Accession Number:

AD0600674

Title:

EXPLORATORY EXPERIMENTS ON KINETICS AND MECHANISMS OF COMMINUTION.

Descriptive Note:

Special rept.,

Corporate Author:

AEROJET-GENERAL CORP DOWNEY CALIF

Personal Author(s):

Report Date:

1963-10-01

Pagination or Media Count:

22.0

Abstract:

Sodium chloride was milled in a standard laboratory ball mill for various periods of time between 15 minutes and 16 hours at two relative humidities of the air, 0.5 and 4. The particle size was determined by sieve analysis. The particle shape was observed in the microscope. At 4 RH, severe caking occurred during 8 hours of milling. At 0.5 RH, there was substantial agglomeration, but much less than at 4 RH. The particle size increased continuously when milling was continued for 4 hours or more. The mechanism of comminution could be easily followed under these conditions. At 4 RH, the material first cleaved into single crystal platelets of almost perfect squares. These were first reduced by breaking off corners and later by fracture into two equal pieces. It is concluded that the fracture occurs where the stress exceeds the strength of the material, and that the particle size obtained is independent of cracks and flaws. The surface area has nothing to do with the breakup, only with the agglomeration. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE