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sag mills


Feeding Size: ≤400 mm
Discharging Size: 0.074-0.89 mm
Effective Volume: 4.5-225 m3
Customization: support
Material: various metals, nonmetallic ores, rocks, etc.

The semi-autogenous mill is also called SAG mill which is an acronym for semi-autogenous grinding. It is similar to an autogenous mill but uses grinding media like a ball mill grinder. It takes material itself as the main grinding media and grinds through their mutual collision. However, some raw materials with a diameter greater than 20mm and less than 80mm are very difficult to be broken. We usually add a small number of steel balls or steel rods to assist grinding. The ball or rod charge is between 8% and 15%.

The semi-autogenous mill is a new type of grinding equipment with both crushing and grinding functions. It has the advantages of simple process flow, small investment, short construction cycle, and easy operation. It can directly grind raw materials or coarsely crushed materials to 0.074mm. The grinding ratio can reach 4000-5000, which is ten times higher than ball mills and rod mills.


The cylinder diameter of the SAG mill is larger. The diameter of the cylinder body is three times its length.
The semi-autogenous grinding mill can be divided into the dry grinding type and the wet grinding type. Currently, the wet grinding type is more frequently used.

AGICO produces semi-autogenous mills of various specifications. We have a first-class research and design team, perfect test and detection means, and independent intellectual property rights. Our SAG mills can handle metals, ores, rocks, and other raw materials with hardness below medium. If you need the semi-autogenous mill, please feel free to contact us!

Attentive Services We Offer

Free Material Testing
Free Customization
Free Installation
Free Maintenance


The working principle of the semi-autogenous mill is basically the same as the ball mill. But it mainly uses the materials themselves inside the cylinder as the grinding media. For improving the processing capacity, a small number of steel balls or rods are added to the grinding chamber to assist in grinding.

structure sag
Semi-autogenous Mill Structure

Raw materials enter the SAG mill through a feed chute. In the grinding chamber, materials are carried to a high place under the rotation of the cylinder and then fall. In this process, they reduce the particle size by colliding with each other. Besides, a small number of steel balls or rods in the grinding chamber will also help to break the hard particles. After the grinding is completed, fine-sized materials are discharged through the outlet port.


Low power consumption and large output;
Equipped with a PLC controlled protection system;
No dust pollution, less auxiliary equipment, and a high degree of automation;
Equipped with a sealed gear cover, low-speed driving unit, and automatic glycerol spray lubrication device;
Simple process, small consumption of grinding medium and lining plate, low investment and maintenance cost;
sag ball mill
Semi-autogenous Mill Onsite


ModelCylinder Diameter(mm)Cylinder Length(mm)Effective Volume(m3)Rotation Speed(r/min)End CoverMotor Power(kW)Motor Rotation Speed(r/min)Dimensions(m)Weight(t)


Crushing Ratio

The data shows that the crushing ratio of the SAG mill can reach 4000-5000, while the ball mill’s crushing ratio is smaller.

Grinding Media

SAG mills use less grinding media than a comparable ball mill, while less efficient in actual grinding. SAG mills need a lower investing and operating cost, especially at large particle sizes.

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