AG mill and SAG mill

AG Mill and SAG Mill

Applications: It is commonly used in the mineral processing industry and ferrous and non-ferrous metal ore and nonmetal ore processing plants. It can also be used in cement plant, refractory plant, fertilizer plant and smelting plant.

AG Mill and SAG Mill Details

AG mill (autogenous mill) is a medium-free mineral grinding equipment. The raw ore and the coarsely crushed ore are directly fed into the AG mill. No other medium is involved in grinding. Only the impact between the ore is used for self-grinding. The ore larger than 100mm in the AG mill plays the role of grinding medium. When the AG mill operation is started, the ore is directly self grinding.

What is a SAG mill? The structure of the SAG mill (semi-automatic grinding mill) and the AG mill (autogenous grinding mill)are exactly the same, except that a certain proportion of auxiliary grinding media such as steel balls or steel rods are added as needed. During the process of the AG mill operation, some ores with diameters greater than 20mm but less than 80mm are not easily ground. In this case, the SAG mill design can do that. In general, the SAG mill manufacturers will control the addition amount of medium such as steel ball at 2-8%, so that the capacity of semi SAG mill to process materials can be increased by 10-30%. The SAG mill liners wear will increase by 15% due to the impact of medium such as steel ball during the SAG mill operation.

Later, people were inspired by the semi-automatic grinding mill, adjusted the amount of medium in the semi-automatic mill, and evolved our most common ore dressing mill, ball mill and rod mill.

SAG mill for mineral processing

Structure characteristics of AG Mill and SAG Mill

  • The SAG mill (AG mill) has both crushing and grinding two functions. The grinding mode can be divided into dry type and wet type, also known as aerofall type SAG mill and dump type SAG mill.
  • The SAG mill (AG mill) needs less auxiliary equipment, is easy to realize production automation, and the product granularity is relatively stable.
  • The SAG mill (AG mill) has a large diameter and a small length. It looks like a flat round drum. The diameter of the SAG mill is generally about three times its length.
  • The diameter of the hollow pivots at both ends of the barrel of a SAG mill is large. This SAG mill design can facilitate large-sized materials to enter the barrel smoothly.
  • There are two different driving modes of semi autogenous grinding mill, namely variable speed and constant speed. At the same time, according to the needs of specific working conditions, a micro-motion device can also be added, which greatly facilitates the difficulty of the cylinder jacking device during maintenance.

Working principle of AG Mill and SAG Mill

How does a SAG mill or AG mill work? The working principle of the SAG mill and AG mill is basically the same as the ball mill machine, but the barrel diameter of the SAG mill and AG mill is larger. The raw ore enters the AG mill through the feeding inlet, and the material is brought to a high place under the rotation of the barrel and then falls. During this process, materials collide and rub against each other. The thrown material falls on the AG mill liners, and is rebounded to the other side of the barrel wall due to impact, and then collides with the falling material again. The impact from different directions makes the materials of different sizes evenly distributed in the barrel. Due to the action of inertia, centrifugal force and frictional force, the material makes reciprocating grinding movement in the AG mill. In the SAG mill, the materials themselves collide with each other and at the same time, they also collide with the grinding media such as steel balls for grinding.

This is a AG mill project
This is a AG mill project
This is a SAG mill project
This is a SAG mill project

There are differences between dry and wet SAG mill (AG mill) in the way of discharging finished products.

Dry type SAG mill (AG mill)

During the dry type SAG mill operation, the materials that have been ground to meet the requirements are discharged from the SAG mill with the airflow of the fan, and then enter the corresponding classification equipment for classification. In the process of discharging, the coarse-grained materials return to the SAG mill with the help of self weight for regrinding.

The structure of dry type SAG mill
The structure of dry type SAG mill

Wet type SAG mill (AG mill)

In the design of wet type SAG mill, the materials that meet the grinding requirements will be sent out of the barrel by the force of water, and the unqualified large-particle materials are left in the SAG mill due to gravity.

The structure of wet type SAG mill
The structure of wet type SAG mill

Selection of conventional grinding mill and SAG mill (AG mill)

Conventional grinding mill machine(ball mill, rod mill, etc.) and SAG mill (AG mill) have different requirements for the properties of the materials to be ground. Therefore, when selecting the grinding mill machine in the mineral processing process, it is necessary to select the appropriate equipment after material test and analysis and careful comparison. The following are several principles that should be followed when selecting mining equipment.

  1. When the ore material is suitable for both conventional grinding mill machine and SAG mill, SAG mill is preferred. Under the same conditions, it is preferred to recommend the mining plant to choose SAG mill and AG mill for mineral processing.
  2. When the ore material is not suitable for semi-automatic grinding equipment, the conventional grinding process equipment is selected.

Relevant Projects

Technical Data

Specification(mm)Capacity(t/h)Output Size(mm)Rotate Speed(r/min)Grinding Media Load(t)Motor Power(kW)Weight(t)

Material Application

Cement clinker
Cement clinker
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