Function: flake caustic soda NaOH is used for industrial sewage treatment, because flake caustic soda mainly contains hydroxyl OH- and sodium ion Na+, in which hydroxyl can combine with many metal ions to form flocs or precipitates. For example, sewage contains metal ions such as aluminum ions (Al3+) or iron ions (Fe3+, Fe2+), strong acid salts and weak acid salts. React with OH- ions in flake caustic soda to form flocs or insoluble precipitates Fe3++3OH- = Fe (OH) 3 and Al3++3OH-= Al(OH)3. The main component of polyaluminum chloride is Al2O3, and its flocculation principle is mainly to combine with OH- ions in sewage to generate Al (OH) 3 floc, thus achieving flocculation effect.

Soda soda and sodium hydroxide can also remove excess acid ions in industrial sewage, such as Cl-, (SO4)2-, (PO4)3- and so on. Sodium hydroxide is also commonly used to adjust the PH value, and the dosage of sodium hydroxide depends on the PH value.

Sewage treatment:

Sewage treatment (wastewater treatment): the process of purifying sewage to meet the water quality requirements of discharged water bodies or reused water bodies. Sewage treatment is widely used in construction, agriculture, transportation, energy, petrochemical, environmental protection, urban landscape, medical treatment, catering and other fields, and it has also entered the daily life of ordinary people more and more.