DETERMINATION OF GRINDABILITY INDICES OF FUELS BY THE VTI METHOD.

The recently published All-Union Scientific State Standard (GOST) 15,489-70, ″The Brown and Pit Coals and Bituminous Shales. A Method to Determine Grindability Indices,″ is discussed and justified. The method was developed 25 years ago by V. P. Romadin and subsequently improved. In this method fuel is milled in a mill with a porcelain drum 270 mm in diameter and 210 mm in length, loaded with porcelain balls. The drum is charged with an air-dried fuel sample 500 g in mass. Grinding is carried out for 15 mins. A 25 g portion of the ground sample is sieved and tested. The grindability index is determined at a constant consumption of power and variable fineness of dust.