Composition and properties of Kazakhstani diatomaceous minerals and synthesis on their base calcium silicates for building production

Abstract

The review covers existing modern technologies and researches on applying diatomaceous minerals as silicate additives to building materials. Specialists of industrially developed countries actively work in this direction and there are some of the works on the stage of implementation now. The article also describes researches of the authors on synthesis of calcium silicate and hydrated forms of ferro-calcium silicates using different kinds of Kazakhstani diatomaceous minerals from Zhalpak deposit (Aktobe region) as main siliceous component. Main topological and physical-and-mechanical characteristics of natural diatomaceous minerals were studied. It was found out that using thermally activated diatomite mixed with a plasticizing agent enlarges strength under compression and raises the brand of building materials while lowering water absorption and specific weight. It was observed that use of thermally activated highly ferriferous diatomite (20-30 % of Fe2O3) increases the strength of building materials dramatically. X-ray phase analysis of the samples of cubes from obtained composites exposed to semi-dry pressing with thermally activated ferrous diatomite followed by steam tempering showed that there were Ca(Fe, Mg)Si2 and FeAl2SiO5(OH)2 in their composition in the amount up to 1 mas. %.The technical characteristics of cubes of composition obtained with the use of thermally activated diatomite, in particular its highly ferriferrous forms, are completely meet requirements of inter-state standards GOST 379–95 to siliceous stones and bricks and sometimes overcome this norms. In future, the technology for obtaining the synthesized materials can become a base to organize new and to improve the existing industries producing dry building mixtures and strong silicate bricks in Kazakhstan.