摘要
针对冶金行业产生的高盐废水,采用纳滤冷冻析硝耦合工艺处理NaCl和Na_(2)SO_(4)的混合模拟废水,实现对Na_(2)SO_(4)的资源化利用。纳滤实验考察NaCl和Na_(2)SO_(4)的质量浓度比、压力、流速和温度对膜分离效果的影响,同时确定纳滤工段的最优方案。冷冻析硝实验考察纳滤浓缩液浓缩倍数、冷冻温度和冷冻时间对产品中芒硝纯度和Na_(2)SO_(4)回收率的影响,确定冷冻析硝工段的最优方案,并采用分步冷冻析硝对工艺进行优化。结果表明:在NaCl和Na_(2)SO_(4)的质量浓度比为5∶40、压力为3.0 MPa、流速为8 L/min和温度为30℃的条件下,经纳滤分离后的纳滤浓缩液中,Na_(2)SO_(4)与NaCl的质量浓度比≥18.51,可实现NaCl和Na_(2)SO_(4)的有效分离。在浓缩倍数为3.5倍、冷冻温度为0℃和冷冻时间为120 min时,得到的芒硝纯度在98%以上,Na_(2)SO_(4)的回收率为64.28%。采用分步冷冻析硝工艺优化后,Na_(2)SO_(4)的回收率可以提高6.39%。此工艺研究为该公司产生的高盐废水中Na_(2)SO_(4)的资源化利用奠定了理论基础。
To realize the recycling utilization of Na_(2)SO_(4) in wastewater with high salinity for the wastewater produced by metallurgical industry,the cascade technique of nanofiltration-refrigeration denitration was applied to treat the mixed simulated wastewater of NaCl to Na_(2)SO_(4).The effects of some technological parameters such as mass concentration ratio of NaCl and Na_(2)SO_(4),pressure,flow rate and temperature for the membrane separation efficiency were investigated by means of the nanofiltration experiment.Thus,the optimal scheme was also determined.The separation of NaCl and Na_(2)SO_(4) could thus be achieved effectively.The effects of the concentration ratio,refrigeration temperature,refrigeration time of the nanofiltration concentrate on the purity of the product and the recovery rate of Na_(2)SO_(4) were examined by the refrigeration denitration experiment.The optimal plan for the refrigeration denitration section was determined.Then,the experiment was optimized by stepwise refrigeration denitration.Results showed that the mass concentration ratio of Na_(2)SO_(4) to NaCl≥18.51,when the mass concentration ratio of NaCl to Na_(2)SO_(4) was 5∶40 in the nanofiltration concentrate separated by nanofiltration,the pressure was 3.0 MPa,the flow rate was 8 L/min,and the temperature was 30℃.The purity of mirabilite obtained was above 98%,and the recovery rate of Na_(2)SO_(4) was 64.28%,when the concentration was 3.5 times,the freezing temperature was 0℃,and the freezing time was 120 min.After the optimization of the stepwise refrigeration and denitration process,the recovery rate of Na_(2)SO_(4) could be increased by 6.39%.This experimental research of this process has laid a theoretical foundation for the resource utilization of Na_(2)SO_(4) in the high-salt wastewater produced by the company.
作者
张栋强
陈彦安
李保胜
赵静
苏娜
段润豪
ZHANG Dongqiang;CHEN Yan'an;LI Baosheng;ZHAO Jing;SU Na;DUAN Runhao(College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050, China)
出处
《南京工业大学学报（自然科学版）》
CAS
北大核心
2021年第5期553-559,574,共8页
Journal of Nanjing Tech University(Natural Science Edition)
基金
国家自然科学基金(21666018)。
关键词
高盐废水
纳滤技术
冷冻析硝技术
硫酸钠
资源化利用
high saline wastewater
nanofiltration technology
refrigeration denitration technology
sodium sulfate
recycling utilization
