Notes on dental metallurgy : for the use of dental students and practitioners / by W. Bruce Hepburn.

  • Hepburn, W. Bruce (Walter Bruce)
Date:
1911
Catalogue details

Licence: In copyright

Credit: Notes on dental metallurgy : for the use of dental students and practitioners / by W. Bruce Hepburn. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    trunnions, on which it can be rotated for the purpose of fiUing or emptying. A blast of air is supphed from a blower, through pipes which pass through the trunnions to the wind-box at the bottom of the vessel, and thence by twyers to the metal. The usual size of converter holds a charge of 10 to 15 tons of metal. In the original Bessemer process, the. converter was lined with ganister, a very sihceous, refactory material. This is still the case in what is known as the acid process. Iron containing phosphorus in considerable quantities cannot be employed in the acid process, as phosphorus can only be eliminated in the presence of a strong base capable of combining with the phosphoric acid produced by its oxidation to form a stable phosphate. Hematite pig iron has therefore to be employed in an acid-lined converter. The process is carried out as follows : The converter is first heated strongly by a coal or coke fire, the ashes cleaned out, and the vessel turned down to a horizontal position. The necessary amount of pig iron is poured in, the blast put on, and the vessel raised to a vertical position. The silicon and manganese are at once attacked by the oxygen of the air, forming silica and manganous oxide, with evolution of heat. The oxide of manganese, together with some oxide of iron produced, combines with the sihca, forming a slag consisting of manganous and ferrous silicate. As the silicon and manganese are removed, the carbon of the metal becomes attacked, being first converted to combined carbon and then burnt ; the charge of metal boils from the escape of carbon monoxide, which burns at the nose of the vessel with a long flame, and at the same time sparks of burning iron particles are emitted. As soon as all the carbon is removed the flame disappears, and the vessel is turned down, necessary additions of spiegeleisen made, and the metal poured into ladles, and then turned into the moulds. In the basic Bessemer process the converter is lined with a basic material, such as dolomite