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Publikācija: Aluminium Silicates and Their Formation in the Rocks and Technological Products

Publication Type Publications in RTU scientific journal
Funding for basic activity Unknown
Defending: ,
Publication language Latvian (lv)
Title in original language Alumīnija silikāti un to veidošanās iežos un tehnoloģiskos izstrādājumos
Title in English Aluminium Silicates and Their Formation in the Rocks and Technological Products
Field of research 2. Engineering and technology
Sub-field of research 2.4 Chemical engineering
Authors Uldis-Jānis Sedmalis
Gaida Maruta Sedmale
Ingunda Šperberga
Keywords kyanite minerals, mullite, crystallic structures, molecular volume
Abstract Zināmi četri alumīnija silikātu minerāli – kianīts, andaluzīts, silimanīts, kuru kopējā formula ir Al2O3•SiO2 un mullīts, kura formula ir 3Al2O3•2SiO2. No tiem visbiežāk un tikai metamorfos iežos sastopami pirmie trīs nosauktie minerāli, kas izveidojušies augsta spiediena un temperatūras apstākļos. Mullīts kā minerāls iežos ir reti sastopams, jo mullīta molekulārais tilpums ir trīs reizes lielāks par kianīta grupas minerālu molekulāro tilpumu. Kianīta grupas minerālus pie normāla spiediena, neatkarīgi no temperatūras, tehnoloģiski iegūt nav iespējams. Savukārt, mullītu tehnoloģiski var iegūt augstās temperatūrās un tikai pie normāla spiediena, t.i. apstākļos, kad nepastāv molekulāro tilpumu ierobežojoši faktori. Rakstā dots arī mineralizatora klātienes nozīmes skaidrojums mullīta veidošanās procesā.
Abstract in English Four aluminosilicate minerals – kyanite, andalusite, sillimanite with common formula Al2O3•SiO2 and mullite, that have the composition 3Al2O3•2SiO2 are known. Naturally occuring most often and just in metamorphic rocks are the first three mentioned minerals developing under the high pressure and temperature circumstances. Mullite is rarely occuring as the mineral in nature because of mullite molecular volume that is three times bigger than molecular volume of kyanite group minerals. Structure forming motifs of the all kyanite group minerals are similar to kaolinite and other clay-mineral nucleus, as well as corundum, quartz and feldspar structural motifs. Besides mullite structure forming motifs are similar to the mineral kyanite group ones. It is shown that kyanite group minerals have formed in metamorphic processes, mainly from clay minerals and feldspar and most often are in association with corundum, quartz and other minerals with similar structural motifs. It is impossible to obtain kyanite group minerals technologically at normal pressure in spite of temperature. Besides mullite can be obtained technologically at high temperatures and just at normal pressure, t.i. under conditions when do not exist limiting factors of molecular volume. Explanation of the importance of mineralizer presence in the mullite forming process is given in this article as well.
Reference Sedmalis, U., Sedmale, G., Šperberga, I. Aluminium Silicates and Their Formation in the Rocks and Technological Products. Materials Sciences and Applied Chemistry. Vol.22, 2010, pp.83-87. ISSN 1407-7353.
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