WHAT IS FLUORSPAR USED FOR?
Fluorspar is used extensively as a flux in the steel industry, but over 50 percent of the spar produced in Illinois in 1963 was consumed in the manufacture of hydrofluoric acid. A large portion of this acid production is used in the aluminum industry. Hydrofluoric acid is also employed in the preparation of many fluorine compounds, particularly those used in the production of fluorocarbons (refrigerants, plastics, aerosols), insecticides, and high-energy fuels for rockets and missiles. The fluorocarbons utilize about 40 percent of the hydrofluoric acid production.
LEAD AND ZINC
WHAT ORES YIELD LEAD AND ZINC IN ILLINOIS?
The mineral galena is the principal ore of lead. Galena is gray in color, very heavy, has a bright metallic luster, and breaks into cubes along steplike cleavage surfaces ([fig. 18]). It is composed of lead and sulfur.
The chief ore of zinc is the mineral sphalerite. It may be brown, yellow, or black. Sphalerite is a combination of zinc and sulfur, has a resinous luster, and is not as heavy as galena.
WHERE ARE LEAD AND ZINC MINES LOCATED AND HOW LONG HAVE THESE ORES BEEN MINED?
Although the lead deposits of extreme northwestern Illinois (now Jo Daviess County) were reported by the French explorers in 1658 and are said to have been worked by the Indians, the influx of white settlers in the early 1800’s marked the beginning of an extensive mining industry, which was an important factor in the early development of that part of the state. The town of Galena takes its name from the mineral galena, which was the principal ore mined.
Figure 18—Galena cubes.