Sodium sulfate wastewater treatment process

Abstract

The invention relates to a sodium sulfate wastewater treatment process. The treatment process sequentially comprises the following steps: (1) introducing new sodium sulfate wastewater into a preheating unit, and preheating to raise the temperature; (2) introducing the preheated sodium sulfate wastewater into a single-effect falling film evaporator, and performing heating evaporation concentration to obtain a single-effect concentrate; (3) introducing the single-effect concentrate into a double-effect falling film evaporator, and performing further heating evaporation concentration to obtain a double-effect concentrate; (4) feeding the double-effect concentrate into a forced circulation evaporation crystallizer through a material transfer pump, performing heating evaporation crystallization, and discharging crystal slurry containing sodium sulfate crystals from a salt leg at the bottom of an evaporation chamber of the forced circulation evaporation crystallizer; (5) separating the crystal slurry containing sodium sulfate crystals discharged from the salt leg by a centrifuge; (6) feeding the sodium sulfate crystals separated out by the centrifuge into a fluidized bed drying system through a material conveyor belt, and drying; and (7) introducing the dried sodium sulfate crystals into an automatic packaging system, and packaging to obtain an industrial sodium sulfate finished product. The process is low in energy consumption, and can realize full recovery of sodium sulfate.

Description

technical field [0001] The invention relates to a treatment process for sodium sulfate wastewater, belonging to the technical field of industrial wastewater treatment. Background technique [0002] Sodium sulfate-containing wastewater is one of the most common high-salt wastewater in industrial wastewater. Generally, due to its high salt content, it cannot be completely treated by wastewater treatment methods such as biochemical degradation. [0003] The Chinese invention patent application with the publication number CN 105776466A discloses a method for purifying sodium sulfate wastewater, which is carried out continuously in a purification system with three reaction tanks, and the waste water is put into the primary reaction tank where sodium sulfate wastewater is placed. Calcium bisulfite and calcium hydroxide emulsion with a mass fraction of 10-25% in the amount of sodium sulfate and other substances in the medium, and then put into the secondary reaction tank and the te...

AI Technical Summary

Problems solved by technology

Using a multi-effect evaporator to desalinate sodium sulfate wastewater will consume a large amount of steam, resulting in high energy consumption costs and high unit treatment costs for wastewater; at the same time, the solid salt produced by evaporation can only be treated as solid waste because it contains impurities, and additional increase Dealing with cost and environmental pressures

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