Aluminosilicates of alkaline earths

From the economical viewpoint, the known methods of the preparation of these compounds are insufficiently effective. As a rule, they are synthesized by solid-phase methods from ordinary or complex oxides by heating the mixtures at high temperatures (1100 - 1400°C) for a long time (100-185 h). 

Cordierite. This material possesses a rare combination of properties, i.e., relatively high strength and hardness, low thermal expansion coefficient, high heat conductivity and plasticity it conserves mechanical strength under thermal shocks. Therefore, its application areas are varied. 

Cordierite synthesis method based on mechanical activation of mixtures of hydrated oxides of calcium, aluminium and silicon, as well as natural hydrated compounds (talc, kaolinite and gibbsite), has been developed in [2, 3]. Mechanical activation of these mixtures does not lead to the formation of new phases but provides good mixing at the cluster level giving aggregates that form cordierite during the subsequent thermal treatment. 

202 nm) are observed in the patterns. When the mixture of hydroxides is used, the diffraction patterns contain the reflections of magnesium silicates  

194 nm) and forsterite Mg2SiOa (0.173, 0.244 nm), besides the reflections of the final product (cordierite). This means that the reaction in the mixtures of hydrated oxides follows the route different from that in the mixture of anhydrous oxides. At first, magnesium and aluminium hydroxides interact with each other to give double oxides, the latter reacting with alumosilicate to form cordierite  

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