By. Dr. Thomas Engelhardt
Last month CEA and the Institute of Scrap Recycling Industries Inc. (ISRI) ® announced the winner of the “CRT Challenge.” The goal was to identify financially viable, environmentally conscious proposals for using recycled CRT glass. This CRT challenge was a crowd-sourced technical competition to find new uses for old CRT glass, a powerful way to dispose of old TVs and monitors.
Dr. Thomas Engelhardt was the winner of the CRT Challenge. Here is an explanation of his winning proposal.
The disruptive impact of modern flat screen displays on the established recycling system of cathode ray tubes (CRTs) is an interesting example of how technology changes affect manufacturing and the environment.
Since making new CRTs is no longer an option, other uses for this material have to be found. CRT glass contains up to 30 percent lead and could be seen as very rich lead ore, which sounds good, but the glass portion gets in the way. A brilliant way of getting lead out of the CRT glass is being commercialized but requires investing in a dedicated plant. Without new uses, the outlets for recycled lead containing glass are limited and do not allow for processing all the CRT material.
The solution is simple—why not use lead-containing glass in the vitrification process? Vitrification of nuclear waste is a mature technology that has been used for more than 40 years in France, Germany, Belgium, Russia, Japan and the United States. It involves the melting of waste material with glass-forming additives so that the final glassy product immobilizes the waste material, trapping the lead and the other elements in the glass. The Environmental Protection Agency has declared vitrification to be the “best demonstrated available technology” for heavy metals and high-level radioactive waste.
The Hanford vitrification plant in Washington State is projected to produce approximately 160,000 cubic meters of glass material which, at five percent dosage of CRT glass, would consume around 24,000 tons of CRT material. The Hanford Waste Treatment Plant represents a long-term outlet for CRT glass, since operations are planned to run until 2028.
This potential outlet for the CRT waste stream uses established technology and covers the time span relevant for recycling CRT material. The main hurdle will be to qualify the CRT material as a new component in the vitrification process.
Final storage of the vitrified material is done under extremely controlled conditions, which reduces the risk of lead emissions. Safety and environmental aspects of nuclear waste processing and storage may trigger lengthy tests and prevent a fast implementation. Working with an organization such as the Savannah River National Laboratory (SRNL) is crucial to identifying the best solution and speeding up the development and testing phase for CRT glass containing vitrification material.