[1] Univ Hertfordshire, Ctr Engn Res, Sch Phys Engn & Comp Sci, Hatfield, England
[2] Univ Sheffield, Dept Mat Sci & Engn, Sheffield, England
[3] Autonomous Univ Madrid, Fac Sci, Dept Geol & Geochem, Madrid, Spain
[4] Paul Scherrer Inst, Lab Waste Management LES, Villigen, Switzerland