Ceramicrete binder

According to ANL, the cost of the Ceramicrete binder is 10 to 12 cents per ponnd when apphed at 70% loading. The iron-containing ferroceramicrete binder costs 3 to 4 cents per ponnd with the same loading ratio (D22652I, p. 7). 

Five-gallon size waste forms were fabricated. Typical waste loading was 35-40 wt%. A small amount of potassium sulfide was added to the Ceramicrete binder mixture for stabilization of Hg, and dense and hard ceramic waste forms were produced. Just before solidification, TCLP results were obtained on small aliquots of the mixing slurry that was separated and allowed to set. Mercury levels in the leachate were found to be 0.05 /rg/1, well below the LfTS limit of 0.025 mg/1. The entire waste was treated, removed from the inventory, and sent to the Radioactive Waste Management Complex at the Idaho National Engineering and Environmental Laboratory for disposal. 

Researchers state that Ceramicrete technology is a low-cost, low-tech process. The technology nses almost the same eqnipment as that nsed in the cement indnstry. The binder powders are more expensive (approximately 50%) than cement, bnt ANL scientists estimate the cost of treating low-level mixed waste is less than 50 cents per ponnd (D177495, p. 5). 

Commercially available pure KH2PO4, when reacted with MgO, produces high quality ceramics [4]. This raw material is comparatively more expensive than other hydrophosphates, but a very large proportion of fillers can be incorporated in the ceramic formation and hence the net cost of the binder components in making products is less. The binder formed by reaction of KH2PO4 and MgO has been studied extensively at Argonne National Laboratory and is named as Ceramicrete . Details of Ceramicrete are discussed in Chapter 9 and its subsequent applications from Chapter 14 onwards. 

Though the open porosity in the ash-containing Ceramicrete is very low, the matrix has a significant amount of closed or isolated pores. Estimates, based on the densities of individual minerals formed in the final products, show that the closed porosity is =20 vol%. Coupled with this closed porosity, a significant amount of bound water (typically 15 wt%) in the binder component makes this cement lightweight. 

As Table 15.3 indicates, the heat offormation of Ceramicrete-based permafrost cement is typically 50-60% of the heat of formation of conventional cement. Even though the acid-base reaction is highly exothermic, i.e., it releases a significant amount of heat during setting. In CBS compositions, the binder that produces heat is only a part of the entire CBS formulation, and the remaining components are extenders. Thus, the net amount of heat generated is about half that in the equivalent amount of conventional cement. 

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