Glossary

Find here the explanations of several terms that need clarifying.

A B C D E F G H I K L M N O P Q R S T U V W Z
A
aes brundisium: latin name for →Bronze. Literally ore from brundisium, the important port, where shipments of this material arrived. Ore is often used to describe metal. This was done until the 19th century.
aes corinthium: Corinthian ore is a copper →alloy whose surface can be treated to a dark-brown to aubergine colour. The main components are Copper (Cu), Silver (Ag) and Gold (Au).
aes cuprum: latin for →Copper
Alloy →(die) Legierung: An alloy is a solution of two or more chemical elements, of which one at least is a metal. Good examples are →bronze a mixture of →Copper and Tin, or Carbon-steel, an alloy of →Carbon and iron.
Azurite →(der) Azurit, (die) Kupferlasur: Etymology: lat. azzurum for blue originating from arab. lazaward = blue
Chemical formula: Cu₃(C0₃)₂(OH)₂
Mohs scale: 4
Density: 3,9
Environment: Azurite is a secondary mineral of the oxidized zone of an ore deposit.
More specific details can be found in the mineralogy database
B
Black copper →(das) Schwarzkupfer: Product of a smelting process of sulfidic ores known as→matte smelting. Black copper has a copper content pf 90% and has to be refined before it can be used for further metallurgical processes such as casting.
Blister copper →(das) Schwarzkupfer: see →black copper
Brass →(das) Messing, (der) Gelbguss: An →alloy of →Copper und →Zinc (Zn). The discovery that Zinc and Copper are the components of brass was only discovered in 1657 by Johann Rudolph Glauber (1604 - 1670). Before that brass was produced by the cementation process. Copper, finely ground →calamine, a zinc ore and charcoal were heated in a crucible to approximatey a 1000°C. The forming Zinc gas diffused into the Copper and formed the alloy in a solid state process. Then copper-alloy might have eventually liquified in the crucible. The chemical process is as follows:
ZnCO₃ → ZnO + CO₂
ZnO + C → Zn + CO
Alchemists did NOT understand that an alloy was produced. They regarded this as the colouring of copper by the arts; probably because ZnO (Zinc oxide) is a white substance and it was not acknowledged as a metal ore.
Bronze: Etymology: lat. aes brundisium: ore from Brindisi after the ancient port of Brundisium. We think the alloy might have been shipped to this port and then distributed through the Roman empire. The →alloy consists of →copper (Cu) and →tin (Sn). With 10% tin contents the alloy is liquid above 1020°C.
Bronze age →(die) Bronzezeit: Term was introduced by Christian Jürgensen Thomson in 1836 and divided the prehistory of mankind into stone age, bronze age, and iron age. In central Europe the Bronze Age starts roughly at 2300 BC and ends around 800 BC.
C
calamine →(der) Galmei: Old fashioned name for the zinc ores zinc spar (Smithsonite, zinc carbonate) ZnC0₃ und Hemimorphite (zinc silicate) Zn₄Si₂O₇(OH)₂ x H₂O. The name was used for both minerals. Zinc spar produces zinc oxide ZnO and Carbondioxide CO₂ when annealed .
Carbon-steel →(der) Kohlenstoff-Stahl: An alloy of Iron (Fe) and Carbon (C). Up to a Carbon content of 2.06% it is called Carbon-steel. Above we refer to it as →cast iron.
Cassiterite →(der) Kassiterit, (der) Zinnstein: Etymology: From phoenician "Cassiterid", which described the English and Irish islands. Another phoenicin word for Tin-land is B'ratan' of which Aristotele developped the word "Britannic".
Chemical formula: SnO₂
Crystal system: tetragonal (vierkantig)
Mohs scale: 6 - 7
Density (g/cm³): 6,8 - 7 / average = 6,9
Notes: Most important Tin-ore
More specific details can be found in the mineral database
Cast iron →(das) Gusseisen, (der) Grauguss: Cast iron or grey cast iron is an alloy of Iron (Fe) and Carbon (C), just like Carbon-steel. The major difference is the proportion of Carbon. Cast iron has contetnts of more than 2.06% C. The →eutectic →alloy has a Carbon contents of 4.3%.
Cementation →(die) Zementation: Cementation is a metallurgical solid state process. In a heated environment one metal stays solid, the other substance/metal is gaseous and is absorbed by the solid substance, thus forming an alloy. There are a few example for this process, e.g. the production of →brass or Wootz-/crucible-steel.
Chalcocite → (der) Chalkosin, (der)Kupferglanz: Etymology: gr. chalkos - Copper, Bronze
Chemical formula: Cu₂S
Crystal system: monoclinic - prismatic
Mohs scale 2,5 - 3
Density: 5,8
Environment: Secondary mineral near or in oxidized copper sulfide ore deposits.
More specific details can be found in the mineralogy database
Chalcopyrite (der) Chalkopyrit, (der) Kupferkies: Etymology: gr. chalkos = Copper and gr. pyr = Fire.
Chemical formula: CuFeS₂
Crystal system: tetragonal
Mohs scale: 3,5
Density: 4,1 - 4,3
Environment: Abundant in sulfide ore deposits. Chalcopyrite is the most important Copper ores, with copper contents up to 34,5%.
More specific details can be found in the mineral database
cope →(der) Oberkasten: Upper part of the →flask
Covellite →(der) Covellin, (der) Kupferindig: Etymology: in honour of the italian Mineralogist N. Covelli, who did the first chemical analysis.
Chemical formula: CuS
Crystal system: hexagonal
Mohs scale: 1,5 - 2
Density: 4,6
Environment: Mostly a secondary mineral of sulfide ore bodies in the oxidation zone.
More specific details can be found in the mineral database
Copper →(das) Kupfer: Etymology: lat. aes cuprum: Ore of Cyprus, origin: gr.: κϒψρος 'kypros': name of the island Cyprus, were copper ores were mined since prehistoric times. Copper (Cu) has a melting point of 1083,4°C.
Crucible →(der) Tiegel: Crucibles are the containers in which metals are molten. They are often made of clay material. These are usually refractory enough to withstand the temperature shocks during melting and subsequent casting.
Crucible steel →(der) Tiegelstahl: Wootz-steel is a steel which is formed in a processed called cemetation. This steel was produced as early as the 6th century AD in India. Another important centre for the production of crucible steel was Uzbekistan in the 10th century.
Iron and carbon-rich material (e.g. plants, charcoal, etc) were placed in a →crucible and heated for a prolonged period of time. The carbon would form Carbonmonoxide (CO) and enrich the carbon content of the iron, thus forming the steel alloy.
Cu: see →Copper.
Cupellation → (die) Kupellation, (die) Treibarbeit, (das) Abtreiben: A process for the production of silver, by enrichment of argentiferous (silver-bearing) lead (Pb). Oxygen is blown onto a molten silver-bearing lead "alloy". The base metal lead is oxidized, the noble metal Silver stays as rest = regulus in the cupelle. The lead oxide (Litharge) is absorbed by the cupelle. The chemical process can be described as follows:
Pb _{and metals} + O₂ → PbO _{and
base metal oxides} + Pb _{and noble metals}
The process is discountinued, when all lead is oxidized.
Cupelle → (die) Kupelle, (die) Kapelle (old fashioned): Cupelles are containers for the metal in the →cupellation process. In contrast to →crucibles cupelles consist of compressed bone-, or plant-ash or magnesia (magnesium oxide). This is necessary for the molten →litharge (lead oxide) has to be absorbed by the porous cupelle.
Cuprite →(der) Cuprit, (das) Rotkupfererz: Etymology: lat. cuprum = Copper
Chemical formula: CU₂O
Crystal system: isometric - hexoctahedral
Mohs scale: 3,5 - 4
Density: 6, 1
Environment: Oxidation zone of copper ore bodies
More specific details can be found in the mineral database
D
deposit →(die) Lagerstätte: The source of →ores are called deposits. Ores can occur in deposits or →placer deposits
Die →(die) Kokille: Dies are →permanent moulds consisting of metal, usually steel, but sometimes also cast iron, or for prehistoric times of copper alloy.
downsprue →(der) Eingusstrichter: The casting funnel or slip cap. The first, usually vertical part of the →gating system in which metal is poured to reach the mould cavity. See also →sprue, →vent, →runners
drag →(der) Unterkasten: Lower part of the →flask
E
Eutectic →(das) Eutektikum: Etymology: griech. ευ 'eu': good and τεκτειν 'tektein': build. An alloy is eutectic when the proportions of the components are such that the alloy is above a given →melting point liquid (→Liquidus temperature) and below the same temperature (solidus temperature) completely solid. The eutectic is reached when both points fall together, the eutectic point. This is usually the lowest melting point of any proportion of components. Since this alloy will solidify almost instantly at a given temperature a fine grained and uniform microstructure is produced.
F
Feeder →(der) Speiser, (der) Steiger: Feeders or risers are reservoirs of molten metal in the mould that are used to feed the mould with metal during solidification. As metal shrinks when it solidifies, the risers have to be applied in way the solidify last. This is an industrial concept where huge amounts of metal are poured, or great wall thicknesses have to be realised. It is rarely applied in prehistoric or art casting.
Flask →(der) Kasten: Flasks are frames that hold the molding sand of sand moulds. They are usually made from steel, aluminium or bronze. They consist of two halves called →cope and →drag.
G
Galena →(der) Bleiglanz, (der) Galenit: Lead sulfide (PbS); important lead ore, called argentiferous if Silver is built into the crystal structure. Therefore can also be an important Silver ore.
Gangue →(die) Gangart: Minaerals and rock that are intergrown with →ores and do not contain any metal you can smelt.
Gate →(der) Anschnitt: The specific part where the sprues connect with the mould cavity. The term is also used in a more general way to describe the →gating system.
Gating system →(das) Anschnittsystem: The system of →downsprue, →sprues, →vents, →runners, →risers and →feeders, which allow for the metal to reach the cavity.
Gossan →(der) Eiserne Hut
Grey cast iron →(der) Grauguss: see →Cast iron
Grog; grog, to →(die) Magerung →(die) Schamotte: Ground pot sherds, ceramics, high fired ceramics, which are used to influence the properties of clay, e.g. refractoriness or shrinking.
H
I
J
K
L
Liquidus temperature →(die) Liquidustemperatur
Litharge →(die) Bleiglätte: Lead oxide (PbO). Amongst others a by-product of Silver enrichment/Silver production (→cupellation); The liquidus temperature marks the point when all components of an →alloy are present in a liquid state.
Loam →(der) Lehm: Loam is a naturally occuring soil consisting of the three mineral size fractions →clay, →silt und →sand.
lycopodium →(das) Lykopodium: Parting agent in sand moulding. It prevents green sand from sticking to the pattern or from cope and drag to stick together. In the olden days lycopodium bisdepuratum was used for this purpose. Today it is made from ground resins.
M
Malachite →(der) Malachit: Chemical formula: Cu₂(C0₃)(OH)₂
Crystal system: monoclinic
Mohs scale: 4
Density (g/cm³): 4
Environment: Secondary mineral in copper deposits; very common. Important depostis aer in Katanga, Kongo.
Usage: Malachite was used as pigment in antiquity. It is an important indicator for copper deposits.
More specific details can be found in the mineralogy database.
Marcasite →(der) Markasit: Chemical formula: FeS₂
Crystal system: orthorhombic - dipyramidal
Colour: bronze, lightbrown yellow, tin-white, greenish black
Mohs sclae: 6 - 6,5
Density (g/cm³): 4,89
More specific details can be found in the mineralogy database.
Matte →(der) Stein: A typical range of products of the smelting process of sulfidic ores if →roasting is an integral part of the →smelting process. Alternating roasting and smelting under reducing atmosphere results in an enrichment of the metal component in the ore. The English terminology is less exact than the German one which differentiates several matte phases with increasing metal contents, until the preliminary endproduct, the black copper or blister copper is produced. Blister copper has a copper contents of 90%. (BACHMANN 2000, S. 133f)
Minerals →(das) Mineral: Minerals occur naturally and are defined by their chemical compound, their chrystal structure and their mechanical and physical properties.
Miner's tools →(das) Gezähe: Tools used by miners to mine the ore.
Model →(das) Modell: A model resembles in shape and dimensions exactly the object you would like to cast in metal. Depending on the moulding process you will either create a lost model or a permanent pattern (for sand casting). Models for the lost-wax process are obviously made from bee's wax, or nowadays from microccrystalline wax.
Moulding loam →(der) Formlehm: Moulding loam is the loam you prepare for the use of loam moulds. It is compostion of clay, sand and grog. If it is prepared carefully it will have all the necessary properties moulding materials must exhibit, such as →refractoriness, →permeability and ruggedness.
N
Naturally bonded moulding sand →(der) Naturformsand: This sand consists mainly of →quartz (SiO₂) in the form of fine-sand (0.063mm - 0.2mm) bonded by naturally occurring clay. For moulding purposes the proportion of clay should range between 8-15% clay.
O
Ore →(das) Erz: Ores are →Minerals of which metal is produced by employing the process of →smelting. Two main groups of ore exist: oxidic and sulfidic ores. Oxidic ores are in general of limited availability, are free of gangue and can esily be smelted.
Sulfidic ores (compounds wih Sulfur (S)) are more abundant, are usually required to undergo a preceding →roasting process and are often intergrown with gangue. It becomes immediately apparent that these are by far more challenging to smelt.
Ore is an economic term, and another prerequisite is that is has to be economically worthwile to smelt these in order to produce metal.
For →Copper there are few economicall important ores: →Chalcopyrite, →Chalkocite, →Covellite and →Cuprite.
→Cassiterite is the most important ore for the production of →Tin.
Oxidation →(die) Oxidation: Chemical reaction where in the simplest case Oxygen (O₂) is accepted. During oxidation the substance to be oxidised (electron donator) gives off electrons to the oxydiser (electron acceptor). The oxydiser is at the same reduced (→Reduction). An oxidation is always associated with a reduction and both are parts of the redox reaction.
P
Permanent mould →(die) Dauerform: Permanent moulds are re-usable moulds; they are opened rather than destroyed to retrive the cast. They can consist of steel, cast-iron, bronze, sandstone or soapstone.
Permeability →(die) Gasdurchlässigkeit: Permeability is an important property of the moulding material and describes the degree of gas flow through the moulding material. It facilitates the filling of the mould cavity. Although this does usually subsitute for the application of →vents.
Placer deposit →(die) Seife: Placers or placer deposits are deposits of secondary origin. Through wheathering and mechanical (fluvial) transportation ores can be congregated and enriched. Concentrations of ores are usually higher than in the original rocks. Typical ores of placers would be those of tin, gold, platinum, niobium, tantalum, titanium, zirconium. Diamonds are also to be found in placers. (EDWARDS, R. & K. ATKINSON 1986, S.175ff).
Potassium →(das) Kalium: Chemical element. Chemical formula K for Kalium (lat.) from al qalja = plant ash. Interestingly the word potassium has the same meaning, since it the latinised form of pot ash. Potassium is the main component of pot ash (K₂CO₃). Since this potssium salt is present plant ash and furthermore is water soluble, it was enriched in water and the water subsequently evaporated in clay pots. Hence pot ash. Find more information on sodium at Wikipedia.
Q
Quartz → (der) Quarz: SiO₂, abundant chemical mineral, as opposed to →silica, the chemical compound. Refractory material which liquifies at 1650±75°C. Main component of many moulding materials.
Quenching →(das) Abschrecken: Rapid cooling of red hot metal to room temperature or below, for example by immersing in water or oil.
R
Reduction →(die) Reduktion: Chemical reaction where in the simplest case Oxygen (O₂) is given off. For →smelting it is important that electrons are accepted. See also →oxidation.
Refractoriness →(die) Feuerfestigkeit
Riser →(der) Steiger, (der) Speiser: see →feeder
Roasting →(das) Rösten, (der) Röstvorgang: Roasting is a step in the primary production of metals from →ores. It is a step preceding the →smelting of the ore. It →oxidises compounds that could otherwise not be smelted in reducing conditions. This step is necessary for almost all sulfidic ores.
S
Sand →(der) Sand: Mineral size fraction of the soil between 0,063mm und 2,0mm. Sand is next to →silt and →clay a constituent of →loam.
chamotte →(die) Schamotte: Chamotte are highly fired and ground clays, which are mainly used as →temper or →grog.
Silt →(der) Schluff: Mineral size fraction of the soil between 0,063mm und 2,0mm. Sand is next to →clay and →Sand a constituent of →loam.
Shrink hole →(der) Lunker, (der) Gusslunker: Casting defect, due to the solidification of metal in layers from the outside to the inside of the mould cavity. As metal shrinks when solidifying, this creates a lack of metal. In large diameters shrink holes appear as funnel shaped recesses with a rough surface. The correct apllication of →risers in the gating system will prevent this kind of casting flaw.
Silica →(die) Kieselsäre: Silicon dioxide SiO₂; chemical compound of Silicon (Si) and Oxygen (O₂).
Smelting →(die) Verhüttung: Primary production of metals. Ores are smelted to metals. Simple ores, such as oxidic ores can be →reduced to metal in a single smelting process. More complex ores, such as sulfidic ores have to be →roasted, i.e. compounds that cannot be directly reduced have to be oxidised first, before the ore can be reduced to metal.
Depending on what ore is smelted, it has sometimes to be →beneficiated as well, which is the separation of ore and gangue.
Smithsonite: See →zinc spar
Sn: see →Tin
Sodium →(das) Natrium: Chemical element. Chemical formula Na. From egypt. netjer = natron arab. natrun = (sodium bicarbonate or sodium hyrogen carbonate) NaHCO₃. Find more information on sodium at Wikipedia.
Solidus temperature →(die) Solidustemperatur: Denomoinates the temperature at which an alloy is completely solid. In case of a 10% Tin alloy this is 798°C. Above this temperature there are two phases present in the alloy: a liquid and a solid one. The alloy is in the mushy stage. Once the →Liquidus temperature is exceeded the alloy is completely liquid.
T
Tempering 1. →(das) Anlassen 2. →(die) Magerung: 1. Reheating of metal object, i.e. after hardening to tempeartures up to 732°C. Tempering releases internal strain and promotes toughness as opposed to brittleness resulting from hardening. →Temper colours are an important indicator for the assessment of the temperature.
2. Step in preparing clay for the use for pottery or ceramics, such as pots, crucibles, moulds, etc. Usually ingredients other than clay, e.g. →grog, sand, chaff, animal hair, plant fiber, etc.
Temper colour →(die) Anlassfarbe: Temper colours originate from →oxidation of the surface of clean metals when heated. Distinct colours represent distict temperature intervals; e.g. carbon-steel has a cornflower-blue colour at 300°C. A standard temper colour chart can only be applied to carbon-steels.
U
V
Vent →(der) Luftkanal, (die) Entlüftung: Vents connect the mould cavity with the outside, but contrary to the gates, they are for the gases and air which, otherwise would be trapped with thae cavity. Sometimes with large moulds these gases can be ignited, thus creating a negative pressure in the mould. Generally speaking it is enough if the vents are attached to the highest points of the cavity.
W
Z
Zinc →(das) Zink: Zn. Melting Point 419,5°C; Boiling Point 907°C. It was only in the 17th century discovered that zinc is a metal. William Champion patented his method of zinc production by distillation in 1738.
Since zinc's boiling point is so low it was previously impossible to produce zinc-metal with the known smelting processes. It would have rather evaporated than liquified.
Zinc spar →(der) Zinkspat: Zinc carbonate ZnCO₃. Important zinc ore. Also known as Smithsonite.

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