Cobalt (Co) – part of a series on metals commonly alloyed with stainless steel to form varying grades of material.
Cobalt is a chemical element with an atomic weight of 58.9332. On the periodic table, cobalt sits between iron and nickel – atomic number 27.
Cobalt in ancient Egypt
The ancient Egyptians used cobalt to produce beautiful and strikingly coloured glass. Howard Carter, the famous British archaeologist, found various small glass statues and beads in the tomb of Egyptian Pharaoh Tutankhamun. Carter also found that Tutankhamun’s head was resting on a cobalt blue glass headrest; all of which would have been fabricated before the young king’s early death at the age of 18 in 1323 BC.
The cobalt blue glass that the Egyptians produced was not a product for the ordinary people of Egypt. This beautiful, blue glass was the reserve of kings and queens.
Discovery of cobalt
The name, ‘cobalt’, comes from early 16th century miners in Saxony. They gave the metal the title, ‘kobald’, which is the German word for goblin. The German miners thought that they had found a new type of silver-bearing ore. When they tried to refine the ore using heat, all they managed to produce were toxic fumes called cobalt arsenide. They assumed that a goblin had bewitched the ore.
Cobalt was isolated from its ore by Georg Brandt in 1730. Brandt was the Swedish Director of the chemical laboratory of the Council of Mines in Stockholm and he was the first person to be the named discoverer of a metal as all other existing metals had unknown origins. Early peoples had extracted blue pigment from cobalt ore but never considered that it might contain metal.
Brandt was also one of the first modern chemists to abandon the ideas and theories associated with alchemy – the process of transmuting base metals into gold. He spent his later years exposing fraudulent alchemical processes for producing gold.
In 1748, Brandt gave a presentation to the Royal Swedish Academy of Sciences. He intended to show how simple it was to trick people into believing that alchemists could produce gold. At the time, people were often conned out of money by alchemists.
Brandt first dissolved a little gold in a hot nitric acid solution which he had prepared from sodium nitrate and sulfuric acid. He then added silver to the solution and the audience watched in amazement as gold precipitated out of the solution. It led them to realize that if they had seen only the second part of Brandt’s experiment, there was a good chance they could have been tricked into thinking Brandt had transmuted silver into gold.
Use and applications of cobalt
Cobalt is a metal used in many large and diverse commercial, industrial and military applications. The metal is used in the process for making airbags and catalytic converters for cars, it is added to paint to help the drying process and is used to manufacture diamond-tipped cutting tools. We also still add cobalt to glazes, varnishes and inks.
The metal is a phenomenal catalyst. A catalyst is an element that facilitates a chemical reaction while remaining unchanged itself. The catalytic property possessed by cobalt allows it to be used to produce vast amounts of rechargeable batteries.
One of cobalt’s other main modern uses is the production of advanced superalloys. These super-strong and expensive metals are used to make parts that will spend their working lives in extremely harsh environments such as the inside of gas turbine engines.
Cobalt is relatively rare and only around 140,000 tons were produced in 2018. The increasing demand for cobalt saw the metal’s price double in 2017 and its importance to the renewable energy industry has seen investors speculatively buying the metal.
It is possible that cobalt will be one of the main objects of geopolitical competition in a world running on clean energy and dependent on batteries, although countries with reserves are likely to increase production to meet the demand.
Cobalt and the human body
Cobalt is a crucial constituent of vitamin B12. This vitamin is essential for a healthy nervous system and brain function. Our body’s production of red blood cells is also dependent on B12 and without it, we can not produce enough of these cells to carry sufficient oxygen around our body.
Oily fishes, eggs and liver contain large amounts of B12; vegans need to take supplements to get their requirement of the vitamin.
Cobalt alloyed to stainless steel
A small amount of cobalt is added during the production of stainless steel grade 348 to increase its durability against high temperatures. At Double Stone Steel, we use PVD technology to give our clients the ability to colour their stainless steel sheets and profiles in various shades of blue stainless steel; this colour can be considered to be cobalt blue.