Partitioning of mercury from actinides in the TRUEX process

A mercury complexant, L-cysteine hydrochloride, was tested for use in separ ating Hg(II) from actinides during transuranic extraction (TRUEX) processin g of wastes at the Idaho National Engineering and Environmental Laboratory (INEEL). Mercury, americium, plutonium, and uranyl distributions for the TR UEX solvent were characterized over a nitric acid concentration range of 0. 01 to 2M with and without cysteine. The applicability of cysteine was evalu ated for selective Hg(II) complexation in an INEEL sodium-bearing waste sim ulant. A test was also conducted to evaluate the applicability of cysteine to separate Hg(II) from Sr in the strontium extraction (SREX) process with Sr Resin used as a stand-in for the SREX process solvent. In all cases, the use of L-cysteine HCl retained Hg in the aqueous phase while causing no or little perturbation in the actinide and Sr distribution behavior.