The technology of synthesis of porous microgranular material based on diatomaceous clay is considered. The process of foaming microgranules in an industrial furnace was implemented in the way of obtaining granular foam-glass ceramic of coarse fractions. The main properties of microgranular foam-glass ceramic samples were investigated depending on the NaOH content in the charge, as a result of which its composition was optimized to obtain particles with a size of 75 ?m and a minimum content of particles sinking in water. The peculiarity of the porous structure of microgranular foam-glass ceramic makes it possible to obtain more durable lightweight grouting slurries in comparison with the traditional additive. The research results expand the range of materials made of foam-glass ceramic and the raw material base due to the more accessible for development deposits of diatomaceous clays in the arctic regions.