Zinc Patent Granted in the USA

1 August 2013

Alexander Mining plc

('Alexander' or the 'Company')

Patent Granted in United States for a Method for Extracting Zinc from Aqueous Ammoniacal Solutions

Alexander Mining plc is pleased to report that it has received notification that its MetaLeach Limited ("MetaLeach") subsidiary has now been granted a patent in the United States for a Method for Extracting Zinc from Aqueous Ammoniacal Solutions. The patent, number 8,323,596, has a standard term of twenty years from the effective date of 22 December 2009 (being the date of original filing of the PCT Application from which the United States patent is derived).

The patent, which has also been granted in Australia and Mexico (as announced on 10 September 2012 and 8 April 2013, respectively), describes a method for extracting zinc from an aqueous ammoniacal zinc solution containing impurities; the granted claim is as follows:

A method for extracting zinc from an aqueous ammoniacal zinc solution containing impurities, the method comprising the steps of:

i. contacting the aqueous ammoniacal zinc solution containing impurities with an organic phase comprising an ammonium salt of an organic extractant dissolved in a hydrophobic diluent, allowing transfer of the zinc to the organic phase and transfer of ammonium to the aqueous phase, thereby providing a zinc-enriched, ammonium-depleted organic phase and an ammonium-enriched, zinc-depleted aqueous phase containing impurities;

ii. separating the zinc-enriched, ammonium-depleted organic phase from the ammonium-enriched, zinc-depleted aqueous phase containing impurities;

iii. contacting the zinc-enriched, ammonium-depleted organic phase with an aqueous solution containing positively charged species, allowing transfer of the zinc from the organic phase and transfer of positively charged species from the aqueous phase, thereby providing an aqueous zinc solution and an organic phase containing a zinc-depleted organic extractant; and

iv. recovering the zinc from the aqueous zinc solution.

ENDS

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