POLYMER ENCAPSULATION OF ARSENIC-CONTAINING WASTE

The potential for encapsulation of arsenic waste by combination with t wo commodity polymers was evaluated. Initial studies employed nontoxic substitutes, these being gypsum and calcium carbonate, with host poly mers being predominately a recycled grade of polyethylene (PE) and a s ynthetic elastomer. The latter was used at low processing temperatures with rather volatile arsenic compounds. The gypsum caused processing difficulties due to evolved water, but the CaCO3 was able to be readil y combined at high volumes. Arsenic trioxide was able to be incorporat ed at modest levels in PE and was less successfully combined with the rubber. However, the higher processing temperatures needed for PE caus ed the As2O3 to sublime. Less volatile calcium arsenite, readily prepa red from As2O3, was able to be mixed at high volume ratios with the ru bber, although processing with PE was less successful. These results m ay be used in conjunction with other methods for stabilization and wou ld be applicable to other forms of medium- to high-level waste. (C) 19 95 John Wiley & Sons, Inc.