Experimental Study of Silicate Phosphatization under Supergene Zone Conditions: Hornblende, Orthoclase, and Labradorite

Abstract

The hypothesis of silicate phosphatization under supergene zone conditions was experimentally tested. To extend our previous experimental work on clay minerals (kaolinite and montmorillonite), we studied the phosphatization of aluminosilicates of other structural types (hornblende, orthoclase, and labradorite) interacting for nine months with 1.2–6.0 mM orthophosphate solutions over a wide range of solution acidity. Nearly linear dependence common for all minerals was found between variations in phosphorus and silicon concentrations in the solution: Δ[Si] ≈ –Δ[P]. It was demonstrated that aluminosilicates can be replaced by phosphate minerals at relatively minor concentrations of dissolved phosphorus corresponding to phosphate abundances in soil solutions.