Sodium carbonate is one of the important chemical raw materials, which is widely used in light industry, daily chemical industry, building materials, chemical industry, food industry, metallurgy, textile, petroleum, national defense, medicine and other fields. Among industrial alkali, light industry, building materials and chemical industry account for about 2/3, followed by metallurgy, textile, petroleum, national defense and other industries. It is used as an alkaline neutralizer in wastewater treatment to neutralize free acid ions. The supplied carbonate ions react directly with metal ions to form insoluble precipitates; Adjust the pH value to alkalinity to obtain conditions conducive to metal oxide deposition.