Abstract:

With the increase of phosphorus fertilizer production, the phosphogypsum pollution on environment has become more and more prominent. To solve the problem caused by phosphogypsum storage to the environment and realize the resource utilization of phosphogypsum, this study clarified the influence of phosphogypsum on the regional water environment media through field investigation, sampling, simulation test and establishing prediction model of phosphogypsum storage sites in phosphogypsum resource concentrated areas of Yunnan Province. The results showed that: (1) phosphogypsum at different storage sites was acidic, the phosphorus content of phosphogypsum in Dianchi watershed was relatively high while the fluorine content of phosphogypsum in Fuxian watershed was relatively high; (2) through surface runoff test, the content of total phosphorus and fluoride in surface water decreased with the increase of migration distance; a regression model was established for the migration of surface water pollutants along the way, showing that when the total phosphorus and fluoride in surface runoff migrated to 186.4 m and 167.30 m away from the storage site, respectively, their contents in water could reach the surface water standard of Class III; (3) through the soil column leaching test, the total phosphorus content in leachate decreased with the increase of leaching times, the fluorine content in leachate of different soil columns showed a positive correlation trend; except individual soil column leachate, the fluorine content of leachate at other depths was basically within the range of 0.15 to 0.45 mg/L, which could meet the groundwater standard of Class I to Class III. Thus, the study could provide a quantitative theoretical basis for solving the pollution load caused by phosphogypsum to water environment in phosphate mining area and even in regional river basin.

Key words: phosphogypsum, surface water, ground water, phosphorus, fluorine