Activated Carbon Production
Activated carbon is known to everyone. Most know about it as small black tablets used in food poisoning – on the principle of “cheap and cheerful.” However, did anyone wonder what activated carbon is made of, and how this happens? After all, this process is much more complicated than it might seem at first glance.
What is activated carbon
Roughly speaking, activated carbon is carbon with virtually no impurities, having the appearance of a very light and very porous substance. Actually, it’s very porous – the surface of 1 gram of the finished substance, depending on the manufacturing method, can have a surface of 500 to 1800 m² – just imagine, a tablet that you take when poisoned has a surface of more than a kilometer square!
Coal is made from many different types of raw materials, both mineral and organic. For different brands and purposes, it can be charcoal, coal, petroleum coke, peat, walnut and coconut shells, fruit bones and much more. Medical activated carbon is made from coconut coal.
Areas of application of activated carbon in modern life
The scope of activated carbon is very wide. They knew about its properties in ancient times – in Russia it was made at home, most often from birch logs; you didn’t even have to do anything for this – just the coals left after kindling the bath were brought into the steam room for activation. In terms of quality, this prototype could not be compared with modern brands of coal, but even then it was used to treat gastric disorders in both people and livestock, it was filtered with water and home-made alcoholic drinks, and much more.
On an industrial scale, the military began to use it for the first time. Activated carbon has become a key element of the gas mask developed by N.D. Zelinsky during the First World War – when German troops began to release chlorine on the battlefield. Thanks to its absorbent properties, coal saved many lives in those years.
In the modern world, it is used in many areas:
In the food industry (e.g. sugar refining)
In the chemical industry as a reaction catalyst
In the pharmaceutical industry
In treatment plants for the purification of air and water from industrial waste
In household filters for drinking water
as well as in many other areas.
The thing is its properties – activated carbon is a great absorbent, very light, very effective, and most importantly – very cheap. It can be manufactured almost everywhere, although the production technology is not simple, but does not require a long time and too complicated processes – only two devices can cope with everything. The site elgreloo.com invites you to get acquainted with the technology of manufacturing activated carbon.
Industrial technology for activated carbon
The whole process of activated carbon production consists of two stages:
Production begins with the fact that raw materials, whether coal, peat or shells, are crushed to particles as small as a few centimeters. After that, it is loaded into special carbonization furnaces. There are several furnace designs used for this purpose. The most common ones are:
Despite the differences in design, they have one principle of operation – the raw material is subjected to heat treatment without oxygen. The temperatures in the furnaces are extremely high – from 600 to 950 degrees Celsius. As a result, carbon-containing raw materials are transformed into coals like those that remain from firewood after an extinct fire – they have primary strength of coal, but they have very small pores, and they absorb substances quite poorly.
In order for activated carbon to become such, carbonized raw materials go through another stage of production – directly activation. As a result, it receives a specific internal structure, which is responsible for the excellent adsorption properties of the finished product.
There are two ways to activate. In the first embodiment, the carbonate is impregnated with zinc chloride or potassium carbonate, and then heated to a temperature of about 600 degrees Celsius – again, without oxygen. Activated carbon generally does not like open air – it rapidly oxidizes and absorbs foreign substances from the air, losing its properties.
The second, most common method is the legacy of the ancient Russian activation method, which was mentioned earlier. Carbonated raw materials are treated without access of air with superheated steam or its mixture with carbon dioxide. Such processing requires a temperature of up to 900 degrees Celsius, which is already more difficult to achieve – and therefore an apparatus was created that uses the properties of coal itself to activate it. In devices of this design, a strictly metered amount of air is passed into the activation zone, due to which part of the coal spontaneously ignites.