农药废盐回转窑高温熔融处理技术实践与分析

Practice and analysis of high temperature melting treatment technology for pesticide waste salt in rotary kiln

采用蒸发技术对化工行业产生的高盐水进行脱盐处理时,会产生工业废盐,其中含有大量有机物,难降解、毒性大。利用回转窑高温熔融技术处理农药废盐,调试运行期间废盐处理量可达18-23 t/d,窑内温度、压强、气体流量等参数波动范围稳定。高温熔融处理农药废盐技术参数:熔融温度1 000-1 150℃,停留时间0.5-1.5 h,结晶温度88-95℃;经进一步过滤、精制后,副产盐的NaCl质量分数达97.4%,钙镁离子质量分数为0.219%,SO_(4)^(2-)质量分数为0.118%,可达到GB/T 5462—2015《工业盐》中精制工业湿盐的优级品质,有机污染物去除率达99%以上。采用回转窑高温熔融处理农药废盐技术可行,但存在进料不稳、停留时间控制难等问题,需进一步完善工艺技术和设备。

Evaporative desalination of high salinity water produced in chemical industry will produce industrial waste salt,which contains a lot of refractory and toxic organic matter.Rotary kiln high temperature melting technology was used to treat waste pesticide salt.During the commissioning and operation,the waste salt treatment capacity reached18-23 t/d,and the fluctuation range of the temperature,pressure,gas flow and other parameters in the kiln was stable.The main technical parameters were as follow:melting temperature 1000-1150℃,residence time 0.5-1.5 h,crystallization temperature 88-95℃.After further filtration and refining,the mass fraction of NaCl in the recovered byproduct salt reached 97.4%,the mass fraction of calcium and magnesium ions was 0.219%,SO_(4)^(2-)was 0.118%,which could meet the premium quality of refined industrial wet salt in Industrial Salt(GB/T 5462—2015).The removal rate of organic pollutants was more than 99%.It is feasible to treat waste pesticide salt by rotary kiln high temperature melting technology.However,there are some practical engineering problems such as unstable feed,uncontrollable residence time,etc.,needing to be solved through the improvement of process,technology and equipment.