Modification of porous anhydrite compositions with carbon nanostructures

Abstract

Fluorine-anhydrite deposit was used to produce porous anhydrite compositions. Aluminum powder combined with alkaline additive, being at the same time the activator of anhydrite solidification, was used as a gas-former. Carbon nanostructures were used as structure modifiers as well as to improve physical-mechanical properties of porous anhydrite compositions. The additive represented the product with the density of 0.086 g/cm3 containing carbon nanoformations of various morphologies, and it was added to the composition in the amount of 0.05 percent from the anhydrite mass. Being distributed in the volume of porous anhydrite compositions, carbon nanostructures act as centres of directed crystallization, thus leading to the formation of fibrillar structure within the pore walls, and providing its continuity and uniformity. Besides, the formation of structure-oriented permolecular envelopes around nanosystems with the formation of gypsum crystals with concave dome-like structure was observed. When porous anhydrite compositions are modified with carbon nanostructure additive, the increase of mechanical strength by 19 percent, structure stabilization by pore sizes and shapes as well as the decrease in heat conductivity and gas-anhydrite average density are achieved.