J. Dutrizac, O. Dinardo, S. Kaiman
1981
Citations
0
Influential Citations
21
Citations
Journal
Hydrometallurgy
Abstract
Abstract Selenate analogues of sodium jarosite and potassium jarosite have been produced by precipitation from aqueous solution; it is concluded that selenate analogues probably exist for the nine known jarosite-type compounds. The selenium compounds possess the ( R 3 m ) structure of their jarosite analogues, although the unit cell dimensions are somewhat larger. During jarosite formation, sulphate and selenate are precipitated in approximately the same ratio as they are present in solution; also, the unit cell parameters of the mixed sulphate—selenate compounds increase linearly with increasing selenium concentration. The thermal decomposition behaviour of the selenate analogues is generally similar to that of sodium or potassium jarosite. Initially, water is evolved and subsequently selenium oxides are emitted. The selenium oxides are, however, evolved at a lower temperature (400–450°C) than for their sulphur counterparts, and the two weight-loss reactions tend to overlap slightly for the selenate analogues.