Mechanical coke conditioning after differing carbonizing periods. [After mechanical treatment and sieving]

The effects of mechanical conditioning (a series of revolutions in a standard micum drum followed by sieving) on coke properties are discussed with reference to the carbonizing period, the coke size analysis and quality indices M25, M10, shatterability, abradability, etc. Maximum and minimum M25 values are invariably found for the 60 to 80 and 25 to 40 mm size fractions respectively. Mechanical conditioning increases the M25 index for every size fraction and structural type. If the coke structure is already of uniform size and high strength, ''severe'' conditions should be applied to shatter the largest lumps without substantial abrasion loss. It was concluded that mechanical conditioning is cost-effective and justifiable for coke of almost any quality; the optimum degree must be determined for each individual coke, in the light of its properties, the organization of the process, and the price structure of the various grades.