Copyright © 2006 by Ana Minerva Bonilla Updated: August 28, 2006 21:32
Reprinted by permission at http://theweekendminer.com
THE WEEKEND MINER
Rediscovering American Mineral Resources
THOUGHTS FROM THE “OLD MINER”
Zinc and Its Unleaded Friends
For many years in this country, and most of Western Europe, Zinc has been “persona non grata” due to its close association with Lead. The old saying “you are judged by the company you keep” seems to apply to Zinc, and to a much lesser extent the third mineral often found with them, Silver. Lead and Zinc have been in the “gunsights” of the Environmental movement for over 50 years and the effect is telling. The once-largest Lead-Zinc producer in the United States, ASARCO, has exited the Lead-Zinc business. The Copper unit still exists, but it was taken over and then spun off by Grupo Mexico. It operates today as a Lilliputian shadow of its former self. My guess is that the demise of ASARCO, and other US Zinc Miners, pleased the cadres of Environmentalists who fought them into oblivion; who insisted that Zinc be added to the list of the worst and most persistent bioaccumulative and toxic chemicals on the hazardous waste list, and shout that all mining should be brought to an end in the US.
I guess we need to know a little more about this “evil element”. Zinc is one of the Transition Elements, with an Atomic Number of 30, an Atomic Weight of 65.38 and a Density of 7.14. On the Periodic Table it lies between Copper and Gallium and above Cadmium. It has four stable isotopes; 64 (48.6%), 66 (27.9%), 68 (18.8%) and 67 (4.1%). World production, per the USGS, in 2005 was 10,100,000 Metric tones. The biggest producer was China, with 2,300,000 MT; Australia at 1,400,000 MT; Peru at 1,300,000 MT; Canada at 790,000 MT; followed by the US with 760,000 MT. About 50% of the US production was recovered from waste and scrap. While the US relies on 52% of its needs from imports, primarily from Canada, Mexico and Peru, it has the third largest reserves in the world – behind China and Australia. Zinc’s major uses are galvanizing of steel (55%), zinc-based alloys – many of which are used for diecasting (21%), alloying of Copper to make brass (16%), and the rest in various other applications. Most commercial Zinc mining done in polymetallic, sulfide ore bodies. The knock is “Acid Rain” from the Sulfur Dioxide emitted from the smelters. However, today, the Sulfur is recovered as a by-product, either in the form of Sulfuric Acid or elemental Sulfur. Both of these are positive income streams for the Zinc processors and offset much of the cost of the very expensive pollution control systems required at the plants.
So what do we loose when we close the Zinc industry down? The first thing most people think of is jobs. This isn’t a really big number, although for the 2,100 people who lost their jobs between 2001 and 2005 in the industry, it was a life-changing event. The US Steel Industry (what is left of it) also lost a US-based Supplier of a critical raw material. A couple of Zinc plants are left in the US; one in Tennessee and one in Illinois, but they both are owned by the Australians and the British. The British one, located in Illinois (Sauget) will be modernized and partially dedicated to the recovery of Zinc Oxide from Electric Arc Furnace (Steel Mini-Mill) “Baghouse Dust”. Hopefully, this will produce about 30,000 tons per year of Zinc; from about 150,000 tons of Baghouse Dust. Since this dust is land filled today it’s an environmental plus for Zinc.
But there is another side to Zinc. It tends to be found in polymetallic ore bodies, most generally with Lead and often Silver. Some of the other minerals or elements found with it are critical to many emerging, high-tech industries, to which the future prosperity of the US is tied.
Take Sphalerite (ZnS), probably the most common Zinc ore. It is found, usually as a vein deposit, in all classes of rocks, often along with Galena (PbS). Contained in Sphalerite ore you often find Gallium, Indium and Cadmium. In fact, Sphalerite is the chief ore of those elements and their minerals also. To practically recover them, you have to process the ore, by smelting and refining the Zinc – an industry that has all but shut down in the US. Why worry?
Well, Gallium, probably the most recognized of the group, as Gallium Arsenide (GaAs) or Gallium Nitride (GaN), is critical for electronic components, which represented most all of the Gallium use in the US (est. at 98%). About half went to integrated circuits, the rest to the production of LEDs (light-emitting diodes), solar cells, laser diodes, research and photo detectors made up the balance. It is kind of interesting that environmental issues shut down an industry so critical to many of the “Green Technologies”, especially solar power.
Indium is also critical to the electronics industry. It is the key element for the liquid crystal displays used in flat panel video screens (Indium-Tin Oxide coatings) and electro luminescent lamps. It is also used in semiconductor compounds for high-efficiency photovoltaic devices (again, solar power), infrared detectors and high-speed transistors. Another interesting application is the use of Indium in nuclear reactor control rods.
The third “by-product” item in Sphalerite is Cadmium, whose major use (more than 80%) is in batteries. Some Cadmium is produced by the Tennessee smelter, but a large portion is from recycling Cadmium-containing scrap from batteries and Copper-Cadmium alloys.
For this metal, the recycling input has resulted in reduced dependence on foreign imports, now less than 10% of consumption. This is a positive for the solar power industry, as researchers in Berkley, California, have developed ultra-thin photovoltaic films of Cadmium Selenide (CdSe) and Cadmium Telluride (CdTe) nanocrystals that have great potential for highly efficient conversion of sunlight to electricity.
Since we shuttered most of our Zinc processing in the US, where do we have to go to get these elements and compounds? For the period 2001-2004 almost 40% of our Gallium came from – you guessed it – China, with about 20% from France, and 10% each from Russia and Japan. For the same period we got about half of our Indium from China, 20% from Canada and 15% from Japan. None of these countries, with the exception of Canada, seems to be too big of a fan of the US or anxious to help us with supply in a time of shortage. They would much rather export finished products containing the minerals to the US than supply US industry with raw materials in shortage situations. In this case Canada is also a hostile supply, as much of the Indium comes from the Trail Mine in British Columbia. US Environmentalists are trying to shut that mine down, because it is upriver from Indian Lands in the US that they claim are polluted by drainage from the mine and processing facility.
Sales into the US have been limited recently, driving up prices on the basis of the lack of physical availability. Many of the exporting countries comment that they will export critical metals only after they have satisfied the needs of their home industry. Remember, the most expensive raw material there is, is that which you don’t have, and which causes you to shut down your plant. This is especially true in capital-intensive industries such as electronics and autos, where unionized workers have to be paid if they work or not.
Indium, which a few years ago, was about $100 per kilogram is now near $1,000 per kg. Gallium went from $275 per kilogram at the beginning of 2005 to about $500 later in the year. Price increases such as these tend to destroy the value of research projects that are done over long periods of time – such as our solar power research efforts. It also leaves us vulnerable to the forced transfer of the developed technology to countries that hold the critical raw materials. Countries who wish to reap he fruits of our research labors, and the jobs associated with them.
Once again, with Zinc, we have shut down our own production and placed our futures in the hands of foreign powers, whose main interests do not include the maintenance of the American living standard, but rather the transfer of that living standard to their own people, albeit at the expense of the Americans.
We have to take another look at what we really want for our country and children in the long run. It might be time to take a hard look at the “all mining is bad” philosophy so prevalent in our media. Responsible mining must have a place in America, if America wants to stay relevant in the World Economy. We stand to loose not only the technology we have developed to countries controlling key raw materials, but with it, the very way of life we hold so dear.
Note: Sphalerite (ZnS) is highly prized as a mineral specimen because of its cubic hextetrahedral crystalline structure. The most prized crystal specimens are found where little or no iron is present. Iron turns Sphalerite dark, almost a lustrous black. However, if you find it in areas without iron concentrations, it is often red or green, and sometimes colorless. While it is too soft to be a gemstone, it is very attractive as a crystal or mineral specimen addition to a collection. The crystal structure with the sulfide tends to be far more robust than with some of the carbonates (such as Hydrozincite or Aurichalcite), which are attractive but often have fragile, wispy, needle-like structures. Aurichalcite, a Copper-Zinc carbonate, often called “Natural Brass”, has blue-green, wispy needle crystals, usually in thin crusts or fragile scales. It’s a great addition to your collection, if you can keep it intact until you get it back to your specimen case. Sphalerite, on the other hand, can withstand the jarring of your vehicle as you make your way back from remote locations after a day of hunting, and tends not to disintegrate to dust by the time you get home.