FEED GRADE PHOSPHATES

Phosphate rock is used as the basic source material in the production of highly purified forms of phosphorus-containing products for use as supplements in livestock and poultry feeds. All phosphate ores contain levels of fluorine which are toxic to animals. Defluorination is required in the production of feed phosphates and is essential for the health of the animals to which they are fed. To insure this protection the Association of American Feed Control Officials has established that a feed phosphate product must contain not more than one part of fluorine (F) to 100 parts of phosphorus (P) in addition to meeting rigid specifications for the other constituents.

The feed phosphate produced by several different companies in the Florida phosphate industry include calcium phosphates, defluorinated phosphates, ammonium phosphates and defluorinated phosphoric acid. Concentrated wet-process phosphoric acid from which the fluorine has been removed is used in the manufacture of the calcium phosphates, ammonium phosphates and defluorinated phosphoric acid. The calcium phosphates are produced from the defluorinated phosphoric acid and high grade limestone while the ammonium phosphates are produced from the same quality acid and anhydrous ammonia. Defluorinated phosphates are produced by adding defluorinating agents, such as phosphoric acid and soda compounds, in controlled amounts to phosphate rock and calcining the mix at temperatures ranging from about 2400 degree Fahrenheit to 2750 degrees Fahrenheit. All feed phosphate products require guarantees for minimum percent phosphorus (P), minimum and maximum percent calcium (Ca), and maximum percent fluorine (F). For ammonium phosphates the guarantee requires a minimum percent nitrogen (N) rather than calcium as well as guarantees for minimum phosphorus, maximum fluorine, maximum ppm of arsenic (As) and maximum ppm of heavy metals reported as lead.