The authors examined the pretreatment of CST with sodium hydroxide to remove these components prior to placing the CST in radioactive service. Additionally, researchers analyzed solids discovered in the feed line during a test by non-destructive techniques. These tests provide the following conclusions. Sodium hydroxide, under column flow conditions, will elute the excess materials of manufacture. Sodium hydroxide concentrations of 3 M effectively remove silicon and Proprietary Material 1.
Lower concentrations prove less effective.
Volumes of sodium hydroxide needed to remove the excess materials of manufacture proved excessive for practical implementation in a single-pass flow operation. The tests showed no evidence of lead leaching from the sorbent as previously reported by other researchers. Hence, previous reports of lead leaching may represent errors from interpretation of the analytical spectra. The stability of these forms of silicotitanate proves important for the design of the pretreatment facility. These observations included discoloration of the salt solution, formation of hazy colloidal precipitates, and column pluggage.