Using magnets to collect ferrous metal from process streams has a long history in the mining industry. This is especially true in the collection and disposal of grinding ball fragments in ball/SAG mill operations. Though often small in size, worn and broken metallic grinding balls can cause serious problems if they are not detected and removed from the milling operation.
Eriez Trunnion Magnets provide a unique system for separating and removing balls, chips or scats in a typical ball/SAG mill operation. This technology replaces the dead weight of ball magnets with fresh ore.
By effectively removing an estimated 80% or more of worn or broken media, a trunnion magnet reduces power consumption from the mill drive and prevents expensive damage to other equipment. Observations indicate a 250% increase in equipment life.
How Trunnion Magnets WorkIn a typical grinding mill application, the grinding media eventually fractures and wears into a fine metallic powder because of the heavy re-circulating load in the mill. Energy is unnecessarily wasted to mill the milling media.
As shown in Figure 3, the trunnion magnet is mounted at the ball mill discharge point to replace a trommel screen. It consists of a barrel or blind trommel that is mechanically attached to the trunnion or discharge of a ball mill. The barrel rotates around a fixed assembly of ferrite and rare earth magnets positioned on the outside of the barrel.
The stationary magnetic assembly attracts chips and scats to the inside diameter of the barrel. As the ball mill slurry discharges through the barrel, eight strategically placed lifters inside the barrel carry the ball fragments to the top, where they fall onto a sloping discharge chute.The Trunnion Magnet System includes four basic components: the blind trommel (barrel), magnet sector, support structure and the discharge hopper.
The barrel, or blind trommel, is a short extension that bolts directly to the discharge flange of the ball mill. Its function is to transport the mill discharge material through the magnetic field. It is fabricated from stainless steel and has an abrasion-resistant wear liner. The barrel is fitted with eight equally spaced bi-metallic cleats, which assist capturing and transporting chips into the discharge area.
The magnet sector consists of permanent magnets and has approximately a 200-degree arc. This magnetic arc is mounted on a steel support pedestal and positioned around the blind trommel. The permanent magnets are enclosed in stainless steel canisters and incorporate a steel backbar for support and projection of the magnetic field. Trunnion magnets can also be installed in bi-directional mills using a magnetic sector that covers 310 degrees.
The discharge hopper and support structure are positioned just inside the blind trommel to collect the grinding ball fragments. The hopper collects the grinding ball fragments as they rotate past the end of the magnetic sector at the top of the blind barrel.
Trunnion Magnet Performance AdvantagesTo improve performance, Eriez Trunnion Magnets are available in several design variations so they can be matched to specific ball/SAG mill operations. Mill capacity, ball size and other parameters are used to select and specify the design features for each installation.
When designing the trunnion magnet, Eriez considered the magnetic capture of grinding balls/fragments directly opposed by the drag force of the mill discharge slurry. Several techniques were used in the magnet design to compensate for the drag force:
Economic JustificationThe expenses to continue to use a trommel screen should be considered when comparing against costs to buy a trunnion magnet. Potential trunnion magnet users are using the following guidelines to assess the savings possible after installation:
Retrofitting With Trunnion MagnetsDepending upon user requirements, several variations and modifications of the Trunnion Magnet System are possible. For example, the magnetic circuit is designed to provide maximum strength for high slurry throughputs and up to 4-in. diameter grinding balls. The trunnion magnet can be configured for reversing or bi-directional mills. In addition, the ball retention ring is fitted in the barrel to prevent full-size balls from exiting the mill.
ConclusionThere are hundreds of installations of Eriez Trunnion Magnets worldwide. This system for separating and removing balls, chips or scats in a typical ball/SAG mill operation replaces the dead weight of ball magnets with fresh ore.
By effectively removing 80% or more of the worn or broken media, the trunnion magnet reduces power consumption from the mill drive and prevents expensive damage to other equipment, such as pumps and hydroycyclones. Cost estimates of a typical 18-ft. diameter mill indicate savings of up to $100,000 per year.
Mill rubber linersis usually suitable for wet grinding, the temperature is not higher than 80 degrees of normal work, but for high-temperature dry grinding, strong acid and Alkali resistance, oil resistance and other special environment, need to be explained in advance by separate design formula and custom made, in addition, the storage process must be placed in indoor proper custody, it intends the rubber liners to prevent outdoor exposure under the high temperature and rain.
Trivett Contracting has been servicing Ball mills since its inception from day one. Power generation is an industry we know well, we take pride in keeping your Mills rolling without issues. We have assembled the best quality team in the industry to inspect, maintain and repair Ball mills. Utilizing exceptional labor and the best equipment on the market we can provide the top service and quality for your Mill.
I would fully recommend Trivett Contractings services to anyone. We see their business as a staple and example of a well run company in the Indianapolis area. They are fully capable of handling any job in and out of state. Gregory T. Taylor, Maplehurst Bakeries LLC
Trivett Contracting is a highly motivated millwright company with a very strong emphasis on maintaining safe work environments and providing high quality work performance.Kevin Gay, KN Platech America Corporation
The return on investment has always been immediate when Trivett Contracting is utilized to perform not only repairs and maintenance; but also, project work, and shutdown activities.Mark E. Brady, Pure Power Technologies
We have found Trivett Contracting to be highly motivated on our installations and flexible on their schedules in order to accommodate our corporate deadlines. Additionally, we have seen Trivett demonstrate a good teamwork environment, strong professional leadership and great work ethic while providing superior, fully trained manpower.Kevin Gay, KN Platech America Corporation
I have worked with Trivett Contracting for over 15 years. During this time they have been involved in over $10 million worth of installations surrounding work we have performed together. They are easy to work with, conscientious, safe, and typically reasonably priced. Their people are willing to explain or suggest the best way to make things happen and go out of their way to keep you informed.Mark Llewellyn, Grede LLC New Castle
I predominately have used Trivett for rigging, machine maintenance and fabrication. They have been a Go To company for me when others wouldnt or couldnt provide what I needed.Gregory T. Taylor - Maplehurst Bakeries LLC
Trivett Contracting is considerate and always puts the customer first. The value adds not only show in their cost competitive quoting; but also, when they complete the deliverables on-time and under budget.Mark E. Brady - Pure Power Technologies
"I have called them on numerous occasions with emergency problems and have always gotten a straight answer. Trivett is one of the contractors I consider to be in my go-to group."Mark Llewellyn, Grede LLC New Castle
Eriez has pioneered magnetic separation techniques to improve grinding circuit efficiency in mineral processing plants. The Trunnion Magnet System bolts directly to the ball mill discharge flange to provide continuous magnetic collection of the grinding ball fragments. A permanent magnetic circuit collects the grinding ball fragments and discharges them to a collection hopper.
Grinding ball fragments discharging from ball mills cause extreme wear to downstream processing equipment. These ball fragments, circulating in a milling circuit, will cause excessive wear to sumps, pumps, hydrocyclones and interconnecting piping.Grinding ball fragments contribute very little to the grinding process while consuming power.
The system consists of the blind trommel, magnet sector, support structure and the discharge hopper. The blind trommel is a short extension that bolts directly to the discharge flange of the ball mill. The function of the blind trommel is to transport the mill discharge material through the magnetic field. The blind trommel is fabricated from stainless steel and has an abrasion resistant wear liner. The magnet sector is comprised of permanent magnets and has an approximate 200-degree arc. This magnetic arc is mounted on a steel support pedestal and is positioned around the blind trommel. The permanent magnets are enclosed in stainless steel canisters and incorporate a steel backbar for support and projection of the magnetic field. The discharge hopper and support structure is positioned just inside the blind trommel to collect the grinding ball fragments. The hopper collects the grinding ball fragments as they rotate past the end of the magnetic sector at the top of the blind trommel.
Grinding ball fragments can damage crushers and cause premature wear to pumps, sumps, piping and hydrocyclones. Read this white paper to learn why an Eriez Trunnion Magnet System offers a significant return on investment with tremendous cost savings.
The worlds most comprehensive mill lining supplier Metso is a world leading mill lining supplier. The reason for this is simple; we offer our customers solutions that promote safety, improve grinding efficiency, and enhance profitability. The mill is at the heart of your production process. The yield of your grinding operation is highly dependent on the performance of your mills lining. Select your mill lining partner carefully. Who you trust to take care of the heart of your process is a matter of confidence. Why choose Metso mill linings? One supplier for your whole process Metso is...
A mill lining is more than wear protection it performs a vital function and has a great effect on grinding efficiency With the largest product range to choose from, Metso offers mill linings with optimal materials and design for each specific application
The markets most complete product and service offering Metso combines high quality mill linings with service, capital equipment expertise and process know-how, to offer our customers sustainable results, reduced operating costs, and lower maintenance expenses. All types of linings* No other mill lining supplier has as wide a product range as Metso. Different lining types can be combined in the same mill to achieve optimal performance. Rubber mill linings Poly-Met mill linings Metallic mill linings Orebed mill linings Megaliner See pages 10-15 All types of mills Our state of...
Health, safety and environment Safety is our top priority; we have developed the markets safest lining system and installation methods Our solutions help customers to improve their working environment, while making efficient use of energy Process technology Metso helps you improve profitability through overall process efficiency. We embed intelligence in our machines, services and processes. Audits Action plans SmartEar - measurement system for mills SmartTag - ore tracking system Software 2D and 3D simulations and support software. Charge motion simulations ...
Identifying the appropriate type of lining and design is for optimizing mill throughput and total grinding costs, including costs for energy, grinding media and maintenance The large mills of today process high tonnages, and every minute of production counts. The purchase price of an optimized lining accounts for only a fraction of the total grinding cost, but an inferior lining can prove to be very expensive
Rubber mill linings Our experience enables us to offer a solution that suits your needs and helps you streamline your production processes. In 1959, Metso, through Skega, was the first company in the world to develop and manufacture rubber mill linings. Long experience with the development of rubber mill linings has led to an unparalleled bank of know-how. We offer you superior designs that ensure optimal grinding and lining performance. Metso has developed grades of wear resistant rubber for specific operating conditions in all types of mills. Each grade is based on the experience of...
Poly-Met mill linings Mill linings from Metso are high quality products with long wear life. The development of the Poly-Met concept led to the first patent in 1987. The Poly-Met concept combines the most desirable properties of rubber and steel to maximum advantage. This combination opens the possibility to use harder and more wear resistant alloys of iron and steel than can be used in conventional metallic linings, as the rubber substantially dampens impact forces. Application areas Autogenous mills Semi-autogenous mills Ball mills FGD mills Rod mills Scrubbers and...
Metallic mill linings We rigorously follow up on the performance of our designs, to ensure optimization of your production processes. Iron and steel are traditional mill lining materials, and Metso has produced metallic mill linings for more than three decades. Metso metallic mill linings are produced at our own foundries. Our Cr-Mo steel and high-chromium white irons are specifically developed for mill lining applications and are carefully selected based on the operating conditions of each mill. Liners are designed for maximum performance and minimized replacement time. The Metso foundries...
Orebed mill linings Metso develops tailor-made lining systems with focus on function, lifetime, and rapid installation. During the 1970s Metso developed and patented a magnetic lining system with unique properties, Skega Orebed. The Orebed lining system consists of a series of powerful permanent magnets embedded within a matrix of highly abrasion-resistant rubber. Magnetic force ensures that the lining attracts the ferromagnetic material in the mill load, forming a continuous, self renewing wear layer with a wave profile. As a result, there is very little wear on the lining itself....
Award-winning innovation The innovative Megaliner concept is a product of Metsos unique, in-depth application experience, and understanding of customer objectives. Megaliner In 2012, Metso launched the Megaliner concept, which substantially improves mill availability and worker safety. Based on many years of experience and unique know-how, Metso has pioneered a new mill lining concept, the Megaliner, which substantially improves mill availability and worker safety during mill liner maintenance activities. To make installations even safer and faster, Metso has also developed a camera...
Metsos patented Liner Positioning System uses camera technology to speed up mill lining installations even further and reduce the risk of accidents. Success case Boliden Bolidens Aitik plant in northern Sweden was first to install the innovative Megaliner system in their new 38 x 45 AG mills. Replacement of multiple Megaliner sets has proven to reduce shell liner change-out time by 30-40% as compared to conventional liners. Megaliner shell elements The customer greatly appreciates the comparative safety of the Megaliner system, since nobody needs to be in the danger-zone of the...
The ball mill liner components: Shell Plates , Lifter Bars, Head Plates, Grate Plates, Pulp Lifters, Central Cones, Trunnion and Bell Mouth Liners, Filling and Support Segments. Qiming Mill liners supply the best quality and cheapest price ball mill liner to our customers.
Lifter Bars Available in a range of profiles and dimensions, lifter bars increase the efficiency of the milling operation by maximizing the agitation of the ore. The impact and abrasion resistance of these bars are maximized by Hardox 500 steel along the leading edges of these components. With a high-quality attachment system, lifter bars are easy to install to the ball mill liner.
Shell Plates Shell plate thickness can vary, which helps both in balancing mill capacity as well as extending ball mill liner life. For arduous milling applications, or where drilling patterns produce shell plates that are too wide, thus exposed to high wear, shell plates with Hardox strips can be utilized.
Head Plates We custom-design head plates according to each ball mill to ensure maximum performance and lifespan. Most commonly, our head plates are built from high-quality, specially-formulated rubber. In arduous ball mill applications, Hardox strips can be fitted to the head plates to increase their operational life.
Pulp Lifters Manufactured with a rubber-lined fabricated steel base, our pulp lifters use high-quality designs that ensure the correct volumetric flow of the pulp. Rubber wear plates designed to be bolted onto the high-wear areas of the ball mill liner improve the performance life of your mill.
Grate Plates Grate plates are available in a range of aperture sizes and configurations. Internal frames are designed for different mill loads, and it is possible to use semi-overflow designs in order to control the pulp level in the mill. Different options for extending plate life exist as required by your application, such as built-in MultoMet lifter bars.
Central Cones These components assist in the controlled discharge of the material, maintaining mill capacity across the operation. Cones are provided in segments, which are then assembled inside the mill. This enables easier handling and manageability.
Ball mill is a major equipment in the production of power plants, cement plants, mines, chemical industry, metallurgy and other industries, the liner is one of the components of the mill, the main role is to protect the cylinder, the cylinder from the grinding body and Material direct impact and friction, help to improve the mill grinding efficiency, increase production and reduce metal consumption. As the liner in the harsh conditions of long-term conditions, maintenance and replacement of considerable volume, not only requires human, material and financial resources, but also a direct impact on productivity.
Ball mill liner plays a major role in protecting the inner wall of the anchor windlass. Different shapes of the ball mill lining plate can improve the grinding effect of the ball mill and improve the working efficiency of the ball mill. 1, flat ball mill liner, the surface smooth, suitable for installation in the fine grinding warehouse. 2, the pressure of the type of ball mill liner, suitable for coarse grinding warehouse, for low speed ball mill. 3, ladder-type ball mill liner, ladder liner is better than the pressure liner, suitable for installation in the coarse grinding warehouse. 4, small corrugated liner crest and pitch are small, suitable for fine grinding and coal mill. 5, end cover liner installed in the grinding head cover or cylinder cover to protect the end cover from wear and tear. 6, ring groove liner in the lining of the T surface for casting a circular groove, after installation to form a circular groove, suitable for multi-warehouse grinding of the first and second positions, dry, wet grinding Machine can be. 7, grading liner, grinding mill for the ideal state should be large particles of material with a large diameter grinding body to impact and crush, that is, in the direction of the mill feed with large diameter grinding body, with the material The direction of the material to the gradual reduction of the grinding body should be sequentially reduced.
Qiming Casting is one of the largest manganese steel, chromium steel, and alloy steel foundry in China. Products include crusher wear parts, Crusher spare parts, mill liners, shredder wear parts, apron feeder pans, and electric rope shovel parts.
With a complete range of mill liner components, from lifter bars and shell plates to centre cones and trunnion liners, we use a range of engineering tools including MillTraj modelling software, Inventor 3D and AutoCAD to develop customised mill and scrubber liners to your requirements.
The thickness can vary in order to balance mill capacity and liner life. The width is designed for optimum protection from the lifter bars. MultoMet shell plates, incorporating Hardox strips, are for demanding applications or where the drilling pattern result in the shell plates being exposed to high wear.
Lifter bars are available in a range of widths, heights, and in rubber or composite profiles. Steel reinforced lifter bars are designed to provide maximum impact and abrasion resistance. MultoMet lifter bars have Hardox tempered plates whilst heavy-duty MultoMet lifter bars have castings for larger ball mills and SAG mills.
Head Plates are custom designed for each mill or scrubber for ease of installation and handling. Rubber head plates are available in various designs to combat sliding abrasion. MultoMet head plates, incorporating Hardox strips, are designed for gruelling applications.
Heavy-duty grate plate designs are available for larger mills with a range of aperture sizes. The elastic property of rubber allows for smaller slots than steel grates whilst eliminating blinding problems. Internal frames are designed for different mill loads and semi-overflow designs control the pulp level in the mill.
Manufactured from a fabricated steel base, which is then rubber lined, Multotecs pulp lifters ensure the correct volumetric flow. Rubber lined pulp lifters provide optimum discharge of pulp through the mill in order to minimise bottle-necks. Rubber wear plates, bolted onto the high wear areas, achieve an improved life.
Central cones are designed to assist the discharge of the material to increase capacity. These are supplied in segments that are assembled inside the mill for ease of installation. The centre cone section should be directly underneath the pulp lifters section.
Filling, support and corner segments fit into the corners of the mills and scrubbers to provide a clean interface between the head and shell liners. Multotecs design locks the head plates and grate plates into position and stop material collecting in the corners of your mill.
Multotecs rubber mill and scrubber linings are designed by combining the results of computer simulations and inspection data in order to optimise charge trajectory and wear life. Multotec can provide the correct rubber formulation and attachment systems such as stainless steel T-tracks to suit highly acidic, high pH and even diesel operating environments.
Our lining components are available in a wide range of designs, dimensions and profiles. In addition to the standard rubber components, we also supply MultoMet composite lifter bars, shell plates and head plates.
This specialised trajectory modelling measures the variable speed to demonstrate the impact of mill speed. The display features all representative wear resistant liners and mill charge with a clear Perspex screen on either side in order to assess the trajectory pattern of mill charge during operation.
As gradual wear on the mill liner profile affects the material trajectory inside the mill, resulting in decreased impact grinding or attrition grinding efficiency, operators need to ensure an optimum wear mill liner profile is constantly maintained.
Introducing MultoScan: the most affordable mill liner profile condition monitoring system. Where traditional mill liner monitoring and inspection is unreliable and time-consuming, MultoScan accurately tracks your milling plants liner wear in real time and notifies you when it begins to reduce efficiency.
Utilising computer simulations such as MillTraj software to optimise liner design and MultoScan and Hawkeye to execute condition monitoring, Multotec will help you achieve an optimum mill trajectory, improve equipment service life and tailor a service programme designed to lower your cost per ton.
Ball mill linersfrom Multotecmaximise the lifespan and performanceof your ball mill, with a selection of rubber and rubber composite liners available. Refined through ongoingdesign improvements, our ball mill linersmaximise uptime and service intervalswhile providing animproved crushing of the ore.
Our ball mill liners are the result of state-of-the-artsoftware-drivendesigns with industry-leading inspection data, achieving an optimal charge trajectory and rate of wear life for your ball mill. We ensure your ball mill liners are fitted with precise levels of workmanship, facilitating maximum mill uptime for increased production. Our ball mill liners are available in a wide range of dimensions, designs and profiles. They can be tailored to the specific application requirements of your mineral processing operation, with different rubber formulations and attachment system materials available. With these options, Multotec ensures your ball mill liner can tolerate corrosive levels of acidity and diesel.
Our ball mill liners solutions can be fitted with MultoMet composite lifter bars, shell plates and head plates. The MultoMet range utilises Hardox 500 wear-resistant steel, attached to the leading edges of the lifter bar array and embedded within shell plates and head plates, ensuring maximum abrasion and impact resistance.
Shell Plates Shell plate thickness can vary, which helps both in balancing mill capacity as well as extending ball mill liner life. For arduous milling applications, or where drilling patterns produce shell plates that are too wide, thus exposed to high wear, shell plates with Hardox strips can be utilised. Lifter Bars Available in a range of profiles and dimensions, lifter bars increase the efficiency of the milling operation by maximising the agitation of the ore. The impact and abrasion resistance of these bars is maximised by Hardox 500 steel along the leadings edges of these components. With a high-quality attachment system, lifter bars are easy to install to the ball mill liner. Head Plates We custom-design head plates according to each ball mill to ensure maximum performance and lifespan. Most commonly, our head plates are built from high-quality, specially-formulated rubber. In arduous ball mill applications, Hardox strips can be fitted to the head plates to increase their operational life. Grate Plates Grate plates are available in a range of aperture sizes and configurations. Internal frames are designed for different mill loads, and it is possible to use semi-overflow designs in order to control the pulp level in the mill. Different options for extending plate life exist as required by your application, such as built-in MultoMet lifter bars. Pulp Lifters Manufactured with a rubber-lined fabricated steel base, our pulp lifters use high-quality designs that ensure a correct volumetric flow of the pulp. Rubber wear plates designed to be bolted onto the high-wear areas of the ball mill liner improve the performance life of your mill. Central Cones These components assist in the controlled discharge of the material, maintaining mill capacity across the operation. Cones are provided in segments, which are then assembled inside the mill. This enables easier handling and manageability. Trunnion and Bell Mouth Liners Manufactured with a fabricated steel base that is then rubber lined. Loose steel-reinforced rubber liners are also used in larger trunnions. Filling and Support Segments Extend the wear liner to the corners of your ball mill andscrubber, enabling a clean, smooth lining across the ball mill liner.
A method is presented for measuring mill filling safely from the trunnion.New equations of load volume including in the conical ends and occupied by lifters.Calculate load mass from mill crash-stop and grind-out filling measurements.Spreadsheet calculator and procedure pdf supplied as supplementary material.
The fraction of mill volume occupied by rocks, grinding media and slurry in grinding mills are dominant factors influencing AG and SAG mill power draw and grinding rate. Hence accurate mill filling measurements are needed for modelling mills. To that end, it is usually necessary to enter the confined space of a grinding mill, a task that involves a degree of safety risk and a potentially lengthy plant stoppage. This paper discusses a range of available methods for measuring and calculating mill filling and introduces a new technique for accurately measuring filling that eliminates the need to enter the mill in most cases. The new method offers engineers and researchers a safer and faster method for quantifying the filling level in industrial SAG and ball mills, and allows the surface profile to be surveyed, without requiring the contents to be level. The paper also details formulas for calculating the filling level and load volume, which unlike previously published equations, also consider the volume in the conical ends and the volume occupied by the mill shell lifters.