几种磷矿粉中磷和钙溶出动力学特性

采用间歇实验方法，研究4种磷矿粉在1M NH4OAC（pH4.8）酸性溶液中磷和钙溶出动力学规律，结果表明：磷矿粉中磷的溶出分为2个阶段，0~30min为快反应过程，30min后为慢反应过程，它能较好地符合Elvoich方程，磷的溶出速率（b）与枸溶性磷含量有较好的相关性，主要受磷矿粉中SiO2和碳酸钙含量的影响，枸溶性磷含量愈高，磷的溶出速率愈大，溶出磷的浓度也愈高。磷矿粉中钙的溶出也符合Elvoich方程，且与游离的碳酸钙含量有关，与其他磷矿粉不同，在PR1中钙的溶出浓度较高，很可能来自于碳酸钙的溶解。因而，磷矿粉不仅可以提供磷素营养，还提供植物生长所需的钙素营养。

Characteristics of Dissolution Kinetics of Phosphorus and Calcium from Phosphate Rocks

Characteristics of dissolution kinetics of phosphorus and calcium from phosphate rocks (PRs) by 1 M NH4OAC (pH4.8) acidic solution were investigated by batch methods in laboratory. It indicated that dissolution kinetics of phosphorus could be divided into two stages which was fast reactive process during 0~30 min and slow reactive process after 30 min. Phosphorus dissolution kinetics of the rocks were well described by the Elovich equation. The rates of phosphorus dissolution were highly correlated to citric acid soluble P which was influenced by the amounts of SiO2 and CaCO3. Calcium dissolution from PRs could be also fitted by the Elovich equation and was relative to free calcium carbonate in the rocks. The concentration of Ca dissolution from PR1, different from the others, could partly originate from the dissolution of free calcium carbonate. So the direct applications of PRs would simultaneously supply the phosphorus and calcium nutrition for plants.