The laboratory size hammer mill was fabricated from locally available materials for crushing of minerals such as calcite, dolomite, limestone, granite and other materials of medium hardness. The crushing process is achieved by the use of a set of hammers in a crushing chamber which beats the mineral feeds into smaller particles small enough to pass through the aperture of the replaceable sieve positioned beneath the crushing chamber. The size aimed depends on the aperture of the replaceable screen. Based on the theoretical design, it was found that the main shaft speed of 913.5 rpm transmitted by a belt drive from a three horse power electric motor is suitable to crush effectively. A comparison of the products of the newly fabricated machine with those of a standard Denver laboratory jaw crusher shows that the crushing rate of the new machine is higher, though the standard machine produces coarse products. The results however indicated that the new machine can perform better in terms of products with improved design. The machine is portable, design to be power operated.
Keywords: Design, Fabrication, Laboratory Size Hammer Mill
