Phosphate Fertilizers by Calcination Process Experiments with Different Phosphates

Phosphate Fertilizers by Calcination Process: Experiments with Phosphate Rock in Very Thin Layers1

“…Effect of Increasing the Thickness of the Charge Previous results(8), summarized in TableIII, show that a close agreement exists between the citrate solubility of the phosphorus and the volatilization of the F'b fluorine when comparatively thick charges (2.5 grams, equivalent to a…”

“…In this paper, as in the previous papers of this series (8,10,11), FA represents the fluorine in excess of that corresponding to the fluorapatite [Cal0F2(PO4)6] equivalent of the total phosphorus in the phosphate rock. FB and F'fl represent the fluorine corresponding to the respective atoms of fluorine in the fluorapatite equivalent of the total phosphorus; for convenience these are designated as the first (Fs) and second (F'b) atoms of fluorine.…”

Fertilizer from Rock Phosphate Conversion by Fusion and Treatment with water Vapor

“…Jacob and his co-workers in the United States Bureau of Chemistry and Soils studied this process on a small scale (3,4,5,6).…”

Hygroscopicity of Fertilizer Mixtures

“…Effect of Calcined Phosphates WHEN phosphate rock containing 5 per cent or more of silica is heated at 1400°C. in the presence of water vapor, its phosphorus content is rendered citrate soluble to a degree dependent upon the extent to which the fluorine contained in the rock is volatilized (11,14,15). Thus, under optimum conditions, it is possible to volatilize upwards of 99 per cent of the fluorine and convert the same proportion of the phosphorus into the citrate-soluble condition.…”