Application of Water Treatment Chemicals in Coal Washing Plants
Abstract:
The coal washing process generates wastewater that requires effective treatment to meet environmental standards. This article discusses the use of various water treatment chemicals in addressing the pH imbalance and enhancing the sedimentation of coal sludge in coal washing plants.
Introduction:
Coal washing plants face significant challenges in managing wastewater, primarily due to the alkaline pH levels of the water. To address these issues, a combination of anionic and cationic amines is used to achieve the desired pH balance. The treatment process involves several stages, each requiring specific chemicals to ensure the efficient and economic operation of the plant.
Chemicals Used in Coal Washing Process:
1. Frothers: These chemicals are used to create bubbles in the flotation process, which helps in separating coal from impurities.
2. Flotation Agents: These agents enhance the separation of coal particles from the waste material.
3. Defoamers: Used to control foam during the flotation process.
4. Water: A fundamental component in the coal washing process.
5. Heavy Liquids: Used in the separation process to increase the efficiency of coal recovery.
6. Coagulants: Subsequent treatment involves the use of coagulants such as polyacrylamide, aluminum sulfate, and iron sulfate, along with their polymers. These coagulants help in the aggregation of fine particles.
7. Polyaluminum Chloride (PAC): Commonly used as a coagulant and filter aid in coal washing plants. PAC is particularly effective when coal sludge is highly colloidal, as it helps to break down the colloidal structure before the application of flocculants.
Treatment Process:
The coal sludge, which is often colloidal, requires the initial addition of coagulants to disrupt the colloidal structure. This is followed by the application of flocculants, such as polyacrylamide, to enhance the sedimentation of coal sludge. In some cases, to improve the dewatering process, PAC is also used as a filter aid. Polyacrylamide is crucial for rapid sedimentation of coal sludge in thickeners, ensuring the production of qualified wash water and efficient pressurized coal sludge.
Conclusion:
Based on recent years of practical experience in coal washing plant water treatment, polyacrylamide has proven to be effective in treating coal sludge water. It accelerates the settling of coal sludge and aids in the pressurized filtration process, contributing to the high efficiency and economic operation of coal washing plants. The appropriate selection of flocculants is essential for strengthening the treatment of coal sludge water and ensuring the environmental sustainability of coal washing operations.
