期刊
MINERALS
卷 8, 期 9, 页码 -出版社
MDPI
DOI: 10.3390/min8090416
关键词
rare earths; phosphorite; wet-process phosphoric acid production; leaching efficiency
资金
- US Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office [SC-14-392]
Phosphorite, or phosphate rock, is the raw material of phosphoric acid production. It has also been regarded as the most important secondary rare earth element (REE) resource due to low contents of rare earth elements contained in the ore. In Florida, there is about 19 Mt of phosphate rock mined annually. After beneficiation, the phosphate rock concentrate is utilized to produce phosphoric acid via a wet-process in which sulfuric acid is used to digest phosphate. During these processes, REEs and some phosphorus get lost in the byproducts including phosphatic clay, flotation tailings, phosphogypsum (PG), and phosphoric sludge. Recovering REEs and phosphorus from these wastes is beneficial to maximize the utilization of these valuable resources. This study focused on the effects of wet-process operating conditions on REE and phosphorus leaching from a kind of flotation tailing of Florida phosphate rock. The tailings were first beneficiated with a shaking table, and then a series of leaching tests were conducted on the shaking table concentrate. The results indicated that REEs had similar trends of leaching efficiency to those of phosphorus. Under the conditions of 16% phosphoric acid concentration in the initial pulp, a temperature of 75 degrees C, a stoichiometric ratio of sulfuric acid (H2SO4) to calcium oxide (CaO) of 1.1, and a weight ratio of liquid to solid of 3.5, REE and phosphorus leaching efficiencies reached relatively high values of approximately 61% and 91%, respectively. Analyses indicated that the phosphate ions (PO43-) in the leaching solution tended to combine with REE ions to form REE phosphates which precipitated into PG, but the other large amount of anions such as sulfate ions (SO42-) and fluoride ions (F-) took effect of steric hindrance to prevent PO43- from combining with REE cations. These two opposite effects determined the REE distribution between the leaching solution and PG.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据