Cpd fertilizers - by granulating thomas phosphate with sulphuric acid digest of phosphate rock

摘要

Compound fertiliser in the form of hard, abrasion-resistant granules is produced by preparing a digestion soln. or slurry contg. no free H2SO4 by intimately kneading pre-ground rock phosphate with sulphuric acid (or a mixture of sulphuric and nitric acids) and water, and using this as a granulating agent for Thomas flour or its mixtures with other nutrient salts. Even after artificial drying, the granules re-dissolve relatively rapidly in water, and have full plant-physiological activity.