关键词:
A1. Cocrystallization
A1. Distribution coefficient (Henderson–Kraček, Chlopin)
A1. Impurities
A1. Purification
B1. Zinc selenate hydrates selenates
摘要:
Abstract: Coefficients, D2/1 (Henderson, Kraček, Chlopin) of cocrystallization of low amounts of M2+ ions (M2+={Ni2+, Cu2+, Co2+, Mg2+, Mn2+, Cd2+}) with ZnSeO4·5H2O at 40°C and ZnSeO4·H2O at 50°C have been determined. Their values are very diverse, ranging from 0.12 (for Cu2+ at 50°C) to 1.87 (for Co2+ at 50°C) and generally differ significantly from those obtained at 25°C. Apart from the change of the solubility ratio of cocrystallizing selenates (m 01/m 02) they are very strongly affected by crystal structure of selenate hydrates forming at the investigated temperatures. The dependence of the coefficients D2/1, obtained at 40°C on the radii of M2+ ions permits to derive an empirical formula for their estimation. The results obtained show that it is possible to remove most of the investigated M2+ ions by the crystallization of zinc selenate at various temperatures in order to achieve its purification. [Copyright &y& Elsevier]