Mark Childress, age 9, of Muncie, Indiana, for.liis question:
What kind of stuff is bauxite?
One of our useful everyday metals is aluminum. It is sturdy, durable and light to lift. If an aluminum cooking pot weighs two pounds, about 10 pounds of bauxite was used to make it. Bauxite is an aluminum ore. It is found in the ground with hundreds of other rocky and muddy minerals.
Every year, the modern world creates about eight million tons of aluminum. You can write a long list of things we make from this light and sturdy metal. But chances are you would not be able to choose the right ingredients to make it. The main ingredient is bauxite, and bauxite does not look at all like silvery gray aluminum metal.
Some of the earth's bauxite is spread in muddy layers of soft clay. Some is in rocky lumps, sometimes pasty white and sometimes streaked or blotched with reds and yellows, pinks and assorted candy colored browns and tans. Rocky bauxite may be as soft as soapstone or gypsum and a bucket packed full of it weighs no more than two and a half buckets of water.
The earth created her supplies of bauxite from atoms of aluminum and oxygen, iron and silica and mixed them together with moist molecules of water. Aluminum is the earth's most plentiful metal. Traces of it are found almost everywhere in clays and dozens of other different minerals.
Rich bauxite layers are found in warm, rainy climates. This is because the earth uses lots of warm, running rainwater to make her layers of bauxite. The moisture dissolves the special ingredients, washes them down the slopes and dumps them in layers of muddy clay. In time, some of the muddy clays become dry and solid layers of bauxite rock. The United States mines bauxite in Arkansas and a few other states, but not enough to make all the aluminum we need. We buy more bauxite from the plentiful supplies in Jamaica, parts of South America and other countries. Most, but nOt all, of this bauxite is used to make metal aluminum.
Some is added to sulphuric acid to form aluminum sulphate. This useful chemical is needed in the making of fabrics and paper. Tons of bauxite are used to purify thick, gummy petroleum into clear gasoline. It filters out sulphur, oxygen and the dirty colors from the thick oil. The earth's clay minerals contain traces of aluminum and clays are used to make bricks and pottery. Mixtures of clay and bauxite are baked into special bricks that refuse to burn. They are used to line the fiery furnaces for smelting molten iron and steel.
The costly fob of separating aluminum metal from bauxite ore is done in two stages. First the ore is rinsed, powdered and heated with special chemicals. This separates most of the unwanted ingredients into runny red mud, leaving behind a clear liquid called alumina. The next step removes oxygen from the alumina. The liquid is dried and added to special chemicals in seething vats. Plates changed with powerful electric current are dipped into the molten mixture. This separates the oxygen, which escapes as a gas and the liquid aluminum sinks to the bottom of the tank.