Beneficiation of Olivine Foundry Sand by Differential Attrition Grinding.
U S Pat 4 039 625 1977 Aug; :
Olivine sand is produced from dunite rock. The latter is crushed and is subjected to wet, differential attrition grinding of sufficient intensity to finely comminute gangue. Hard olivine sand particles are rounded by grinding, but do not undergo any substantial size reduction. The finely ground softer gangue particles are separated by screening or hydraulic classification. Thus, the North Carolina dunite was crushed to -20 mesh and then slurried with water. The dunite-water slurry was treated by wet differential attrition grinding and beneficiation by using a screw classifier and hydroseparator. Recovery of the composite sand product was 67.2 Wt pct. The loss on ignition of the product was 1.2 pct, which was below the maximum 1.35 pct allowed by the SFSA standard.
U.S. Pat. 4,039,625; Aug. 2, 1977; Chem. Abstr. 88:157,118J