In the first week of November, we went to visit the Los Santos mine, one of the largest tungsten reserves in Spain, with a view to seeing current operations and discussing the other activities of the company in Spain, Australia and South Korea. The CEO of Almonty Industries (TSXV:AII), Lewis Black was on site at the time, as were staff that had worked at or visited the company’s other operations around the globe. Interestingly the staff are composed of a strong component of Portuguese mine staff, many of whom are known to the company management since the days when the Almonty team ran Primary Mining, which owned the Panasquiera Tungsten mine in Portugal.

 

The Los Santos scheelite deposit is in the province of Salamanca in western Spain. It is 180 km west of Madrid, 50 km south of the city of Salamanca. The drive to the mine from Salamanca is an easy one over a double carriageway most of the way through flat to lightly rolling landscape. The area around the actual mine is low hills with a mix of small holdings. The cultivation of pigs is the major industry in the region as the “capital of Jamon Iberico” is a small town nearby where the pigs fed on acorns produce this famous and costly product. 

 

Los Santos is a large village of around 2,000 people. The mine has become quite an important feature of the local economy over the nine years it has been operating. With around 65 contract staff and tens of direct employees, the mine has a significant trickledown effect in such a small community. It is also worth remembering that unemployment in Spain is 25% at this time and has been even higher since 2008 and that in isolated rural areas it can be significantly higher. The company has strong relations with local mayors and councils. It has even established its company “canteen” in the town, rather than out at the minesite. This has effectively doubled the number of eating places in the town!

 

The mine is one kilometre east of the town of Los Santos and there is a newly paved road to the mine gate.

Aizenberg stated that electrochemical deposition was an established technique used in manufacture of steel.

“I don’t want to create another line that would cost millions and millions of dollars and that no one would adopt,” Aizenberg said. She wanted to create a scalable process that would not affect the standard practices followed by the steel industry.

The material was tested in different ways - by scratching with diamond-tipped scribers, screwdrivers and stainless steel tweezers, and by repeatedly being hit with huge number of heavy, hard beads.
 

Following this, the material’s anti-wetting properties were tested using various types of liquids, including highly corrosive media, oil, water and biological fluids that contained blood and bacteria. The material demonstrated anti-biofouling behavior and repelled all of the liquid. Additionally, the tungsten oxide coating also enhanced the strength of steel.
 

Philseok Kim, co-author of the paper and co-founder and vice president of technology at SEAS spin-off SLIPS Technologies Inc., stated that the material holds significant promise for medical steel devices. “Because we show that this material successfully repels bacteria and blood, small medical implants, tools and surgical instruments like scalpels and needles that require both significant mechanical strength and anti-fouling property are high value-added products we are exploring for application and commercialization,” said Kim.
 

The material also holds considerable promise for functional 3D printing and microarray device applications. It could be very useful for printing highly sticky and viscous polymeric and biological materials, where contamination and friction are significant hindrances.

Every year, the effects of biofouling on hulls have cost the U.S. Navy tens of millions of dollars. Barnacles, algae and other such organisms create drag and increase the amount of energy required. Additionally, significant cost is involved in cleaning the hulls and reapplying anti-fouling paints. If this super-slick material could be scaled up, then it would hold promise as a cost-efficient, clean material.
 

“This research is an example of hard core, classic material science,” said Aizenberg. “We took a material that changed the world and asked, how can we make it better?”

The study paper on the new SLIPS-enhanced steel has been published in Nature Communications.

German scientists hunting dark matter are set to produce half a tonne of high-purity calcium tungstate for their detectors, one 1kg crystal at a time. The CRESST-II experiment based in Gran Sasso, Italy is currently seeking this enigmatic substance, thought to explain the universe’s structure, with 10kg of calcium tungstate (CaWO4). Now Andreas Erb and Jean-Côme Lanfranchi are preparing crystals for its larger successor EURECA, which will begin operation in the French Alps in 5–10 years.

Gravitational effects suggest as-yet-unobserved dark matter in the universe outnumbers more familiar atomic matter four to one. Erb, Lanfranchi and their colleagues are hunting leading theoretical candidates, Weakly Interacting Massive Particles (WIMPs). That name reflects their size – up to a lead atom’s mass – and the limited interaction with atomic matter that makes them hard to find, or ‘dark’. ‘They have to interact weakly to agree with the matter needed,’ says Richard Gaitskell from Brown University in the US, who isn’t involved in the calcium tungstate experiments.

 

Erb explains that the detectors should be able to pick up dark matter particles when they hit atomic nuclei in the crystals. ‘A higher sample mass gives a higher probability of such events.’ But distinguishing the miniscule amount of heat WIMP–nucleus collisions would produce requires detectors cooled to 10mK and shielded from ambient radioactivity.

 

CRESST/EURECA is the only team hunting dark matter with calcium tungstate, which has two advantages. Firstly, its different atoms cover a range of possible WIMP masses. ‘No matter the mass, you always have a nucleus with a high probability of interacting,’ Erb says. Second, it would also emit light when a WIMP hits it and monitoring the different signals will help the scientists eliminate background noise. 

 

Having initially purchased crystals, this need for extreme sensitivity drove Erb and Lanfranchi to produce their own. ‘They weren’t pure enough for the background we want,’ Erb recalls. To avoid oxidation at calcium tungstate’s 1600°C melting temperature, the crucibles are made from rhodium, with their 12cm diameter vessel costing €120,000 (£97,300). Erb says that if they can grow two or three 1kg crystals per week then they will have the required amount for EURECA in about five years.

“Our slippery steel is orders of magnitude more durable than any anti-fouling material that has been developed before,” said Aizenberg. “So far, these two concepts – mechanical durability and anti-fouling – were at odds with each other. We need surfaces to be textured and porous to impart fouling resistance but rough nanostructured coatings are intrinsically weaker than their bulk analogs. This research shows that careful surface engineering allows the design of a material capable of performing multiple, even conflicting, functions, without performance degradation.”
 

This material holds promise for a wide range of applications, such as non-fouling medical devices and tools including scalpels and implants, 3D printing nozzles, and marine and building applications.
 

The team had to find out ways to ensure that the structure of the steel maintained its anti-fouling capability without undergoing any mechanical degradation due to the new surface. The team grew an ultrathin film that was made up of hundreds of thousands of nanoscale rough, tungsten-oxide islands on a steel surface using an electrochemical technique.
 

“If one part of an island is destroyed, the damage doesn’t propagate to other parts of the surface because of the lack of interconnectivity between neighboring islands,” said Alexander B. Tesler, former postdoctoral fellow at SEAS, current research fellow at Weizmann Institute of Science in Israel and the paper’s first author.
 

“This island-like morphology combined with the inherent durability and roughness of the tungsten oxide allows the surface to keep its repellent properties in highly abrasive applications, which was impossible until now.”