Paper is an indispensable consumable in daily life. The amount of paper is huge. The more paper is consumed, the more paper mills will increase their production capacity to meet demand. The sewage discharged from paper mills will also increase, and the pollution to the environment will also increase. Bigger. At this time, polyacrylamide PAM is needed to treat wastewater from paper mills.

Polyacrylamide for paper mill

Water quality characteristics of paper mill

Papermaking wastewater has high COD and suspended solids (SS) content and serious color. The concentration of SS and COD in papermaking wastewater is relatively high. COD consists of two parts: insoluble COD and soluble COD. Generally, insoluble COD accounts for most of the total COD composition. When SS in wastewater is removed, most Insoluble COD is removed at the same time. Therefore, the main problem to be solved in waste paper and papermaking wastewater treatment is to remove SS and COD.

Approach

Using air flotation or precipitation method, by adding polyacrylamide, most of SS can be removed, while most of insoluble COD and partially soluble COD and BOD can be removed.

Polyacrylamide

The role of PAM in paper mills

Polyacrylamide PAM is widely used as a retention agent, filter aid, leveling agent, water treatment, etc. in the papermaking field. Its function is to improve the quality of paper, improve the dewatering performance of the slurry, increase the retention rate of fine fibers and fillers, and reduce the consumption of raw materials and environmental pollution. The effect used in papermaking depends on its average molecular weight, ionic properties, ionic strength and the activity of other copolymers. Non-ionic PAM is mainly used to improve the filterability of pulp, increase the strength of dry paper, and increase the retention of fibers and fillers; in addition, PAM is also used in papermaking wastewater treatment and fiber recycling.

Anionic polyacrylamide

Selection of Wastewater Treatment in Paper Mill

When selecting polyacrylamide for wastewater treatment in a paper mill, the choice should be based on water quality. In the case of the same amount of use, the ion product used should be selected according to the pH value. If the PH value is below 5.5, cationic polyacrylamide can be used; if it is higher than 7, anionic polyacrylamide can be used; if it is between 6.5-7.5, non-ionic polyacrylamide can be used. If it is white water, it is usually better to use weak cationic products.

Precautions

1. The water used to dissolve paper-making polyacrylamide must be tap water, clean water;

2. The water for dissolving paper-making polyacrylamide must be at room temperature, and the water temperature should not be higher than 60°C. Although high temperature can increase the dissolution rate, high temperature will cause paper-making wastewater treatment polyacrylamide to degrade and cause performance degradation;

3. When matching, you must choose a certain concentration ratio, generally more than one thousandth, and higher than three thousandths.

4. When dissolving, the stirring time is generally about 45 minutes.

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The types and stages of polyacrylamide for papermaking wastewater used from paper mills are widely used in water treatment in the papermaking field. Its role is to reduce the consumption of raw materials and pollution to the environment. The effect used in papermaking depends on its average molecular weight, ionic properties, ionic strength and the activity of other copolymers. Cationic polyacrylamide is mainly used for the treatment of papermaking wastewater and filtering aid. In addition, it has a good effect on improving the retention rate of filler.

The papermaking wastewater contains high levels of COD and suspended solids (SS) and serious color. The concentration of SS and COD in papermaking wastewater is relatively high. COD is composed of two parts: insoluble COD and soluble COD. Generally, insoluble COD accounts for most of the total COD composition. When SS is removed from the wastewater, most of it Insoluble COD is also removed. Therefore, the main problem to be solved in waste paper and papermaking wastewater treatment is to remove SS and COD.

Anionic polyacrylamide for paper mill wastewater, with a molecular weight of about 14 million. Main application: wastewater precipitation.

Cationic polyacrylamide for paper mill wastewater, with a molecular weight of about 12 million. Main application: sludge dewatering.

Types and stages of Polyacrylamide for papermaking wastewater from paper mills. The effect used in papermaking depends on its average molecular weight, ionic properties, ionic strength and the activity of other copolymers. A combination of physicochemical and biochemical treatment is adopted. The general physicochemical and biochemical treatment methods are wastewater → screen → adjustment → precipitation or air floatation → A/O or contact oxidation → secondary sedimentation tank → discharge. In this treatment process scheme, cations are used Polyacrylamide to treat sewage.

Papermaking and papermaking wastewater flocculation and sedimentation treatment of anionic polyacrylamide flocculant, sludge dewatering cationic polyacrylamide flocculant pam, papermaking dispersion of 16 million to 18 million molecular weight polyacrylamide flocculant, papermaking retention retention and filtration quality imported polyacrylamide.

In the papermaking process, the paper fibers and fillers in the pulp are hydrophobic and tend to flocculate into agglomerates, and it is often difficult to produce paper with uniform performance and strength that meets the requirements. It is necessary to add an auxiliary agent to increase the viscosity of the pulp, so as to facilitate the even dispersion of the fibers and fillers, so that the paper produced is even and smooth and flexible without holes, so that the performance of the papermaking is stable, and it is not easy to break the paper and raise the powder during the papermaking. Improve the tensile strength and dry and wet strength of paper products and save paper pulp. The added additive is called paper dispersant.

Paper-making dispersant has high dispersion efficiency, stable coating viscosity, less foam, non-toxic and non-corrosive, can improve the solid content of the coating, and has good fluidity and scrub resistance, can maintain the gloss of the paper product, and is not easy to mold. Paper-making dispersants can also increase the speed of papermaking, save beating time, reduce energy consumption, and have significant economic benefits. It has the characteristics of pyrolysis, its viscosity decreases rapidly with increasing temperature, good water solubility, high viscosity, and good lubricity, so as to ensure that it does not affect the performance of the original fiber in the dried paper. The product is a water-soluble organic polymer, which is easily soluble in water and forms a high-viscosity liquid. It can promote good dispersion of papermaking fibers and excellent paper forming effects at low addition levels, improve pulp uniformity and paper softness , Can also increase the strength properties of paper.

The Papermaking dispersant can show good fiber dispersion effect in a very small amount of addition (less than 1kg per ton of dry pulp). The product is non-ionic, relatively less affected by water quality and other additives, and has stable papermaking performance, and is not easy to break paper and powder. Its advantage is that it can improve the softness and uniformity of the finished paper. The principle of the dispersant is to distribute the solid fine particles as evenly as possible in another incompatible material. That is to say, the internal phase is a coarsely dispersed system composed of insoluble particles distributed in the external phase being liquid or semi-solid. The dispersant can make the solid dispersed particles in the suspension fully wetted and evenly dispersed by the liquid phase, and minimize the separation, aggregation and settling speed of the solid particles in the system to maintain the maximum kinetic stability of the suspension.

Papermaking dispersant can also increase the speed of papermaking, save beating time, reduce energy consumption, and has significant economic benefits. Papermaking dispersants are currently widely used in the production of low-quantitative paper such as toilet paper, newsprint, cigarette paper, tea filter paper, liner paper, napkins, colored crepe paper, electrolytically soluble paper, and electrostatic copy paper.