Activated Carbon

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Infobox on Activated Carbon
Example of Activated Carbon
Activated carbon.jpg
Facts
Origin Various
Stowage factor (in m3/t) 2,55/2,97 (drums)
Humidity / moisture -
Ventilation -
Risk factors See text

Description

Black powder or granules packed in drums, bags or cartons, both plastic and paper.

Activated carbon is carbon produced from carbonaceous source materials such as nutshells, peat, wood, coir, lignite, coal, and petroleum pitch. It can be produced by one of the following processes:

Physical reactivation: The precursor is developed into activated carbons using gases. This is generally done by using one or a combination of the following processes:
Carbonization: Material with carbon content is pyrolyzed at temperatures in the range 600–900°C, in absence of oxygen (usually in inert atmosphere with gases like argon or nitrogen)
Activation/Oxidation: Raw material or carbonized material is exposed to oxidizing atmospheres (carbon dioxide, oxygen, or steam) at temperatures above 250 °C, usually in the temperature range of 600–1200°C.

Chemical activation: Prior to carbonization, the raw material is impregnated with certain chemicals. The chemical is typically an acid, strong base, or a salt (phosphoric acid, Potassium Hydroxide, Sodium Hydroxide, Calcium Chloride, and zinc chloride 25%). Then, the raw material is carbonized at lower temperatures (450–900 °C). It is believed that the carbonization / activation step proceeds simultaneously with the chemical activation. Chemical activation is preferred over physical activation owing to the lower temperatures and shorter time needed for activating material.

Applications

Activated carbon is used for the purification of gases or clarification of gases or clarification of liquids, water and oil. The product is liable to heat slowly and ignite spontaneously in air. Damage may render this commodity unfit for use with edible liquids, but may be fit for clarification of non-edible products. The advice of an analytical chemist should be obtained as to alternative uses.

Activated carbon is used in gas purification, decaffeination, gold purification, metal extraction, water purification, medicine, sewage treatment, air filters in gas masks and respirators, filters in compressed air and many other applications.

One major industrial application involves use of activated carbon in the metal finishing field. It is very widely employed for purification of electroplating solutions. For example, it is a main purification technique for removing organic impurities from bright nickel plating solutions. A variety of organic chemicals are added to plating solutions for improving their deposit qualities and for enhancing properties like brightness, smoothness, ductility, etc. Due to passage of direct current and electrolytic reactions of anodic oxidation and cathodic reduction, organic additives generate unwanted break down products in solution. Their excessive build up can adversely affect the plating quality and physical properties of deposited metal. Activated carbon treatment removes such impurities and restores plating performance to the desired level.

Shipment/storage

Activated carbon is categorised as Dangerous Goods.

Dangerous substances are classified according to their main characteristics and properties into 9 classes of the IMDG Code (International Maritime Dangerous Goods Code). Some substances have properties fitting them for inclusion in more than one Class: these have been placed in the class appropriate to the most dangerous property when carried in ships.

The IMDG Code provides an index which lists all the substances. It should not, however, be assumed that if a particular item is omitted it is either non-hazardous or forbidden for shipment. Non-inclusion of any substance possessing dangerous properties does not relieve the shipper from responsibility for declaring the nature of the substance, and under common law for any damage caused through default.

In the IBC Code, dangerous chemicals in bulk are listed with standards and guidelines on board ships.

Additionally, the Material Safety Data Sheet(s) should be consulted for chemical product identification, composition and information on ingredients, hazard identification, handling, storage and transport information etc.

Reference is also made to the Merchant Shipping (Dangerous Goods) Rules.

Note: No (packaged) dangerous goods shall be taken on board any ship to which these Rules apply for carriage in that ship unless the shipper of the goods has furnished the shipowner or master of the ship with a dangerous goods declaration. Such declaration shall indicate with the correct technical name, the identity of the goods and the United Nations number (whenever such a number exists) and shall indicate to which of the classes the goods belong.

Risk factors

Where carbon is not made by the steam activation process, it is subject to the provisions of the IMDG Code and should carry spontaneously combustible label.

Reference is also made to the applicable Material Safety Dat Sheets, IMO Regulations and Merchant Shipping (Dangerous Goods) Rules.