Polyaluminum chloride (PAC) is an inorganic substance, an emerging water purification material, and an inorganic polymer coagulant, abbreviated as polyaluminum. It is a water-soluble inorganic polymer between AlCl3 and Al (OH) 3, with a chemical formula of [Al2 (OH) nCl6-n] m, where m represents the degree of polymerization and n represents the neutrality of the PAC product. N=1-5 are highly charged polymer cyclic chains with Keggin structure, which have high electrical neutralization and bridging effects on colloids and particles in water, and can strongly remove trace toxins and heavy metal ions, with stable properties. The inspection method can be carried out according to the national standard GB 15892-2003. Due to the bridging effect of hydroxide ions and the polymerization effect of multivalent anions, the produced polyaluminum chloride is an inorganic polymer water treatment agent with a relatively large molecular weight and high charge.  [3]

Physical and Chemical Properties

Polyaluminum chloride has properties such as adsorption, coagulation, and precipitation, but its stability is poor and it is corrosive. If it accidentally splashes onto the skin, it should be immediately rinsed with water. Production personnel should wear work clothes, masks, gloves, and long rubber boots. Polyaluminum chloride has the advantages of good spray drying stability, wide adaptability to water area, fast hydrolysis speed, strong adsorption capacity, large alum formation, fast mass density and sedimentation, low effluent turbidity, and good dehydration performance. Using spray drying products can determine safety, reduce water accidents, and be safe and reliable for residents' drinking water. Therefore, polyaluminum chloride is also referred to as high efficiency polyaluminum chloride, high efficiency PAC or high efficiency spray drying polyaluminum chloride. Polyaluminum chloride is suitable for various turbidity levels of raw water and has a wide pH range. However, compared to polyacrylamide, its settling effect is far inferior.
The basicity of polyaluminum chloride is a relatively important indicator in polyaluminum, especially for polyaluminum products of drinking water grade. The lower the salinity, the higher the price, and each purchaser can operate according to the actual situation of the manufacturer. In addition, the basicity of polyaluminum chloride products produced and processed by different raw materials and processes also varies, which requires manufacturers to make adjustments. Improving the basicity of polyaluminum chloride products can significantly enhance the economic benefits of production and use. The increase in salinity from 65% to 92% can reduce production raw material costs by 20% and usage costs by 40%.

Concentration ratio method

When diluting solid polyaluminum chloride into liquid, the appropriate dosage should be determined by conducting a small test before use based on the raw water conditions. When using polyaluminum chloride in production, it can be dissolved by mixing it in a mass ratio of solid polyaluminum chloride: water=1:9-1:15. Solutions with alumina content less than 1% are prone to hydrolysis, which can reduce the effectiveness of use. If the concentration is too high, it should not be evenly distributed. After the medication is used, if there are few alum flowers and a large amount of turbidity in the sedimentation tank, the dosage is too low; If the alum in the sedimentation tank is large and flipped up, the dosage should be adjusted appropriately.

Color Type

The colors of polyaluminum chloride generally include white, yellow, and brown. Different colors of polyaluminum chloride also have significant differences in application and production technology. Polyaluminum chloride with alumina content between 27% and 30% within the national standard range is mostly in solid powder form, ranging from earthy yellow to yellow or light yellow. These types of polyaluminum chloride have good water solubility, accompanied by physical and chemical changes such as electrochemistry, coagulation, adsorption, and precipitation during the dissolution process. The formation of flocs is fast and coarse, with high activity, fast precipitation, and significant purification effect on high turbidity water.
White polyaluminum chloride is called high purity iron free white polyaluminum chloride, or food grade white polyaluminum chloride. Compared with other polyaluminium chloride, white polyaluminum chloride is a product of high quality. The main raw materials are high-quality aluminum hydroxide powder and hydrochloric acid. The production process adopted is the advanced technology of spray drying. White polyaluminum chloride is used as a sizing agent for papermaking, a decolorizing and clarifying agent for sugar production, tanning agents, pharmaceuticals, cosmetics, precision casting, and water treatment in various fields.

The raw materials of yellow polyaluminum chloride are calcium aluminate powder, hydrochloric acid and bauxite, which are mainly used for sewage treatment and drinking water treatment. The raw materials for drinking water treatment are aluminum hydroxide powder, hydrochloric acid, and a little calcium aluminate powder. The process adopted is the plate and frame filter pressing process or spray drying process. For the treatment of drinking water, the country has strict requirements for heavy metals, so both raw materials and production processes are better than brown polyaluminum chloride. Yellow polyaluminium chloride is generally produced by drum drying or spray tower drying, and has two solid forms, namely, flake and powder.

The raw materials for brown polyaluminum chloride are calcium aluminate powder, hydrochloric acid, bauxite, and iron powder. The production process adopts drum drying method, which is mainly used in sewage treatment. Because iron powder is added inside, the color is brown. The more iron powder added, the darker the color. If the iron powder exceeds the quantitative limit, it is also called polyaluminum chloride iron at some times, which has excellent effect in sewage treatment.

superiority

PAC polyaluminum chloride has the advantages of good drying stability of spray, wide adaptability to water area, fast hydrolysis speed, strong adsorption capacity, large alum formation, fast density and sedimentation, low effluent turbidity, good dehydration performance, etc. Under the same water quality, the dosage of spray drying polyaluminum chloride is reduced. Especially under the condition of poor water quality, the dosage of spray drying products can be reduced by half compared with drum drying polyaluminum chloride, which not only reduces the labor intensity of workers, but also, more importantly, reduces the water production cost of users. In addition, drying products with spray can ensure safety and reduce water accidents.
Polyaluminum chloride, also known as high-efficiency polyaluminum chloride or high-efficiency PAC. Adopting advanced production technology and using efficient and high-quality raw materials for reaction polymerization. Production shall be carried out in accordance with the requirements of the national standard GB15892-2009. Polyaluminium chloride is processed by spray drying process Therefore, it can also be called high-efficiency spray drying polyaluminum chloride.

Basic information

Chinese name: Polyaluminum chloride (abbreviated as polyaluminum chloride)

Poly aluminum chloride is codenamed PAC. Commonly known as a water purifier or coagulant, it is a water-soluble inorganic polymer between AlCl3 and Al (OH) 3, with the chemical formula [Al2 (OH) nCl6-n] m, where m represents the degree of polymerization and n represents the neutrality of PAC products.

The color is yellow or light yellow, dark brown, dark gray resin like solid. This product has strong bridging adsorption performance, and during the hydrolysis process, physical and chemical processes such as coagulation, adsorption, and precipitation occur. The fundamental difference between polyaluminum chloride and traditional inorganic coagulants is that traditional inorganic coagulants are low molecular weight crystalline salts, while polyaluminum chloride's structure is composed of multi carboxyl complex compounds with diverse forms. It has a fast flocculation and precipitation rate, a wide range of applicable pH values, no corrosiveness to pipeline equipment, obvious water purification effect, and can effectively support the removal of heavy metal ions such as color SS, COD, BOD, arsenic, mercury, etc. This product is widely used in the fields of drinking water, industrial water, and sewage treatment.