Crucible
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Platinum crucible and fused silica muffle and crucible scissors
Crucible under heating
Crucible(Crucible ) Is a heat-resistant container in the form of a fountain used for melting and synthesizing substances by utilizing high heat in physicochemical experiments and mining and industrial fields. As crucible holding toolCrucible scissors (Tong). Often covers are covered with the same material lid.
table of contents
Materials and fields of use
Various materials are used for crucible materials depending on the purpose. In the laboratory, one made of about 20 ml in volume is generally used, which is used when melting and mixing metals, melting ionic crystals, or making samples.
Industrially, an inexpensive product may be used. In particular, when a high temperature (1600 to 2000 ° C.) is required, a crucible made of,,, or the like is used.
When melting by analytical chemistry, it is sometimes used for the purpose of preventing the melting and mixing of the crucible components (melting point about 1800 ° C.) or made by (manufactured by melting point about 2500 ° C.). There are also quartz glass and things with Teflon processing.
Quartz crucibles made by the factory are used. In a large crucible, there are things that are as big as people can put in.
The one made of ceramics was once used for melting, but nowadays it is made of platinum because it hates the contamination of trace impurities. Gold crucibles and platinum crucibles are very expensive, especially the price of platinum crucibles is usually posted as "in the catalog of scientific experimental equipment" but this is due to the fact that material costs account for much of the price, Because it is greatly influenced.
In this way, in selecting, the application, the heating temperature, the influence of impurities from the crucible material, the corrosion resistance, the price, and the like are taken into consideration.
heating
For heating at the laboratory level, use a small electric furnace or the like.
As the metallic material, … is used, and as the ceramics, … ,,, etc. are used. Crucibles made of metal, silica, alumina titanate are said to be resistant to cracking even under sudden temperature changes.
A general crucible is heated by a gas burner, but when it reaches a high temperature, the amount of radiation of infrared rays increases, and as the temperature does not rise, the crucible often covers it. There is also an electric crucible furnace (from around 50,000 yen), which heats the inner crucible by power.
important point
The crucible expands when it gets hot, so it may crack depending on the material. Especially avoiding rapid cooling with water should be avoided.
Platinum crucible
Platinum crucibles are preferred for use in analytical chemistry and specialty ceramic manufacturing areas, but it is necessary to keep in mind that platinum at high temperatures unexpectedly lacks chemistry. When platinum is heated intensely under or atmosphere, halogen compounds are generated and damaged. Also, the same reaction as heating a mixture of dilute hydrochloric acid and dilute nitric acid in a platinum crucible occurs, and the crucible is corroded. Furthermore, it is known that in the case of directly heating a platinum crucible with a reducing flame, carbon in the flame melts into platinum and deteriorates. Likewise, if a reaction such as the formation of a simple substance of heavy metal is carried out while heating it, platinum turns into damage and it is damaged. Because platinum crucible is expensive to play and repair due to the nature of the material, it is necessary to pay sufficient attention.
Gold crucible
Gold is chemically stable but its melting point is as low as 1064 ° C.
Alumina crucible
Because it is large, it is easy to break if it is heated suddenly. It is also easy to react with.
Related item
footnote
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1. *Illustrated lenses are known Shinichi Nagata Japanese business publishing company 2002 P61 2. *Industrial Technology Research Institute Technoknowledge network About the handling of platinum instruments (The notes on the use of platinum crucibles are listed briefly and exhaustively) [__]
External link
- \ - MEXT National Education Policy Research Institute
Acquired from ""
Post Date : 2018-03-03 08:30
This article is taken from the Japanese Wikipedia Crucible
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