Limestone is a common artificial aggregates raw material, with a Mohs hardness of 3, which belongs to medium and low hardness rocks. Two-stage crushing and three-stage crushing solution are commonly used to produce artificial sand and gravel. Usually, small-scale artificial sand and gravel production lines use two-stage crushing and screening solution, and some large-scale artificial sand and gravel production lines use three-stage crushing and screening solution due to bigger input sizes, there are relatively few four-stage crushing and screening processes.

The two-stage crushing solution is divided into two-stage crushing with open-circuits and two-stage crushing with closed-circuits. Generally, there are two configurations of equipment: jaw crusher + impact crusher; jaw crusher + cone crusher.

The crushing ratio of the two-stage crushing solution is generally around 15 to 25, the total crushing ratio is not large, and the capacity of crushed materials is not much, usually less than 1,000 tons per day, except for the use of large crushers.

As far as the two-stage crushing solution is concerned, most crushing plants usually adopt a two-stage and one closed-circuit process, that is, the secondary-stage crusher and the screening equipment form a closed circuit, so as to ensure that the product particle size meets the requirements and meet the demand for sand and gravel aggregates.

The three-stage crushing solution is divided into three-stage crushing with open-circuits and three-stage with closed-circuits. Mainly has five process configurations: jaw crusher + impact crusher + sand making machine(shaping); jaw crusher + cone crusher + sand making machine(shaping); jaw crusher + fine jaw crusher + sand making machine(high efficiency); impact hammer crusher + sand making machine(high efficiency) + sand making machine(shaping); jaw Crusher + Ultra fine jaw crusher + sand making machine(shaping).

The limestone sand production line mostly adopts the equipment configuration of jaw crusher + impact crusher + sand making machine(shaping) in the three-stage crushing process.
Three-stage with one closed-circuit process, that is, in the tertiary crushing stage, the crusher and the screening equipment are used to form a closed circuit, which is the most common crushing solution. The total crushing ratio of this production process is relatively large, which can reach about 25-200, the maximum feeding materials size can reach about 1000 mm, and the products size of crushed materials can reach 12 mm or finer, so it is suitable for large and medium sand and gravel aggregates production line.