Abstract
Calcium silicate hydrates were synthesized using fly ash as a silica raw material by hydrothermal reaction, and its filter aid property was studied.
The results were summarized as follows.
(1) Formation of hydrogernet was inhibited by adding alkali raw material, and aluminum content with raw material was introduced into tobermorite to form Al substituted structure. The sample synthesized with adding KOH was suitable for filter aid material. The sample synthesized with adding NaOH had stiff surface of secondary particles.
(2) Blain specific surface area increased with increasing of KOH content and its value drastically increased with increasing of NaOH content. The average filtration resistance of cake was more largely influenced by its Blain specific surface area than porosity.
(3) When large amounts the fine particle slurry were added to calcium silicate hydrates filter aid slurry system, the filtrate passage was preserved since it had large void volume.
(4) In the case of using the sample synthesized with adding KOH, filtrate became clear immediately. In the case of using the sample synthesized with adding NaOH, filtrate did not become clear since the fine particle slurry passed through filter material.
