Boron is not as flashy as gold, nor as elusive as rare earth metals, and not as well-known as copper, but it is an important industrial metal nonetheless. In fact, a recent article on phys.org calls it the “unsung hero of the periodic table” and says that to call boron boring is a mistake. Boron is very versatile because it easily accepts electrons from other elements to form many interesting compounds with both metals and non-metals. Boron is primarily used in glass and ceramics, but it is also used to make smartphones, flat screen TVs, and neodymium magnets. Boron is also used to prepare detergents, buffer solution, insecticides, insulation and semiconductors. Read the article to learn why scientists are investigating boron as a source of energy, as an energy carrier, and for heat conservation.
Boron doesn’t occur in nature in an elemental state but combines with oxygen and other elements to form boric acid, or inorganic salts called borates. According to the U.S Geological Survey 2017 Boron Mineral Commodity Summary, boron compounds, chiefly borates, are commercially important; boron products are priced and sold based on their boric oxide content (B2O3), varying by ore and compound and by the absence or presence of calcium and sodium. The four borate minerals— colemanite, kernite, tincal, and ulexite—make up 90% of the borate minerals used by industry worldwide.
Most borate is mined in Turkey, the United States, and South America. In the U.S., Borax, a part of Rio Tinto, operates California’s largest open-pit mine and the largest borax mine in the world, producing nearly half the world’s borates, according to the company’s web site. Borate deposits were discovered in 1872. Originally, the ore was hauled out using twenty mule teams. The current open pit in the Mojave Desert began as an underground mine in 1927, and Boron Operations was converted to a surface mine in the late 1950s.
The web site Mining Geology HQ offers the following tips on finding borate deposits:
- The right rocks: Find a Cenozoic suite (the more recent the better) of non-marine, fine-grained sediments and tuffs in an arid environment with known historic hydrothermal activity. Existing hot springs and epithermal deposits in the area are a good sign you’re in the right neighborhood.
- Chemistry data: Soil, rock chip and groundwater geochemical surveys have proven successful in identifying prospective areas for borate occurrences. Pathfinders include: strontium, arsenic, and lithium, not to mention boron itself. In Asian borate skarn deposits, beryllium has been used successfully as a pathfinder.
- Remote sensing data such as Thematic Mapper (TM) bands can indicate the presence of ulexite in soils otherwise obscured by halite as is common in salar-type deposits. This method has proven effective in salars of South America in the late 1980s.
- Hunt in elephant country, just under cover: It’s probable there are proximal deposits in established districts that are under cover. As is common with major mining companies, once a multi-decade reserve has been identified, there is little appetite for continued exploration resulting in poor near mine exploration and prospects being under-explored or shelved indefinitely.
- Try somewhere new: Less explored regions of the globe such as central and western Asia, North and East Africa, Australia, and northwestern Mexico are likely areas for further investigation.
- Geophysics first, then drill: Gravity, magnetic, and seismic surveys won’t directly find borates but can provide indications of depth to basement, sedimentary sequence thickness, and most importantly structural information. These are all important aspects to understand the potential for the presence of a borate deposit.
Geochemical analysis can be easily obtained using portable X-ray fluorescence (XRF) analyzers in a variety of applications. XRF (X-ray fluorescence) is a non-destructive analytical technique used to determine the elemental composition of materials. XRF analyzers determine the chemistry of a sample by measuring the fluorescent (or secondary) X-ray emitted from a sample when it is excited by a primary X-ray source. Each of the elements present in a sample produces a set of characteristic fluorescent X-rays (“a fingerprint”) that is unique for that specific element, which is why XRF spectroscopy is an excellent technology for qualitative and quantitative analysis of material composition. Learn more about geochemical mapping with XRF.