Full
Outline
The precipitation extraction process of rare earths from ionic rare earth ore by ammonium salt leads to eutrophication of receiving water bodies and disruption of aquatic ecological balance. It also triggers cascading ecological issues such as soil acidification and compaction in surrounding areas, as well as threats to human health. To address this ammonia nitrogen pollution problem, the leachate from an ionic rare earth mine in Longnan was taken as the research object. A light-burned, ammonia-free, high-activity magnesium oxide precipitant was prepared, and its influence on the rare earth precipitation behavior was investigated. Meanwhile, XRD, SEM, and TG-DTG characterization techniques were employed to systematically compare and analyze the precipitation products derived from different magnesium oxide systems. The results show that the reactivity of the prepared magnesium oxide is significantly higher than that of industrial magnesium oxide. Using active magnesium oxide slurry as the precipitant under the optimal precipitation condition (molar ratio of 8, reaction temperature of 90 ℃, and reaction time of 4 h), a precipitation product with a purity of 37.45% and a precipitation rate of 96.17% can be obtained. In contrast, when industrial magnesium oxide slurry is used as the precipitant, the product purity is 32.07% and the precipitation rate is 90.17%, both of which are significantly lower than those achieved in the active magnesium oxide system. The mixed rare earth oxides from the active magnesium oxide system exhibit distinct diffraction peaks for Y2O3 and Dy2O3. Furthermore, the crystallinity of the products is superior to that of the industrial magnesium oxide system, characterized by a dense and smooth surface, clear contours, and uniform particles. The research results can provide new theoretical and technical support for the green chemical extraction of ionic rare earth ores.
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| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
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