Magnesium Industry

By: Diana J. Kleiner

Type: General Entry

Published: 1976

Updated: April 1, 1995

The magnesium industry in Texas produces magnesium for defense purposes, for making industrial machinery, and for the aircraft, textile, printing, and transportation industries. Magnesium sulphate, found in the brines of the playas of the High Plains, was commercially processed at several places, the most important being near O'Donnell in southern Lynn County. Magnesium chloride compounds, which occur in the brines of the playas of the High Plains and the Pecos valley, were commercially processed at a plant in Ward County. The largest commercial production has been from sea water processed through electrolysis beginning in 1941 at a Dow Chemical plant at Freeport, Brazoria County, in amounts of 50,000 pounds daily. In 1941 The United States Defense Plant Corporation also contracted with Dow to build a plant near Velasco. The two locations provided access to harbors, sea water for use as raw material, natural gas for power, oyster shell for use in processing, brine for chlorine, and fresh water for cooling. The two Dow plants, recovering magnesium from sea water, had a combined capacity of 92,000 short tons annually. In addition to magnesium, they produced refractory magnesia, magnesium chloride, caustic-calcined magnesia, and magnesium hydroxide. A smaller Freeport plant produced periclase from magnesium hydroxide. In 1942, Dow provided more than 84 percent of the total United States output of magnesium. During World War II a plant near Austin used Burnet County Ellenburger dolomite rock for large-scale production of magnesium. Between 1945 and 1947 demand declined, but Dow continued to stockpile ingots, and in 1948 Texas ranked first in quantity and value of magnesium production in the United States. In the Korean War magnesium was used in long-range bombers and incendiary bombs.

After 1952 no estimate of Texas magnesium production was reported by the United States Bureau of Mines, but the two Dow Chemical Company electrolytic plants at Freeport continued to be a primary source of magnesium in the nation and one of the largest Texas industries. Ample deposits of dolomitic limestone and magnesite, the principal world source of refractory magnesium oxide, also existed in Burnet and other Texas counties. In West Texas magnesium-bearing brines found in the Permian Basin were used as raw material for a Scurry County plant founded in 1969 near Snyder. During the 1960s, the recovery of magnesium and the manufacture of magnesium compounds increased in Texas. The Dow plants at Freeport increased their capacity to 100,000 short tons annually through improved processing. By 1964 the American Smelting and Refining Company in Houston was engaged in secondary magnesium production, and in Round Rock the production of dead-burned dolomite had begun. In the early 1970s Texas produced more than half the world's magnesium, most of which was used for weapons and industry. Magnesium compounds were used by the chemical, sugar, paper, rayon, fertilizer, rubber, ceramic, and petroleum industries, for preparation of special cements, and in refractories. Dow increased its capacity in 1969 and 1970 to 120,000 tons a year, while its major competitor, American Magnesium, which began operations in 1969, produced smaller quantities. Two smaller companies with plants at Freeport used materials obtained from Dow to produce other compounds. The use of caustic-calcined or light-burned magnesia in air-pollution-control applications grew, as did use as a fuel additive and agent for removing sulfur dioxide from stack gases. In 1980 specific values were not disclosed, but magnesium had the highest value of metallic minerals produced in Texas, as output of magnesium chloride for metal increased slightly and magnesium compounds not used for metal production declined. In 1990, six companies produced magnesium compounds from sea water in California, Delaware, Florida, and Texas, but both production and value fell drastically below the level of 1989.

J. D. Hanawalt, "Economic Status of Magnesium," Modern Metals, January 1948. U.S. Bureau of Mines, Minerals Yearbook.

The following, adapted from the Chicago Manual of Style, 15th edition, is the preferred citation for this entry.

Diana J. Kleiner, “Magnesium Industry,” Handbook of Texas Online, accessed June 26, 2022,

Published by the Texas State Historical Association.

April 1, 1995