Research on modified fly ash for high iron and high manganese acid mine drainage treatment

This paper researched on simulated mine water treated with fly ash modified by Na2CO3. The ratio of fly ash and sodium carbonate solution is 1g∶10mL, stirred, dried, crushed and screened. The main chemical components analyzed with GENESIS XM260SX- EDS. The experimental mine water is prepared with AR FeCl3 · 6H2O, MnSO4 · H2O, HCl and deionized water, based on the actual range of mine water quality , the simulated quality range is total Fe 40 mg/L, Mn 2.5mg/L, pH 2.5. The optimum operating parameters were determined through experiments: modified fly ash/simulated mine drainage 0.9g/500mL, reaction time 30 min, stirring intensity 350r/min, reaction temperature 35°C. Under the optimum experimental conditions, the results of continuous dynamic test are: in the effluent, total iron concentration range is 0.18–0.28mg/L, manganese concentration range is 0.08–0.17mg/L, turbidity range is 3.1–4.2NTU, pH range is 8.12–8.51. The effluent quality fulfills <Code for design of wastewater reclamation and reuse> (GB50335-2002), that is total iron 0.3mg/L, manganese 0.2mg/L, turbidity 5NTU, pH 6–9. Modified process improved the settling characteristics, adsorption ability and neutralization reaction capacity of fly ash. This research can provide technical support for comprehensive utilization of high iron and high manganese acid mine drainage, meanwhile solve the fly ash problem of the environmental pollution.