Flotation Plant

The most important solid fuel, coal is not a homogenous substance. The most important ones are boneblack, clay, gypsum, marcasite and pyrite. Therefore, coalfields differ alot in various firms, there is even difference between coal samples from the same coalfields. There is oxygen, hydrogen, azote and sulphure in coal other than carbon. The dispersion percentage of these elements vary in different coal types. Brown coal has a water absorbing characteristics. Hence, it involves more humidity. Humidity absorption skill decreases from brown coal to anthracite. The less the absorption skill is, the more the flotation skill increases. Coal is naturally a floatable substance. Some neutral oils are used in flotation to reduce the flotation time and increase the performance. These are gas oil, creosote and fuel oil. Newly acquired coal usually floats more easily than the coal which was extracted from the mine a couple days earlier and left for spooling. The oxygen of the air gets the coalÆs surface oxidized and reduces its floatability even in normal atmosphere temperature. When the coal is not wished to float, it is oxidized with tassium permanganate. %1 NaOH is required to break the oxide layer. Oxidation occurs more in low quality coal when compared to the high quality one. Floatation skills decrease upon that. Control reactives that suppress the foreign minerals should be used to acquire clean coal concentrations. Sodium carbonate and sodium silicate are used to suppress clay and discharge.

Percentages of Various Elements
Coal Type C H O N S
Anthracite 94,5 3 1,25 0,75 0,5
Semi-Bituminous 91,5 5 1,75 1,25 0,5
Bituminous A 89 5,5 3,5 2,5 0,5
Bituminous B 84,5 5,5 8 1,5 0,5
Sub-Bituminous 79,5 5,5 12,75 1,75 0,5
Brown Coal 73,5 5,3 19 1,7 0,5.