Design and fabrication of a spiral classifier for off-shore sand washing

Abstract

The rapid growth of construction industry has created a significant demand for sand. Consequently, it has increased the exploitation rate of river sand giving rise to adverse environmental impacts. Therefore, the tendency now is to find alternatives for river sand avoiding massive environmental damages. Among the potential alternatives, offshore sand could be the best alternative, because of particle size distribution and availability. However, the demand on offshore sand is low, due to its soluble Cl- content which could influence badly on the structural properties of concrete. As a solution, sea sand could be stored in open air until the Cl- content is decreased to acceptable limits (<0.075% by weight) under the influence of rain water. However, considering the increasing demand and changing weather patterns, the above method appears to be inappropriate to meet the demand. In this research, a spiral classifier was designed and fabricated in order to wash offshore sand from salts and other suspended materials. The separation is done on sea sand by optimizing critical parameters of the spiral classifier such as feed rate, rotational speed of spiral, inclination angle of the spiral and weir height.