Influence of ceramic bonds on sintering process of biogenic silica
Katarzyna Konopka, Przemysław Kubiak, Ewa Bobryk, Mikołaj Szafran
Quarterly No. 1, 2010 pages 15-19
DOI:
keywords: biogenic silica, sintered material, nanoporosity
abstract Diatomaceous earth is the sedimentary rock formed by sedimentation of diatoms frustules through thousands of years. Diatoms are unicellular eukaryotic algae, which can be found in almost all aqueous and humid environments. They have unique morphology of skeletons with the pattern such as pores, ridges, areoles and other forms, and their cell walls are made of silica (hydrated silicon dioxide). Because of this specific morphology, diatoms are considered in nanotechnology. On the other hand, the wide application of the diatomaceous earth as building and abrasive materials, fillers and materials used for filtration or insulation results from the fact that this sedimentary rock is available in nature in large quantities and at a low cost. This rock is also easy to posses source of biogenic silica. Because of that diatoms have to be processed and sintered. The paper presents results of diatoms consolidation experiments. Especially the attention was made of influence the ceramic bonds on sintering process, degree of consolidation and preservation of the nanopores that naturally exist in diatoms. The bulk materials obtained by pressing and sintering were examined by scanning electron microscopy (SEM), the porosity and strength were estimated. Results showed that ceramic bonds help in sintering diatoms, sintered samples obtained at 900°C. Some naturally existed pores in diatom’s frustules were not closed. The results are important for the application of cheep biogenic silica.