E. R. Landa 1991 <p><span>A sequential extraction procedure was used to characterize the geochemical forms of&nbsp;</span>²²⁶<span>Ra retained by mixtures of quartz sand and a variety of fine-grained rock and mineral species. These mixtures had previously been exposed to the sulfuric acid milling liquor of a simulated acid-leach uranium milling circuit. For most test cases, the major fraction of the&nbsp;</span>²²⁶<span>Ra was extracted with 1 mol/1 NH</span>₄<span>Cl and was deemed to be exchangeable. However,&nbsp;</span>²²⁶<span>Ra retained by the barite-containing mixture was resistant to both 1 mol/1 NH</span>₄<span>Cl and 1 mol/HCHCl extraction.</span></p> application/pdf 10.1016/0304-386X(91)90010-J en Elsevier Leaching of 226Ra from components of uranium mill tailings article