Coal of CC rank (low-caking)

Low-caking coals are one of the coal ranks that are determined as CC coals.

The remains of the plants are transformed into hard coal under the influence of time, high temperature, pressure and absence of oxygen. Hard coal also has changes - it gets to a different degree of chemical maturity over time. Low-caking coals get arguably the highest degree of metamorphism and are known as the charring types of coal. This type of coal lies in layers with less than 6mm of  thickness of plastic layer. The average chunk size is 0-50 mm.

In Russia the low-caking coals are not examined very well. There are around 7 millions of tons in the Far East in the Sakhalin District. South-Yakut Basin also conducts low-caking coals mining. Particularly, in Neryungri coal strip mine the amount of mined coal is 4-5 millions of tons per year. Kuznetsk basin is also rich with this rank of coal - the total reserve is around 97130 millions of tons (Batchatsky District -  2098 millions of tons, Zavyalov - 696 millions of tons, Kemerovo - 18265 millions of tons, Krapivinsky - 45922 millions of tons, Prokopyev-Kiselevsky - 11562 millions of tons, Saltymakovsky - 3107 millions of tons, Tersinsky - 1586 millions of tons, Tomi-Usinsky - 13894 millions of tons).

Low-caking coal is the natural resource that consists of high-molecular weight and has certain properties.

The coals of CC rank contain vitrinite, the reflecting power of which is 0,7-1,79%. One of the most important properties of CC coals is that they are low-caking or they cannot be caked at all. Subject to average or high metamorphism, low-caking coals gain an important property - they are hard to burn. But once burned, they do it for a long time and produce much heat. It is necessary to underline that low-caking coals burn almost without flame and smoke.

During the burning process the organic mass of the particles from which CC rank coals consist are turned into two types of products - gas (15-30%) and solid (65-80%). The proportion of liquid is just 2-5%.

There are no serious requirements to the volume of chamber and the maximum of loaded raw materials. This is explained by the fact that the burning process occurs due to the coke remains. However, during the burning process of CC rank coals it is necessary to control the blast as there is big probability of stopping the fire due to the lack of air. On the contrary, if there is abundance of air, the temperature in the chamber may increase to critical mark, or there might be the loss of heat. You can determine the amount of additional air by the color of the flames. If there is too much air the flame becomes white.

Low-caked coal produces much heat  and is usually used on big power plants or industrial boiler plants. It is also used for burning in reverberatory furnace (industrial smelting chamber) to produce metal, smelt them and for glass smelting. Specialists advise to use this rank of coal to heat metal and cast-iron boilers or stone chambers with natural and low level of draft. Such coal is also used for burning in mobile heating stations and for utility purposes. Low-caked coals are used to produce construction materials, for example lime and cement.

Low-caked coals are used in some proportions in the feeds of coke processors. It is necessary to underline that pure low-caked coal (if not mixed with other types of coal) does not provide chunks of coke. Such coke may be expected only in the mix with fat coal, which presence should not be less than 70-85%.

Characteristics of CC rank coals