Molybdenum discovery and Industry Development
Brief history of molybdenum discovery
Although molybdenum was found in late eighteenth Century, has been used before it was found, such as in Fourteenth Century, Japanese use molybdenum steel knife. In sixteenth Century, molybdenite was similar to lead, galena and graphite in its appearance and properties, and was used as a graphite. The Europeans also called these minerals as "molybdenite" at that time.
In 1754, Swedish chemist Bengt Andersson Qvist tested the molybdenite and found there is no lead, so he thought molybdenite and galena were not the same substance.
In 1778, Scheler, a Swedish chemist, found that nitric acid did not react with graphite and reacted with molybdenite to obtain a white powder, which was boiled with alkali solution to crystallize a salt. He believes that the white powder is a metal oxide, mixed with charcoal after intense heat, and no metal, and when it was the original molybdenite and sulfur together after heating, so he thought molybdenite is an unknown mineral.
Inspired by Scheler, in 1781, Hjelm, Sweden, used the carbon reduction method to separate a new metal from the white powder and named the metal "Molybdenum".
Development of molybdenum industry
Because molybdenum is easy to oxidize and brittleness, and molybdenum smelting and processing level is limited, molybdenum has not been able to be processed mechanically, so it can not be applied to industrial production on a large scale, and only some molybdenum compounds are used. In 1891, France's Snyder Schneider took the lead as molybdenum alloying element to produce molybdenum armor plate, found its performance is superior, and the density of molybdenum is only half of tungsten, gradually replaced the tungsten to become alloy elements of steel, thus beginning the industrial application of molybdenum.
In 1900, ferromolybdenum production process has been developed, molybdenum steel can meet the special performance need of gun steel also been discovered, which makes the production of molybdenum steel has been developed rapidly in 1910. Since then, molybdenum has become an important component of heat-resistant and anti-corrosion structural steels, and has also become an important component of nonferrous metals nickel and chromium alloys.
The metal molybdenum is widely used in electrical industry. One of the reasons is that the production of powder metallurgy and pressure processing technology of these two kinds of dense metal have been studied successfully, which can be used in production, another reason is that the outbreak of the first World War led to a surge in demand for tungsten, and molybdenum supply shortage has accelerated as many high hardness and impact resistance of tungsten steel substitutes. With the growth of demand for molybdenum, people began to search for new sources of molybdenum, and finally, a large Clay Max molybdenum deposit was discovered in Colorado, USA, and began to be mined in 1918.
To address the sharp decline in demand for molybdenum after the first World War, people began to study the application of molybdenum in new civilian industries, such as the use of alloy steels containing molybdenum for the production of wheels. In 1930, researchers have proposed the forging and heat treatment of molybdenum based high speed steel must have the appropriate degree, this discovery opens the new application market for molybdenum, as alloying elements has also entered a new stage of molybdenum in steel and other fields. By the end of the 1930s, molybdenum had become a widely used industrial raw material. During World War II, the American clay Max molybdenum company developed a vacuum arc smelting process, in which 450-1000 kilograms of molybdenum ingots were obtained, which opened the way for molybdenum as a structural material.
Now, the high pure molybdenum material, nano composite, is the main direction of research, molybdenum application scope is more and more wide, including steel, petroleum, chemical, electrical and electronic technology, medicine and agriculture field.
Classification of molybdenum ores
Single molybdenum ore
The main useful component of ore is molybdenum.
Copper molybdenum ore
Molybdenite ore is associated with sulphide minerals of various copper minerals.
Molybdenite ore is associated with tungsten ore.
Carbonaceous copper molybdenum ore
Ore contains organic carbon and carbonaceous shale. Molybdenite and carbonaceous siliceous shale coexist, this kind of carbonaceous copper molybdenum ore is black, dense, massive, solid, containing 2.94% of carbon, the density is 2.73g/m3. Carbonaceous shale is composed of microcrystalline quartz, fine carbonaceous particles, small amounts of iron oxide particles and argillaceous chlorite.