Improving the Quality of Porous Silica Ceramics by the Method of Plasticization of Slurries for their Application in Thermal Protection Structures

Abstract

Objectives: The problem of producing a cellular ceramic from well-foamed slurries with low water content can be solved by introducing diluting additives - salts of sodium, potassium, lithium and organic plasticizers. Methods/Statistical Analysis: Suttard's viscometer was used to study the theology of silica slurries. The experimental data were processed by methods of mathematical statistics, using Student-Fisher criterion. It was established, that there are two different areas of concentration of diluents: effective (reducing the viscosity of suspension) and inefficient (increasing the viscosity of suspension). Findings: The experiments show, that in the case of concentrated siliceous suspensions siliceous inorganic diluents show the maximum water-reducing effect. This refers to salts based on lithium and sodium compounds (Na 4 P 2 O 7 , NaOH, Na 2 SiO 3 , Li 2 CO 3 , Na 2 CO 3 ), with their content not exceeding 0,5...0,75 %. The effect of the concentration of electrolytes on the viscosity index is described by complex processes associated with specific adsorption of ions (electrolytes are determined by the more complicated processes associated with the specific adsorption of ions). The purpose of this work is to determine the applications of the effective concentration of different types of diluents. Application/Improvements: Experiments and numerical calculations show that diluting effectiveness of the admixes in the suspensions of the gaize was achieved: for water-reducing effect 1.25…1.29; for reduction of water demand 20…22.6 %.