Luminophorous Powder Recycling Plant
The Luminophorous Powder Recycling Plant utilises a patented chemical process to produce valuable rare earth metals by recycling lamp bulbs. The process produces high purity rare earth metal oxides such as Yttrium oxide and Europium oxide as well as non-toxic Mercury sulphide (cinnabar), from the fine residues (luminophorous powders) of the lamp. The sale of the rare earth metals can help to drastically reduce the treatment costs for the residues.
On average, approximately 100 million mercury-containing light bulbs and fluorescent tubes are imported into South Africa per year. This provides a good approximation of light bulbs used annually because most of these bulbs replace existing lamps. Therefore it can be inferred that there are 100 million spent mercury-containing lighting bulbs require recycling every year. Due to the implementation of legislation concerning the disposal of such bulbs has been intensified, it can be expected that the bulbs that require recycling would be close to this estimated number. The amount of luminophorous powder that will be produced from these bulbs can vary substantially depending on the size, make and type of bulb. However, even considering only those bulbs containing the smallest amounts of luminophorous powder (the compact fluorescent bulb, at 1 g of powder per bulb) the total amount of luminophorous powder that is produced in South Africa would be greater than 50 tons.
The use of fluorescent light bulbs has been encouraged in South Africa over the last decade in an attempt to improve the cost-efficiency and electrical economy of providing lighting. The major driving force behind this strategy has been our central electricity supplier, Eskom, as an attempt to alleviate the deficit between the electricity generated versus the demand in South Africa.
Although fluorescent lighting is seen as an environmentally friendly means of producing light, each bulb requires a small amount of mercury (a couple of milligrams per bulb) to operate. Due to the mercury content, these bulbs should not be dumped into landfill sites. Instead, they should be recycled.
The new government legislation that came into effect on the 23 August 2016 (Gazette No. 36784, 23 August 2013, Vol. 578 No. 10008) prohibits any mercury-containing light bulbs from being disposed of in landfill sites. Therefore there is only one solution for disposing of bulbs containing mercury. This is to collect, crush and recycle the constituent components. Recycling of bulbs is already being practiced in South Africa, by companies such as E-Waste Africa and RecLite. The technologies used by these companies for this purpose has been developed over several years, and are fairly mature. They are equipped to separate the bulbs into a glass fraction, a plastics fraction, a metal fraction, and lastly, a luminophorous powder fraction. Of these different constituents, only the luminophorous powder remains contaminated with mercury. Due to the mercury content in the luminophorous powder, this recycled component has no downstream use. Currently, the options for treating this mercury contaminated powder are either to heat the powder to above 600°C (autoclaving) and thus remove the mercury, after which the powder can be disposed of. Or to attempt to recover more components (including pure mercury) from the powder before disposing of only the non-valuable and non-toxic components. The autoclaving of the powder is expensive, due to the energy costs and due to the care required to ensure that no mercury vapour does not escape into the environment.
Rare Earth Recycling Technologies, in conjunction with researchers from the University of KwaZulu-Natal, have developed the LPX Luminophorous Powder Treatment Process. This process recovers valuable materials, such as rare earth metals from the luminophorous powder, whilst simultaneously capturing the mercury in a natural, non-toxic form that it can be safely disposed of as. The recovery of rare earth metals from the luminophorous powder drastically reduces the costs of treating the powder via this method. The income from the sale of the rare-earth metals potentially converts this waste treatment process into an income generating venture. A pilot plant, commissioned at the University of KwaZulu-Natal, capable of processing small volumes of luminophorous powders on a batch basis has been constructed to test this process.
At present, the only solution available for fluorescent powder in South Africa is to autoclave it. This is undertaken by companies such as A-Thermal. This means that the market for the treatment of the powders using the LPX Plant, is wide-open, as our costs are substantially lower and we provide a potential revenue stream in the production of rare-earth metals.
The technology used in this recycling plant is novel, and the opportunity exists to manufacture fully commercial LPX Luminophorous Powder Recycling Plants in South Africa and to export them throughout the world.
Due to the increased interest in the recycling of waste materials over the last few years, there are numerous bulb recyclers that now operate throughout the world. These lamp recyclers, for the most part, utilise lamp crushing machines such as those sold by Balcan Engineering and MRT System. However, the systems that are sold by both companies produce a luminophorous powder that must be treated or disposed of.
The LPX Luminophorous Powder Recycling Plant is a back-end process that can be directly integrated with these systems, allowing the treatment of the luminophorous powder that is produced by the lamp crushing systems. The LPX Plant does not require any special treatment of the powder and can treat the powder produced from CFL (compact fluorescent light) bulbs and powder from mixed sources with only small changes to the operating parameters. As such, the LPX Plant should be seen as an add on that can move the lamp crushing company closer to the target of 100% recycled.
We wanted to find a safe way to recycle Fluorescent bulbs and tubes that could generate revenue by selling the resulting rare-earth metals.
Professor Deresh Ramjugernath
Professor Deresh Ramjugernath has a Ph.D. in Chemical Engineering, and is currently the DVC: Research at the University of KwaZulu-Natal. He has developed several spin-off companies, including a Chemical Engineering Consulting Company. His areas of expertise are in process synthesis and separation technologies. He also provides much of the business strategy, management, and negotiation skills to the team.
Professor Milan Carsky
Professor Milan Carsky has a Ph.D. in Chemical Engineering and is currently a Professor Emeritus at the University of KwaZulu-Natal. He is also the Editor-in-Chief of the South African Journal of Chemical Engineering. His area of expertise is in liquid-liquid extraction, mixing hydrodynamics, fluidised bed technology, and process safety.
Dr. Mark Williams-Wynn
Dr. Mark Williams-Wynn has a Ph.D. in Chemical Engineering. Mark has a strong background in research and experimental measurements, particularly in the field of chemical thermodynamics. Mark has also undertaken a substantial amount of consulting work, providing research and basic design capabilities for several companies. He has been the lead engineer on the construction and commissioning of the LPX plant, after being instrumental in the design of the facility.
We worked in collaboration with Rare Earth Recycling Technologies to develop the LPX Luminophorous Powder Treatment Process.