Process for comprehensive use of fly ash

摘要

1,248,416. Beneficiationofflyash; pozzolanic compositions. ENERCON INTERNATIONAL Ltd. 29 Nov., 1968 [4 Dec., 1967], No. 56919/68. Headings C1A and ClH. [Also in Division B2] A process for the complete beneficiation of fly ash comprises the following steps in any order: (i) air classification to recover a pozzolanic material of extremely fine and uniform particle size wherein at least 85% by wt. passes a 325 (USS) mesh screen; (ii) dry-screening to recover a coarse carbon-containing material containing a minimum of 25% by wt. of carbon; and (iii) magnetic separation to recover an iron concentrate product. The product left after these steps have all beeen carried out is suitable for agglomeration, optionally in admixture with some of the pozzolanic product, by moistening, pelletizing and sintering at 1900‹ F. to 2800‹ F. The pozzolanic product should be treated by magnetic separation to remove the iron therefrom before use in concrete. Variation of the screen-mesh size in step (ii), changes the relative proportions and carbon contents of the products obtained.