Question

what is fluxing material?
why is limestone used as a fluxing material? ​

Answer 1

Answer:

1 Ans. Flux in metallurgy, any substance introduced in the smelting of ores to promote fluidity and to remove objectionable impurities in the form of slag.

2 Ans. Limestone is used as a fluxing material because of its flux action which allows it to lower the concentration of impurities in the steel and to produce slag.

Answer 2

Flux, in metallurgy, any substance introduced in the smelting of ores to promote fluidity and to remove objectionable impurities in the form of slag. Limestone is commonly used for this purpose in smelting iron ores. Other materials used as fluxes are silica, dolomite, lime, borax, and fluorite.

In the process of smelting, inorganic chlorides, fluorides (see fluorite), limestone and other materials are designated as "fluxes" when added to the contents of a smelting furnace or a cupola for the purpose of purging the metal of chemical impurities such as phosphorus, and of rendering slag more liquid at the smelting temperature. The slag is a liquid mixture of ash, flux, and other impurities. This reduction of slag viscosity with temperature, increasing the flow of slag in smelting, is the original origin of the word flux in metallurgy. Fluxes are also used in foundries for removing impurities from molten nonferrous metals such as aluminium, or for adding desirable trace elements such as titanium.