Aggregate Optimization Using a Y-Blender

Abstract

Equipment and procedures were developed to use large samples of coke (2–20 kg) to determine optimum aggregate sizing. The equipment was made from 100–200 mm diameter pipe welded into the shape of a “Y”. The apparatus can be partially filled with coke and rotated manually to produce good blending. Bulk density is calculated from the weight and volume of the coke after blending. Rather than discard an entire sample after testing, about 5% of the charge is removed and the same amount of a pure fraction (coarse, intermediate, etc.) is added. After a series of tests, resultant data are smoothed and plotted on a triangular diagram. For tests of typical cokes, a single maximum bulk density peak was found on the bulk density vs composition response surfaces. This peak was fairly flat near the top--more like a plateau than a sharp spike. Four samples of coke taken over a two-month period showed only a slight change of the maximum density composition with time.