Polyaluminum chloride for drinking water is filtered using 60 filter plates. After filtering through various material filter plates, the water insoluble content is greatly reduced, and the 10% aqueous solution is a light yellow transparent liquid. Can ensure that the user's pipeline is unobstructed, and at the same time increase the drug use rate, which is not achieved by the natural sedimentation method. In addition to the small amount of water-insoluble matter, the content of heavy metals and other harmful substances is also very small, and the use effect can be comparable to that of spray-polymerized aluminum chloride.
Use plan of drinking water polyaluminum chloride:
1. Before use, put the product into the dissolving tank at a certain concentration (10-30%), inject tap water and stir it to fully hydrolyze, leave it to be a colorless transparent liquid, and then dilute with water to the required concentration and add coagulation. Water plants can also be formulated directly at 2-5%, and industrial wastewater treatment can be directly formulated at 5-10%.2. Determination of the dosage, depending on the nature of the raw water, it can be determined by the proper amount of alum flower formation through production debugging or burnout experiments. Water plants can use the original dosage of other medicines as a reference. Under the same conditions, the amount of this product and solid polymerized alumina is slightly lower, which is 1 / 3-1 / 4 of the amount of solid aluminum sulfate. If the original liquid product is used, it can be calculated according to the concentration of the corresponding agent.
3. When in use, pump the prepared medicinal solution into the metering tank, and coagulate with the raw water by metering and adding the medicinal solution.
4. In general, the preparation is used on the same day. The dispensing requires tap water, and a slight precipitation is normal.
Method for preparing drinking water polyaluminum chloride
There are many methods for synthesizing polyaluminum chloride. According to different raw materials, they can be divided into aluminum metal method, active aluminum hydroxide method, aluminum trioxide method, aluminum chloride method, and so on.
Metal aluminum method
The raw materials for the synthesis of polyaluminum chloride by the metal aluminum method are mainly aluminum processing scraps, such as aluminum shavings, aluminum ash, and aluminum slag. Liquid aluminum chloride is slowly added from aluminum ash according to a certain proportion under stirring to react, and liquid polymerized aluminum chloride is obtained through aging polymerization and sedimentation, and then diluted, filtered, concentrated, and dried to obtain. It can be divided into three types: acid method, alkaline method and neutralization method. The acid method mainly uses HCl, and the product quality is not easy to control; the alkaline method has a difficult production process, large equipment investment and large amount of alkali, pH control costs, and high raw materials costs; the most commonly used method is the neutralization method. Good matching, generally can meet national standards.
Aluminum hydroxide method
The purity of aluminum hydroxide powder is relatively high, and the content of toxic substances such as synthetic polyaluminum chloride heavy metal is low. Generally, the production process of heating and pressing acid solution is adopted. This process is relatively simple, but the salinity of the produced polyaluminum chloride is relatively low. Therefore, aluminum hydroxide is generally used to heat and pressurize the acid and then add calcium aluminate powder to neutralize the two processes.
Three alumina method
The raw materials containing alumina are mainly gibbsite, bauxite, kaolin, coal gangue and so on. The production process can be divided into two steps: the first step is to obtain crystalline aluminum chloride, and the second step is to obtain polyaluminum chloride by pyrolysis or neutralization.
Polyaluminum chloride in drinking water
The flocculation of poly (combined) aluminum chloride is as follows:
a. Strong electrical neutralization of colloidal substances in water.
b. The excellent bridging adsorption effect of the hydrolysate on suspended matter in water.
c. Selective adsorption of soluble substances.
Polyaluminum chloride is an inorganic polymer coagulant. Due to the bridging effect of hydroxide ions and the polymerization of polyvalent anions, it has the characteristics of large molecular weight and high charge inorganic polymer water treatment agent Mainly determined by the working principle of the pressure atomizer, this drying system has its own characteristics. Because the products obtained by pressure spray drying are porous particles or hollow particles, pressure spray drying and anionic polyacrylamide are used for the purpose of obtaining granular products. The obtained granular products have excellent dustproof performance and flow performance.
Polyaluminum chloride properties in drinking water
Compared with other coagulants, this product has the following advantages:
1. Wide application range and wide adaptability to water.
2. It is easy to form large alum flowers quickly and has good precipitation. The floc formed by the coagulation reaction is coarse, not easy to break, good recoagulability, fast sedimentation speed, good filtration of sedimentation water, strong compressibility of sediment, and easy dehydration. Purified water is better than inorganic coagulants such as aluminum sulfate, and the cost of water purification is 15-30% lower than that
3. Due to the rapid coagulation reaction of this product, strong neutralization and destabilization power, long molecular chain links and rapid bridging, it can overcome the difficulties of low temperature and low turbid water treatment.
4. The suitable pH range is wide (between 5 and 9), and the pH and alkalinity of the treated water decrease little.
5. When the water temperature is low, it can still maintain a stable precipitation effect.
6. Alkalinity is higher than other aluminum and iron salts, easily soluble in water, convenient to use, and stable in quality. Solubility is better than aluminum sulfate, less corrosive to equipment.
7. The floc produced by this product is network-shaped and has a large specific surface area, so it has a strong adsorption and removal effect on iron, fluorine, arsenic and bacteria in water.
8. This product has a high content of active ingredients and low transportation costs.