MODIFICATION OF LIGNOSULFONATE WITH ENVIRONMENTALLY FRIENDLY MATERIALS

Abstract

To replace expensive and environmentally hazardous synthetic resins, lignosulfonate binders (LST) are used, a product of secondary wood processing, which is an environmentally friendly, non-scarce and relatively inexpensive material. Lignosulfonate is a water-based organic binder, which, according to the classification of A. M. Lyass, belongs to class B3, i.e. it has reduced strength properties both in dry and wet states. The presence of weak sulfite and carbonyl bonds on the surface of lignosulfonate does not allow it to be used alone as a binder. Lignosulfonate is used in the processes of manufacturing molds and rods as a component in a complex binder. Currently, the key directions for increasing the strength properties of lignosulfonate are either the addition of sulfo-groups by introducing anionic substances into mixtures, or the addition of water-soluble salts containing a polyvalent cation, which makes it possible to increase the highmolecular fraction in lignosulfonate. Thus, the modification of lignosulfonate consists in the purposeful introduction of special substances into the composition of the material, which make it possible to increase their binding capacity by changing the polymerization processes. By acting on lignosulfonate, it is possible to solve the problems of stabilizing the strength properties, increasing their reactivity, and, consequently, improving the binding ability, and, consequently, increasing the strength of molds and rods based on them. In addition to the strength properties, when modifying lignosulfonate, an equally important characteristic is the specific viscosity, and its reduction can positively affect transport transitions, that is, the transportation of lignosulfonate from one operation to another in the technological process, especially in winter. For wider use of lignosulfonate, it is necessary to ensure the required level of its properties, quality stability and possible modification of the manufactured product.