Silica (dust) that is created during the crushing of aggregates is presently one of the main causes of silicosis to mining employees and to the surrounding community. The silica created normally attached to the crushed aggregates (road-stone) during manufacturing. This dust must be wash off to prevent the spread of silicosis and other illness during mining process. Currently, the major problem faced in washing the crushed aggregates is that the spray nozzle that are currently used by most companies required the aggregates to be washed twice, which in turn costs the company extra money for washing twice.  Water again is being wasted due to continuous usage. Currently there is no adequate study on aggregates washing at low cost under high efficiency. More so, most spray nozzle are so complicated to operate and they are usually very expensive. In the current study we have designed a spray nozzle that is cost effective and very easy to operate under high operating efficiency. The tools of fluid dynamic and design theorem were used to model the nozzle diameter for optimal flow of water distribution during operation. The parameters used in modelling are velocity of the spray nozzle, flow rate of the spray nozzle, and the area that the nozzle will cover. The optimal velocity, flow rate and nozzle diameter were obtained for efficient flow of water during operation. The following facts were theoretically revealed by the model and validated. It was shown that there was an optimal nozzle diameter that gave optimal flow of water. It was shown that there is a certain nozzle diameter size that will offer maximum efficiency during operation. It was also shown that to cover a certain washing area a certain angle of the nozzle must be achieved during operation.

Keywords: spray nozzle, flow rate, velocity, nozzle diameter and efficiency