The effectiveness of paramagnetic separation to remove plutonium from soils from the Aldermaston (UK) site has been investigated and reported to the commissioners of the project, AWE plc, and also subsequently at the WM'05 Conference (Tucson, AZ). The results showed that plutonium can be effectively concentrated in soils using magnetic separation and size fractionation. The work also investigated other methods to enhance the separation process.

These approaches were:

• the use of sodium hexametaphosphate (ca. 1% by weight soil) to disperse the clay minerals;

• roasting to remove organic matter and to oxidise any organically-compIexed plutonium;

• ultrasonic vibration to break physical bonds between any plutonium oxide and soil particles;

• leaching of the <75mm fractions with selected reagents to extract plutonium.

As a result of this work, engineering concepts are being developed which will enable more than 95% of some of the AWE contaminated soils to be rated for free release.