Modified sulphur cement : A low porosity encapsulation material for low, medium and alpha waste
Modified sulphur cement, available under the trade name Chement 2000, is a thermoplastic candidate material for the matrix of low, intermediate and alpha radioactive waste. The main source of sulphur is the desulphurisation of fossil fuels. In view of the future increase of this product a modified compound of sulphur has been developed at the US Bureau of Mines. Modified sulphur cement as matrix material has properties in common with Portland or blast furnace cement and bitumen. The mechanical strength is comparable to hydraulic cement products. The process to incorporate waste materials is identical to bitumisation. The leachability and the resistance to attack by chemicals is nearly the same as for bituminised products. This study showed also that the radiation resistance is high, without radiolytic gas production and without any change in dimensions (swelling). The rigidity of the matrix is a disadvantage when internal pressures are built up. The thermal conductivity and the heat of combustion of sulphur is low, resulting in slow damage to the waste form under fire conditions, even when the temperature of self ignition in air is 220 C. The low leachability, the very slow effective diffusion of H(2)0 and HTO, and the low permeability are due to the small pore diameters in the modified sulphur matrix. The loading capacity of modified sulphur cement depends on grain size and distribution and is for ungraded ashes, precipitates dried sludges, etc., in the order of 40-50% of weight. The price of `Chement 2000' per tonne is equal to those of blown bitumen.
Bibliographic Reference: EUR 12303 EN (1989) FS, 150 pp., ECU 12.50
ISBN: ISBN 92-826-0802-6;CD-NA-
Record Number: 198911192 / Last updated on: 1994-12-01
Original language: en
Available languages: en