Method of treating formation to remove ammonium ions

Abstract From the Canadian patent

Abstract of the Disclosure, A method of treating a subterranean formation which has undergone an in situ leaching operation which utilized an ammonium carbonate and/or bicarbonate lixiviant. In such a leach operation, ammonium ions will absorb onto the clay in the formation and will present a threat of contamination to any ground waters that may be present in the formation. The present method involves flushing the formation with a strong basic solution, e.g. sodium or calcium hydroxide to convert, the ammonium ions to ammonia which is easily carried from the formation by the basic solution. After substantially all of the ammonium ions are removed, the formation is then flushed with water to …