钡渣氯化铵浸出工艺试验及过程机理研究

Study on the Leaching Process and Related Mechanism of Barium Slag Using Ammonium Chloride as the Leaching Agent

针对大量堆存的危险固体废弃物钡渣,作者开展了氯化铵浸出工艺试验研究,通过氯化铵循环浸出从钡渣中提取碳酸钡产品,并实现浸出渣的无害化。结果表明,在最佳浸出条件下(球磨时间15 min、氯化铵浓度3 mol/L、液固比10∶1、反应温度90℃、反应时间3 h),钡渣中碳酸钡一次浸出率可达到60%,通过3次循环浸出,可使钡渣中碳酸钡含量由25.09%降低至3%以下,浸出渣中Ba2+浸出毒性及碳酸钡毒性物质含量均低于相关危险废物鉴别标准限值。最后,采用扫描电子显微镜和电子微探针探究了浸出前后钡渣的表面形貌及化学组成变化,揭示了钡渣与氯化铵的作用过程机制。

Barium slag is a significant amount of hazardous solid waste stored in China.The present study proposes the use of the ammonium chloride leaching process to treat barium residue.By cyclically leaching with ammonium chloride,barium carbonate product was extracted from the residue to obtain the harmless leaching residue.The results indicate that using 15 minutes of ball milling time,3 mol/L of ammonium chloride,10:1 of liquid-solid ratio,90℃of temperature,and 3 hours of leaching time,a one-time leaching rate of 60%for barium carbonate in barium slag was achieved.Through three cycles of leaching,the content of BaCO_(3)in barium slag was reduced from 25.09%to less than 3%.The leaching toxicity of Ba*and the content of toxic substances in the leaching slag are superior to the identification standards for extraction toxicity.Furthermore,we investigated the surface morphology and chemical composition of barium slag before and after leaching using a scanning electron microscope(SEM)and electron probe micro analyzer(EPMA),revealing the interaction mechanism between barium slag and ammonium chloride.