INFRASTRUCTURE RESEARCH PROGRAM
REMOVAL AND VITRIFICATION OF LEAD-BASED PAINTS
Exposure to lead is associated with adverse health effects including permanent damage to the central nervous system. One main problem is the removal of lead-based paint from steel bridges without contaminating the surrounding areas. Thermal Spray Vitrification process, a new and novel technique, has been developed to remove and contain the lead- based paints without contaminating the surrounding areas.
The TSV process employs the flame spray technique; whereby the glass feedstock powder is injected into a gas stream and passed through a combustion flame where it becomes molten. The molten powder is projected onto the painted surface. The lead paint is absorbed into the glass layer when the molten glass droplets impact and spread on the painted surface.. This glass layer is fused with the spray flame so that the lead diffuses into the glass network and get trapped inside, achieving in situ vitrification. The sprayed glass layer spalls from the substrate as it cools, and the crumbled glass fragments can be remelted to ensure that the vitrification process is driven to completion. Vitrification immobilizes the lead inside the glass network, thereby preventing environmental or acidic solution leaching.
A systematic research program was carried out to develop, optimize and fine tune the TSV process. A field demonstration of the TSV process was conducted in collaboration with the Triborough Bridge and Tunnel Authority. The concept and technique of removal and containment of lead from the lead painted panels of the bridge was successfully demonstrated.
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03/29/02