Working principle of manganese and iron removal from manganese sand
There are many methods to remove iron and manganese, generally using the principle of oxidation to remove iron and manganese, which is currently the most economical and effective treatment method. Many equipment use natural manganese sand as the filtering medium. Adopting treatment processes such as aeration oxidation, manganese sand catalysis, adsorption, and filtration; The oxygen in the air is dissolved into water using an aeration device. When it flows through the filter layer for filtration, it is adsorbed by the biofilm covering the surface of the filter material, and is oxidized by the dissolved oxygen under catalytic action, and adsorbed on the filter material. The trivalent iron oxide generated by oxidation is used as a new filter membrane to participate in a new catalytic reaction. The excess oxide is washed away by backwashing the produced water after one cycle of operation. The principle of manganese removal is the same as above. Due to the principle of ion selective absorption, the filter layer removes iron first and then manganese. At a pH value of 6.8-7.2, Fe (OH) 3 and MnO2 form a colloidal precipitate that can be removed by filtration.
The reaction equation for iron manganese oxidation is as follows:
Iron oxidation: 4Fe2++3O2+6H2O=4Fe (OH) 3 ↓
Manganese sand: MnO · Mn2O+4Fe2+2O2+6H2O=3MnO2+4Fe (OH) 3 ↓
Manganese oxidation: Mn2++O2=MnO2 ↓
Manganese sand: Mn2++MnO2 · H2O=MnO2 · MnOH2O+2H
technological process
When the iron concentration in groundwater is between 5-10mg/l and the manganese concentration is between 1-2mg/l, or when groundwater contains only iron but no manganese and the iron concentration is around 10mg/l, aeration single-stage iron and manganese removal filtration can be used.
Process flow: groundwater → deep well pump → aeration device → water tank → filtration pump → iron and manganese removal device → reservoir → water using unit.
If the groundwater contains high levels of iron and manganese, i.e. iron greater than 10mg/l and manganese greater than 2mg/l, aeration two-stage iron and manganese removal filtration should be used.
Process flow: groundwater → deep well pump → aeration device → water tank → filtration pump → primary iron and manganese removal device → secondary iron and manganese removal device → reservoir → water using unit.
Manganese removal equipment
Activated carbon filter for removing iron and manganese
Schematic diagram of filter filtration
Equipment features
1. The effluent from the iron manganese water purifier can be directly supplied to the pipeline network without the need for a secondary water supply system; Equipped with its own backwash function, no need to install a separate backwash water pump; Reduce equipment investment and avoid secondary pollution.
2. The pressure filter has high backwashing intensity, which ensures uniform and thorough backwashing of the filter without forming dead corners. The backwashing time is short, the filtration cycle is long, and the service life of the filter material is extended.
3. This device has a reasonable structure, is easy to use, and reduces operation and maintenance costs.
4. A strong oxidation chamber is installed inside the equipment to increase the saturation of steam and water, accelerate the oxidation rate, and have strong applicability to the content of iron and manganese in raw water.
5. This device adopts a decentralized water distribution method to shorten the distance between the filter layer and the water distribution pipe, which can save a lot of backwash water.
technical parameter
Gas water oxidation time: 3-5 minutes Filter filtration rate: 10-14m/h
Backwash strength: 16-19L/m2s Filter layer thickness: 1.2m
Work pressure: 0.05-1.0MPa Raw water iron content: ≤ 20mg/L
Manganese content in raw water: ≤ 10mg/L Iron content in filtered effluent: ≤ 0.3mg/L
Manganese content in the effluent after consideration: ≤ 0.1mg/L
Manganese oxide: Manganese oxide is a type of amphoteric oxide that exhibits oxidizing properties when exposed to reducing agents. Heating manganese dioxide in a hydrogen stream to 1400K yields manganese monoxide; Heating manganese dioxide in an ammonia stream to obtain brownish black manganese trioxide; Reacting manganese dioxide with concentrated hydrochloric acid yields manganese dichloride and chlorine gas. When encountering strong oxidants, it also exhibits reducibility. If manganese dioxide, potassium carbonate, potassium nitrate, or potassium chlorate are mixed and melted, a dark green melt can be obtained. Dissolving the melt in water and cooling it yields potassium permanganate, a compound of hexavalent manganese. It is a strong oxidant in acidic media. Widely used in steelmaking, as well as in the production of glass, ceramics, enamel, dry batteries, and as a catalyst. When reacting with potassium chlorate as a catalyst, it does not simply catalyze, but rather reacts with the raw material, ultimately producing manganese dioxide for the synthesis of organic compounds: manganese dioxide is very useful in organic chemistry. The forms of manganese dioxide used as oxides vary, as manganese dioxide has multiple crystalline forms and can be written as MnO2-x (H2O) n in terms of chemical formula, where x ranges from 0 to 0.5 and n can be greater than 0. Manganese dioxide can be produced through the reaction of potassium permanganate (KMnO4) and manganese sulfate (MnSO4) at different pH values. The brown manganese dioxide sediment is very dry and active. The most effective organic solvents include aromatic substances, carbon chloride, ethers, tetrahydrofuran, and esters.
