A method of obtaining a putty cement additive that provides Polymineral clay rocks (refractory clays, argillites, Thermal modification of clay shales by heating at a temperature of 600-800 0C, with a delay of 1-1.2 hours at the maximum temperature and further cooling,
differs in that they cool quickly, in cold air flow at a rate of 5-10 m / s by decreasing the temperature of the fired rock at a rate of 30-35 oC / min.