Metallurgy

Rock metallurgy is the study of the working and processing of rocks and soils whose character is non-metallic.

Rock metallurgy is divided into materials science and manufacturing processes and techniques and is a technology in which thermodynamic processes are often used. The products of mineral engineering are always changed by thermal influences and are mostly made from natural raw materials. They are essentially:

Differentiation from metallurgy

The silicate chemistry on which mineral engineering is largely based differs significantly from metallurgy , the aim of which is the production of metals.

The silicate chemistry is primarily about complex aluminosilicate compounds and the products to be made from them, such as glass, industrial ceramics or cement. The pure material, silicon or aluminum , is not the primary production goal.

history

Murano glass chandelier

The manufacture of ceramics and glass is one of the oldest cultural techniques of mankind and their products were sought-after goods. The oldest ceramic vessels in the world are proven from the Jomon culture of Japan and date to 13,000 BC. Chr.

During excavations in Syria ( Mumbaqat ) one found ceramic ovens from the 4th millennium BC. Chr.

Cement was already known to the Romans , while the development of refractory materials only began in modern times with the introduction of steel and glass production on an industrial scale. However, as far as glass and ceramics in particular were concerned, this technology was such an important trade factor that the process was kept absolutely secret. As a result, there was no independent teaching at the universities.

The Murano was the time of the Renaissance made on a sealed off from the rest of the world island off Venice, where the workers were treated as slaves by the operators. The Italian glassmakers from Altare in the Ligurian Alps were severely punished for betraying glassmaking secrets. The sentences ranged from confiscating their property to killing them.

The development of glass at the beginning of mercantilism by the Compagnie de Saint-Gobain and the porcelain production (the white gold) of the Meißen porcelain factory were manufactured in strictly isolated locations, in which the production techniques were subject to confidentiality, which can be compared with today's absolutely. The glassworks operated by Johannes Kunckel on Pfaueninsel in Berlin and financed by Elector Friedrich Wilhelm was also kept under strict secrecy.

Furnace technology

The products, the manufacture of which is concerned with metallurgy, are all subjected to a heat treatment. They are either made from granular raw materials (glass, cement) that are melted and refined using heat, or they are fired after they have been shaped (ceramic, refractory material).

The process heat required for this is generated in furnaces that have undergone profound technical development with the change in processes. In the early days of glass and ceramic production, round ovens were used. They were heated with wood, which is why all European production facilities were in wooded areas. The manufacturing processes were discontinuous and batch-wise, the glass batches were melted down in large ceramic harbors.

Continuous production was only possible with the development of furnaces in which a hot flame or hot combustion gases, which can be set to oxidize or reduce, brush over the fuel-free melt material. In this case, the furnace chamber is a closed, fixed tub (tub furnace) or a rotatable cylinder (drum furnace) with a front loading and unloading opening. Hand in hand with this development went the addition of regenerative chambers to the ovens, which use the thermal energy of the hot combustion gases emitted to preheat the incoming air ( Siemens-Martin oven ).

By mastering electric melting, melt-cast refractory material could be produced, which in turn benefited modern glass furnace technology. Today's ovens are well insulated as rotary kilns, glass ovens or ceramic ovens to save energy. Oil or gas is used as fuel if the product to be manufactured does not require an inert or reducing atmosphere; in this case, electrically heated ovens are used.

literature

Georg Horn describes the history of the glass industry and its workers . Collection on the history of the workers Vol. 11 JHWDietz Nachf. Stuttgart 1903

Lexicons

Darmstaedter, Ludwig (Ed.) Manual on the history of natural sciences and technology in chronological representation. 2., reworked. u. increased edition, ed. by L. Darmstaedter, Berlin: Springer 1908

Specialist literature

Hermann Salmang The physical and chemical basics of glass production ; Berlin, Springer, 1957
Hans-Ernst Schwiete, among other things, on the use of X-ray fluorescence analysis in rock metallurgy, taking into account the secondary components and traces of West German. Ed., 1967
G. Ondracek: Materials science. Guide to study and practice. 2nd edition, Expert-Verlag, 1986, ISBN 3-88508-966-1
Gerald Routschka and Hartmut Wuthnow pocket book Feuerfeste Werkstoffe Vulkan Verlag ISBN 3-8027-3157-3

swell

Siegmar Geiselberger "Cast" or "pressed" glass - glass relief with the portrait of Louis XIV by Bernardo Perrotto: Bernardo Perrotto, the Jewish glassmaker from Altare, the Gonzaga family and the glass figures from Orléans and Nevers Jan. 2002 Pressed glass correspondence 2002- 1

Metallurgy

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