Generally, in the formulation of refractory castables, the proportion of aggregate and refractory cement is about 80%, while the proportion of additives is less than 20%. Although the proportion of additives is only less than 20%, there are many types of additives including water reducing agents, plasticizers, gelling agents, degelling agents and other additives, and they play a vital role in refractory castables. effect. It improves the construction performance, physical performance and use performance of refractory castables. The method of using additives is to add them during or before the stirring of the refractory castable. The amount of additives added is proportional to the properties and functions of the refractory castables, and is a few ten thousandths to a few percent of the total.
Classified by chemical composition and nature of additives:
(1) Inorganic type: various inorganic electrolytes, some simple metals, a small amount of inorganic minerals, oxides and hydroxides.
(2) Organic type: Most of them are surfactants, which have hydrophilic and hydrophobic groups. Hydrophilic groups that can ionize in water are called ionic surfactants, and those that do not ionize are called non-ionic surfactants. The ionic surfactants can be divided into anionic, cationic and amphoteric surfactants. In addition, there are some polymer surfactants, organic acids, etc.
Next issue we will continue to introduce function and classification of additives in refractory castables. Please stay tuned.
