热解法脱除工业废盐中总有机碳的工艺研究  

Study on removal process of total organic carbon from industrial waste salts by pyrolysis

作　　者：李鸿源 张建华[1,2] LI Hongyuan;ZHANG Jianhua(Key Laboratory of Industrial Biotechnology Ministry of Education,Jiangnan University,Wuxi 214122,China;School of Biotechnology,Jiangnan University,Wuxi 214122,China)

机构地区：[1]江南大学工业生物技术教育部重点实验室,江苏无锡214122 [2]江南大学生物工程学院,江苏无锡214122

出　　处：《无机盐工业》2024年第10期95-102,共8页Inorganic Chemicals Industry

基　　金：国家重点研发计划项目(2021YFC2102204-02)。

摘　　要：高效率、低成本地脱除废盐中的总有机碳(TOC),是实现废盐资源化途径中重要的预处理手段。以两种代表性工业废盐(简称高氯化钠、高硫酸钠)为对象开展高温热解工艺研究,结果表明:高氯化钠在350℃、堆积厚度为12.5 mm条件下热解60 min,TOC去除率为94%;高硫酸钠在450℃、堆积厚度为18.5 mm条件下热解40 min,TOC去除率为94.2%。热解前向高氯化钠中添加7.5 mL/kg双氧水,250℃热解时的TOC去除率和350℃不添加双氧水的去除率相当,向高硫酸钠中添加10 mL/kg双氧水后,350℃热解的TOC去除率和450℃不添加双氧水的去除率相当,即采用双氧水氧化协同热解后两种废盐的热解温度均降低了100℃,节能效果显著。开展了分步结晶实验并对回收的盐分进行检测,结果表明,在回收率为90%的条件下,回收的氯化钠、硫酸钠的TOC含量分别为22.7 mg/kg和26.5 mg/kg,氯化钠纯度为93.2%,满足国家工业盐标准中日晒工业盐二级标准,硫酸钠纯度为93.0%,满足国家工业无水硫酸钠标准中Ⅲ类合格品标准。Highly efficient and low-cost removal of total organic carbon(TOC)from waste salt is an important pretreatment method in achieving salt resource utilization.This study focused on the high-temperature pyrolysis process of two representative industrial waste salts(sodium chloride and sodium sulfate).The results showed that under the condition of 350℃and a stacking thickness of 12.5 mm,sodium chloride underwent pyrolysis for 60 min,the TOC removal rate was 94%.Under the condition of 450℃and a stacking thickness of 18.5 mm,the pyrolysis time of high sodium sulfate was 40 min,the TOC removal rate was 94.2%.Before pyrolysis,7.5 mL/kg hydrogen peroxide was added to high sodium chloride.The TOC removal rate during 250℃pyrolysis was comparable to that at 350℃without hydrogen peroxide.After adding 10 mL/kg hydrogen peroxide to high sodium sulfate,the TOC removal rate during 350℃pyrolysis was comparable to that at 450℃without hydrogen peroxide.The pyrolysis temperature of both waste salts was reduced by 100℃after using advanced oxidation synergistic pyrolysis,and the energy-saving effect was significant.A stepwise crystallization experiment was conducted and the recovered salt was tested.The results showed that under the condition of a recovery rate of 90%,the TOC content of the recovered sodium chloride and sodium sulfate were 22.7 mg/kg and 26.5 mg/kg,respectively.The purity of sodium chloride was 93.2%,which met the secondary standard of sun industrial salt in the national industrial salt standard.Sodium sulfate had a purity of 93.0%and met the ClassⅢqualified products standard in the national industrial anhydrous sodium sulfate standard.

关 键 词：废盐 高氯化钠 高硫酸钠 热解 总有机碳 结晶 

分 类 号：X705[环境科学与工程—环境工程]