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Hazardous waste


Turning difficult waste into a useful resource


Swindon-based Tetronics specialises in a thermal processing system that treats hazardous waste at source. Geraldine Faulkner talks to CEO, Stephen Davies, to find out about the benefits the company’s plasma process can bring to waste management; especially when it comes to dealing with ‘difficult’ materials.


Geraldine Faulkner Editor


D


AVID CAMERON is not the only person who is encouraging engagement with Europe; particularly when it comes to promoting UK technology. Stephen Davies,


CEO of Swindon-based Tetronics, also sees possibilities across the channel. “We’re finally starting to see some


engagement in the UK and Europe in the way technology is being picked up,” states the CEO. Tetronics International is a specialist in


the supply of direct current (DC) plasma arc systems. It is a thermal processing system which enables Tetronics to treat organic and inorganic hazardous and industrial wastes, transforming them into an inert, safe product called Plasmarok (pictured below), which is harmless to the environment and can be used as a building material, protecting human health and improving sustainability. The technology can be used in a range


of applications, including waste recovery, hazardous waste treatment, industrial waste treatment and metal recovery.


A final solution As Davies points out: “The beauty of plasma is that it is a final solution. We resolve the hazardous waste issue at source rather than storing it for future generations to deal with, which is a good message to have. “We have already been selected as the


plasma provider for treating the air pollution control residues (APC) for EnergyPark Peterborough that is due to start construction in early 2013. The facility will divert circa 30,000 tpa of APC away from landfill.


“We are currently talking with several other


clients about treating APC.” The CEO is keen that the UK is not left


behind when it comes to dealing with APC, particularly as other parts of the world have been quicker to recognise the potential of Tetronics DC plasma arc systems. “In Japan, the reason APC plants have


moved so quickly is due to the population growth and available landfill space. They made the decision early on so as not to have landfill and so the majority of residual waste is incinerated. Both bottom ash and APC are dealt with in our system. In the case of APC, it is fed into a furnace system where it is transformed into Plasmarok. Basically, it goes in as waste and comes out as a product.” For anyone who is still struggling with


the concept of ‘plasma’ here is Tetronics’ definition: “Plasma is an ionised gas, and is often


described as the fourth state of matter, i.e. when energy is added to a solid (first state) it becomes a liquid (second state); with more added energy it becomes a gas (third state) and when further energy is added it becomes a plasma. “Examples of plasma are lightning, sparks


coming from static electricity, fluorescent lights, arc welding and the aurora borealis (northern and southern (polar) lights).”


Confused? Don’t be. Tetronics’ DC plasma arc technology uses ultra-high temperatures and functional light to melt, gasify or vaporise waste material. Nor is it a new fangled system with no pedigree. According to Davies: “The technology


has been tried and tested over five decades, and has been used globally in more than 80 plants across a wide and varied range of applications.” And here is an important thing to bear in mind; as plasma arc formation does not


involve the direct combustion of a fuel to generate heat, it is considered to be a ‘clean’ heat source. And as well as intense heat, the plasma also emits high levels of light, which helps the rapid destruction of organic compounds.” As well as disposing of ‘difficult wastes’


such as spent potliner (SPL), a contaminated graphite/ceramics cell lining waste generated from the production of primary aluminium, plasma technology is reported to be effective in metal recovery processes. By using plasma’s unique combination of


ultra-high temperatures and functional light to melt, gasify or vaporise waste material, the system is said to be able to treat, recover or generate commercial products. These applications include transforming


hazardous waste and industrial waste into environmentally safe building products and precious metal recovery from spent catalyst waste. “The process chemistry in Tetronics’


plasma-enhanced recovery technology is designed to symbiotically and preferentially separate and recover the valuable material while destroying any hazardous components,” explains Davies.


e-waste Plasma treatment of e-waste enables more than 98% technical recovery rates of precious metals. Typically the furnace is tapped every eight or so hours and the metal collected. The valuable collected metal then goes through final chemical refining. “In the case of recovery of platinum the


collected metal is placed in steel drums and put into a vault. The irony is that it is still defined as a waste albeit a very valuable one. We had to hire a security firm to oversee its transport


and yet to move it, you still need a waste transport permit,” smiles the CEO. The catalyst waste applications include


both auto catalytic converters and industrial catalysts, e.g. petrochemical catalyst, which contains precious metals and platinum group metals (PGMs) that are valuable due to their low natural abundance and the complex processes that are required for their extraction and refining from primary sources. Davies again: “These metals may also be


obtained by recycling PGM bearing wastes. When recycled, these waste streams are typically orders of magnitude richer in PGMs than their naturally occurring ore equivalents, helping to conserve natural resources and balance supply and demand. “Therefore, it is both financially beneficial


and environmentally responsible to recycle spent catalysts.” The process chemistry in Tetronics’


plasma waste recovery technology smelts and separates the precious metals from the less valuable material, which is vitrified into an inert, non-hazardous material in a single processing step. “The high specific values of these waste


streams provide a compelling justification for investment in a plasma based precious metal recovery plant; capital payback is typically achieved within one to two years at waste throughputs of 1,500–2,000 tonnes per year,” explains Davies.


A small footprint One of the biggest advantages, according to the CEO, is that a plasma facility occupies a relatively small footprint. “The majority of our systems are installed into existing facilities which don’t have special building requirements and consequently the technology lends itself to being retro-fitted.” An overriding impression


from a visit to Tetronics’ offices is the team’s belief in its technology. Having


relocated to Swindon in 2007, the company invested £2m in its trial facility that, according to Davies, is the “most sophisticated in Europe. Companies such as


Sellafield hire our trial facilities as they


are the most sophisticated in our sphere. With regard to nuclear waste, we can reduce its volume by 8-10 folds. We can deal with nuclear sludges and materials from labs, i.e. a real hotchpotch of materials. After we’ve treated it, it is smaller in volume and more manageable,” adds the CEO proudly. As for plans for the future, Davies says the


emphasis now is on making people aware of Tetronics’ work and how plasma is a proven technology that can be applied to their problems. “It’s exciting times,” says Davies gazing


around the compact R&D facility. “We’re turning ourselves into a company supplying complete packaged systems designed to solve problems around the world.” So here’s to ‘the push’ into Europe.


• Tetronics will be speaking at Energy from waste 2013 at Westminster, London, on February 27-28. For details on the conference visit www.efwlondon.eu


4 January 24 2013 www. r e c y c l i n gwa s t ewo r l d . c o . u k Recycling & WA S T E W O R L D


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