How To Break Hard Rock? Take Granite As an Example

Published time:26 May 2020

Granite is a hard rock with a saturated uniaxial ultimate compressive strength greater than 30 MPa. For this type of rock, we usually adopt three stages of coarse crushing, medium crushing, and fine sand making.
This article takes granite as an example to give a brief introduction to the configuration of the hard rock crushing plant. The configuration of the granite crushing plant configuration is also suitable for basalt, diabase, andesite and other materials.

Granite Rock Property

Granite is a high-quality building stone with a uniform structure, a hard texture and a beautiful color. The density is 2790 ~ 3070kg / m³, the compressive strength is 1000 ~ 3000kg / cm², the elastic modulus is 1.3 ~ 1.5x106kg / cm³, and the water absorption is 0.13 %, Shore hardness> HS70, specific gravity 2.6 ~ 2.75.

Crushing Mechanism and Equipment

According to the different finished products, a crushing process can be divided into coarse crushing section, intermediate crushing section, fine crushing section and grinding section. The product particle size range after feeding and crushing in each crushing section is as follows:

Crushing stageCoarse crushingMedium crushingFine crushing
Feed size D/mm500-1500100-35040-100
Output size D/mm100-35040-1000-40

The crushing products commonly used in the whole crushing process are as follows:

  • The jaw crusher is used in the first crushing process of the crushing line, which can crush large particles with a compressive strength not exceeding 320MPa to a size of 100mm ~ 300mm.
  • The impact crusher can generally process ore or rock with a compressive strength of up to 350 MPa and less than 500 mm. After crushing, the material appears as cubic particles. The impact crusher is generally used in the second crushing process of the crushing line. It can also be used as the first crushing process for materials with small feed.
  • The cone crusher uses the principle of lamination crushing to form a protective layer of the material layer. It has the characteristics of reliable structure, high crushing efficiency, easy adjustment, and economical use. The feed particle size is 13 ~ 369mm. Cone crushing is the same as the impact crushing. It is often used in the second crushing process of the crushing line. It can also be used as the first crushing process for materials with small input materials. However, the feed particle size of cone breaking is generally smaller than that of counter-breaking.
  • The sand making machine is suitable for the crushing and shaping of soft, medium hard and very hard materials. It is generally used as the last process of the crushing sand production line. The feed particle size is 35 ~ 60mm.

In addition to the main crushing equipment, some auxiliary equipment such as vibrating screens, feeders and conveyors are needed to complete the configuration and work of this production line.

Granite Crushing Plant Layout

Due to the hard texture, the granite production line configuration generally needs to pass through three stages, namely the coarse crushing of the jaw crusher (first break), the medium and fine crushing of the cone crusher (second break) and the sand making and shaping of the sand making machine (shaping).
sand making process flow
The large granite material reaches the vibrating feeder through the silo for uniform feeding, and then enters the jaw crusher for the first crushing. After the coarsely crushed materials are screened by vibrating screen, they are transported by a belt conveyor to a cone crusher for the second medium and fine crushing. After medium and fine crushing, the circular vibrating screen is used for sieving, and the larger particle materials are returned to the cone crusher and crushed again. Materials that meet the requirements enter the sand making machine for further crushing and shaping. If the materials need to be cleaned, they can be sent to the sand washing machine for cleaning. Finally, the materials that meet the requirements are classified according to different particle size ranges.


The granite (or basalt) crushing production line with an output of 600 ~ 700t per hour, according to the configuration scheme described above, can be equipped with equipment that meets the task of hourly production. Cone breaking HPC400 (2 sets) — circular vibrating screen 3YZS2160 (2 sets) — sand making machine 5X1145 (2 sets), each equipment transports materials through the conveyor belt.

Words in the end

The selection of hard rocks such as granite needs to be considered from two aspects: first, the configuration of the production line equipment is selected according to the particle size of the finished product; second, the matching production equipment is selected according to the production task volume. Ensure that the above two points can basically determine the production line process to ensure production efficiency.

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