Introduction to the Classification of Polyaluminum Chloride (PAC) Products

Polyaluminum chloride, abbreviated as PAC, is produced by adding a certain amount of aluminum sulfate to a specific quantity of industrial waste hydrochloric acid in a reaction tank. The mixture is heated using steam under agitation. After the reaction is complete, a certain amount of calcium aluminate powder is added, and the mixture is stirred at a specific temperature until the reaction is complete. This is the PAC mother liquor. The PAC mother liquor settles in a sedimentation tank and, after rotary drum drying, becomes yellow-brown granules. Generally, this type of PAC has a concentration below 28%. If the PAC mother liquor undergoes filtration using a plate-and-frame filter press and is then dried in a rotary drum, it becomes yellow-brown granules with a concentration generally at or above 28%.

Polyaluminum chloride can be classified into three categories based on different properties:
The production process is different
Whether it undergoes plate-and-frame filtration
Whether iron elements are added

Within these three main categories, further classification is possible:

Classification based on different production processes:
a. Granular form obtained through rotary drum drying
b. Powder form obtained through spray drying

Classification based on whether it undergoes plate-and-frame filtration:
a. Yellow-brown color for PAC without plate-and-frame filtration
b. Light yellow color for PAC with plate-and-frame filtration

Classification based on whether iron elements are added:
a. Red-brown color when iron elements are added
b. Yellow-brown color when no iron elements are added

To determine the quality of PAC based on its appearance, the higher the dryness, the higher the concentration. Uniform particle size without agglomeration is preferable.

It is desirable for PAC to have a higher content of aluminum trioxide (Al2O3), a lower content of insoluble substances in water, and a lower content of heavy metals.

In practical applications, the optimal PAC concentration depends on the specific requirements and usage scenario, rather than simply aiming for the highest concentration.

Last Updated on 2024-01-04 by system