optimum conditions for dissolution of phosphate ore in hydrochloric acid

ABSTRACT

The optimum conditions to prepare pure phosphoric acid by dissolution of Sebaiya phosphate ore in hydrochloric acid were studied. The phosphate ore was ground and submitted to complete chemical and sieve analyses. The percentages of P[2]O[5] and Fe were determined spectrophotometrically and the fluoride content was determined by means of an ion selective electrode. The factors affecting the dissolution of the ore in hydrochloric acid including percent P[2]O[5] particle size of the phosphate grains, period of acidulation, acid concentration, temperature and acid-to-rock ratio were investigated. The results showed that the optimum conditions for the preparation of phosphoric acid are P[2]O[5] - 26.3, F- = 3.18, Fe = 0.962 and SiO[2] = 12.84 for chemical composition of the phosphate ore, particle size = 125-250 micro m, period of acidulation = 30 min, acid concn. = 6N, temperature = 25 degree and HC1 ore ratio = 30.861. The obtained results were discussed and compared with the literature data. It is concluded that the variation of the optimum conditions may be affected by the chemical composition and the particle size of the phosphate ore, besides the other factor