Lead hazard evaluation for cathode ray tube monitors in Brazil

Abstract

Cathode ray tube (CRT) monitors are electronic equipment mainly made of glass, polymers and metals. These devices became obsolete because of emerging technologies such as LCD, LED and plasma; thus generating a huge stockpile of e-waste worldwide. In this CRT study, a natural leaching simulation (NBR10005) was performed to determine the toxicity of this e-waste. The standard NBR 10005 procedure was performed for 7 different monitors. The results show all samples are hazardous according to local environmental law (NBR 10004) due to lead leaching. The CRT panel is lead free, while the CRT funnel and neck have about 20% of lead oxide in their composition. Moreover, six optimum thermal lead removal procedures were performed and the NBR 10005 procedure was repeated. The results reveal that vacuum atmosphere and the addition of 5% carbon graphite as reducing agent are optimum conditions to turn the CRT into a non-hazardous waste. Three out of six parameters were capable of satisfactorily removing the lead and turning the post-procedure waste lead-leaching safe.