| 摘要 |
This invention relates to the purification of sand containing iron or iron compound impurities. The sand to be purified is contacted with concentrated hydrochloric acid which dissolves the impurities and the purified sand is freed from the unreacted acid and reaction products. This unreacted acid and the reaction products are then heated, giving hydrogen chloride gas and a decomposition product which is sent to waste. The hydrogen chloride gas is converted to concentrated hydrochloric acid which is then used to purify fresh sand.
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