Contribution to the mineralogy of acid drainage of Uranium minerals: Marecottite and the zippeite-group

An integrated study of uranyl mineral dissolution processes: etch pit formation, effects of cations in solution, and secondary precipitation

“…Minerals of the zippeite group occur proximal to oxidized uraninite and sulfide minerals [6,47]. For example, zippeite has been identified as the major U-mineral at the mine tailings sites at Key Lake, Saskatchewan, Canada (Kotzer and Schindler, pers.…”

“…These minerals are important in controlling the mobility of uranium in the contaminated subsurface. For example, the uranyl silicate, boltwoodite, and the uranyl phosphate, metatorbernite, have formed in contaminated sediments of the Hanford site [2][3][4], uranyl phosphates occur in contaminated soils of the Fernald site [5], and uranyl sulfates are common in altered mine tailings [6]. The interactions of these minerals with aqueous systems, and the details of how they dissolve and precipitate, are integral to understanding and predicting the mobility of uranium.…”

The recent weathering of uraninite from the Červená vein, Jáchymov (Czech Republic): a fingerprint of the primary mineralization geochemistry onto the alteration association

“…21). The water content was assumed to be equal to the ideal one determined by the crystal structure refinement (Brugger et al 2003), i.e. that needed for the charge-balance.…”

“…The obtained data allowed us to refine the unit-cell parameters giving reasonable results, similar to the published data. The unit-cell parameters were refined based on the Rietveld refinement algorithm, whereby the crystal structure parameters of Brugger et al (2003) of minute crystals. According to SEM, the pseudojohannite crystals are long prismatic and form multiple intergrowths (Fig.…”

“…Uranyl-sulfates are typical products of uraninite alteration in the acidic oxidizing environment (Ondruš et al 1997;Finch and Murakami 1999;Meisser et al 2002;Brugger et al 2003Brugger et al , 2006Plášil et al 2012a, b;Krivovichev and Plášil 2013;Plášil 2014). The sulfate-rich solutions, resulting from the decomposition of the primary sulfide minerals by descending oxidizing waters, are responsible for the migration of the uranyl ion (UO 2 ) 2+ under the low pH conditions (Fernandes et al 1995;Brugger et al 2003, and references therein).…”