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Bauxite is the main source of the rare metal gallium. [17] During the processing of bauxite to alumina in the Bayer process, gallium accumulates in the sodium hydroxide liquor. From this it can be extracted by a variety of methods. The most recent is the use of ion-exchange resin. [18]
The preheater recuperates most of the heat in the combustion gases, dehydrates and de-hydroxylates the bauxite and de-carbonates the limestone. The calcined material drops into the "cool end" of the melt bath. The melt overflows the hot end of the furnace into molds in which it cools and solidifies. The system is fired with pulverized coal or oil.
Bauxite forms by the weathering of aluminum-rich and silica-poor rocks in hot, humid, climates, at places with good drainage. Under the proper conditions, weathering disintegrates the aluminium silicate minerals, and dissolves and removes the silica, creating bauxite. The mined US bauxite deposits have all been in the southeastern United States.
The limestone and aggregate mining operation and cement plant is owned by Lehigh Southwest Cement, a subsidiary of Heidelberg Cement. Limestone was mined beginning in 1902 but remained a small operation until 1939 when it was purchased by Henry J. Kaiser to supply the 5.5 million barrels of cement to build Shasta Dam. With increased production ...
In pyroprocessing industries such as lime,calcined bauxite, refractories or cement manufacture, the loss on ignition of the raw material is roughly equivalent to the mass loss it will experience in a kiln. Likewise, in minerals, the loss on ignition indicates the material actually lost during smelting or refining in a furnace or smelter.
Bauxite mining was the main industry in Linden, and so the reduction of bauxite mining led to many workers having to find employment outside of the city. [22] In 2009, 57 employees of the Bauxite Company of Guyana Inc. were fired for participating in a strike to campaign for higher wages and better workers' rights. [25]
Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource. [2]
The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef Bayer.Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al 2 O 3), the rest being a mixture of silica, various iron oxides, and titanium dioxide. [1]