Limestone is a carbonate rock mainly composed of calcite. Sometimes it contains dolomite, clay minerals, and clastic minerals, with gray, grayish white, grayish black, yellow, light red, and maroon colors, and generally has a low hardness. Limestone machine-made sand is made of limestone quarry waste, slag, stone powder, etc., which are mechanically crushed, washed, and screened. The limestone machine-made sand processed according to the above process flow has the following advantages.

1. Technical indicators such as the particle size of machine-made sand can be controlled according to national standards and project quality requirements to meet project requirements.

2. Machine-made sand particles are mostly angular in shape and have a rough surface, which is conducive to bonding with cementitious materials such as cement and improving the strength of concrete.

3. The production of machine-made sand can be combined with the production process of crushed stone, which is conducive to the comprehensive utilization of mineral resources.

The production process of machine-made sand mainly includes two categories: two-stage crushing and three-stage crushing. Smaller machine-made sand production lines mostly use two-stage crushing and screening processes, while some large machine-made sand production lines often use three-stage crushing and screening processes due to large material fragmentation.

Generally speaking, the production of limestone machine-made sand mainly adopts three stages of crushing, namely coarse crushing, medium fine crushing, and sand making.

Generally, jaw crusher is used for coarse crushing. Medium crushing generally uses an impact crusher. Vertical shaft impact crusher or cone crusher is generally used for fine crushing and sand making.

1、 Jaw crusher

Jaw fracture has the advantages of simple structure, high reliability of continuous operation, and low price. The discharge port can be adjusted, and the plant height difference required for equipment layout is small. Jaw crusher is not easy to block when crushing wet materials and ores with high clay content, and is more suitable for processing sand aggregate raw materials. It is often used in the primary crushing stage in domestic sand aggregate projects.

2、 Impact crusher

The impact crusher has the characteristics of high crushing ratio and low energy consumption, and is more suitable for handling fragile materials. The product particle size of the impact crusher is more uniform, and the impact crusher is commonly used in the second stage crushing stage in domestic sand and gravel aggregate projects.

3、 Vertical shaft impact crusher

The vertical shaft impact crusher has the advantages of small size, simple foundation, high crushing efficiency, large output, and low maintenance. The various cavity types of the vertical shaft crusher under different working conditions are suitable for fine and ultra-fine crushing of most materials, taking into account the dual functions of shaping and sand making.

The "stone to stone" crushing method is suitable for materials with high abrasion resistance, such as basalt, that are medium to hard or above. During the crushing process, the material ejected from the throwing wheel impacts the material liner without directly contacting the metal components of the equipment, reducing iron consumption and thus reducing maintenance time. The finished product has a good particle shape under the working condition of "stone striking". The "stone to iron" crushing method is suitable for materials with low abrasion resistance, such as limestone, below medium hardness. Under the working condition of "striking iron with stone", the crushing efficiency is higher.

The above is the main crushing equipment used in the production of machine-made sand and gravel aggregate using limestone. How to configure the machinery and equipment for the specific sand and gravel production line should be analyzed on a case by case basis. CFTC provids customers with the best production line design solutions, allowing them to worry nothing about production.