The Mechanism Research Of The Influence Of White Mud On AKD Sizing When The Mud White As Paper Filler

In the paper-making industry, the white mud from alkali recovery was an important bulk solid wastes. Its high-value utilization was not only helpful for better utilization of resources, at the same time, also could be beneficial to prevent secondary pollution that made by the white mud. In many of resource utilization technology of white mud, white mud used as paper filler after refining was a kind of advantage prominent high value using way. However, when the white mud used as paper filler, there were some interference in wet chemical additive used process, especially for the AKD sizing agent, it would reduce the sizing efficiency. So that it restricted the substitution rate of precipitated calcium carbonate, and limited its range of application and utilization rate as paper filler.In order to improve the application performance that white mud used as paper filler, this study researched the effect mechanism of white mud on AKD sizing efficiency, so as to provide theoretical basis for the quality control of white mud,and promote the development of white mud used as paper filler.The main research results were as follows.There was some relationship between the content of AKD in paper and the sizing degree, but affected by the migration of AKD, part of the AKD in paper failed to complete the esterification reaction with fiber, and it could not produce water resistance, so the content of available AKD in paper can better explain the water resistance.Compared with the PCC, the adsorption of AKD on white mud would lead to a drop in AKD sizing efficiency, but the relationship between adsorption and AKD sizing efficiency is not necessarily. The content of available AKD was not only affected by the adsorption, but also affected by the migration of AKD.When the migration of AKD was less in the drying process, high adsorption ability of white mud may exhibit good AKD sizing efficiency. The adsorption of AKD on white mud calcium carbonate was given priority to the electrostatic adsorption, and the physical adsorption was supporting.The content of fine particles had obvious influences on AKD sizing, the content of fine particles was higher, the AKD sizing degree of the paper filled with white mud was lower. it’s mainly because the fine particles had strong adsorption for AKD and difficult retention, leading to the loss of AKD when fine particles lost so the content of available AKD in paper was reduced. The content of calcium ion in white mud calcium carbonate also had some effect on AKD sizing.Compared with the porosity, the amount of hole in the white mud had more important influence, the more holes, more prone to migrate. While the pore characteristics of white mud, it made the water molecular of white mud surface increasing, that would affect the orientation and fixation of the esterification product β-ketonic ester, thereby reduced the generation of effective AKD. When the paper filled with white mud was dried by a way with fast rate, the sizing degree of paper was higher; it’s good for improving AKD sizing performance of this paper to improve the drying temperature reasonably; after rapid curing, the sizing degree of the paper was higher, and rapid curing could reduce “sizing reversal” phenomenon.Controlling the adsorption of the white mud on AKD colloidal particles and reducing the internal hole number of the white mud could improve the quality of the white mud fillers effectively and the AKD sizing efficiency of the filled paper.Reducing the internal hole number of the white mud related to causticizing reaction, but controlling adsorption only simply add CS or PAE to the white mud.In comparison, the control of the AKD colloidal particles adsorption of white mud was more easily to be implemented. Under the experimental conditions, CS dosage was 0.05%, the sizing degree increased by about 39.3%; PAE dosage was0.2%, sizing degree increased by about 79.1%.