Metal cation exchange reactions of ore minerals in Fe–Mn crusts of the Marcus Wake Rise (Pacific Ocean) in aqueous–salt solutions

Abstract

It is shown that the reaction ability of metal cations of ore minerals in Fe–Mn crusts of the Marcus Wake Rise increases in the following manner: (Co²⁺ < Cu²⁺ < Ni²⁺) < (Mg²⁺ < Mn²⁺ < K⁺ ≈ Ca²⁺ ≈ Na⁺). The composition of the exchange complex of the ore minerals is constant and includes these metal cations. Ca²⁺ and Na⁺ are major contributors to the exchange capacity of the ore minerals. The capacity of the ore minerals by cations of alkali and base metals is 0.43–0.60 and 2.08–2.70 mg-equiv/g, respectively. The exchange capacity of the ore minerals by cations of base metals increases linearly with the increase in the MnO₂ content of the crust and does not depend on the geographical locations of the Marcus Wake guyots.