An economic evaluation has been made of the silica gel adsorption process for the separation of hafnium and zirconium. It is estimated that hafnium-free zirconium can be prepared at a cost of $7.10 per pound in the form of ZrOCl-2·8H-2O. This salt is satisfactory for the preparation of ZrF-4 by the Ames wet process.
Millard, W. R. and Maitland, R. H., "An economic evaluation of the silica gel adsorption process for the separation of hafnium from zirconium" (1952). Ames Laboratory ISC Technical Reports. 44.