Abstract
The following equation, derived by P. Rosin and E. Rammler, was reported to be in good agreement with experimental results about many foreign coals.
R=100e-bxn
where R;Residue on the screen of opening x, n, b;Constants The authors tried to determine the accuracy of this. fornrula, about Japanese coals.And, using ball mill as pulverizer, the relations between constants, n, b, and condi-tions of pulverizing, kinds of coals, degree of coalification were experiMentalily determined, and furthermore, criticized the meaning of A.S.T.M.Ball mill method, Shatter Test method of J.E. S., Drum Test method of J.E.S., Hardgrove method, etc.
