Protactinium losses

Protactinium losses. The equilibrium Pa - concentration can be computed from the relationship... 

However, the quantity of Pa produced in this manner is much less than the amount (more than 100 g) that has been isolated from the natural source. The methods for the recovery of protactinium include coprecipitation, solvent extraction, ion exchange, and volatility procedures. AH of these, however, are rendered difficult by the extreme tendency of protactinium(V) to form polymeric coUoidal particles composed of ionic species. These caimot be removed from aqueous media by solvent extraction losses may occur by adsorption to containers and protactinium may be adsorbed by any precipitate present. 

Non-productive neutron absorption in the absorption zone, however, has a more serious effect. For example, protactinium is an intermediate stage between the thorium and the uranium isotope desired, and as far as is presently known is not fissionable. This element can cause a neutron loss in two ways. First, a neutron loss by 0Q the neutrons which Pa absorbs, and second, by formation of an element decaying into instead of into a known fissionable isotope. This effect however can be kept to a minimum by extracting the Pa from the slurry at sufficiently frequent intervals to reduce the ab-55 sorption by the Pa to about. 5 percent of the absorption by the thorium. 

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