The Collaborative International Dictionary of English v.0.48:

Lixiviate \Lix*iv"i*ate\, v. t. [imp. & p. p. Lixiviated; p.
   pr. & vb. n. Lixiviating.]
   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.
   [1913 Webster]