Steel wet desulphurization wastewater treatment system and method

Abstract

The invention discloses a steel wet desulphurization wastewater treatment system and method. The method comprises the following steps: carrying out plate-and-frame pressure filtration, secondary chemical hardness removal, concentration precipitation on steel wet desulfurization wastewater, conducting filtration treatment to remove impurities in the wastewater, carrying out deamination treatment to remove ammonia nitrogen in the wastewater, and carrying out softening treatment, nanofiltration membrane treatment, membrane treatment or electrodialysis treatment and evaporative crystallization treatment to obtain clear water and high-purity sodium sulfate and sodium chloride. According to the method, complex factors such as gypsum suspended solids, high hardness, high chloride ions, high ammonia nitrogen, high sulfate ions, fluorine ions, heavy metal ions and COD in the wastewater can be effectively removed, the obtained clear water can be recycled as industrial new water, and zero discharge treatment of the steel wet desulfurization wastewater is realized; and high-purity sodium chloride and sodium sulfate salt with certain economic recovery value are obtained, so that recycling of resources is realized.

Description

Technical field[0001]The present invention relates to the field of resource environment wastewater treatment, in particular, to a steel wet method desulfurization wastewater treatment system.Background technique[0002]Commonly used flue gas desulfurization methods are wet, semi-drying and dry methods. In many desulfurization techniques, limestone-gypsum wet flue gas desulfurization processes become a wide range of desulfurization techniques for steel mills in terms of technology maturation, high desulfurization efficiency and good intention to flue gas conditions. However, during operation of the desulfurization process, HCl, particulate matter, heavy metals in flue gas is constantly enriched in desulfurization slurry, enriched to a certain extent, causing a variety of desulfurization efficiency, equipment corrosion acceleration, etc., therefore, must be discharged A certain amount of wastewater is controlled to control the concentration of various impurities in desulfurization.[0003...

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Problems solved by technology

At present, the main treatment processes for this kind of wet desulfurization wastewater mainly include chemical precipitation method, concentration reduction + evaporation crystallization. The wastewater or crystallized salt produced by the above process has complex components and secondary pollution, which will increase the production cost and burden of enterprises. And can not completely realize the zero discharge of desulfurization wastewater pollutants

After the wet desulfurization wastewater is treated, it must meet the direct discharge standard in the "Discharge Standard of Water Pollutants for the Iron and Steel Industry" (GB13456-2012). However, the pollution factors of this type of wastewater are complex and the concentration is high. Without good operation, it is difficult to meet this standard. The wastewater contains a large amount of gypsum suspended matter, chloride ions, ammonia nitrogen, sulfate ions and COD and other complex factors, which are highly corrosive and difficult to circulate. use

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