink particles are removed by flotation after homogenization and dilution of the suspension.

The mixture of substances can also be added directly to the pulperIndustrial applicability

The method of the invention can be used to remove ink from newsprint and magazine paper.

Claims (2)

PATENT CLAIMS A method of lightening waste paper with surfactants, characterized in that the waste paper is disintegrated in water and into a disintegrated suspension having a content of 1 to 15% by weight. waste paper in water was treated with a mixture of surfactants based on condensates of ₂ to C fatty alcohols wire 3 to 25 moles of ethylene oxide in an amount of from 0.08 to 0.55% by weight. the fiber or the alkyl ester is added to a mixture of saturated or unsaturated fatty acids and C _g oxyethylated alkyl phenol, in a ratio of 30 to 50: 70 to 50 parts by weight of the particles and the released inks, after homogenisation and dilution of the slurry to flotation. The method of lightening waste paper with surfactants according to claim 1, characterized in that the mixture of surfactants based on C ₁₂ to C ₁₄ fatty acid condensates is used. _{% Of} alcohols with 3 to 25 moles of ethylene oxide in an amount of 0.08 to 0.55 wt. the fiber or the addition of the alkyl ester of saturated or unsaturated fatty acid or C _ls with the addition of an oxyethylated alkyl phenol, in a ratio of 30-50: 70-50 by weight. 5 parts are added directly to the pulping.