Customizable Mill Liners
Key considerations a mill lining system
Grinding mills are production critical equipment, continuously grinding crushed ore to liberate valuable metals ahead of the concentration process.
The design configuration and ongoing optimisation of mill lining systems is extremely influential in the effective grinding of material prior to extraction. When selecting a mill lining system, several key considerations must be taken into account.
Numerous factors must be considered when selecting a mill liner design, including required grinding action, mill size as well as ore and grinding media characteristics, among others. These considerations will help determine the best liner material and geometry. Depending on the mill size and material being ground, a lining system can be manufactured from either rubber or composite, with cast metal alloy inserts moulded into the liners at wear critical locations. In large diameter SAG mills, for example, high energy impacts may require the use of abrasion resistant hardened plate inserts. The key is to select the appropriate lining material for the intended application.
Type of milling process and operational parameters
SAG and ball mills grind material through different actions and are usually applied in different stages of the process. SAG mills usually have a larger diameter than length and are used to reduce large feed size ore (typically ~300mm) down to ~3mm, often for further grinding in a secondary process.
Ball mills are smaller in diameter than length and can be used in either primary, secondary or tertiary grinding applications to reduce material from ~20mm to very fine product sizes measured in microns or mesh.
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.
A mill lining system serves two purposes:
to protect the mill shell from wear caused by the impact and abrasion of the mill charge, and to elevate and tumble the mill contents in the necessary manner to create a grinding action. To achieve this, the mill liner profile must be constructed from high wear resistant materials and incorporate correct geometry to help determine the elevation of the mill charge and how the material is ground.
Chemistry Standard for Mill Liners
|Standard Specification for Cr-Mo Alloy Steel:|
|Reference Standard||Nominal Chemical Composition (W%)|
Double-Media Quenching Chromium-Molybdenum Alloy Steel Series
We specially design the material for ball mill liners in mines, coal-fired power plants and cement plants,etc..
With our special double media quenching process,the material can not only achieve ideal hardness (HRC48~55) but also ideal toughness value (AK30~100J).
It can completely meet the requirement of liners of large and middle size ball mills at home and abroad.
The match of Middle Chrome Liners and High Chrome Cast Balls has been the typical model in coal mills and cement mills.Meanwhile,
the material is applicable to the teeth plates,armored plates and hammers of crushers and excavator, bucket teeth.
Pearlitic Chromium-Molybdenum Alloy Steel Series
The Pearlitic Chromium Molybdenum Alloy Steel Liners are widely used in AG Mill,SAG Mill and Ball Mills.
Hardness: HB310-375 (equivalent to HRC33-42)
Impact resistant Value: Ak≥60J (60×10×10mm) in normal ambient temperature.
We can produce pearlitic Cr-Mo steel as per AS2074 Gr. L / 2B.
High Chrome white iron we can produce include 15%Cr, 18%Cr, 20%Cr and 26%Cr.
Under same working condition,the wear performance of High Chrome mill liners is four times of that of high manganese steel liners and twice of that of low Chrome alloy steel liners.
Meanwhile, we can produce high Chrome castings as per AS2027, ASTM A532 and BS4844.
Customer-made Mill Liners
In addition to our patented Boltless Mill Liners, we can produce liners as per the request of customers.
So far, we have been the regular suppliers of mill liners Now, we have supplied steel caps inserted in rubber lifters for SAG mills and AG mills to some mines in Australia and New Zealand.
Wear Parts for Crusher
Jaw plates and cheek plates for jaw crushers,blow bars and impact plates for impact crushers, cone liners for gyratory crushers,hammers for hammer crushers and concaves and mantles for cone crushers.
Depending on the specific working conditions,all wear parts can be ordered as Manganese Steel,high Cr cast iron or Cr-Mo Alloy Steel.
Our foundry has complete melting, heat treatment and test equipments,such as mid-frequency induction electrical furnaces,quenching and tempering furnaces, blast shot,spectrometer,Rockwell and Brinell Hardness tester,impactor,UT tester and metallographic microscope.
We achieved the certificate of quality management system ISO.
We have been exporting castings to oversea
Rubber and composite mill lining systems
In the past, grinding mills were typically lined with cast metal linings of varying steel or iron alloys, and lining system selection was typically driven by level of wear protection and cost. As materials technology and design technique has advanced, today many superior alternatives exist to metal linings.
Rubber compounds have been developed to protect mill shells from wear, while new cast alloys and wear resistant plates can be bonded into rubber to withstand high impact abrasiveness. There is a greater understanding of how mill lining systems influence mill performance. Operators now select mill lining systems on more criteria including ability to deliver mill process performance, wear resistance, ease of installation and safety. Furthermore, return on investment and total cost of ownership models are important factors in the decision making process, rather than cost alone.
Rubber and composite mill liners are increasing in popularity, with several advantages when compared to metal mill liners:
- Ease and speed of manufacture, with shorter lead times
- Customisable, with ability to optimise abrasion and wear resistance
- Outlast metal linings when designed and manufactured correctly
- Composite designs provide the benefits of rubber with the strength of steel
- Faster and safer to install and replace. Removing metal liners can be time consuming, with considerable hammering and gouging using a cutting torch often required
- Rubber and composite lining systems can comprise minimal components to reduce relining times and increase mill availability. With rubber and composite liners up to 35% lighter than metal liners, safety is enhanced when handling larger components.
- Rubber grate plates are more resistant to pegging than steel grate plates, when fragments of rock or grinding media become wedged into grate screen apertures, this in turn restricts flow.
- When used in gold applications they are resistant to particle lock up behind the liners
- Lighter mill linings can be optimised to increase mill volumetric capacity. This can enhance mill power efficiency and reduce energy wastage, increasing throughput and operational revenue
Eternal Bliss Alloy Casting & Forging Co, Ltd.
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