CRT锥玻璃碳热还原强化玻璃分相脱铅

Lead recovery from CRT funnel glass through carbon thermal reduction enhanced glass phase separation process

通过碳热还原强化玻璃分相的方法实现CRT含铅锥玻璃高效脱铅的同时制备出高硅氧玻璃粉末。将锥玻璃与一定量B_2O_3混合后在还原气氛下进行热处理。在热处理过程中,锥玻璃中的部分氧化铅被还原成单质铅并从玻璃相中析出,剩下未被还原的氧化铅则主要富集在呈网状连通结构的富B_2O_3相中。析出的单质铅与富B_2O_3相通过5 mol·L^(-1)的硝酸高效去除。当锥玻璃与20%的B_2O_3混合均匀,在1 000℃还原气氛下保温30 min,铅的酸浸脱除效率可达99.80%,并得到SiO_2含量大于95%的高硅氧玻璃粉末。高硅氧玻璃粉末可作为催化剂载体、吸附剂或者重新熔炼制备成与石英玻璃类似的耐高温、透光性强的高硅氧玻璃,故为含铅玻璃的无害化与资源化利用提供了一条新的途径。

In this study,toxic lead was removed from cathode-ray-tube funnel glass and synchronous preparation of high silica glass powder was developed using a carbon-thermal-reduction enhanced glass-phase-separation process.Part of the PbO contained in the funnel glass was reduced to metallic Pb and extracted from the glass.The remaining unreduced Pb O was mainly concentrated in the interconnected pore network of the B_2O_3 phase.Most of the metallic Pb phase and B_2O_3 were leached out using 5 mol·L^（-1）HNO_3.The optimum temperature,amount of added B_2O_3,and holding time for the process were 1 000 ℃,20%,and 30 min,respectively.The lead removal rate was 99.80% and porous SiO_2（purity95%） was obtained.The prepared high-silica glass powder could be used as a catalyst carrier or adsorbent,or be re-melted to form high-silica glass as the ideal substitute for quartz glass due to its novel properties of thermal stability and excellent light transmission.Therefore,this work resulted in development of a practical and economical process for detoxification and recycling of waste lead-containing glass.