Flux (melting)

The articles melt treatment agent and flux (melt) overlap thematically. Help me to better differentiate or merge the articles (→  instructions ) . To do this, take part in the relevant redundancy discussion . Please remove this module only after the redundancy has been completely processed and do not forget to include the relevant entry on the redundancy discussion page{{ Done | 1 = ~~~~}}to mark. Zinnmann d 09:59, Jan. 13, 2015 (CET)

As flux is known additives that both the melting of metals and alloys may be used, as well as in the melting of metals from their inorganic compounds, such as oxides or chlorides . In addition, the melt phase formers used in the sintering of ceramic masses are called fluxes.

How metallurgical flux works

Basically, a flux has to become liquid below the melting temperature of the batch material, because only in this way can it promote the transition of the insert located in a crucible , hearth or tank furnace from the solid to the molten state.

The low melting point of the flux and its composition tailored to the task - usually as a mixture of inorganic salts - cause oxides to be detached from the feedstock and slagged. At the same time, the slag flow protects the insert from renewed oxidation because the access of atmospheric oxygen is prevented.

Areas of application

In metallurgy , therefore, oxide-binding fluxes are used in a wide variety of processes, e.g. B. used in soldering . For the range of metals and their alloys be cast industry flux is related to the supply of liquid metal to vergießendem and thus the generic term melt processing means associated with

Flux in the foundry industry

An important task for minerals or mixtures of these, which are simply referred to as fluxes, is found in the foundry industry , here mostly under the aforementioned term melt treatment agent. The practice in metal works and foundries requires the rapid liquefaction of coarse to finely charged metals and alloys and in this way to limit oxidation losses. This task also includes, under the premise of the sustainability of raw materials, both scrap metal of all types and processing waste in foundries and semi-finished products, which are usually contaminated, to return to unrestricted use in a recycling process.

Flux in aluminum extraction

The tasks of fluxes also include making it possible to extract metals from mineral compounds. The best-known example is the production of aluminum from alumina , in which melted cryolite (ice stone) serves as an electrolyte and thus as an oxide-absorbing flux.

Literature used

• Flux - Metallurgy. In: Holleman-Wiberg: Textbook of Chemistry. Part one inorganic chemistry. Walter de Gruyter publishing house, Berlin.
• Fluorspar. In: Josef Bersch: Lexicon of metal technology. Handbook for all traders and artists in the metallurgical field. A. Hartleben Verlag, Vienna a. a. 1899.

Individual evidence

1. ↑ Entry on flux. In: Römpp Online . Georg Thieme Verlag, accessed on January 2, 2015.
2. ^ Hermann Salmang, Horst Scholze, Rainer Telle (ed.): Ceramics . 7th edition, Heidelberg 2007, p. 646.
3. ↑ Cryolite was originally only known from natural occurrences on Greenland. The need as a flux in the electrolysis cells, which occurs particularly in the electrolysis of alumina for aluminum production, led to its synthesis.