Preparation method of modified bentonite particle retention aid for papermaking

Abstract

The invention relates to a preparation method of a modified bentonite particle retention aid for papermaking, comprising the following steps of: mechanically pulverizing mined natural bentonite into particles below 200 meshes, then dispersing the pulverized bentonite in water, and washing and sieving to remove impurities; adding an acid solution into bentonite suspension for reacting and then separating to remove the precipitated impurities; extruding and dehydrating the separated bentonite suspension, repeatedly washing and extruding until the pH value is 3-6.5; and finally, diluting and dispersing bentonite subjected to acidization with water, adding sodium salt for reacting and then diluting the bentonite suspension until the mass concentration is 0.01-5% to obtain the modified bentonite particle retention aid. In the invention, the adopted two-step modification method can be used for favorably removing the impurities in the bentonite so as to improve the content of the active ingredients in the bentonite, and in addition, the extrusion and dehydration treatment can be carried out before drying so as to improve drying efficiency and reduce production cost. The method benefits the improvement of the quality of the bentonite particle retention aid and use effect of the same in papermaking.

Description

technical field [0001] The invention belongs to the fields of chemical industry and papermaking industry, and in particular relates to a preparation method of a modified bentonite particulate retention aid for papermaking. Background technique [0002] In 1986, Langley, Litchfield and others studied the use of bentonite particles in the wet end of papermaking, marking the emergence of particle retention and drainage systems. This system has a very good retention and drainage effect on paper materials. Therefore, it has been rapidly promoted once it appeared. At present, most modern paper machines at home and abroad use this retention and drainage system. In this retention and drainage system, the modification method of the bentonite particulate retention aid is as follows: the natural bentonite is first washed with water, screened, and impurities are removed to increase the content of the active ingredient montmorillonite in the bentonite, and then, use sodium hydroxide or ...

AI Technical Summary

Problems solved by technology

But this modification method has the following disadvantages: one, the densities of natural bentonite and impurities such as fine sand are basically the same, and they are insoluble in water, so the separation of impurities is difficult, resulting in low active ingredient content; two, bentonite is modified by sodium After curing, the bentonite becomes a hydrated state and becomes a gel. Although impurities are easy to precipitate and separate at this time, the concentration of bentonite after sodium modification is generally only below 20%, and it cannot be dehydrated by extrusion. If it is directly dried, very high cost