Dissolution kinetics of fluorapatite in the hydrochloric acid solution

Dissolution of Tunisian phosphate ore by a mixture of sulfuric and phosphoric acid: Kinetics study by means of differential reaction calorimetry

“…Therefore, the dissolution process could be stated by a first-order pseudo-homogeneous model. In compliance with these results, the semi-empirical equation illustrating the kinetics of this process can be written as follows: (7) Linear regression was used to calculate the slopes of lnk as function of against 1/T, ln (C), ln(S/L), ln(G) and ln(SS) (Figs. 11-14).…”

“…Several studies on the dissolution of synthetic phosphate [5][6][7][8][9][10][11][12] or phosphate ore [13][14][15][16][17][18][19][20][21][22][23] in acid solutions have been carried out such as phosphoric acid [5,[15][16][17], succinic acid [18], acetic acid [19], and hydrochloric acid [6,[20][21] to illustrate the kinetics and process mechanism as well as enhancing the yield of the phosphate attack. Nevertheless, phosphate ore dissolution by sulfuric acid remains the most extensively used process [22] and over 90% of the phosphoric acid produced globally is manufactured through the decomposition of phosphate ore with sulfuric acid as an acidulate [23].…”

“…However, another study by Amira et al [17] studied the phosphoric acid acidulation of Tunisian phosphate and established that the attack rate increased with increasing temperature and the experimental results fit the shrinking-core model with an ash layer diffusion control with an activation energy equal to 25.4 ± 1.8 kJ mol -1 . The attack of the natural phosphates being complex, is the reasonthat our team initially used synthetic phosphate for the modelization of the reaction of acid attack of phosphates [5][6][7][8][9][10][11].…”

“…Indeed, only some studies performed in our laboratory used these techniques [2][3][4][5][6][7][8][9][10]. Amira et al [14,17,35] performed them on a Tunisian phosphate ore (from Gafsa) using phosphoric acid in the 25-60°C range using a DRC.…”

Attack of Tunisian Phosphate Ore by a Mixture of Sulfuric and Phosphoric Acid: Thermochemical Study by Means of Differential Reaction Calorimetry

“…The resulting apparent activation energy equals 25.4 ± 1.8 kJ•mol −1 . In the same context, another study was carried out by Brahim et al [13] to investigate the attack of a Fap in the hydrochloric acid solution showed that the dissolution kinetics was examined according to the heterogeneous reaction models and proved that the dissolution is controlled by the product layer diffusion process.…”