United States Steel Corp., Clairton, PA
Prilled Pitch


Prilled pitch, used in making carbon electrodes and synthetic graphite, was introduced in 1965. It has become popular because the free-flowing prills are like buckshot which can be handled easily and loaded directly into railroad cars, trucks and barges and can withstand varying temperatures in transit. Prills are made by converting liquid pitch into droplets which are solidified by air and water. They were formerly dried and cooled in two separate steps. Two Wyssmont dryers each combine drying and cooling in one operation. This simple operation has doubled plant capacity and cut operating costs. Dust control and vapor collection are built in. With less dust, prills are now shiny rather than pebbly surfaced. Prill breakage and fines formation are practically eliminated, resulting in very little product caking in storage.


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