Chemical properties of carbonate

Bihaikang Environmental Protection Technology Co., Ltd. With the popularization of water treatment knowledge, carbonate precipitation method is to add some precipitants to water to react with metal ions to generate carbonate precipitation. According to different treatment objects, carbonate method has three different applications: ① adding soluble carbonate (such as sodium carbonate) to make metal ions in water generate insoluble carbonate to precipitate out, which can remove heavy metal ions and noncarbonate hardness in water; (2) Adding insoluble carbonate (such as calcium carbonate), using the principle of precipitation transformation, heavy metal ions in water will generate carbonate with less solubility and precipitate out; (3) Adding lime can harden carbonate in water to generate insoluble calcium carbonate and magnesium hydroxide, which can remove the hardness of carbonate in water. Here are only some examples of treating heavy metal sewage.

(1) Zinc removal For wastewater containing zinc, sodium carbonate can be used as a precipitant and added to the wastewater. After the mixed reaction, zinc carbonate precipitate is generated and separated from water. The sediment can be recycled after being washed with clean water and filtered in vacuum.

(2) Lead removal For lead storage battery wastewater, sodium carbonate can be used as precipitant to react with lead in wastewater to generate lead carbonate precipitate, which is then filtered by sand. When the pH value is 6.4~8.7, the total lead content in the effluent is 0.2~3.8mg/L, and the soluble lead is 0.1mg/L/L. When the lead-containing sewage is filtered by dolomite, the soluble lead can be converted into lead carbonate precipitate and then removed from the sewage.

(3) When using chemical precipitation method to treat copper-containing sewage, sodium carbonate can be used as precipitator. When the pH value of sewage is in alkaline condition, the following chemical reaction is adopted to make copper ions generate water-insoluble basic copper carbonate and separate it from water.