Micronutrient metal-containing phosphate glasses - United States Patent 3930833
Roberts January 6, 1976
Glasses Patent Abstract
Glass compositions are disclosed that are particularly useful in comminuted form as sources of micronutrient elements for soils. The glasses are based on phosphorus as P.sub.2 O.sub.5 and contain a nutrient amount of a micronutrient metal in oxide form, such as zinc, copper, manganese, molybdenum, or boron oxides or mixtures thereof, plus a solubility control agent. The control agent is a metal compound or mixture of metal compounds, usually potassium or sodium oxide or potassium or sodium chloride, and is present in the glass to provide a controlled release of the micronutrient metal, both as to amount and rate. (more…)