Synthesis of Dicalcium Phosphate Used as Feed Additive for Animals from Phosphate Rock as Potential Cost Effective Raw Material

Author(s): Muhammad Abdul Qadir, Mahmood Ahmed, Saghir Ahmed and Iftikhar-Ul-Haq

Dicalcium phosphate (DCP) an animal feed additive was synthesized from phosphate rock under optimum condition of pH, temperature of reaction mixture, time of reaction and acid concentration. Concentrated slurry of 200 mesh sieve calcium hydroxide was used to remove impurities. Solution was filtered and pH of filtrate was again adjusted to precipitate dicalcium phosphate. Dicalcium phosphate was filtered, washed, dried and grinded. The best values in terms of quality and quantity of dicalcium phosphate from locally phosphate rock were achieved at acid concentration of 10% w/w, reaction time of 1.5 hrs, at 30°C and pH values of 2.3-2.4 (during precipitation of impurities) and 5.5-5.6 (for the final synthesis of dicalcium phosphate). Pure dicalcium phosphate (98.20%) was prepared using above method. Purity of the dicalcium phosphate in terms of phosphorus content and total assay were determined using ICP-OES and British Pharmacopoeia, respectively. Impurities like fluorides were determined by ISE, and arsenic, barium, iron, aluminium, magnesium and lead by ICP-OES, while chlorides and sulphates were determined by UV-Vis Spectrophotometer. The amount of impurities found were fluorides (80.02 ppm), Iron (360.2 ppm), arsenic (3.41 ppm), lead (22.08 ppm), aluminium (5.04 ppm), chlorides (240.8 ppm), barium (5.04 ppm), magnesium (155.27 ppm) and sulphates (0.303 %).

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