The cleaning process in manufactured sand production is an essential step in quality control, driven by technical requirements along three dimensions. First, the raw material characteristics necessitate cleaning. Most ore materials (such as granite and limestone) have a 5%-15% clay layer attached to their surfaces before crushing. This impurity forms fine dust with a particle size of less than 0.075mm during the sand-making process. Unwashed manufactured sand typically contains 8%-12% fine dust, which, when used directly, can reduce concrete strength by 20%-30%.

Second, secondary pollution is a significant issue in the production process. Stone dust generated during crushing can mix with the finished sand, causing the fineness modulus to deviate from the optimal range of 2.4-3.0. The water washing process, through spiral agitation and water flow classification, removes over 90% of the free stone dust, ensuring that the finished sand gradation meets Zone II standards.

Finally, market demand is driving quality upgrades. Key projects have stringent requirements for the alkali-aggregate reactivity of sand and gravel. Water washing effectively removes soluble alkali metals from the sand particle surface, keeping the alkali content below 0.6%.

The water washing process is irreplaceable for improving the quality of manufactured sand. In terms of physical properties, the surface roughness of sand treated by a spiral sand washer is significantly improved, and its bond strength with cement paste is increased by over 40%, which is crucial for the impermeability of concrete.