428 



CEMENTS, LIMES AND PLASTERS. 



a 100-mesh sieve would probably pass not over 60 per cent through 

 200-mesh. As it is the percentage of very finely ground particles which 

 gives the chief value to the cement, the use of separators on the clinker- 

 grinding side of a cement-plant would seem to be inadvisable. In pul- 

 verizing raw materials the same objection can be made, though it is 

 not so important as in grinding the finished product. 



The following papers contain data on the subject of separators: 



Eckel, E. C. Some of the reasons why separators are not used in Portland- 

 cement works. Engineering News, vol. 51, p. 344. April 7, 1904. 



Fraser, G. H. Recent results obtained with the Kent mill as a fine grinder. 

 Cement, vol. 6, pp. 74-79. May, 1905. 



Humphrey, R. L. The plant of the Buckhorn Portland Cement Co. Engi- 

 neering News, vol. 50, pp. 408-414. Nov. 5, 1903. 



Michaelis, W., jr. Air separation of cement. Cement and Engineering News, 

 vol. 15, p. 2. Oct., 1903. 



