THE INFLUENCE OF THE META-STABLE TRIPLE POINT SOLUTION OF MONOCALCIUM PHOSPHATE MONOHYDRATE UPON THE CLAY SEPARATES OF TWO ONTARIO SOILS

Abstract

Samples of material less than 2 μ in diameter were obtained from the surface horizon of a Guelph loam and of a Haldimand clay loam. These samples were subjected to six successive treatments with the meta-stable triple point solution of monocalcium phosphate monohydrate (MTPS) to simulate the environment near a dissolving superphosphate granule. Samples of montmorillonite and illite standard clays were also included. The dissolution losses in per cent were: Guelph clay 59.5, Haldimand clay 40.4, montmorillonite 3.4, and illite 8.1. Total chemical analyses, X-ray diffraction techniques, differential thermal analyses and electron microscope observations were used to determine the nature of these losses. In the soil clay separates, vermiculite and interstratified montmorillonite were more susceptible to the action of MTPS than were the illite or halloysite clay minerals.