摘要
Abstract
[Objective]This paper aims to comprehensively enhance the competitiveness of integrated steel enterprises,achieve better performance in all indices,and address characteristic refractory wastewaters(such as desulfurization wastewater,sintering acid-making wastewater,and coking wastewater).These wastewater,after being treated to meet standards,are often sent to blast furnace slag flushing,converter slag steaming,sintering material mixing,etc.They are corrosive to equipment and the salts transfer to water slag and steel slag products,posing a risk of organic pollution being transferred to the air.[Methods]A steel enterprise generated 5 000 m³/d of high salt,high concentration wastewater from power plant desulfurization,sintering acid-making,and coking processes.Through a newly constructed zero-discharge treatment system,these refractory wastewaters were classified and collected based on their water quality characteristics.Using the"waste treatment with waste"strategy,high calcium ions in desulfurization wastewater and resin acid regeneration wastewater were utilized to react with the high fluoride ions and high alkalinity in acid-making wastewater,forming precipitates via a two-phase reaction.This reduced the dosage of defluorination and hardness-removal agents,creating stable operating conditions for subsequent membrane separation concentration and evaporation crystallization processes.[Results]This research results created stable operating conditions for the subsequent membrane separation concentration and evaporation crystallization process sections.After two months of engineering commissioning,the system achieved an overall water production rate of 98%.The produced water had an average conductivity of 423.9 μS/cm and a chloride ion mass concentration of 78.8 mg/L.The purity of the generated industrial salts—sodium chloride and sodium sulfate were over 99.8%and 98.3%,respectively,successfully realizing zero discharge of the enterprise's refractory wastewaters with significant social benefits.[Conclusion]This practice demonstrates that the technology is mature,feasible,and stable operation.For mixed refractory wastewater with a conductivity of approximately 50 000 μS/cm,the zero-discharge operation cost per ton is controlled at 25-35 yuan.关键词
钢铁废水/零排放/以废治废/脱盐率/工业盐Key words
steel wastewater/zero discharge/treating waste with waste/desalination rate/industrial salt分类
建筑与水利
