Process for producing defluorinated phosphate rock granules

In a process for preparing defluorinated phosphate rock granules for use as an animal feed which comprises:

• (a) forming a mixture of fluorine-containing phosphate rock, phosphoric acid, sodium carbonate and water,
• (b) granulating the resulting mixture,
• (c) heating the resulting granules to a temperature to defluorinate said fluorine-containing phosphate rock without fusion whereby sufficient fluorine is evolved to produce defluorinated phosphate rock granules, said defluorinated phosphate rock granules having a phosphorus content of less than 18% by weight,
• (d) cooling said heated defluorinated phosphate rock granules in a fluidized bed, and
• (e) recovering said cooled defluorinated phosphate rock granules, wherein said improvement comprises:
• adding phosphoric acid to said defluorinated phosphate rock granules during said cooling step when said granules are at a temperature from about 175.degree. C. to about 400.degree. C., the amount of said added phosphoric acid being sufficient to raise the phosphorus content of said granules to at least 18% by weight.