Sulphate removal

BioteQ Environmental Technologies has joined up with Freeport McMoRan to construct and operate a demonstration plant for the removal of sulphate.

BioteQ Environmental Technologies has joined up with Freeport McMoRan Copper and Gold to jointly engineer, construct and operate a demonstration plant for the removal of sulphate and other dissolved solids at the Sierrita copper mine site in southern Arizona.

The plant, to be constructed in 2008, which will use BioteQ’s proprietary Sulf-IX ion-exchange technology, is anticipated to have a total capacity of 125 gallons per minute. The Sierrita project will be the first large-scale application of BioteQ’s Sulf-IX process.

To make it happen, BioteQ will license its technology to Freeport McMoRan and provide the process on an on-going license basis. Freeport McMoRan will use the demonstration plant to evaluate whether the technique is suitable for any of its other sites.

The Sulf-IX ion exchange process itself is a two stage process employing two different resins to remove calcium and sulphate ions (Ca2+ and SO42-) from water. The resins are regenerated using the low-cost reagents, sulphuric acid and lime, so that the only products of the process are clean water that can be discharged or re-used, and a solid gypsum product that can be used in building products and fertilizer production.

Gypsum is non-toxic and forms under atmospheric conditions, which is in contrast with conventional membrane processes for sulphate removal that require the energy intensive formation of solid crystals and their subsequent disposal in licensed depositories.

The process is claimed to have several potential advantages over other sulphate removal technologies, such as reverse osmosis, including lower capital and operating costs, and elimination of a residual product that would require either further treatment and/or costly disposal.