Extracting fluorine from aluminium electrolysis spent carbon anode by phase transformation roasting—water leaching process was studied. The effects of various factors during phase transformation roasting and water leaching on fluoride leaching rate were investigated. The results indicate that under the optimal conditions of alkali fusion temperature of 700 ℃, alkali fusion time of 2 h, alkali-to-material mass ratio of 1.25, insoluble cryolite is transformed into soluble sodium fluoride and sodium meta-aluminate phases. Under the optimal conditions of water leaching temperature of 65 ℃, liquid volume to solid mass ratio of 22/1, water leaching time of 2 h, the fluorine leaching rate achieve 95.86%. XRD analysis of the leached residue reveal that the remaining fluoride existed as calcium fluoride. The soluble fluorine mass concentration in the residue is 48 mg/L, which can meet the harmless requirements. The harmless and resourceful recovery of carbon residue can be achieved by converting the fluoride occurrence form through calcination and combining it with a one-step water leaching process. The method offers advantages such as a simple process flow, rapid reaction kinetics, high treatment efficiency, and promising industrial application prospects.
| 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 |