Cements in waste management

Cement has been used extensively in nuclear and hazardous waste disposal for many years. Early attempts to incorporate constituents of high-level radioactive wastes during the clinkering stage had limitations due to the high processing temperatures employed and have now been superseded by low-temperature applications for less active and non-radioactive, industrial waste. Retention mechanisms for key heavy metals and metalloid ions in the cement matrix are reviewed and are shown to be irreversible in the majority of cases, provided a degree of physical durability is maintained. Quality control is often lacking, however, and there is an urgent need to establish performance standards and protocols analogous to those in the construction sector.