What’s the difference of Ball mill, SAG mill, AG mill?

Attrition mill is a type of grinding mill by kinds of media to crush lump to powder-like substances. The impact can be rock on rock such as in an Autogenous Grinding (AG) mill, rock and a small ball charge (~10%), used in Semi Autogenous Grinding (SAG) mills, balls of various sizes in Ball Mills , steel rods in Rod Mills.

These machines are used to grind or mix metals or raw materials for further processing. Various materials are placed into the mill drum and rotated with the mined materials that are to be crushed. The ball mill contains materials meant for crushing and grinding, such as balls of ceramic, small rocks, or balls made from stainless steel. The internal device of the ball mill grinds material into powder-like substances, and can rotate continuously for optimal grinding and refinery production.

These grinding mills are designed to grind ore into smaller particles, but they operate differently. Understanding the difference of Ball mill, SAG mill, AG mill can help you choose the right equipment in mineral processing plant. Now let’s explore the differences between ball mill, SAG and AG mills, their respective advantages and disadvantages, and how to select the right mill for your operation.

What is SAG mill?

A Sag mill is most often used in the mining fields, particularly in the mining of precious metals such as gold, copper, silver, and nickel. The sag mill serves in the line of industrial mining equipment designed to process, crush, separate, or locate precious metals from mined coal. The Sag mill is one of the large mining equipment pieces, and often requires mining equipment repair and maintenance. This is most often due to the large amount of heavy, residue bearing material being churned through the large drums of the grind mill. The Sag mill uses lifting plates along the interior of the drum, which lift material throughout the rotations, causing them to fall onto one another to promote crushing.

What is ball mill?

A ball mill has many steel or porcelain balls put in a drum to grind the feed between balls and between the balls and drum inner wall as the drum rotates. This mill is capable of grinding lumps whose size is tens of millimeters into a product tens of microns or even several microns. The ball mill can grind various ores and other materials with dry type and wet type. There are two kinds of ball mill, grate type and overfall type due to different ways of discharging material.

SAG mill vs Ball mill

1.Appearance

Both sag mill and ball mil are cyclinder type grinding mill. SAG mills usually have a larger diameter than length. While ball mills have a larger length than diameter, so that there can be more grinding time and finished material could be more finer.

2.Crushing stage

SAG and ball mills grind material through different actions and are usually applied in different stages of the process.

SAG mill is the primary tool for grinding and it is used before the other mills. The SAG mills are generally used in pre-processing of any type of material in grinding process. SAG mills are also known as first stage grinders.  These mills are one of the most used and necessary equipment in grinding.

Ball mill is a secondary fine powder grinder and it is used after the SAG mill. A horizontal rotating cylinder which is filled partially with steel balls, or ceramic balls to grind raw material into the powder-like material, And if extreme fineness and refinery are required then rotation go on continue.

3.Grinding ball filling rate

These two types of mills are filled with varying compositions of grinding media. SAG mills contain balls of up to 150mm in diameter that occupy 5%-18% of mill chamber volume. Ball mills, conversely, contain grinding media up to 50mm in diameter, occupying between 25% - 40% of mill chamber volume. To effectively reduce material size, each type of mill needs to generate different charge load actions, or the type of motion characterised by the mill’s contents. SAG mills generate higher levels of impact reduction and ball mills higher levels of abrading action.

4.Different size of finished product

SAG mill is used for grinding large fragments into small pieces. Pieces are then used for further processing. SAG mill does not create pulverized form of matter. These heavy output SAG mills are usually powered by electricity. As requirements and needs in grinding field are enhanced. Improved SAG mills came in trend, which gives highly rated production.

Ball mill is a fine powder grinding mill with material feeding size less than 25mm. The final powder size is 0.074mm ( 200mesh), even could get ultrafine powder 0.01mm( 1250mesh). The finished size from ball mill is usually as final product to be sold, or in benefication plant. Ball mill could create pulverized form of matter.

5.Different application

SAG mills are very important equipment of industrial mining. SAG mills are commonly used in mining fields. From mined coal, it separates out some precious metals. In the mining, some precious metals found are like gold, silver, nickel, and copper etc.

Ball mill machine is a kind of mining and cement milling equipment with the highest application ratio in the industrial field. According to production mode: dry ball mill (without adding water) and wet ball mill. According to the process used: dryer mill, superfine ball mill, open-circuit mill, closed-circuit grinding mill, etc. According to raw materials: raw mill, cement ball mill, coal ball mill, steel slag ball mill, slag ball mill, quartz ball mill, aluminum ash ball mill, etc.

AG mill vs SAG mill

AG and SAG mills are two types of grinding equipment used in mineral processing. Both mills are designed to grind ore into smaller particles, but they operate differently. Here we will explore the differences between SAG and AG mills to help how to select the right mill properly.

SAG mills, or Semi-Autogenous Grinding mills, use a combination of steel balls and rock particles to grind ore. They are larger in size and are capable of grinding larger quantities of ore than AG mills. SAG mills are often used in conjunction with a ball mill or pebble mill to achieve the desired grind size. SAG mills are primarily used in the mining industry, particularly in the processing of gold, copper, and platinum group metals.

SAG mills and AG mills are both commonly used in mineral processing operations, but they operate in different ways and have unique characteristics. In this section, we’ll explore the main differences between SAG and AG mills, including their definition, operation, design, and applications.

1.Design and Components

SAG mills and AG mills also differ in their design and components. SAG mills have larger diameter and length ratios than AG mills, and are typically equipped with rubber or steel liners to protect the mill shell. AG mills, in contrast, have smaller diameter and length ratios, and are often lined with rubber to protect the mill shell from wear and tear. Both types of mills may also have different motor types and gearing systems. Understanding the design and components of each mill is important for optimizing performance and reducing maintenance costs.

2.Differences in Grinding Media

SAG mills use a combination of steel balls and rock particles as grinding media. The addition of rock particles to the SAG mill feed allows the mill to break larger rocks, thus increasing the grinding efficiency. However, the use of rock particles can also lead to increased wear of the mill liners and decreased efficiency.

AG mills use only steel balls as grinding media. The use of steel balls leads to a more uniform grinding process and reduced wear on the mill liners compared to SAG mills. However, the lack of rock particles in the mill feed can lead to reduced grinding efficiency, especially when processing softer ores.

The type of grinding media used in a mill can have a significant impact on the grinding efficiency. SAG mills typically have higher grinding efficiencies compared to AG mills, but this can vary depending on the ore characteristics and the operating conditions of the mill. In some cases, AG mills may outperform SAG mills due to the lack of rock particles in the mill feed.

3.Power Consumption

The power consumption of SAG and AG mills depends on several factors, such as the ore type, feed size, mill speed, and grinding media. However, in general, AG mills have a lower power consumption than SAG mills. SAG mills and AG mills differ in their power consumption, which is an important factor to consider when selecting between the two.

SAG mills typically have a higher power consumption than AG mills due to their larger diameter and longer length. The power consumption of SAG mills is also influenced by the ore hardness, feed size, and mill speed.

AG mills generally have a lower power consumption than SAG mills, as they have a smaller diameter and length. AG mills also use a fraction of the energy needed for SAG mills to grind the same amount of ore.

4.Cost and Maintenance

Cost and maintenance are also important considerations when selecting a mill. SAG mills are generally more expensive to operate and maintain due to the need for a high level of power and the larger grinding media. AG mills, on the other hand, are generally less expensive to operate and maintain due to their smaller size and lower power requirements.

In conclusion, selecting the right mill for a particular application requires careful consideration of several factors, including the material characteristics, process requirements, and cost and maintenance considerations. By understanding the differences between SAG and AG mills, it is possible to make an informed decision and select the mill that best meets the needs of the application.

FAQ People also asked for :

What are ball mills used for?

Ball mills are commonly used for crushing and grinding the materials into an extremely fine form. It is a cylindrical machine used in grinding (or mixing) materials like ores, cement, chemicals, ceramic raw materials and paints.

What are the different types of ball mills?

There are two kinds of ball mills according to their ways of discharging material: grate type, and overfall type. According to material characters and grinding process requirement, it has dry ball mill and wet ball mill.

How much is a ball mill?

Ball mill price is relative to its model, capacity, needed final powder size, lining plate, Motor drive system etc. Baichy could help you select a suitable model ball mill and a detailed price list.

If you want to choose suitable ball mill machine for your mineral ore processing plant, welcome to contact us by email: hnbc@baichy.com . Our professional engineer give you instant response .