A process is provided for the production of dicalcium phosphate form a
phosphate source material in which a solution of phosphoric acid is
produced by the action of a suitable mineral acid, generally sulphuric
acid, on a phosphate source material. Calcium fluoride is precipitated at
a pH of between 3.5 and 4.5 followed by hydrolyzing the solution by
diluting it with water to a ratio of approximately 1:7 to about 1:10
monocalcium phosphate to water at a temperature of approximately 40
degrees Centigrade to form a primary precipitate containing substantially
all of the fluoride present as CaF.sub.2 together with some dicalcium
phosphate and a primary calcium and phosphate containing solution. The
primary precipitate is dissolved, the pH adjusted to form 3.5 to 4.5 and
the hydrolyzation repeated to form a secondary precipitate containing
substantially all of the fluoride present as CaF.sub.2 together with some
dicalcium phosphate and a secondary calcium and phosphate containing
solution. The secondary precipitate can optionally, if required, by again
processed in the same way to recover more phosphates. The product
dicalcium phosphate is recovered from the combined calcium and phosphate
containing solutions.