Recovery of Mercury from Spent Fluorescent Lamps via Oxidative Leaching and Cementation

Abstract

In this work, the recovery of mercury from spent fluorescent lamps by oxidative leaching followed by cementation process was studied. Two different reactive solutions (NaOCl/NaCl and KI/I 2 ) during oxidative leaching were investigated whereas at the cementation process, metallic powders of iron (Fe), copper (Cu), and zinc (Zn) were used as reducing agents to capture mercury in solid phase. Mercury could be transferred to the solution with an efficiency of 96 % from the spent lamp samples through the NaOCl/NaCl reagent. The optimal leaching conditions were determined as 2-h contact time, 120 rpm agitation speed, pH 7.5, and 50°C of temperature. The reducing agent, Zn, provided 99 % of the cementation. The optimal process conditions were observed to be as 5-min contact time, pH 1, and 5 g L −1 of reducing agent concentration. This combined approach appears to be technically effective for the recovery of mercury from spent fluorescent lamps.

An example of environmental risk assessment with L-type method: Cold storage in food industry

“…In order to reduce the risk, the lamps must be collected safely and delivered to licensed hazardous waste collection companies. The number of scientific studies containing applicable results on the recycling of lamp parts following mercury removal from waste fluorescent lamps is increasing day by day (Coskun and Civelekoglu, 2014;Coskun and Civelekoglu, 2015;Gedik et al, 2020). For example, the use of fluorescent lamp glasses as a suitable filler in the asphalt binder layer instead of traditional crushed stone dust can provide advantages such as reducing the solid waste load, protecting the ecosystem, and reducing the costs of pavement construction (Gedik, 2021;Viana et al, 2022).…”