Excellent layman summary.

=======================================

https://www.siliconinvestor.com/readmsg.aspx?msgid=33193229&fbclid=IwAR3d1WSbVWVHVUjo9C-iwzhe5shjrz6JIGsYHvN5EJdKAqla3lquoSlLmns

Home Technology The Zen way to fight COVID-19

TECHNOLOGYThe Zen way to fight COVID-19
Ontario-based graphene company turns ore from an unusual graphite deposit into a coronavirus-killing coating for N95 facemasks
By Carolyn Gruske
February 11, 2021



Zen Graphene bulk sampled 110 tonnes of magmatic-sourced graphite from its Abany site in northern Ontario. Coutesy of Zen Graphene
Since its discovery in 2004, interest in graphene has waxed and waned, but as COVID-19 continues to plague the world, the team at Zen Graphene expects the nanotechnology to be put to use in combatting the virus.

“When the Nobel Prize was given in 2010 [to University of Manchester professors Andre Geim and Kostya Novoselov, who were able to isolate single-atom-thick crystallites from bulk graphite], there was a big rush. People tried to work with graphene but they didn't know how. There was a big boom-bust cycle. Now, we know a lot more. It’s not like other material. We have to learn how to work with it properly, how to disperse it, as dispersion of the graphene is actually key,” said Francis Dube, CEO and director of Zen Graphene.

Learning how to work with graphene is exactly what Guelph, Ontario-based Zen is trying to do. Founded in 2009 as a nickel-copper-sulfides exploration company, Zen has evolved into one focused on graphene research and marketization, after finding what it calls a unique graphite deposit consisting of two large breccia pipes known as the Albany deposit (part of the southern Marmion terrane of the Superior Province), in northern Ontario.

“[The exploration team] sent it out to get evaluated because it really didn’t look like regular flake sedimentary graphite,” said Dube. “It came back as a graphite that was basically a different formation. It was from a magmatic source – methane gas and CO2 gas came up really quickly, really hot, through the whole strike, solidified in the host rock there and degassed and left behind some very small flakes of graphite. The average size of the flakes is 20 microns where most flake graphites are in the one millimetre range. So we’re substantially smaller than the average flake graphite deposit.”

According to Dube, the smaller east pipe is about five per cent grade, with some sections hitting 15 or 16 per cent. The larger west pipe produces a 2.8 per cent grade. “As these two pipes are side-by-side, the thought is that they may join up at the bottom because they’re so unique in their formation. They came up through a single event,” he said.

The Albany discovery (which eventually triggered a proxy battle and a shareholder takeover) fuelled Zen’s 2018 corporate repositioning and refocused the company’s energy strictly on finding ways to use its extra-fine graphite. To that end, it has partnered with university researchers, received funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) and is working on a number of different applications, with the most commercially promising being a virucidal graphene-based ink – a patented graphene oxide product that can be used to coat the fibres and materials that are used to make N95 facemasks thereby helping to stop the spread of COVID-19.

Dube explained that the COVID-19 virus is extremely small, 0.1 or 0.2 microns, but that it is carried in water droplets that are considerably larger, typically averaging between three and eight microns. In comparison the pore size of facemasks tends to be approximately three microns, depending on the manu­facturing process and materials used.

“The water droplet will tend to hit the mask material. The membrane – the coating that we put on it – is hydrophilic, which means it likes the water. When the droplet comes in, it’s attracted to our coating. As the droplet with the virus hits the coating, the graphene oxide that’s functionalized will activate and go into the water and basically kill the virus there,” said Dube.

Zen reports that testing at Western University’s ImPaKT facility Biosafety Level 3 laboratory found that the ink achieved 99 per cent inactivation of the SARS-CoV-2 virus and that ongoing virucidal properties were still present, even 35 days later.

In early November, the company signed a binding letter of intent with Trebor Rx, a Collingwood, Ontario-based personal protective equipment manufacturer. Trebor intends to purchase enough vircidal coating to treat a minimum of 100 million masks or filters, subject to approval from Health Canada. According to Dube, Zen expects to have its graphene oxide ink on the market and being used in Q1 2021. It will be Zen’s first widely available commercial product. The company already sells researchers small quantities of graphene oxide (in either a powder or in a solution form) in sizes rang­ing from 100 milligrams to one gram, but they amount to a very low volume of sales.

RELATED: HOW MINERS ARE CONTINUING PRODUCTION DURING A PANDEMIC

While mask coating may be the application Dube expects to push the company out of its pre-revenue status, it is just one of many being pursued. Another that Dube said is showing promise involves the Royal Canadian Navy (RCN) and the Waterloo, Ontario-based nanotechnology processing and testing company Evercloak Inc. Zen’s graphene oxide is being incorporated into a membrane created by Evercloak and applied to HVAC systems on the RCN’s Halifax-class frigates as part of a test. The membrane removes moisture from the air and seems to reduce air conditioning energy usage by up to 75 per cent.

Zen is also co-operating with Mohammad Arjmand, a professor at the University of British Columbia (UBC) Okanagan Campus, who received a $200,000 Department of National Defence Innovation for Defence Excellence and Security (IDEaS) award to research ways to create a graphene-based polymer coating to shield satellite electronics from electromagnetic radiation.

Besides coming up with specific applications, Dube said that Zen wants to be the creator of the basic materials – the alloys and the metals – that manufacturers can use to build their own products, especially since working with graphene is tricky.

“It’s a nano material. It’s super thin. You work very hard to break this down into atomic layers. Unless you’re using a surfactant, unless you’re mixing it in right away into a polymer or a product, if you just let it sit there, it will tend to bunch up together again and kind of reform graphite to some degree.”

To that end, Zen intends to produce master batches of alloys or polymers that have a prescribed amount of graphene already combined into them.

“If we can create a master batch at a very high loading of graphene in it already dispersed properly, then all [customers] have to do is take this, mix it with their material, bring it down to the right percentage in the end product. Depending on the product, you’ll want one per cent or 0.5 per cent or 0.1 per cent – it’s different for different products, but it tends to be a very low number. If I can get you a product that has 20 per cent graphene in it, and 80 per cent plastic, you’ll know how much to put in to get an end product that is going to have 0.5 [per cent] loading, and then you don’t have to worry about dispersion and all that, because we’ve already done that work for you.”

While Zen’s Albany graphite may be finer than typical, it still requires treatment to improve the product before turning it into graphene or graphene oxide. In winter 2019, Zen did bulk sampling at the Albany site, removing 110 tonnes of material out of the east pipe that graded to about 6.3 per cent. That ore was sent to SGS Canada in Lakefield, Ontario, to undergo crush-grind-float processing, resulting in a concentration that was 86 per cent graphene. Then Zen performed chemical upgrading (caustic leaching, hydrofluoric acid and heat treatments) to increase the concentration to 99.8 per cent.

Applying energy to the graphite and exfoliating it – splitting it into atomic layers in a way the Dube likens to pulling one card out of a deck at a time ­– is what makes it graphene. This is done through the application of energy, any type of energy. It can be mechanical, chemical, even sound. While Zen uses sonication in the lab, Dube said it is not practical on a commercial basis, and that Zen is looking at a number of shearing technologies, including rapid high-energy extruders, with the goal of licensing them.

Fortunately, Dube said that turning Albany graphite into graphene should take less energy than more geologically conventional graphite, which is harder to exfoliate.

“There are three characteristics of our graphite that lends itself best to exfoliation. Number one is the size of the flakes. Number two is something called turbostratic alignment. Because of the way the graphite was formed here ­– really hard, very fast into the whole strata – the sheets of graphite are not perfectly stacked on top of each other. They’re all a little bit twisted off each other. That actually helps, as opposed to sedimentary flake graphite, which is millions of years of heat and pressure compressing carbonaceous material. Those flakes of graphite tend to be non-turbostratic if you will. They’re very straight-on aligned. The other thing is the space in between each layer is slightly bigger with ours.”

According to Dube, Zen’s waste from mining and processing activities will be limited. He said most of the caustic chemicals will be reused and that the company hopes to sell the waste rock (which is primarily feldspar without any sulfides) for a partial cement replacement at 10 to 20 per cent loading or clean-fill replacement.

Mining is still an activity that is important to Zen. While COVID-19 is providing a business opportunity for mask treatment, the pandemic interfered with the company’s timeline to turn the deposit into a working mine, as 2020 was supposed to be the year when it finished the second year of its baseline study – a study necessary to obtain a permit in Ontario.

Still, Zen has gone ahead with some geochemistry studies and has begun to evaluate some mine-design choices. The original PEA (which was conducted by RPA – now SLR Consulting – in 2015 and projected a 22-year mine life with 977,000 indicated tonnes and 441,000 inferred tonnes with a total operating cost of $2,046 per tonne based on a purified graphite (>99.9 per cent) price of $7,500 per tonne) was based on an open-pit concept. That approach is being reconsidered.

“We think there is about 40 metres of overburden, on average. We think a ramp down or shaft down approach might be better environmentally and, potentially, economically. So we’re in the midst of doing studies on those approaches,” said Dube.

“While COVID won’t be gone next year, we’re hoping that we have ways of moving forward next year and doing the baseline work. Hopefully, by this time next year, we’ll be into permitting.”

In the meantime, there is no concern about running out of graphite. Dube said Zen can still pull plenty out of the ground – more than enough to meet its current production needs.

“When we applied for the bulk permit that allowed us to take out the 110 tonnes, we looked at the [Ontario] Mining Act and it stipulated that if you’re doing a bulk sample of 990 tonnes or lower, you don’t need an environmental assessment and you don’t need a reclamation plan. So we applied for 990. We can actually go back and get another 880 tonnes anytime we want.”

While 990 tonnes may seem like a minuscule amount to most mining companies, the nano-scale of graphene must be taken into account. The 110 tonnes that Zen bulk sampled is enough material to produce coatings for two billion face masks.

Even at scale, he added that it only takes tiny amounts of graphene to significantly improve products. Dube cited Ford Motor Company as an example, saying that Ford is making Mustangs and F-150s with graphene-infused components.

“They started using graphene in their polyurethane foam. Although they’re not giving out the exact recipe, they said it was under 0.5 per cent – so very small amounts of graphene created a polyurethane foam that was 20 per cent stronger, 30 per cent more heat resistant and 17 per cent more sound absorbing. It’s creating a pretty strong business case when a very small amount of material can have such a dramatic effect on a product.”