Prepn of high quality sand mixture for industrial use

摘要

Fine sand fraction with grain sizes of between 0-2 mm. is separated from the raw material which is fed into the plant. The fine fraction is made more compact and is fed in dosed amounts to a coarse mixture. The final mixture is then dried. As a further improvement grain sizes in the order of 0-0.25 mm. are separated from the fine sand. This fine sand is fed back into the original fine mixture in controlled amounts.