November 2006

Discovering Borax

Cruising down Highway 58, east of Mojave in Boron, California, a sign we had seen dozens of times before, “Borax Visitor Center,” finally drew us in.

Borax is best known for its 20-mule-team-wagon advertising symbol and as the sponsor of the TV show “Death Valley Days,” which was hosted over the years by such notables as Robert Taylor, Dale Robertson and Ronald Reagan. The company traces its roots back to 1872, when its founder discovered borates in Nevada. Today the company is officially known as Rio Tinto Borax, and is part of the Rio Tinto group, one of the world’s largest mining companies.

For $2, you can park inside the gate at Borax seven days a week from 9 a.m. to 5 p.m., and explore the past, when wagons pulled by 20 mules brought borax from Death Valley, and view the present, when huge trucks haul borax out of massive open pits. Inside the Borax Museum, you will find a display on “Death Valley Days,” and exhibits of borax products and ore. Visitors can also see a short film and get a sample of borax—a piece of ore with interesting transparent properties.

Borax? Isn’t that something our mothers used for laundry or cleaning?

Yes, but in addition to washing powders, water softeners and soaps that 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 make a hard glaze for dishes, and glassmakers mix it with sand so it will melt easily and provide strong, brilliant glass. We recently heard that mixing borax in equal parts with powdered sugar works as a deterrent for ants.

Borax is an important compound of the element boron. Its chemical name is sodium borate or sodium tetraborate. It consists of soft, white, many-sided crystals that readily dissolve in water, and clump together when exposed to moist air.

Although Tibet is said to have been the first important source of borax, now most of the world’s supply comes from Death Valley and the open-pit mines in the nearby Mojave Desert.

Borax may be taken from blasted, open-pit mines or from “dry” or “bitter” lakes where the brine, containing many salts, is pumped from the lake into containers. The heavy salts sink to the bottom, and the remaining brine crystallizes to refine borax. Solid borax taken from open-pit mines is crushed and dissolved, and goes through purification steps to obtain the crystals.

It is estimated that boron deposits formed 12 to 18 million years ago. The first boric acid was produced in 1702, and the element boron was isolated in 1808. F.M. (Borax) Smith discovered borates in Nevada in 1872 and in Death Valley in 1881. Twenty-mule teams were established two years later to haul borax out of Death Valley.

An original 20-mule-team wagon that was used to haul ore out of Death Valley is on display outside the Borax Visitor Center. Pulling the wagon are 20 life-size, lifelike mules—with a set of bells mounted on the lead mule.

Rio Tinto Borax operates California’s largest open-pit mine in Boron. It is one of the richest borate deposits on the planet, supplying nearly half the world’s demand for refined borates.

Next time you pass through Mojave or Boron, California, take a short trip off Highway 58 to visit the Borax Museum—and revive your interest in chemistry.

Marilyn McDonald is a writer who divides time between Oregon and Mexico.