Working principle of manganese and iron removal by manganese sand

      There are many methods to remove iron and manganese. Generally, the principle of oxidative removal of iron and manganese is adopted. It is the most economical and effective treatment method at present. Many equipment use natural manganese sand as the filter medium. Aeration oxidation, manganese sand catalysis, adsorption, filtration and other treatment links are adopted; The oxygen in the air is dissolved into the water by the aeration device. When it flows through the filter layer for filtration, it is adsorbed by the biofilm covered on the surface of the filter material, oxidized by the dissolved oxygen under the action of catalysis, and adsorbed on the filter material. The ferric oxide generated by oxidation participates in the new catalytic reaction as a new filter membrane. The produced water runs for a cycle of backwashing to wash away the excess oxide. 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. When the pH value is equal to 6.8-7.2, Fe (OH) 3 and MnO2 are precipitated as colloid and can be removed by filtration.

The reaction formula of 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

1. When the concentration of iron in groundwater is 5 ~ 10mg / L and the concentration of manganese is 1 ~ 2mg / L, or when the concentration of iron in groundwater is about 10mg / L, aeration single-stage iron and manganese removal filtration can be adopted.

Process flow: groundwater → deep well pump → aeration device → water tank → filter pump → iron and manganese removal device → reservoir → water user.

2. If the content of iron and manganese in groundwater is high, that is, when iron is greater than 10mg / L and manganese is greater than 2mg / L, aeration - two-stage iron and manganese removal filtration should be adopted.

Process flow: groundwater → deep well pump → aeration device → water tank → filter pump → primary iron and manganese removal device → secondary iron and manganese removal device → reservoir → water user.

Manganese removal equipment

Activated carbon filter iron and manganese removal filter

Schematic diagram of filter

Equipment characteristics

1. The effluent from the iron manganese water purifier can be directly supplied to the pipe network without setting another secondary water supply system; It has its own backwashing function, and there is no need to set another backwashing water pump; Reduce equipment investment and avoid secondary pollution.

2. The pressure filter has high backwashing intensity, so that the filter can be flushed evenly and thoroughly without forming a dead corner. The backwashing time is short, the filtration cycle is long, and the service life of the filter material is prolonged.

3. The equipment has the advantages of reasonable structure, convenient use and reduced operation and maintenance cost.

4. A strong oxidation chamber is set inside the equipment, which can increase steam water saturation and accelerate oxidation speed, and has strong applicability to the content of iron and manganese in raw water.

5. The equipment adopts the decentralized water distribution mode to shorten the distance between the filter layer and the water distribution pipe, which can save a lot of backwashing water.

technical parameter

Air water oxidation time: 3-5min filter filtration speed: 10-14m / h

Backwashing intensity: 16-19l / M2S, filter layer thickness: 1.2m

Working pressure: 0.05-1.0mpa iron content in raw water: ≤ 20mg / L

Manganese content of raw water: ≤ 10mg / L, iron content of filtered effluent: ≤ 0.3mg/l

Manganese content of treated effluent: ≤ 0.1mg/l

Manganese oxide:

    Manganese oxide is a kind of amphoteric oxide, which is oxidized when it meets reducing agent. For example, manganese dioxide is heated to 1400k in hydrogen gas stream to obtain manganese oxide; Manganese dioxide is heated in ammonia stream to obtain brown black manganese trioxide; Manganese dioxide reacts with concentrated hydrochloric acid to obtain manganese dichloride and chlorine. In case of strong oxidant, it also shows reducibility. If manganese dioxide, potassium carbonate and potassium nitrate or potassium chlorate are mixed and melted, a dark green melt can be obtained. The melt can be dissolved in water and cooled to obtain potassium manganate, a compound of hexavalent manganese. It is a strong oxidant in acid medium.

It is widely used in steelmaking, glass, ceramics, enamel, dry batteries and catalysts

When the catalyst reacts with potassium chlorate, it is not simple catalysis, but will react with raw materials, and finally form manganese dioxide

For organic synthesis: manganese dioxide is very useful in organic chemistry. Manganese dioxide used as oxide has different forms, because manganese dioxide has multiple crystalline forms. The chemical formula can be written as mno2-x (H2O) n, where x is between 0 and 0.5, and N can be greater than 0. Manganese dioxide can be produced in the reaction of potassium permanganate (KMnO4) and manganese sulfate (MnSO4) at different pH. The brown manganese dioxide deposit is dry and active. The most effective organic solvents include aromatic substances, carbon chloride, ether, tetrahydrofuran and esters.