Disposal of heavy metal-contg. solids and liquids - using hydraulic binder giving low water permeability prod.

摘要

In the immobilisation and consolidation of heavy metal-contg. solids and liq. using an at least latent hydraulic binder, extremely low elutriation' and low water permeability are achieved by using a binder comprising (a) an at least latent hydraulic silicate component (flyash, boiler ash, slag or the like) of below 100 microns particle size, at least 80 wt.% of the particles being below 40 microns size; (b) an alkaline and/or alkaline earth component based on CaO, Ca(OH)2, MgO and/or Mg(OH)2, as activator for the latent hydraulic component; and (c) anhydrous or hydrated calcium sulphite and/or calcium sulphate; the wt. ratio (a):(b+c) being 60-92:8-40 and the (b) content being at least 3-5 wt.%. This binder is mixed in the wt. ratio 20-60:40-80 with the material to be disposed of, at a water content of 15-32 wt.% (based on the hydrated phase-forming substance), and the mixt. is compacted and then hardened. ADVANTAGE - A consolidated product with a lower water permeability than in prior art is obtained at a lower binder cost.