Particles fabrication by chemical process for hazardous waste management
As an alternative to the waste solidification/stabilisation technology applied to cement sludge mixtures, granulation technology seems to meet the requirement of easy handling, transport by pneumatic conveyor and heat treatment to improve the leaching resistance and decompose organic hazardous wastes. In the present report, a method for the fabrication of granules prepared in the aqueous phase is described. Powders or aqueous suspensions were blended with carbohydrate compounds such as methylcellulose, hydroxypropyl methyl cellulose or hydroxybutyl methyl cellulose. Drops of slurry were formed in a column containing an alkaline hydroxide solution. Chromium was chosen for immobilisation because of the similar chemical amphoteric behaviour of actinides in the presence of a highly alkaline solution, forming insoluble hydroxide compounds. The advantage of this method is that it controls the dimensions of spheroidal particles by a choice of the process parameters such as concentration of additives, suspension temperature and diameter of injectors. Granules of cement or clay with chromium, simulating waste generated in tanning or electroplating factories, were prepared and calcined on N(2)-5% H(2) gas to stabilise a Cr(3+) compound. Physical properties and a leach test in water renewal were performed on gas reduced particles put in a closed system in 100 ml of distilled water at a solid surface-to-liquid volume ratio S/V(L) below 0.1/cm. The chemical analysis of the liquid fractions indicates a very good immobilisation of Cr(3+) in the spherical particles.
Bibliographic Reference: Paper presented: 15th International Symposium on the Scientific Basis for Nuclear Waste Management, Strasbourg (FR), Nov. 4-7, 1991
Availability: Available from (1) as Paper EN 36468 ORA
Record Number: 199111552 / Last updated on: 1994-12-02
Original language: en
Available languages: en