Cementation (metallurgy)

Cementation is a term metallurgy, applied to various methods:

• The electrochemical deposition of metals from solutions
• The surface treatment of metals by introduction of foreign metals
• Reducing the carbon content of metals,
• The increase of the fine gold content.

Electrochemical Deposition

Cement copper occurs as an intermediate in the recovery of copper from copper- poor ores or waste. By inserting of iron in a copper sulfate solution (cement water) falls from elemental copper:

Cement water also comes in copper mines as mine water several times before.

If, in ores or waste prior elemental copper, these starting materials are first roasted. By heating in the presence of oxygen caused this cupric compounds.

The starting materials with cupric ions are then leached in dilute sulfuric acid. Here, the copper ions ( Cu 2 ) dissolved in the sulfuric acid. These copper sulfate solution is cleaned of solids and mixed with scrap iron. This drops from elemental copper, which is then merged and cleaned electrolytically (see copper refining ).

Furthermore, it also cemented by copper or zinc ores, creating a shiny gold surface. ( Knitter gold).

Surface treatment

The surface of metallic workpieces is first treated with the so-called cementing containing extraneous metals or metal compounds. By the subsequent heating, the metal layers are connected without that the substances to be melted.

Given to using airtight containers. Smaller objects are covered in clay pots ( Zementierbüchsen ), large in iron or clay -lined boxes ( Zementierkasten ). In the containers, the workpiece is surrounded with the cementing powder and heated.

Steel production

• Mainly found in the cementing in the production of cement steel application.
• Adoucieren: By annealing of carbon-rich, brittle pig iron between oxygen-containing substances, such as hematite, magnetite, pyrolusite, the workpiece is removed from carbon. This will make it tough and ductile.

Feingold

Silver-bearing gold is finely made by cementation: The silver content is decreased, which reduces the relative gold content ( fineness ) increased. The gold is heated in the form of fine grains or thin sheet metal with ferrous sulphate, salt and brick dust. Here, silver chloride, which melts and is absorbed by the clay, while the gold is not attacked forms.

Other applications

Nickel oxide is reduced in a lined with carbon crucible by heating to malleable nickel. In the marine geology in the cementing for the development of sedimentary rock is responsible. This is done by means of the cementing of binders.