College of Land and Environment, Shenyang Agricultural University, Shenyang, China.
Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
PLoS One. 2019 Nov 7;14(11):e0224423. doi: 10.1371/journal.pone.0224423. eCollection 2019.
Mechanochemical treatment of phosphate rock is considered as an effective and ecologically clean way of treating the medium- and low-grade phosphorite which could be used as fertilizer instead of the high-grade phosphorite. In order to investigate the effects of different milling times on the mechanochemically activated phosphorite (lower total phosphorus content) by more efficient milling equipment with enhanced milling speed, phosphorus solubility in citric acid and structural characteristics of natural and mechanochemically activated phosphorite from Yichang, China were studied using scanning electron microscope, infrared spectroscopy and X-ray diffraction. Phosphorus solubility in citric acid increased proportionately with the milling time until 30 min (57.51%), but then gradually reached an equilibrium with the maximum (59.03%) in 50 min. These changes were mainly manifested in considerably reduced particle size, decreased crystallinity and increased structural defects of phosphorite due to substitution of PO43- with CO32- and the incorporation of OH-. With the incorporation of CO32- and OH-, the non-activated carbonate-fluorapatite (type B) was transformed into a mixture of carbonate-fluorapatite, hydroxyapatite, fluorocarbon hydroxyapatite and/or carbonate apatite, respectively during the process of mechanochemical activation. As a result of the structural and phase transformations after mechanochemical activation, phosphorus solubility remarkably increased.
机械化学处理磷矿被认为是一种有效且生态清洁的方法，可以处理中低品位磷矿，将其作为肥料使用，而不必使用高品位磷矿。为了研究不同的研磨时间对通过具有增强研磨速度的更高效研磨设备进行机械化学活化的磷矿（总磷含量较低）的影响，利用扫描电子显微镜、红外光谱和 X 射线衍射研究了来自中国宜昌的天然和机械化学活化磷矿的柠檬酸中磷的溶解度和结构特征。柠檬酸中磷的溶解度随着研磨时间的增加而呈比例增加，直到 30 分钟（57.51%），但随后在 50 分钟时逐渐达到最大值（59.03%）。这些变化主要表现为由于 PO43-被 CO32-取代以及 OH-的掺入，磷矿的颗粒尺寸显著减小、结晶度降低以及结构缺陷增加。随着 CO32-和 OH-的掺入，非活性碳酸盐-氟磷灰石（B 型）在机械化学活化过程中分别转化为碳酸盐-氟磷灰石、羟磷灰石、氟碳羟磷灰石和/或碳酸磷灰石的混合物。由于机械化学活化后的结构和相变，磷的溶解度显著增加。
