US4804422A - Method of purifying quartz sand - Google Patents
Starting from pegmatitic sand, the invention provides a method of purifying quartz sand, in which the amount of iron is reduced to less than 0.3 ppm, the amount of zircon to less than 1 ppm, and the amount of phosphor to less than 0.2 ppm. Gas nuclei are also removed. The method is carried out by washing with solution which contains at least 15% by weight of HF in water until at least 40% by ...
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