Production

BACKGROUND

Useful properties of coal were known back in the ancient Egypt, where charcoal was used for medical purposes already in XV century BC. Egyptians used charcoal to clean water, beer and wine.

Later, at the end of the XVIII century a remarkable ability of wood charcoal to absorb various vapours, gases, odorous and dyes of solutions was discovered. In 1773, the famous chemist Carl Scheele observed gases adsorption with charcoal. The exact day (June 5, 1785) of the discovery of substances’ adsorption out of solutions by charcoal by Tobias Lowitz is known. Lowitz applied charcoal to clean a wide variety of products (drugs, drinking water, grain vodka, honey and other sugars, nitrate, etc.). This discovery led to the first commercial use of charcoal at the English sugar-refinery in 1794. Later, in 1808, one of the plants in France also used charcoal for clarification of sugar syrups.

In the XIX century, research of carbon adsorption properties continued, but it was only at the beginning of XX century when the foundation for industrial production of activated carbons was laid down. During WW I, N.D. Zelinsky designed masks based on wood activated carbon. This invention had saved thousands of lives and served as an impetus for further research on the ability of carbon to absorb various fumes and gaseous substances that resulted in increase of activated carbons applications.

With the development of industrial production of activated carbon in the beginning of this century, use of this product was steadily increasing. Currently activated carbon is used in the following areas: drinking and waste water treatment; recycled water cleaning at enterprises; sugar syrups clarification, cleaning of gases and vapour recovery, obtaining medicines, cleaning of alcoholic-water solutions and wines, use as catalysts and catalyst supports, in gold mining to extract gold out of working solutions. It is only activated carbon that allows meeting ever-increasing requirements to purity of our drinking water. A successful development in modern technologies of adsorption is significantly facilitated by the on-going quality improvement of the product due to the development of its manufacturing processes.

CLASSIFICATION OF ACTIVATED CARBONS

There is no standard classification of activated carbon; the choice of carbon for a particular purpose is primarily based on granulometric composition, nature and content of impurities, volume and nature of pores.

By raw-materials used to obtain finished product

• Wood and wood-based coal (beech, birch, pine, linden, oak, spruce, aspen, alder, poplar)
• Nuts shell, fruit pits
• Peat, peat coke
• Fossil fuels
• Lignite

By appearance

• Powdered activated carbon. Made specifically in powder or micro granules smaller than 1.0 mm in size with an average diameter in the range of 0.15-0.25 mm.
• Granular or crushed activated carbon. Determined with the faction: 8 × 20, 20 × 40 or 8 × 30 for liquid phase of substances and 4 × 6, 4 × 8 or 4 × 10 for vapour phase of substances.
• Extruded activated carbon. Used for gas phase compounds.
• The impregnated (soaked) coal. Porous carbon containing one of several types of inorganic impregnations, such as iodine, silver, cations.

Pore Distribution by size

According UIPAC (Union of International Pure and Applied Chemistry), there are several types of pores identified in activated carbons.

• Super-mircopores – these are pores of up to 0,4 nm in diameter;
• Mircopores – pores of 0,4 nm to 2,0 nm. Micropores are particularly important for sorption capacity, their size (2 nm) is comparable to the size of molecules being adsorbed. Micropores make about 90% of the whole area per unit volume;
• Mesopores – pores of 2 to 50 nm in diameter;
• Macropores are called the large pores of a diameter larger than 50 nm.

ACTIVATED CARBON APPLICATIONS

• for water treatment (treatment of water from dioxins and xenobiotics, coaling);
• in food industry in liquor-distillery production, production of low alcohol drinks and beer, wine clarification, in production of cigarette filters, purification of carbon dioxide in production of soft drinks, cleaning of starch solutions, sugar syrups, glucose and xylitol, bleaching and deodorization of oils and fats, production of citric, lactic and other acids;
• in the chemical, oil and gas processing industries to bleach plasticizers, as a catalyst support, in production of mineral oils, chemical reagents and paints, rubber production, in manufacture of chemical fibres, cleaning amine solutions, for organic solvents vapours recovery;
• in conservation and environmental activities for industrial effluents treatment, oil and oil spills liquidation, to clean flue gases at waste incineration plants, for cleaning venting air-gas emissions;
• in mining and metallurgical industries for manufacture of electrodes for flotation of minerals, for gold extraction of solutions and slurries in gold- mining industry;
• in fuel-energy industry for steam condensate and boiler feed water refining;
• in pharmaceutical industry for refining solutions to manufacture medicines;
• in medicine for toxins, bacteria treatment of animals and people, to clear blood;
• in production of personal protective equipment (masks, respirators, etc.);
• in nuclear industry;
• to clean water in swimming pools and aquariums.