| dc.description.abstract | An experimental study in the trommel screen was conducted in order to find the better screening efficiency in separating two dissimilar solid -solid materials in terms of size shape and density. The trommel machine consists of a hexagonal rotating drum with solid outside frame in which the sieve is fixed on the six sides of the rotatory drum, so that the feed material can be separated when the feed material spirals down over the length of the rotating drum, the experiments were carried with 5 different speed of the rotating drum, 7 different inclinations angle of the rotating drum with 5 different mass flow rates of the feed material entering into the drum. The screening efficiency is calculated based on the amount of undersize material inside the hopper to the amount of undersize collected after the screening process. The experimental results are shown that the screening efficiency is increased with increased in rotational speed of the drum, at higher speed 33 and 29.5 rpm the efficiency in separating the undersized material (silica sand) from the oversized material (alumina coins) is higher, this is due to the cataracting motion of the particle inside the drum, whereas the slumping motion of the particles at the lower speeds 18 rpm causes the lesser efficiency at lower speed of the rotating drum. The screening efficiency is higher above well around 98% at the smaller angles at 2.7°and 5°of inclination of the drum, due to the larger residence time of the feed material inside the rotating drum, when the angle is increased the efficiency is decreased, the particles tends to slide over the length of the drum rapidly, the particles physical characteristics such as vast size difference among the feed materials and density parameters affects also has influence in screening efficiency. When the mass flow rate of the feed materials into the drum is increased the efficiency is decreased due to the fact that there is clogging effect near the entry of the drum and which makes the particles to hit surface of the rotating drum, the packing thickness increased so the efficiency is decreased, at higher mass flow rates 320 and 400 g/min at lower speeds of the rotating drum 21.5 and 18 rpm the efficiency is poor, lower mass flow rates of the feed material 80 and 160 g/min with higher rotational speeds 29.5 and 33 rpm of the drum with small angle of inclination of the drum has the better efficiency in achieving the task | en_US |