基于微波热解膜分离蒸发结晶的废盐资源化中试研究

Pilot Study on Waste Salt Resource Utilization Based on Microwave Pyrolysis Membrane Separation and Evaporation Crystallization

为探索可行的医药农药行业废盐资源化路径,采用“微波热解+膜分盐浓缩+蒸发结晶”主体工艺对医药、农药废盐进行中试研究,480~520℃氮气气氛下微波热解50~60 min,热解后盐溶液经超滤过滤后COD为69~78 mg·L^(-1),经过纳滤分盐、膜浓缩、蒸发结晶后,得到的副产氯化钠基本满足《工业盐》(GB/T 5462—2015)中工业干盐二级指标,副产硫酸钠满足《工业无水硫酸钠》(GB/T 6009—2014)中Ⅲ类一等品指标,副产氯化钠中的总有机碳为79.2 mg·kg^(-1),副产硫酸钠中的总有机碳为95 mg·kg^(-1),实现了含有机物危废盐的资源化全流程路径打通。采用该工艺对危废杂盐资源化的综合处置成本为每吨1750元,明显低于危废处置市场价,具有经济可行性。

In order to explore the resource utilization path of waste salt in pharmaceutical and pesticide industry,the main process of"microwave pyrolysis+membrane salt concentration+evaporation crystallization"was used to conduct a pilot study on pharmaceutical and pesticide waste salt.Microwave pyrolysis took place at nitrogen atmosphere of 480~520℃for 50~60 min,and after ultrafiltration and filtration,the COD of the salt solution after pyrolysis was 69~78 mg·L^(-1).After nanofiltration salt separation,film concentration and evaporation crystallization,the by-product sodium chloride met the second-level index of industrial dry salt in"Industrial Salt"(GB/T 5462—2015),and the by-product sodium sulfate met the categoryⅢfirst-grade index in"Industrial anhydrous sodium sulfate"(GB/T 6009—2014).The total organic carbon in by-product sodium chloride was 79.2 mg·kg^(-1),and the total organic carbon in by-product sodium sulfate was 95 mg·kg^(-1),which realized the whole process resource utilization route containing hazardous waste salt of organic matter.The comprehensive disposal cost of this process for the recycling of hazardous waste and miscellaneous salt was 1750 Yuan per ton,which was obviously lower than the market price of hazardous waste disposal and was economically feasible.