Study Of The Quality And Safety Of Feed-grade Dicalcium Phosphate From Different Sources

This reearch was conducted to investigate the quality and safety of feed-grade dicalcium phosphate processed by hydrochloric acid method and sulfuric acid method from different plants in Sichuan province. Five of feed-grade dicalcium phosphate and four of phosphorites were taken from four plants for each processed method. The indexes measured included :(1)technical qulity ind(?)x(?)s: color, volume weight, pH uniformity , content of crystal water, free water. (2) nutrition qulity indexes : content of calcium and total phosphate, copper, zinc, manganese, iron, magnesium, sulfate, wate-solubility chloride. (3)safety indexes: fluorin, arsenic lead, hydragyrum, chromium, cadmium.Results indicated:In the feed-grade dicalcium phosphate processed by hydrochloric acid method: the content of crystal wate was between 4%-10%;the pH was about 5.5; the content of calcium was between 27.20%-28.52%; the content of wate-solubility chloride was about 2.94%; the content of heavy metals were high, especially the content of lead and fluorin were 25.16mg/kg and 1925.16mg/kg. In the feed-grade dicalcium phosphate processed by sulfuric acid method: the pH was about 7.55; the content of crystal wate were about 24.77%, the content of free water was about 1.61 %; the content of calcium was about 22.22%, , the content of manganese and sulfate were 1.75% and 8631.65 mg/kg, the wate-solubility chloride were not detected; the content of heavy metals were low.There were differences in the qulity and safety between feed-grade dicalcium phosphate by hydrochloric acid method and sulfuric acid method. In qulity. the pH, contents of crystal water and free water were different in different methods, the content of calcium, copper and wate-solubility chloride in sulfuric acid method were higher than the production by hydrochloric acid method; the content of zinc, manganese and sulfate in hydrochloric acid method were higher than the production by sulfuric acid method,;In safety: the content of lead, fluorin, hydragyrum in sulfuric acid method were significantly lower than the production by hydrochloric...