Abstract: A study was made of the energy changes of several colloidal systems in relation to weathering.
The total energy change associated with pH, total hydrogen, and bonding energy involved in the weathering of natural phosphates was established by mixing particles of apatite with hydrogen systems of amberlite (I.R. 120), bentonite clay, Putnam clay, kaolinite, and humus. Mixtures of potassium-saturated bentonite, sodium-saturated bentonite, and powdered rock phosphate were also investigated for weathering changes.
The amount of phosphorus weathered was related to hydrogen bonding at the outset and to calcium bonding energy of the colloidal system. H-amberlite, which has the highest bonding energy for calcium of the systems studied, was most effective in weathering phosphate minerals. H-humus, which has the lowest bonding energy for calcium was least effective as a weathering agent. The clay minerals weathered according to the relative energy levels resulting from the consideration of both hydrogen and calcium bonding energies. Bentonite clay was the most effective weathering agent; Putnam clay intermediate, and kaolinite the least effective. Bentonite clay saturated with potassium or sodium was effective as a phosphate mineral weathering agent.