Ernie Calantoni, age 13, of Twin Falls, Idaho, for his question:
WHERE IS SULFUR FOUND?
Sulfur is a solid, nonmetallic element. It is~found in vegetables such as onions, cabbage and horseradish. It is necessary for the growth of plants and animals. Eggs also contain sulfur.
In the mineral world, sulfur is found in large quantities both in a pure state and in combination with other substances. Sulfur can be found in a pure state in places where there are volcanoes. It combines with metals to form certain valuable metal ores such as sphalerite, galena and cinnabar. Gypsum, or calcium sulfate, is an important mineral that contains sulfur.
Sulfur actually comes in three forms, known as "allotropic" forms. Allotropic forms of an element have different physical forms. But they have the same chemical properties and are in the same state of matter.
Sulfur comes in rhombic crystals, monoclinic crystals and amorphous, or plastic, form.
Sulfur is brittle and has almost no taste. When it is rubbed or melted, sulfur gives off a "rotten egg" odor. It does not dissolve in water but it dissolves easily in carbon disulfide. Sulfur ignites at a low temperature and burns very quickly.
Many commercial uses have been found for sulfur. Pure sulfur is used to make up a group of valuable substances known as sulfur compounds. These sulfur compounds include sulfuric acid, the sulfite salts and also sulfur dioxide.
Sulfur mixes with saltpeter and charcoal to form gunpowder and is used to some extent in the manufacture of matches.
For the farm, sulfur is used in the manufacture of fertilizers and in preparations that destroy insects and plant pests. Sulfur also has an important use in the making of paper pulp, which is produced by the action of calcium bisulfite on wood cellulose.
Sulfur is used in various medicines. Photographers also use a sulfur compound to fix photographic images after prints have been made from negatives.
Before 1900 almost all sulfur came from Sicily. Today the United States produces much sulfur, chiefly in Texas and Louisiana. Sulfur is also found in Italy, Japan, Spain and Mexico.
The most common method of mining sulfur is called the superheated water method. This method was invented about 1900 by the American scientist Herman Frasch. By this method, sulfur deposits are heated beyond the melting point.
Water is superheated under increased pressure so that its boiling point rises above sulfur's melting point. Four pipes, one inside the other, bore into the sulfur deposit. The two outside pipes force the hot water into the sulfur, causing the sulfur to melt. The fourth, or innermost pipe, sends down compressed air into the deposit.
The air causes the melted sulfur to form a froth. The increased air pressure forces the froth up the third pipe. Sulfur of about 99 percent purity is obtained in this way. The frothy sulfur is sprayed into binds and allowed to dry thoroughly in the open air.
By another and newer method, the sulfur cools and solidifies on a conveyor belt moving over shallow tanks of cold, running water.