Reduction of Alkali Content in Nepheline Sludge for the Production of Heat-Resistant Insulating Materials From it

Abstract

The results of studies of the reduction of alkali metal oxides in nepheline sludge are presented. The alkali-containing phase is sodium hydroaluminosilicate. The methodology of the experimental studies involved the preparation of a water suspension with a given W:S ratio, mechanical stirring, heating, aging and separation of the pulp on a vacuum filter. Atechnology has been developed capable of reducing the alkali content by 21% of the initial amount of alkali, which has increased the melting temperature by 310°C. Based on the obtained results, pilot plant was designed and refractory heat-insulating materials were developed where the expensive mineral raw materials are substituted with non-scarce man-made waste.