In the production process of wet artificial sand, no matter what type of sand washing machine is used, its biggest disadvantage is that the loss of fine sand (particles below 0.16mm) is serious, and some even more than 20%, which not only loses production, but also seriously affects the gradation of sand, resulting in unreasonable gradation, coarse fineness modulus, and greatly reduces the quality of machine-made sand products. Excessive fine sand discharge will also cause environmental pollution. The main function of fine sand recovery system is to clean, dehydrate and classify sand and gravel. It can recover a large amount of fine sand lost by washing machine in traditional sand making industry, improve economic benefit, reduce the cost of tailings treatment and the pollution and destruction of environment caused by the loss of fine sand.

When the fine sand collecting system works, the vacuum high-pressure pump conveys the mixture of sand and water to the high-pressure separator of mud and sand. The centrifugal classified concentrated tailings are supplied to the dewatering sieve through the settling nozzle. After dewatering through the dewatering sieve, the tailings and water are effectively separated. A small amount of tailings and mud are returned to the cleaning trough through the return tank and discharged through the outlet when the liquid level of the cleaning trough is too high. The weight concentration of material recovered from dewatering screen is 70%-85%. Adjusting fineness modulus can be achieved by changing pump speed, changing mortar concentration, regulating overflow water and replacing mortar nozzle. Thus, three functions of cleaning, dehydration and grading can be accomplished.