Editing Ulexite (section)

== Significance ==

Boron is a trace element within the lithosphere that has an average concentration of 10 ppm, although large areas of the world are boron deficient.<ref name=Woods>Woods, W.G. 1994. ''An introduction to boron: History, sources, uses, and chemistry,'' Environmental Health Perspective 102:5–11</ref>  Boron is never found in the elemental state in nature, however boron naturally occurs in over 150 minerals.<ref name="StamatakisTziritis2009" /> The three most important minerals from a worldwide commercial standpoint based on abundance are [[tincal]] (also known as borax), ulexite, and [[colemanite]] (Ekmekyaper et al., 2008).<ref>{{cite journal |last1=Ekmekyapar |first1=A. |last2=Demirkıran |first2=N. |last3=Künkül |first3=A. |title=Dissolution kinetics of ulexite in acetic acid solutions |journal=Chemical Engineering Research and Design |date=2008 |volume=86 |issue=9 |pages=1011–1016|doi=10.1016/j.cherd.2008.04.005 }}</ref> High concentrations of economically significant boron minerals generally occur in arid areas that have a history of volcanism. Ulexite is mined predominantly from the Borax mine in Boron, California.<ref name=Woods/>

The boron concentration of ulexite is commercially significant because boron compounds are used in producing materials for many branches of industry. Boron is primarily used in the manufacturing of fiberglass along with heat-resistant borosilicate glasses such as traditional PYREX, car headlights, and laboratory glassware. Borosilicate glass is desirable because adding B<sub>2</sub>O<sub>3</sub> lowers the expansion coefficient, therefore increasing the thermal shock resistance of the glass. Boron and its compounds are also common ingredients in soaps, detergents, and bleaches, which contributes to the softening of hard water by attracting calcium ions. Boron usage in alloy and metal production has been increasing because of its excellent metal oxide solubilizing ability. Boron compounds are used as a reinforcing agent in order to harden metals for use in military tanks and armor. Boron is used extensively for fire retardant materials. Boron is an essential element for plant growth and is frequently used as a fertilizer, however in large concentrations boron can be toxic, and therefore boron is a common ingredient in herbicides and insecticides. Boron is also found in chemicals used to treat wood and as protective coatings and pottery glazes.<ref name=Woods/>  Additionally when ulexite is dissolved in a solution of carbonate, calcium carbonate forms as a by-product. This by-product is used in large amounts by the pulp and paper industry as a paper filler and as a coating for paper that allows for improved printability (Demirkiran and Kunkul, 2011).<ref>{{cite journal |last1=Demirkiran |first1=N. |last2=Kunkul |first2=A. |title=Dissolution of ulexite in ammonium carbonate solutions |journal=Theoretical Foundations of Chemical Engineering |date=2011 |volume=45 |issue=1 |pages=114–119|doi=10.1134/S0040579511010039 |s2cid=95451655 }}</ref>
Recently, as more attention is being given to obtaining new sources of energy, the use of hydrogen as a fuel for cars has come to the forefront. The compound sodium borohydride (NaBH<sub>4</sub>) is currently being considered as an excellent hydrogen storage medium due to its high theoretical hydrogen yield by weight for future use in cars. Piskin (2009)<ref>{{cite journal |last1=Piskin |first1=Mehmet Burcin |title=Investigation of sodium borohydride production process: "Ulexite mineral as a boron source" |journal=International Journal of Hydrogen Energy |date=2009 |volume=34 |issue=11 |pages=4773–4779|doi=10.1016/j.ijhydene.2009.03.043 }}</ref> validates that the boron concentration in ulexite can be used as the boron source or the starting material in the synthesis of sodium borohydride (NaBH<sub>4</sub>).