Dibutylbutyl phosphonate

In the early years of plutonium scrap processing operations, the CAW stream was routed to trenches(1 ) specially excavated in Hanford soil. Batch recovery of americium was started in 1965. Later (1970-1976), a continuous countercurrent solvent extraction process employing DBBP (dibutylbutyl phosphonate) as the extractant was operated to recover, at least partially, plutonium and americium values from the CAW stream. Aqueous waste from the DBBP extraction process, still containing some plutonium and americium, was blended with other Plutonium Reclamation Facility (PRF) wastes, made alkaline, and routed to underground tanks for storage. 

There are also thorium recovery processes based on extraction from sulfuric acid solutions, e.g., with primary, secondary, or tertiary amines or alkyl phosphorous acids such as bis-2-ethylhexyl phosphoric acid (HDEHP) or dibutylbutyl phosphonate (DBBP). Thorium is then stripped into a nitric add solution. The alkyl phosphorous acid processes are often employed when recovering thorium as a by-product in uranium production. 

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