In the process of papermaking, a large amount of foam is likely to appear in the pulp, which will affect the quality of the paper and reduce the effect. The foam can be defoamed by adding a paper pulp defoamer. This article analyzes the causes of foaming and stability of paper pulp, and gives solutions for defoaming.
(Picture: The role of paper pulp defoamer)
The reason why paper pulp is easy to foam and stabilize
Foam is a dispersion system in which the gas phase is dispersed in the liquid phase. The gas phase is free air and the carbon dioxide liquid phase is water. The formation of foam is due to the presence of surface-active substances in the liquid phase (water). If there are no surface-active substances in the water, even though the foam is formed, it will not be stable, and will quickly collapse on its own.
Reasons for blistering
In the process of pulping and papermaking, if there are fatty acid soap, rosin soap and lignin derivatives in the pulp, or the pulp contains residual sulfurous acid waste liquid, sulfate waste liquid or its residual alkali is high and poor washing or the slurry is added Chemicals such as sizing agents and retention and drainage aids are likely to form relatively stable foam.
The characteristic of these types of substances is that their molecular structure is asymmetry. The molecule is composed of a polar part and a non-polar part. The polar part is hydrophilic and the non-polar part is hydrophobic. The polar part of the foam is in the water, while the non-polar part is in the air.
Reasons for foam stability
From the point of view of colloidal chemistry, such surface-active substances act as stabilizers. The main reason is that such surface-active substances can reduce the surface tension of liquids. The surface tension is low, and the energy required to form a new interface is small. Therefore, the same work of moving the gas into the paper material system allows the formation of a larger surface area and causes more small foams. Small foams have greater stability than large foams; therefore, in waste liquid treatment or pulping In the papermaking process, these small foams are particularly difficult to remove due to the presence of such surface active substances, which act as a stabilizer.
(Picture: Causes of foaming and stability of paper pulp)
Paper pulp defoaming plan
In the process of papermaking, due to the fact that the raw materials in the pulp contain surfactant substances, it is easy to produce a large amount of foam. Paper pulp foam will affect the quality of paper and affect production efficiency. The harmful foam can be eliminated by adding defoamers.
The Nanhui defoamer manufacturer has developed and designed the paper pulp defoamer for paper pulp which is easy to produce foam and stable. Adding to paper pulp can quickly disperse and reduce the surface tension of the system. It can be quickly dispersed in water to eliminate foam.
(Picture: Nanhui Paper Pulp Defoamer provides free samples)
