The Ngakuru zeolites are located
about 20 km south of Rotorua and comprise a number of deposits dispersed along
several fault lines. Relatively recent volcanic activity (250,000 years ago)
resulted in ash depositions that vary in depth and mineralogy. Subsequent
variable thermal alteration intensities generated predominantly clinoptilolite
and mordenite zeolites with a range of physical characteristics.
Typically the zeolites have low
density (650 kg/m3), have high liquid (60% of dry weight) and odour
absorption characteristics, and a high affinity for soluble cations (CEC : 100
meq/100 g).
Traditional kitty litter and oil
absorbency markets are being expanded. New opportunities in waste and potable
water treatment, organic and synthetic slow release fertilisers, use as a light
weight aggregate for speciality concretes, and pozzalome activity are currently
being researched.