Operation and Storage Notes for Polyaluminium Chloride(PAC)
- 1. In operation, the water purification process of polyaluminum chloride is generally divided into three stages. These three stages are the coagulation stage, the flocculation stage and the sedimentation stage. In the coagulation stage, when the chemical liquid is injected into the coagulation container and the raw water is quickly coagulated, fine alum blooms will be formed in a very short time. At this time, the water body becomes more turbid, which requires the water flow to produce intense turbulence. Then the polyaluminum chloride enters the flocculation stage. The flocculation stage is the process of the growth and thickening of the alum. It requires a proper degree of turbulence and sufficient residence time (10-15min). In the later stage, a large amount of alum clusters can be observed to slowly sink. A clear surface layer is formed.
When the flocculant is in the settling stage, it is a floc settling process carried out in the settling tank, requiring slow water flow. In order to improve efficiency, inclined tube or plate settlers are generally used, and a large number of thick alum flowers are blocked by the inclined tube (plate) wall. While deposited at the bottom of the pool, the upper layer of water is clarified water, and the remaining alums with small particle size and low density slowly drop while continuing to collide with each other and build up, and the remaining turbidity remains basically unchanged in the later stage.
- 2. Polyaluminum chloride must be stored in a dry, moisture-proof, and heat-proof place (<80℃, do not damage the package, the product can be stored for a long time).
- 3. Polyaluminum chloride products must be dissolved before they can be used. The dissolution equipment and dosing facilities should be made of corrosion-resistant materials.
- 4. The effective storage period of polyaluminum chloride liquid products is half a year, and the effective storage period of solid products is two years. The solid products can still be used after being damp.