玻璃分相联用机械化学法脱除废旧含铅玻璃中重金属铅

Removing heavy metal lead from waste leaded glass by phase separation in glass and mechanochemical method

传统分相法采用热酸浸提工艺脱除CRT锥玻璃分相产物中重金属铅,酸浸过程强酸消耗量大,废酸无法回用,易引发酸污染。目的 为了绿色、高效回收CRT锥玻璃分相产物中重金属铅,方法 采用乙二胺四乙酸(EDTA)作为浸提剂,通过机械化学法研究锥玻璃中重金属在快速分相和机械活化浸出过程中的迁移转化规律,揭示影响重金属脱除率的主要因素和作用机制。结果 结果表明:在分相处理过程中锥玻璃所含Pb,K,Ca等元素主要富集在呈连通结构的富B_(2)O_(3)相中。在随后湿法球磨浸提过程中,分相产物中富B_(2)O_(3)相在机械活化作用下快速溶解到水中,同时富B_(2)O_(3)相中所含金属离子与EDTA形成可溶络合物,且可从分相产物中脱除。锥玻璃所含Pb,K,Ca等金属脱除率随EDTA添加量增大、球磨转速提高、球磨时间延长等不断提升,但随液固比增大呈先升高后降低趋势。当EDTA添加量(质量分数,下同)为80%,球磨转速500 rpm,液固比0.8时,球磨处理30 min,分相产物中Pb,K,Ca,Al脱除率分别达到98.79%,94.92%,95.17%,65.71%,获得SiO_(2)质量分数超过92%的高硅氧玻璃粉末。结论 研究结果可为含重金属玻璃绿色、高附加值利用提供借鉴与参考。

The traditional phase separation used hot acid leaching process to remove heavy metal lead from phase separation product of cathode ray tube(CRT) funnel glass.However,the acid leaching process consumed a large amount of strong acid,the waste acid cannot be reused and may cause acid pollution.Objectives In order to achieve green and efficient recovery of heavy metal lead from the phase separation product of CRT funnel glass,Methods ethylene diamine tetraacetic acid(EDTA) was selected as the extractant through mechanochemical method.By studying the migration and transformation laws of heavy metals in funnel glass during the rapid phase separation process and mechanical activation leaching process,the main factors and action mechanism affecting the removal rate of heavy metals were revealed.Results The results showed that during the phase separation process,Pb,K,Ca and other elements contained in the funnel glass were mainly enriched in the B_2O_3-rich phase with interconnected structure.During the subsequent wet ball milling extraction process,the B_2O_3-rich phase was rapidly dissolved into water under mechanical activation,meanwhile,metal cations contained in the B_2O_3-rich phase formed soluble complex with EDTA,and which can be removed from the phase separation product.The extraction rate of Pb,K,Ca and other metals increased with the increase of EDTA addition,ball milling speed and ball milling time,but it shows a trend of first increasing and then decreasing with the increase of water/solid ratio.When the EDTA addition amount was 80%,milling speed was 500 rpm,liquid-solid ratio was 0.8 and ball milling time was 30 min,and,the extraction rates of Pb,K,Ca,Al were 98.79%,94.92%,95.17% and 65.71%,respectively,and high silica glass powder with silica purity exceeding 92% was obtained.Conclusions This study provided reference and guidance for the green and high value-added utilization of heavy metal containing glass.