Tag Archives: metals

Swedish company produces the first slab of steel that didn’t require any coal

Engineers from the SSAB steel-making company have unveiled the world’s first piece of steel cast without burning any coal or fossil fuel. Instead, they used hydrogen to power the process.

The first steel produced using HYBRIT technology. Image credits SSAB

Metalworking and coal burning have been entwined for as long as humanity has been using metals. Coal is a very good source of energy, providing the heat necessary to refine and process most metals. But it is also a source of carbon, a critical chemical in the production of steel, and the compound that allows us to turn metal ores (usually oxides) into actual metals (by leaching out the oxygen).

For most of our history, this wasn’t that much of an issue. Coal smoke is definitely not healthy for you or anyone living near the smeltery or ye olde blacksmith, but overall production of metals was limited in scope — so the environment could absorb and process its emissions.

Today, however, the sheer scale at which we produce metals means that this process has a real impact on the health of the world around us. However, new technology could uncouple the process from coal, and pave the way towards ‘green’ metals. Engineers from the international, Sweden-based steel-making company SSAB have showcased the process, which relies on hydrogen instead of coal to produce the necessary temperatures.

Transition metal

“The first fossil-free steel in the world is not only a breakthrough for SSAB, it represents proof that it’s possible to make the transition and significantly reduce the global carbon footprint of the steel industry,” said Martin Lindqvist, SSAB’s president and CEO, for CNBC.

The “hybrid process” used by SSAB uses hydrogen as fuel to produce the required energy, instead of the traditional approach of burning coal. This process, called HYBRIT (Hydrogen Breakthrough Ironmaking Technology), uses electricity produced through renewable means to produce hydrogen, which is in turn burned to generate heat. Although there is burning involved, it doesn’t produce any pollution — in fact, the only end product is water.

HYBRIT can be used both for the production of iron pellets — the main raw material used by steel foundries — and in the carbon purification process, which is the step that transforms iron into steel. The first piece of HYBRIT steel was produced for the Volvo Group and is going to become a part of the company’s fleet of trucks. A candleholder was also machined from this steel as proof that its mechanical properties are the same as regular steel produced by SSAB.

The candle holder. Image credits SSAB.

“The candle holder, with its softly pleated rays beaming out from the candle, symbolizes the light at the end of the tunnel. It is a symbol of hope. It truly is a piece of the future,” says Lena Bergström, who designed the item.

The steel industry today accounts for roughly 9% of global carbon dioxide emissions, and demand for (as well as production of) steel is steadily increasing.

SSAB developed the process in the context of a joint venture with the government-owned utility Vattenfall and Swedish mining company LKAB. The steel was processed in a pilot plant in the north of Sweden, and full-scale production capability is not expected for another five years or so, according to Reuters. The slab of metal produced so far marks the culmination of over 5 years of research and development of the HYBRIT process.

“The goal is to deliver fossil-free steel to the market and demonstrate the technology on an industrial scale as early as 2026,” a statement form SSAB explained.

SEM

Cheap nano-filter scrubs toxic metals from polluted water

Researchers from the RMIT University and University of New South Wales (UNSW) present a new filter technology that harnesses naturally occurring nanostructures that grow on liquid metals. The team also shows that their new creation can filter both oils and heavy metals from water. The filter works over 100 times faster than current ones.

Filter close-up.

Low- (a,b) and high-resolution (c,d) transmisson electron microscope photos of the filter’s layers.
Image credits Ali Zavabeti et al., 2018, AFM.

Not only is this filter way faster than its currently-available counterparts, but it’s also simple to produce and scale up, meaning that it can be deployed rapidly and en masse in areas or situation that require it.

Quick’n’clean

Water contamination and pollution are a significant threat to public health in many areas of the world today. Roughly 1 in 9 people have no clean water close to their homes, the team writes.

“Heavy metal contamination causes serious health problems and children are particularly vulnerable,” says Dr. Ali Zavabeti, a researcher at RMIT and the paper’s lead author. “Our new nano-filter is sustainable, environmentally-friendly, scalable and low cost.”

The filters rely on a unique internal architecture to perform their job. The team drew on liquid metal chemistry to grow differently shaped nano-structures (either as the atomically thin sheets used for the nano-filter or as nano-fibrous structures) in the process of creating the new filters.

Zavabeti’s team created the alloy by combining gallium-based liquid metals with aluminum. When exposed to water, aluminum oxide moves to the surface of the nano-sheets and start ‘growing’, forming aluminum oxide layers. These layers, which start out 100,000 times thinner than a strand of human hair, end up all wrinkled, making them very porous.

The shapes physically stop pollutants from passing through. Lead and other heavy metals have a very high affinity to aluminum oxide so, as the water passes through billions of layers, each one of these lead ions get attracted to one of these aluminium oxide sheets. Lab testing revealed that the nano-filter could remove lead from water even when concentration passed 13 times safe drinking levels, and was also very effective in separating oil from water.

“We’ve shown it works to remove lead and oil from water but we also know it has potential to target other common contaminants. Previous research has already shown the materials we used are effective in absorbing contaminants like mercury, sulfates and phosphates,” Zavabeti explains.

“With further development and commercial support, this new nano-filter could be a cheap and ultra-fast solution to the problem of dirty water.”

The method Zavabeti’s team developed allows them to grow the material either in nano-sheets or as nano-fibers, each with their own characteristics. The ultra-thin sheets used in the nano-filter experiments have high mechanical stiffness, while the nano-fibers are highly translucent. These two flavors of the material can be mixed to create filters with certain properties for applications in fields such as electronics, membranes, optics, and catalysis.

One particularly exciting trait of the manufacturing process is that it “be readily upscaled, the liquid metal can be reused, and the process requires only short reaction times and low temperatures,” according to Zavabeti, which should keep costs down. The manufacturing process generates no waste, requiring only aluminum and water — the liquid metals are reused for each new batch of nano-sheets.

UNSW Professor Kalantar-zadeh, paper co-author, believes the technology could be put to good use in Africa and Asia in places where heavy metal ions in the water are at levels well beyond safe human consumption.

“If you’ve got bad quality water, you just take a gadget with one of these filters with you,” he said. “You pour the contaminated water in the top of a flask with the aluminium oxide filter. Wait two minutes and the water that passes through the filter is now very clean water, completely drinkable.”

“And the good thing is, this filter is cheap.”

There are portable filtration products available that do remove heavy metals from water, but they are comparatively expensive, often costing more than $100. In contrast, the team’s aluminum oxide filters could be produced for as little as 10 cents a piece.

The paper “Green Synthesis of Low-Dimensional Aluminum Oxide Hydroxide and Oxide Using Liquid Metal Reaction Media: Ultrahigh Flux Membranes” has been published in the journal Advanced Functional Materials.

A malformed (’teratological’) chitinozoan specimen of the genus Ancyrochitina (a) and a morphologically normal specimen (b) of the same genus. Image: Dr Thijs Vandenbroucke

Malformed plankton is a telltale sign of mass extinction

Mass extinctions present both a mortal threat and opportunity. During these events, a great deal of all terrestrial and marine life perishes, but this also makes room for the next lineage to flourish in its stead. Like a bush fire, mass extinctions may be nature’s way of “cleansing” – a reboot for new experimentation to start fresh. Despite being extremely important (it doesn’t get more dramatic than “mass extinction”), the kill triggers that spur these events in motion are still poorly understood.  But we’re learning. For instance, a team reports that ancient malformed plankton are a proxy for mass extinction events.

Life morphed by heavy metals

Thijs Vandenbroucke, a researcher at the French CNRS and invited professor at University of Gent, Belgium, led the team which investigated the fossils. He and colleagues found that the malformed plankton from the Ordovician and Silurian periods (ca. 485 to 420 to million years ago) had high concentrations of lead, iron and arsenic.

It’s well established that these heavy metals cause morphological deformities in modern organisms. The assumption is that the same holds true for these ancient organisms as well.

A malformed (’teratological’) chitinozoan specimen of the genus Ancyrochitina (a) and a morphologically normal specimen (b) of the same genus. Image: Dr Thijs Vandenbroucke

A malformed (’teratological’) chitinozoan specimen of the genus Ancyrochitina (a) and a morphologically normal specimen (b) of the same genus. Image: Dr Thijs Vandenbroucke

Based on these findings, Vandenbroucke suggests that the spread of oxygen depletion and toxic metals are the likely cause of aquatic mass extinction events, rather than glacial episodes as previously suggested. The two are closely intertwined as reduction in ocean oxygenation drives a subsequent increase of these metals. “In normal, oxic conditions, such metals precipitate and remain sequestered in marine sediments,” Vandenbroucke told me in an e-mail.

“We think these are significant factors during the event we studied. In addition, we also observe strikingly similar patterns (i.e. coinciding carbon-isotope excursions, increased malformation, and extinction events) for many of the other Ordovician-Silurian events, including during the Hirnantian, a major mass extinction that eradicated up to 85% of marine species. This suggests that anoxia and metal enrichment may be a contributor to all of these events. Based on the new insights gleaned from the pilot study we now published, we are currently investigating several of these events, in order to test our hypotheses,” Vandenbroucke said.

The high levels of metals suggest changes in the ocean chemistry and the spreading anoxia may have been a contributing kill-mechanism during these early extinction events. This would make any fossilized malformed plankton extremely useful as a forensic tool – a  biological indicator of periods of low oxygen levels. Findings modern day malformed plankton would also be a cause of alarm, one that should be duly noted – and that’s an understatement.

Charles Lyell, a towering figure in the early development of the geologic sciences, suggested that “the present is the key to the past.” Flipping Lyell’s axiom to “the past is key to understanding our future” should always be done with caution – in particular when comparing the modern environment with something as old and different as the Ordovician-Silurian world. The megafauna extinctions of today are not a consequence of marine events but many parts of the marine food web are directly affected by the processes we describe. Our study, for example, might help highlight processes and hidden consequences, caused by fluxes of anthropogenic elements to the world’s oceans, that need to be considered when studying the ever-increasing problem of marine eutrophication and anoxia in some coastal areas,” Vandenbroucke said.

Distribution of potential oceanic anoxic events (OAEs) in the uppermost Ordovician and Silurian. Credit: Thijs Vandenbroucke et. al. Nature Communications

Distribution of potential oceanic anoxic events (OAEs) in the uppermost Ordovician and Silurian. Credit: Thijs Vandenbroucke et. al. Nature Communications

 

flexible_semiconducting_polymer

A first step towards making ‘plastic’ semiconductors for stretchy-electronics

Stanford chemical engineers have developed a theoretical model that sheds light on the electrical conductivity properties of polymers. Their work provides a valuable first step for other researchers to build on, providing an experimental setting for those looking to expand the electrical conductivity of certain polymers (typically plastics) for use in the industry.

The word “polymer” is derived from the Greek for “many parts” which aptly describes their simple molecular structure, which consists of identical units, called monomers, that string together, end to end, like so many sausages. Humans have long used natural polymers such as silk and wool, while newer industrial processes have adapted this same technique to turn end-to-end chains of hydrocarbon molecules, ultimately derived from petroleum byproducts, into plastics.

The constitutive elements that go in your typical electronics like your smartphone or notebook include things like circuitry, transistors, condensers and so on, all typically made out of metallic materials, since these need to be electrically conductive. At the same time, however, these materials, like the reigning king silicon, are brittle and fairly stiff.

Fad or not, in recent years scientists have made various attempts at developing electronics capable of being stretched a significant or even multiple times their width, as well rolling. Imagine clothing electronics, tablets that can fold like a newspaper, a whole range of new possibilities. As such, many have experimented with polymers which are more flexible. It’s clear that there’s a serious trade-off problem here that engineers need to tackle: metals can’t stretch but they conduct electricity better, polymers can stretch, but conduct electricity poorly. Things don’t need to be all black and white, though. The best and quickest solutions are found when engineers have access to as much data and information about the problem they’re trying to solve as possible.

Stanford chemical engineering professor Andrew Spakowitz and colleagues  the first theoretical framework that includes the molecular-level structural inhomogeneity of polymers. Metals have a regular molecular structure that allows electrical current to flow smoothly, but this is also what makes them rigid. Polymers on the other hand, at a molecular level, look more like a bowl of spaghetti: strands are coiled  or run relatively true, even if curved, like lanes on a highway. This variability of molecular structure is reflected in the variability of electrical conductivity as well. In the process of experimenting with polymeric semiconductors, researchers discovered that these flexible materials exhibited “anomalous transport behavior” or, simply put, variability in the speed at which electrons flowed through the system.

“Prior theories of electrical flow in polymeric semiconductors are largely extrapolated from our understanding of metals and inorganic semiconductors like silicon,” Spakowitz said, adding that he and his collaborators began by taking a molecular-level view of the electron transport issue.

flexible_semiconducting_polymer

The yellow electric charge races through a ”speed lane” in this stylized view of a polymer semiconductor, but pauses before leaping to the next fast path. Stanford engineers are studying why this occurs with an eye toward building flexible electronics. (Credit: Professor Andrew Spakowitz)

This insight is fundamental to future experiments and research dwelling into building stretchy electronics. One other important hallmark of the Stanford scientists’ paper is that they provide a simple algorithm that begins to suggest how to control the process for making polymers, with an emphasis on how manipulating their electrical conductivity properties.

“There are many, many types of monomers and many variables in the process,” Spakowitz said. The model presented by the Stanford team simplifies this problem greatly by reducing it to a small number of variables describing the structural and electronic properties of semiconducting polymers.

“A simple theory that works is a good start,” said Spakowitz, who envisions much work ahead to bring bending smart phones and folding e-readers to reality.

The author’s theory was published recently in the journal Proceedings of the National Academy of Sciences.