Experiments on the simultaneous partitioning of divalent metal ions between hedenbergite or tremolite and 2M aqueous chloride solutions under supercritical conditions

Experiments on the simultaneous exchange of Ni²⁺, Mg²⁺, Co²⁺, Zn²⁺, Fe²⁺, Mn²⁺, Ca²⁺ and Sr²⁺ between hedenbergite or tremolite and 2M aqueous chloride solutions were carried out in the temperature range of 500 to 800°C, 1 kb. The PC-IR curves for the both minerals show a similar shape and have peaks near Ni²⁺ and Ca²⁺. The former peak corresponds to 6 coordination and the latter peak to 8 coordination. The PC-IR curves suggest that Ni²⁺, Mg²⁺ and Fe²⁺ are partitioned preferably in 6 coordination of the minerals and Mn²⁺, Ca²⁺ and Sr²⁺ in 8 coordination. However Co²⁺ and Zn²⁺ deviate from such a trend. The ion selectivity decreases with increasing temperature.