China is a large coal producing country. China's coal resources are widely distributed. Due to various reasons, the nature of coal is also very different. This has obvious differences in the process of coal washing.

The properties of coal formed in different geological ages are different. When the geological age of coal formation is short, the raw coal ash content and impurity content are relatively high. When washing coal, the concentration of wastewater generated is relatively large. We call such coal washing wastewater a high concentration coal washing wastewater.

High concentration coal washing wastewater has the following characteristics:

1, the concentration of wastewater is large, the content of suspended solids is large, the COD is high, the wastewater is alkaline, and the PH value is between 8-8.5.

2. The high-concentration coal washing wastewater has a high content of fine particles, and the smaller the particle size of the fine particles, the more difficult the sedimentation separation is.

3. The suspended particles in the high-concentration coal washing wastewater are strongly negatively charged, and the coal washing wastewater is in a colloidal dispersion system with strong cutting stability.

4. The sludge with high concentration of coal washing wastewater has large resistance and poor water filtration, and it is difficult to press and dewater.

High concentration coal washing wastewater treatment:

In view of the characteristics of high-concentration coal washing wastewater, our Noel Group has summarized the following treatment methods through a large number of experiments: firstly adding lime or calcium carbide slag (the composition is calcium oxide) to the wastewater, neutralizing the negative charge in the wastewater, destroying the water body. Stability, to achieve the purpose of mud and water separation. The wastewater suspension treated in this way is slow to settle, complete precipitation is difficult to achieve, and it takes a long time. Usually, flocculant (PAM) is required. PAM has a long molecular chain and has different molecular chains. The group, the long molecular chain can adsorb the suspended particles in the wastewater, and the suspended particles collide with each other to form a larger floc settlement. The sedimentation speed is fast and the muddy water is completely separated. With many years of experience, anionic PAM or non-ionic PAM is generally used for coal washing wastewater treatment, but there are also a few uses of cationic PAM. It is recommended that when using flocculants, the flocculant must be selected first to avoid unnecessary waste.