Effect of Purification on the Solubility of Natural Tahoua Phosphate in Perchloric Acid and Distilled Water
Abdoul Bari Idi Awali *
Faculty of Science and Technology, Department of Chemistry, Abdou Moumouni University, BP 10662, Niamey, Niger.
Doka Daoura Amadou
Faculty of Science and Technology, Department of Chemistry, Abdou Moumouni University, BP 10662, Niamey, Niger.
Mijitaba Sahirou Bachir
Department of Chemistry, Ecole Normal Superior, Abdou Moumouni University, BP 10662, Niamey, Niger.
Dalla Azimi Mahamadou
Faculty of Science and Technology, Department of Computer Mathematic, Cheikh Anta Diop University, BP 5005 Dakar, Senegal.
Manzola Abdou Salam
Faculty of Science and Technology, Department of Chemistry, Abdou Moumouni University, BP 10662, Niamey, Niger.
*Author to whom correspondence should be addressed.
Abstract
The commercial phosphate from Tahoua is a sedimentary phosphate containing impurities that make phosphorus less available to plants. Furthermore, the industrial use of commercial phosphates containing non-essential metals increases the risk of environmental pollution. It is within this context that we undertook this study to enrich the commercial phosphates from Tahoua using particle size analysis and demagnetization techniques. These techniques improve its solubility and preserve its natural structure. After these treatments, we analyzed the commercial phosphate and the purified phosphate (obtained after treatment) using Brunuer-Emmett-Teller (BET) and scanning electron spectroscopy (SEM). The results obtained show that the specific surface area of the raw phosphate obtained is 487.250 m²/g and that of the purified phosphate is 695.864 m²/g. The micropore volume of the raw phosphate before treatment is 0.410 cc/g, and the volume of the phosphate after treatment without the use of any chemicals is 0.591 cc/g. This demonstrates an increase of 208.614 m²/g in the specific surface area and 0.181 cc/g in the micropore volume of the phosphates. Furthermore, the images obtained show a release of phosphate particles from the purified phosphate compared to the initial product. These results indicate an increase in the P₂O₅ content. This confirms a significant decrease in most oxides such as Al₂O₃, SiO₂, Fe₂O₃, MgO, MnO, etc. Finally, we dissolved the obtained products in perchloric acid and distilled water. The results obtained show an increase in the product's solubility. The dissolved phosphorus content, expressed as a percentage of P₂O₅ in the treated (purified) phosphate and in the marketable phosphate in perchloric acid and water, is 69.38% ; 34.21% and 17.44% ; 7.48%, respectively. These particle size analysis and magnetic separation techniques for the marketable phosphate have increased the P₂O₅ content in the solutions. This dissolved P₂O₅ content is more significant in soluble water. However, the purification effect of natural phosphate from Tahoua has direct importance for understanding and optimizing its solubility, a central element for its agronomic use.
Keywords: Purification, solubility of natural phosphate, perchloric acid, water