Method and application of in-situ preparation of heavy metal adsorbent based on high iron and manganese acid mine wastewater

Abstract

The invention discloses a method and application for in-situ preparation of a heavy metal adsorbent based on ferromanganese acid mine waste water. The method includes the following steps: S1. Grinding the quicklime into powder, and preparing the powdered quicklime into a medicine; S2. Adding the medicine in step S1 to the waste water foundation pit of ferromanganese acid mine, and adjusting the pH value of the solution to 3-3. 5. At the same time, carry out aeration treatment on the high iron and manganese acid mine waste water; use the jet aerator to carry out uninterrupted aeration treatment on the acid waste water; S3. After completing the aeration treatment, let the mixed solution in the waste water foundation pit stand for a period of time , and collect the precipitate therein to obtain the heavy metal adsorbent. This method utilizes metal ions such as iron and manganese in the acidic mine water, and realizes the in-situ treatment of metal ions and other pollutants in the ferric manganese acidic mine wastewater through the technical means of dosing chemicals and aeration, and can prepare The heavy metal adsorbent can achieve the treatment and comprehensive utilization of ferromanganese acid mine waste water.

Description

technical field [0001] The invention relates to the technical field of in-situ remediation of groundwater pollution, in particular to a method and application for in-situ preparation of a heavy metal adsorbent based on ferromanganese acid mine wastewater. Background technique [0002] After coal mines and other mines are closed, they are easily filled with water and produce a large amount of acid mine wastewater, which is typically characterized by low pH and high iron and manganese content. Pyrite itself can exist stably under reducing conditions, but due to mining activities, the pyrite originally buried deep underground is exposed to an oxygen environment and undergoes oxidative dissolution. The main reactions are as follows: [0003] 2Fe 2 +2H 2 O+7O 2 ==2FeSO 4 +2H 2 SO 4 [0004] 4FeSO 4 +2H 2 SO 4 +O 2 ==2Fe 2 (SO 4 ) 3 +2H 2 o [0005] Fe 2 (SO 4 ) 3 +6H 2 O==2Fe(OH) 3 +3H 2 SO 4 [0006] During the continuous oxidation and dissolution process...

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Problems solved by technology

[0008] At present, the treatment technologies for acid mine wastewater mainly include neutralization precipitation method, adsorption method, neutralization filter method, and microbial treatment method. Among them, neutralization method is widely used. This method uses lime milk or lime to adjust the pH of wastewater to 8. -9 or so, heavy metal ions in wastewater react with excess hydroxide ions, and finally form heavy metal hydroxides and carbonate precipitation, so that heavy metals can be removed from wastewater. The amount of alkaline chemicals used is large, resulting in increased treatment costs, and the precipitate formed after wastewater treatment cannot be used for secondary use

[0009] The adsorption method removes pollutants, such as heavy metal ion pollutants, by adding adsorbents with active functional groups to the wastewater through the adsorption force between the functional groups and pollutants; although the adsorption method rarely produces additional pollutants during use, and The use effect is good, but for the high iron and manganese acid mine wastewater, due to the high content of iron and manganese ions, the demand for the use of the adsorbent is relatively large, and the cost is high, and the iron and manganese ions in the high iron and manganese acid mine wastewater are directly absorbed by the adsorbent. Its products cannot be reused

[0010] Neutralizing filter material method, a typical technical case is PRB technology, as an in-situ repair technology, it sets a permeable reaction wall system at the cross-section of the pollution plume, and fills the wall with neutralizer, zero-valent iron, or Active filter materials such as microorganisms, after the polluted groundwater flows through the wall, the pollutants are stabilized, degraded, and removed, and the neutralization filter material method is used for treatment, and the products cannot be reused.

[0011] Microbial treatment uses sulfate-reducing bacteria to reduce sulfate in water to hydrogen sulfide, and finally further oxidizes it to elemental sulfur; another type of bacteria oxidizes ferrous iron to ferric iron, and cooperates with lime milk and other blending agents to make heavy metals and Sulfate is removed, and microbial treatment is used, the process is complicated, and a large amount of lime milk is also required, and the formed product cannot be reused

[0012] Acid mine wastewater widely exists in my country's mining areas. With the current mining technology, the production of this pollutant is still unavoidable, and the amount of wastewater produced is huge, which has a great impact on water pollution; in the face of huge wastewater production, especially The content of iron and manganese in acid mine wastewater is very high, and the waste water treatment cost of the prior art is relatively high, and a large amount of iron and manganese metals in acid mine wastewater have not been effectively utilized. The application of in-situ treatment and utilization technology of acid mine wastewater is relatively lacking

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