Abstract
Because of the depletion of phosphate resources and the need for phosphate in agricultural production, the use of low-grade phosphate rocks (PR) is necessary. Partially acidulated PRs (PAPR) are effective phosphate fertilizers from low-grade PR. Herein, we analyzed the changes in properties such as hygroscopicity and phosphate solubility, as well as the applications of the improved PAPR produced, using PRs from Burkina Faso. As the amount of added sulfuric acid increased, the amount of soluble phosphate in the PAPR also increased. However, at PAPR100 and above, the PAPRs became stickier, making them difficult to use as fertilizers. Adding both calcium and potassium carbonates improved the hygroscopicity and pH (H2O) while maintaining sufficient phosphate solubility. Pot experiments showed that the application of these PAPRs resulted in sorghum yields comparable to those of commercial single superphosphate (SSP). These results indicate that the addition of carbonate to the PAPR production process makes phosphate fertilizer easy to handle and yields phosphate fertilizers using low-grade PRs that are as effective as an SSP.
