American Resources Policy Network
Promoting the development of American mineral resources.
  • Through the Gateway: Selenium – More Than Just a Dietary Supplement

    Chances are, you’ve heard of Selenium.  As a trace element, it is an essential mineral found in small amounts in the body, with antioxidant properties. It is also a much-used suite of tools to automate web browsers across many platforms — which is why weeding out our news alerts for stories relevant to ARPN followers can be time-consuming.

    However, more relevant from our vantage point are this rare mineral’s other uses.  According to USGS, Selenium, which is known to have semiconducting properties, is used in glass manufacturing to decolorize the green tint caused by iron impurities, and — increasingly important to new applications — to reduce solar heat transmission.  In catalysts, it enhances selective oxidation, in plating solutions, it improves appearance and durability, and in gun bluing, it improves appearance and provides corrosion resistance.  It is further used in rubber-compounding chemicals, in the electrolytic production of manganese, and in copper, lead, and steel alloys to improve machinability.

    Perhaps its most important use today is its application in solar technology.  Like Tellurium, Selenium plays a critical role in the performance of thin-film photovoltaic cells.  While Tellurium is used in combination with Cadmium for CdTe technology, Selenium is alloyed with Copper, Indium and Gallium, creating a material commonly referred to as CIGS.

    Both CdTe and CIGS technologies were the new kids on the block during the first solar boom, though Selenium’s  photoconductive properties were already discovered by British scientist Willoughby Smith in 1873. Companies engaged in both technologies have since vied for front-runner status  in the solar world by attempting to improve the respective material’s efficiencies.  While CIGS seemed to have a leg up up until recently, new test results for CdTe are promising. The bottom line, however: both materials, and with that Tellurium and Selenium, are in high demand.

    What holds true for most tech metals and minerals, applies here too: substitution may occur, but technological advances in materials sciences will likely continue to fuel demand. Selenium may have been replaced by organic photoreceptors in some plain paper copiers, but new nano-technological applications, for example in electronics, are already being tested by researchers.

    As is the case with Tellurium, most Selenium used in the United States is derived from residues produced during the refining process of Copper, so the supply of Selenium is of course directly affected by the supply of Copper.

    If you’ve read our last post about Tellurium, you probably have Bob Marley’s “No Woman, No Cry” stuck in your head now. You’re welcome.

  • Through the Gateway: Tellurium – A Rare Metal With Abundant Demand


    It may not have felt like it, but spring is here, and love is in the air (not just according to us, but also according to science). We’re here to help – and thought we’d share this gem of a pick-up line (available on T-shirts online):

    “You must be made of Copper and Tellurium, because you are CuTe.”  

     While we’re not sure if this kind of cheesiness has ever helped anyone get a date, it does allude to the close relationship between Copper and Tellurium.  Even less abundant than Rare Earths, most Tellurium used today is recovered as a co-product of mining and refining Copper and other base-metal-rich ore bodies.

    Initially, Tellurium was primarily used as an additive to steel, copper and lead alloys, a process in which it helps improve machine efficiency.  Here, USGS specifically cites thermoelectric cooling applications and highlights Tellurium’s capabilities to improve ductility and tensile strength, as well as sulfuric acid corrosion prevention.

    With the advent of the green technology revolution — and its ability to form a compound exhibiting enhanced electrical conductivity when alloyed with elements such as Cadmium — demand for Tellurium as a critical component for efficient, thin-film photovoltaic cells producing electricity from sunlight has soared.

    Today, these Cadmium-telluride (CdTe — apparently no T-shirts made for this combination) solar cells represent the major end use for Tellurium in the United States – a fact that is unlikely to change any time soon, as solar power is booming, and recent lab results had CdTe technology break efficiency records when it comes to converting energy in sunlight into electricity.

    Meanwhile, for the foreseeable future, experts expect co-product supply via the Copper refinement process to remain the dominant source of Tellurium supply, with secondary production from recycled CdTe having the potential to contribute “a sizeable share of total production.” 

    Bringing things back to our love theme – Bob Marley once famously proclaimed“No woman, no cry.”  Applied to material sciences, one could say “No Copper, No (or only little) Tellurium.” Or, in other words, the path to the very materials underpinning modern technology leads “Through the Gateway.”

  • Through the Gateway: Copper – Far More Than Your “Old School” Industrial Metal

    We’re kicking off our online informational campaign on Gateway Metals and their Co-products by taking a closer look at one of the most well-known industrial mainstay metals – Copper. Lately, “old school” Copper – long acknowledged as an indispensable building block of the industrial age — has been undergoing turbulent times on the global commodity [...]
  • If Orange Is the New Black, Then “Co-product” is the New “By-Product”

    As we set out to take an in-depth look “Through the Gateway” over the course of the next few months, we will be zeroing in on the five gateway metals we examined as part of our 2012 report – Aluminum, Copper, Nickel, Tin and Zinc, as well as the tech metals they“unlock.” These materials have increasingly found [...]
  • Pizza, the Age of Rare Metals and Co-Products

    “If you don’t have yeast, you don’t have pizza.” What may seem like a random – albeit logical – conclusion has more to do with critical minerals than you may think.  David Abraham, director of the Technology, Rare and Electronic Materials Center, recently used the yeast/pizza analogy to exemplify the importance of rare metals, which [...]