Process for agglomerating expanded perlite fines
AssigneeGeneral Refractories Company
InventorsJohn B. Gilmour, Praful K. A. Mehta, Melvin J. Mirliss, Richard B. Nielsen
Life of this patent
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Abstract
Expanded lightly milled perlite fines are mixed with aqueous alkali metal silicates and the wet mixture is dried at temperatures of from 600.degree. F up to 1400.degree. F in a moving air stream to form agglomerates which are useful as filteraids. The agglomerates may be heat treated in an indirect fired rotary kiln to further reduce the water solubility, and may be separated into size factions either before or after the heat treatment.
Claims6
A process for producing an improved perlite filter aid which comprises mixing finely divided expanded perlite particles with an aqueous solution of alkali metal silicate to form a composition having perlite:
- alkali metal silicate:
- water in the ratio of about 100:1:5 to about 100:10:100, removing the free moisture and drying the mixture by suspending said composition in a moving gas stream at a temperature of from about 600.degree. F to less than about 1400.degree. F, whereby the perlite particles form dry agglomerates, and heat treating said dry agglomerates by indirect firing at about 1100.degree. to about 1300.degree. F to increase the water insolubility of the agglomerates.
Dependencies are inferred from the claim text.