In the leaching experiment, it is difficult to flow out simply with clay solution, so some quartz sand should be added. Because the adsorption of organic or inorganic impurities on the surface of quartz sand will affect the composition of leachate, it is necessary to remove impurities by pickling.
The pickling method is to soak quartz sand in 4mol/L dilute hydrochloric acid for 24 hours, then wash it to neutrality, dry it, and sieve it with 0.5- 1 mm for later use.
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