Borax is an important compound of the element boron. It consists of soft, white, many-sided crystals. Borax crystals dissolve readily in water. They will clump together if they are exposed to moist air. The chemical name for borax is sodium borate or sodium tetraborate.
Borax has many industrial uses. Many washing powders, water softeners, and soaps contain borax. Manufacturers mix borax with clay and other substances to make porcelain enamels for sinks, stoves, refrigerators, and metal tiles. Potters use borax to add strength to their products and to make a hard glaze for dishes. Glassmakers mix borax with sand so that it will melt easily and produce strong, brilliant glass. Glass cooking utensils and thermometers are made from glass that contains borax. Borax is also used in the textile industry, in tanning leather, and in the manufacture of paper.
Most of the world’s supply of borax comes from Death Valley in southern California. Borax is also taken from open-pit mines in the nearby Mojave Desert, where miners strip away the covering ground to expose the borax bed. Workers use explosives to blast loose the solid borax. The large chunks of borax are crushed and dissolved. This solution goes through many purification steps until borax crystals are obtained.
Borax is also obtained from “dry” or “bitter” lakes. The brine, which contains many salts other than borax, is pumped from the lake into containers. The solution is allowed to stand in vats to separate the borax from the heavier salts, which sink to the bottom. The remaining brine crystallizes, and the borax is refined.
Another major source of commercial borax is a mineral called kernite. Large deposits of this mineral, which consists of about 75 percent pure sodium borate, are found in the Mojave Desert. Borax is obtained from kernite by dissolving the mineral in water, filtering off impurities, and then allowing it to recrystallize.
Tibet is said to have been the first important source of borax. Since the 1920’s, the United States has produced most of the world’s borax.
