Polyaluminum chloride (PAC) is a kind of water-soluble inorganic polymer polymer between AlCi3 and Al (OH) 3. The general chemical formula is [Al2 (OH) ncl6 NLM].
In general, there is a big difference in the production of white and brown aluminum chloride. In the national standard range, polyaluminum chloride with alumina content between 27% and 30% is mostly earth yellow, to yellow, light yellow solid powder. These types of polyaluminum chloride have good water solubility. In the process of dissolution, accompanied by electrochemical, coagulation, adsorption and precipitation and other physical and chemical changes, the formation of flocs is fast and coarse, the activity is high, the precipitation is fast, and the purification effect of high turbidity water is obvious.
Flocculation of polyaluminum chloride ：
1. Strong electric neutralization of colloidal substances in water.
2. The hydrolysate has excellent bridging adsorption to suspended solids in water.
3. Selective adsorption of soluble substances.
Morphology of polyaluminum chloride
1. The liquid polyaluminum chloride is in the form of non drying. It has the advantages of no dilution, convenient loading and unloading, and relatively low price. The disadvantage is that the transportation needs tank cars, and the unit transportation cost is increased (each ton of solid is equivalent to 2-3 tons of liquid), which is more suitable for users within 100 kilometers
2. Solid polyaluminum chloride is the dried form of liquid polyaluminum chloride. It has the advantages of convenient transportation, no tank car is needed, and the disadvantage is that it needs dilution to increase working strength
Classification of polyaluminum process
1. Drum polyaluminum chloride: the aluminum content is general, and the water insoluble matter is high, which is mostly used for sewage treatment.
2. Polyaluminum chloride with high content and low water insoluble matter is used for municipal sewage treatment and domestic sewage treatment.
3. Spray drying polyaluminum chloride: high aluminum content, low water insoluble matter, fast dissolving speed. Used for drinking water and higher standard water treatment.
Application of polyaluminum chloride
1. Urban water supply and drainage purification: River water, reservoir water and groundwater.
2. Industrial water purification.
3. Urban sewage treatment.
4. Recovery of useful substances in industrial wastewater and waste residue, promotion of coal dust settlement in coal washing wastewater, and starch recovery in starch manufacturing industry.
5. Various industrial wastewater treatment: printing and dyeing wastewater, leather wastewater, fluoride wastewater, heavy metal wastewater, oily wastewater, papermaking wastewater, coal washing wastewater, mine wastewater, brewing wastewater, metallurgical wastewater, meat processing wastewater, sewage treatment.
⒍ paper sizing.
The sugar liquid was refined.
The cloth is wrinkle resistant.
⒑ catalyst support.
⒒ pharmaceutical refining
⒓⒓ cement quick setting.
Make up raw materials.
Application of polyaluminum chloride
The solid product is dissolved into liquid by 1:3 water, and then diluted with 10-30 times water to the required concentration. The appropriate pH value is 3.5-5.0, and it can play a better role in coagulation by selecting the appropriate pH value. The dosage can be determined according to the different turbidity of raw water. Generally, when the turbidity of raw water is 100-500mg / L, the dosage per thousand tons is 10-20kg. When the turbidity of raw water is high, the dosage can be increased appropriately, and when the turbidity is low, the dosage can be appropriately reduced.
For rural use, the agent can be put into the water tank, stirring evenly, standing, the supernatant can be used, about 1g of this agent is added every 50kg. It is better to combine the flocculant with the water purification agent.
The anionic polyacrylamide or cationic polyacrylamide produced by the company can be dissolved together with PAC to form a composite flocculant, or PAC can be added to the treated water to form a coagulant, and then the anionic polyacrylamide produced by Zhengyuan is added to absorb and bridge into a large flocculant.
Dosage of polyaluminum chloride:
1. In low turbidity water, dilute the solid polyaluminum chloride product with tap water in the proportion of 1:3 (weight ratio), and stir until completely dissolved
2. In domestic and production sewage, about 30g of polyaluminum chloride product should be added first according to each ton of sewage. Then add diluted polyacrylamide product, (if the effect is not obvious, please reduce or increase the dosage of product as appropriate. )
3. In paper mill wastewater treatment, the proportion of low turbidity water should be used. If the effect is not obvious, it can be added as appropriate.
4. When the turbidity of raw water is 100-500mg / L, the dosage is 5-10mg, that is, the dosage is 5-10kg per thousand tons of water. Before use, small-scale tests are conducted according to the water quality characteristics to select the appropriate value, and then put into use.
Precautions for polyaluminum chloride
1. 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).
2. Polyaluminum chloride products must be dissolved before use, and corrosion-resistant materials should be used for dissolving equipment and dosing facilities.
3. The effective storage period of the liquid product of polyaluminum chloride is half a year, and the solid product can still be used after being damped.