A mix composition has been developed making it possible to obtain on the basis of diatomite from the Inzenskoe deposit (Ul'yanovsk Oblast') a heat-insulating brick with good strength characteristics exceeding previous values by a factor of 4 -5: compression strength 5.5 -6.5 MPa, density 0.5 -0.6 kg/cm 3 , thermal conductivity at 25°C 0.09 W/(m × K), and structure factor 0.95.The abundance of amorphous silica rocks on Russian territory makes all work on obtaining from them building and finishing materials, heat-insulating brick, and artificial porous fillers for concrete very promising.There are many deposits of diatomite and opoka on Russian territory within Middle and Lower Povolozh'e. In Ul'yanovsk Oblast', deposits of diatomite have been explored at the Zinov'evka station (town of Inza) and other locations. According to the data of [1], the thickness of the Inza formation of diatomite reaches 55 m, and the opoka formation reaches 30 m. Heat-insulating firing articles in the form of brick, shells and segments, as well as open filler for concrete are produced by "Diatomit-Invest" JSC (Ul'yanovsk Oblast') on the basis of diatomite. Two types of heatinsulating brick are produced: foam-diatomaceous articles by means of the slip technology and diatomaceous articles obtained by introducing burn-out additives by plastic molding technology. The drawback of these articles is low strength.A mix composition making it possible to obtain on the basis of diatomite a strong heat-insulating brick whose strength characteristics are four to five times greater than previous such indicators (RF Patent No. 2909793) has been developed at the Kazan State Architectural-Building University.The raw material was Inza diatomite, which is amorphous silica and light, porous, and loose and slightly clayey in places, with the following properties: molding moisture content of diatomite -50 -60%, refractoriness -1450 -1560°C, water absorption -43.3 -66.7%, true density -2.15 -2.2 g/cm 3 , apparent density -0.70 -0.97 g/cm 3 , and total porosity 54.9 -67.5%.According to the data obtained by All-Russia Scientific -Research Institute of Geology and Interior of the Earth (Republic of Tatarstan), Inza diatomite is an opaline-cristobalite rock with an admixture of feldspar, muscovite, and glauconite and containing 30 -50% 3 active silica. The chemical composition of diatomite (according to the All-Russia Scientific -Research Institute of Geology and Interior of the Earth data) is as follows (%): 79.46 -84.98 SiO 2 , 4.43 -8.37 Al 2 O 3 , 0.75 -2.86 Fe 2 O 3 , 0.01 -0.29 FeO, 0.19 -0.41 TiO 2 , 0.45 -1.90 CaO, 0.47 -0.97 MgO, traces -0.02 SO 3 , 0.96 -1.25 K 2 O, 0.18 -0.98 Na 2 O, and 5.44 -6.59 other impurities.According to [2], 1.1 -1.5 m 3 sawdust and 550 -600 kg diatomite, which amounts to 35 -50% sawdust relative to the diatomite mass, is used per 1 m 3 of diatomaceous articles obtained by burning out additives. For this content of sawdust it is impossible to obtain brick with even edges, so that the finished bricks must be straightened out wi...
