Research On Waste Cathode Ray Tubes(CRTs) Management And Recovery Of Lead From Funnel Glass

The unconscious use of technology can generate several consequences,one of which is electronic waste(e-waste);it's chemical components in the environment causes pollution and health damage.Among all the waste electronics,cathode ray tubes(CRTs)constitutes a major part of e-waste around the world.Currently,CRT devices demand may have faded from our market but the trend of the waste stream is still high in developed countries and the similar trend will be followed by developing countries in near upcoming years,whereas the demand for new CRT devices has declined because mainly replaced by liquid crystal display(LCD)and plasma display.The waste CRT television(TV)makes the maximum amount of waste in e-waste and it is also the fastest growing waste stream in China and around the world.Therefore,it requires to evaluate the volume of the waste CRT TVs entering the end of life and also important for the recourse recovery.In this study we intended to evaluate the material flow analysis of the obsolete CRT TVs.In this regard we collected the data of CRT TVs from 2000 to 2010,where,it shows approx.3241.37 kt of CRT TVs were net produced in China,which is approx.containing 183.6 kt of glass,1718.2 kt of plastic,243 kt of steel/Iron,153.5 kt of lead,76.6 kt of copper,7.8 kt of alumimium and 1.6 kt of nickel metals.Currently,the demand for CRT TVs in China almost unknown but the generation of waste CRT TVs will increase in upcoming years as given a lifespan 10 years.In this study,we emphasis on how to recover the valuable materials and to reduce the hazardous effects of CRT devices which has contained lead metal,two novel methods have been developed to accomplish the removal of lead from waste CRT devices in a sustainable way.In the first method,metallic lead was successfully removed via mechano-thermal carbon reduction with acid leaching process.Coarsely ground funnel glass and carbon powder were activated by the planetary ball-milling apparatus.The mixture has been sintered for different lengths of time and then progress evolution in the mixture investigated.In the second method,we developed an efficient mechano-chemical method which has higher efficiency for recovering both lead and barium metals from the funnel glass with the minimum required energy and time,by using the metal chelate reagent 2-[Bis(carboxymethyl)amino] acetic acid(NTA).In this process,primarily CRT funnel glass was activated by the planetary ball-milling and then paced to a polypropylene bottle with the chelating reagent NTA and appropriate amount of water for wet ball-milling process.After the mechano-chemical treatment,the desired more than ca.99 mass % of lead and barium metals contained in the funnel glass powder was extracted as a metal-NTA species and pure non-leaded Si O2 glass material from the funnel glass matrix.The separation phenomenon was accelerated by the ball-milling atomization and high stability constant of the metals-NTA.After the separation,the maximum amount of lead and barium ions ca.99 mass % were obtained as a Pb SO4 and Ba SO4 with addition of ferric sulphate.Notably,the developed method does not required heat and nor generate any secondary waste.Therefore,the results show that the developed method is efficient and eco-friendly,which is also probably applicable to purify any other kind of leaded glass.