What is to subject to a washing process for the purpose of separating soluble material from that which is insoluble; to leach, as ashes, for the purpose of extracting the alkaline substances called?

lixiviate — To subject to a washing process for the purpose of separating soluble material from that which is insoluble; to leach, as ashes, for the purpose of extracting the alkaline substances. (Webster's 1913.)

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