Application of polyacrylamide in coal washing industry, Polyacrylamide for coal mine.
Coal mining, clean coal screening, coal yard sewage treatment, etc. all need polyacrylamide; everyone knows that the coal washing wastewater from the coal industry, the slime water from coal preparation plants, and the ground washing wastewater from coal-fired power plants are all water and The main characteristics of a mixture of fine coal powder are high turbidity, fine particle size of solids, many negative charges on the surface of solid particles, and the repulsion between the same charges keeps these particles in a dispersed state in water and is affected by gravity and Brownian motion; The interaction between solid particles in the slime water (such as adsorption, dissolution, compounding, etc.) makes the properties of coal washing wastewater quite complicated, not only having the properties of suspension, but also the properties of colloid. Polyacrylamide for coal mine
Due to the above reasons, it is difficult to clarify coal washing wastewater naturally, and the supernatant of this kind of wastewater is still black liquid with a large amount of suspended solids such as coal slime after precipitation, which contains various additives and heavy metals in the coal preparation process. substance. A large amount of coal washing wastewater was not discharged up to the standard, causing water pollution, river siltation, and slime loss, causing great economic losses to the country, making the coal industry more scarce of water resources, and seriously restricting the development of coal production. Therefore, it is of great significance to develop new technologies and processes for efficient treatment of coal washing wastewater. Special precipitating agent for coal washing In order to make the slime water quickly settle in the thickening tank, ensure the production of qualified washing water and press-filtered slime, and make the production efficient and economical, it is necessary to select a suitable flocculant to strengthen the treatment of slime water.
1. The mechanism of coal washing precipitant
Flocculant is abbreviated as PAM, which is a linear high molecular polymer, non-toxic, non-corrosive, and easily soluble in water. After its aqueous solution is mixed with slime water, the active groups on the molecular chain of the special precipitating agent for coal washing and slime water Adsorption occurs on the surface of the fine particles, which acts as a connection between the particles, causing the fine particles to form larger flocs, and accelerating the sedimentation speed of the slime. The addition of the special precipitation agent aqueous solution for coal washing is a key link in the treatment of slime water, and appropriate addition methods will help improve the flocculation effect.
2. How to use
The special precipitant for coal washing must be added in an appropriate amount to effectively exert its flocculation effect for the treatment of slime sewage. It can be determined through experiments according to the selected slime water treatment process and the properties of the slime water. A small amount will cause the sedimentation speed of coal slime to slow down, the concentration overflow is very easy to exceed the standard, and the required circulating water index cannot be guaranteed, which makes it difficult to control the coal washing product index stably. Excessive amount, although it accelerates the sedimentation rate of coal slime, it is easy to cause the concentration of underflow concentration to be too high; generally the underflow concentration of concentrated underflow is required to be 500g/L, which can meet the pressure filtration production; too much amount makes the underflow concentration of concentrated underflow as high as 700g/L. L above, and the content in the underflow increases, which is unfavorable for underflow transportation and filter press production. The coal cake is not easy to fall off when the coal cake is unloaded by the filter press, which increases the labor intensity of the operator and reduces the work efficiency; it also causes waste of chemicals. Increase production costs. Therefore, proper use of polypropylene phthalamide can not only improve the flocculation effect and effectively treat the slime water, but also play an important role in ensuring the indicators of coal washing products, improving work efficiency and reducing costs.
The production practice in recent years has proved that our company's medium degree of hydrolysis anionic flocculant has a better effect on the treatment of slime water, and can accelerate the sedimentation of slime and help filter press production.
The polyacrylamide flocculant used in coal mine wastewater can effectively clarify the coal mine wastewater, make the fine particles in the water quickly clump and settle, improve the working efficiency of the sedimentation tank, and thus achieve the effects of saving water and preventing pollution, and further improve the company's profit. Polyacrylamide for coal mine is a more professional polyacrylamide. In fact, only the internal chemical composition has been adjusted. Special polyacrylamide for coal washing The special polyacrylamide for coal washing is several times better than ordinary polyacrylamide. It is very effective in coal washing and pressure filtration, or in the discharged groundwater. Its reaction time is about 5 seconds. Seeing the effect of precipitation, so many coal mines choose the reason for coal washing special flocculant. The coal mined in coal mining usually contains some impurities, and the separation efficiency of coal and impurities can be improved by adding a flotation agent. Clean coal floats out and the tail coal settles. The clean coal in the tail coal is then recovered by sedimentation, filtration or centrifugation. Polyacrylamide PAM is used in the sedimentation process to promote solid-liquid separation. It is then sent to the concentrator, where the clean water is recovered from the overflow of the concentrator and recycled. The powdered clean coal is recovered by filtration and centrifugation. Polyacrylamide is added again during filtration and centrifugation to improve the separation efficiency. In order to meet the needs of users in this aspect, we have produced special flocculants for coal washing, which have better effects on different coal mines, and also greatly reduce the amount of drugs used.
The usage index of Polyacrylamide for coal mine can refer to the following table:
Coal mine wastewater treatment polyacrylamide flocculant use method: 1, formulated into 0.2% concentration of aqueous solution is suitable for practical neutral salt-free water. 2. Due to the wide range of PH value of the water body applicable to this product, the general dosage is 0.1-10ppm (0.1-10mg/L). 3. Fully dissolved. The dissolving concentration is 0.2-0.4%. Non-ferrous containers should be used. When dissolving, the water body should be fully stirred up and then slowly and evenly add medicine powder to prevent blockage of pipes and pumps caused by large flocs and fish eyes; 4. The stirring speed is generally 200 rpm, and the time is not less than 60 minutes. Properly increasing the water temperature by 20-30 degrees Celsius can accelerate the dissolution. The temperature of the drug solution should be less than 60 degrees. 5. Add the dissolved aqueous solution to the coal mine wastewater evenly by using a valve or a metering pump to control the flow rate. 6. Determine the dosage. Determine the dosage by experiment before use. Because the dosage is too low, it has no effect, and the dosage is too high, but it has a reverse effect. When it exceeds a certain concentration, PAM not only does not flocculate, but is dispersed and used stably.
Precautions for the use of polyacrylamide. 1. If dissolved, improperly soluble flocculent suspended substances will hang on the surface of the water. It should be filtered off or slowly wait for dissolution before use, without affecting the use effect. 2. The amount of addition should be moderate, too much or too little can not play an obvious flocculation effect, users should adjust the amount according to different conditions such as wastewater water quality, water flow speed and solid content. 3. If the amount of flocculant used is small during use, the effect is not ideal, but when the amount is increased, it will cause refractory diseases such as wire drawing. The method of reducing or increasing the concentration of the flocculant solution and increasing the flow rate can be used to increase the amount of flocculant. Alternatively, the position of adding the flocculant can be moved back to increase the mixing time of the flocculant and the tailings water to solve the above problem.