Feasibility study of fluorescent lamp waste recycling by thermal desorption

The proposed Minamata Convention ban on the use of fluorescent lamps at the end of 2020, with a consequent reduction in mercury (Hg) light products, is expected to produce large amounts of discarded fluorescent bulbs. In this context, the most effective recycling options are a thermal mercury recovery system and/or aqueous solution leaching (lixiviation) to recover rare earth elements (REEs). Due to the heterogeneous nature of these wastes, a complete characterization of Hg compounds in addition to a determination of their desorption temperatures is required for their recycling. The objective of this study is to assess the feasibility of a fast cost-effective thermal characterization to ameliorate recycling treatments. A pyrolysis heating system with a heat ramping capability combined with atomic absorption spectrometry makes it possible to obtain residue data with regard to the temperature ranges needed to achieve total Hg desorption. The major drawback of these heat treatments has been the amount of Hg absorbed from the residue by the glass matrices, ranging from 23.4 to 39.1% in the samples studied. Meanwhile, it has been estimated that 70% of Hg is recovered at a temperature of 437 °C.

Working together to establish a world-class mercury recovery facility for the Australian liquefied natural gas industry

Mercury is a heavy metal that is widespread and persistent in the environment and, even at low concentrations, poses a risk of adverse effects to human health and ecosystems. Mercury is commonly found in hydrocarbon reservoirs. Approximately 1.5 tonnes of mercury arrive at the Karratha Gas Plant each year in feed gas from offshore platforms. Because mercury reacts with aluminium, it must be removed from the liquefied natural gas (LNG) process before the main cryogenic heat exchangers, which comprise ~1000 km of aluminium tubing. For over a decade mercury has been safely removed from the Woodside LNG process and sent to Switzerland for recovery of metals and complete recycling of waste constituents. Here we present the outcome of a 3-year collaboration between Woodside and Contract Resources that resulted in the opening of Australia’s first industrial-scale state-of-the-art mercury recovery facility in Karratha in July 2018. The AU$20 million plant is the largest of its type in the Southern Hemisphere and was underpinned by Woodside providing foundation funding through a long-term contract. The facility can handle all mercury-contaminated waste produced by the Australian oil and gas sector now and into the foreseeable future. An unparalleled project delivery taking 3 years to implement from initial discussion to the first batch of waste being processed in Karratha. This paper illustrates the collaboration, innovation and acceleration that occurred to deliver a sustainable outcome for Australian LNG.