Tag Archives: Multotec

Multotec looks to optimise SAG mill liner performance, milling efficiency and liner life

As the mining industry moves to larger semi-autogenous grinding (SAG) mills for higher productivity, Multotec says it is developing and applying innovative liner designs to optimise liner performance, mill efficiency and liner wear life.

“Our strong analysis capabilities in the design process – including discrete element analysis (DEM) and finite element analysis (FEA) – allow us to continuously evolve the application of our composite liners,” Sam Hearn, Global Sales and Business Development Manager at Multotec, says.

Hearn highlights how Multotec uses DEM software to simulate the interaction between the mill charge and the liners, and to evaluate liner profile over the life of the liner.

“The DEM analysis considers a range of variables such as the ore’s bond work index, its specific gravity, the size of the grinding media, the mill speed and the slurry density,” he says. “Sophisticated simulation capability allows us to accurately model the performance and wear of our mill liners. This includes predicting the liners’ wear life, to avoid unscheduled downtime and to extend the time between replacements.”

Emphasising that no two mill liner applications are identical, Hearn says this simulation can guide very specific refinements in the liner design for each customer. A detailed understanding of the operating conditions is vital to ensure that the final solution delivers optimal results.

He notes that the traditional use of steel liners in large SAG mills presents a number of challenges. For instance, there may be bending stress inside the steel liner due to inexact fitting on the mill’s curved surface, and the higher rigidity of steel, compared with rubber, makes it less than optimal for absorbing the energy of rock material inside the mill.

“This is where our composite liners come into their own,” he says. “These innovative liners combine the impact resistance of Hardox 500 steel inserts and the absorption capacity of our specially formulated wear-resistant rubber compound. Through the simulation, the structural integrity of the liners can be verified, while the geometric layout of the liners can be optimised.”

The composite liners are locally manufactured at Multotec’s extensive facility in Spartan, Gauteng, South Africa, in an advanced process that includes its unique submerged cutting technique to preserve the surface hardness of the liners.

“We combine our innovative design capacity with the latest tooling capability and production technology for large-scale manufacture,” Hearn says. Following the design and manufacturing process, Multotec conducts field trials to compare with the relative performance of composite liners and steel liners.

“We are confident that, given our product improvement processes and simulation ability, the wear life of our liners will achieve and often exceed expectations,” he says.

Multotec looks for increased resistance, longer wear life from new ceramic-based solution

A new ceramic-based solution from Multotec has opened the door for a range of componentry to be shaped using pressed alumina ceramics for high wear resistance and longer wear life, the South Africa based company reports.

According to Boyd Butterworth, Sales Engineer at Multotec Wear Linings, the opportunity arose when a chrome smelter in the Steelpoort area of South Africa’s Limpopo province was searching for a more cost-effective solution for certain wear parts in their rotary dryer multi-cyclone arrangement.

“The customer initially required the fabrication and ceramic lining of steel components in the multi-dryer cyclones,” Butterworth says. “The units are employed in the process of drying chromite ore particles and other feed material on its way to the pelletising section of the plant.”

The units are essentially dust cyclones – rather than the process or separation cyclones Multotec supplies – and are subject to aggressive wear. The feed to these multi-dryer cyclones typically consists of chromite ore, reductants such as anthracite, char, coke and coal, and fluxes like quartzite, dolomite and lime.

“The multi-dryer cyclone has four main components, made initially of steel and later lined with ceramics in response to the rapid replacement rate,” Butterworth says. “The wear rate is exacerbated by the high velocity of the material, which is required in order for it to remain in suspension while passing through the system.”

The customer’s eagerness to find a more effective solution allowed Multotec to present an unusual – perhaps unique – concept: solid ceramic components custom-shaped for this specific purpose, the company said.

Butterworth noted that the previous installation of standard ceramic tiles by a competitor did not adequately protect the components from the highly abrasive material which, moving at about 18 m/s, was still leading to frequent component replacements.

“Our proposal was to produce a solid ceramic blade and dome arrangement, as well as to provide the rest of the tube and inlet sections with engineered ceramics, installed at a very high standard,” he says.

Paving the way for this solution was a highly specialised and innovative new fabrication technique that saw the ceramics shaped into various complex and intricate designs while they are in the ‘green phase’ of production, using state-of-the art CNC technology.

“Thanks to this technique, we can produce solid alumina ceramic machine components,” Butterworth says.

The company’s research to date suggests that this might be the first time components like these have been produced from pressed alumina ceramics – making them a pioneering achievement.

Multotec expands presence, product line in Asia with new China facility

Bucking global economic trends, mineral processing equipment specialist Multotec says it has opened a new, larger manufacturing facility in China to meet growing demand.

The 3,200 sq.m factory, based in the port city of Tianjin about 100 km southeast of Beijing, is more than double the size of the previous premises, according to Ken Tuckey, Director of Multotec Screening Systems (Tianjin) Ltd. The facility focuses on producing the company’s polyurethane screen panels, including specialised panels for fines dewatering and classification.

“The expanded facility was necessary to increase production capacity, as sales have grown rapidly since Multotec became directly involved in this business in 2017,” Tuckey says. “The investment in China is also an important part of Multotec’s global strategy to get manufacturing operations closer to end-customers wherever possible.”

Multotec had taken over the business from Tema Screening Systems in 2017, which had started up in 2006 and focused mainly on the aggregate and quarry sectors. Multotec’s sales have expanded, mainly into China’s mining industry, but the factory’s increased capacity is also allowing it to produce for other parts of the world.

Running the operation on the ground since 2018 is General Manager, He Pu, a local expert with 20 years’ experience in mineral processing.

“The new factory has taken careful planning over the past year, and had to obtain a range of strict government approvals,” he says. “Even though the COVID-19 pandemic did present some challenges to our schedule, we were still able to move into the new plant in May this year.”

Multotec Screening Systems (Tianjin) Ltd General Manager, He Pu

He Pu highlighted the importance of innovation as a key ingredient for any company looking to break into the Chinese market. This has been vital to the early success of Multotec, which has a range of product advances operating in Africa and other markets. Recent improvements in China’s manufacturing sector has also underpinned the success of the local business, according to He Pu.

“The focus in the mining sector in China has shifted towards increased efficiencies and improved quality,” He Pu says. “Multotec is now well positioned to take advantage of this, especially with the innovative screen panel technology that it can offer the market. This is underpinned by our quality manufacturing processes as well as our excellent local supply chain.”

Multotec’s Chinese company is ISO-accredited with in-house quality control expertise, he says. The number of local staff members has increased and includes a strong sales team with good links to the mining sector. The company also has distributors and agents across China, bringing services and products closer to the mines.

With the new polyurethane moulding machines, the upgraded plant is running double shifts to optimise production levels. The latest technology equipment – combined with Multotec’s experience and ongoing training in factory – ensures a consistently world-class quality of polyurethane panels, it says. Accelerated in-house manufacture is also speeding up the delivery times to local customers.

“The opening of this plant marks the beginning of a new era for Multotec,” He Pu says. “We have ascended to a new level, not only by enlarging the area of the workshop but by adding new equipment.”

Multotec keeps the ferrochrome flow going with new innovate spiral

Following years of detailed test work in the South Africa ferrochrome sector, Multotec says it has successfully developed and proven a spiral concentrator that eliminates beaching and enhances recoveries in the 1-3 mm fractions of high-density material.

Significantly, when compared with traditional spirals, the new spiral has shown extraordinarily higher metal recoveries, even for minus 1 mm fractions in ferrochrome slag, according to the company.

“Our SC25 spiral concentrator features steeper angles which facilitate the flow of material and increase separation efficiency,” Hlayisi Baloyi, Applications Engineer at Multotec, says.

“It also widens the particle size range that can be treated by the spiral. Traditionally, spirals would struggle to efficiently treat material above 1 mm in heavy mineral applications, but this spiral can go well beyond that. The spiral has been a game changer even for the minus 1 mm size range where higher separation efficiencies have been achieved on chromite ore.”

Baloyi says this innovation has provided the minerals processing sector with an exciting alternative to jigs in the “minus 3 to plus 1 size range”, which have been one of the conventional methods of separating larger particles. The solution is cost effective as spirals use no electricity and are also easy to maintain, Multotec says. “So attractive is the new model that the first order for the commercialised version has already been placed,” the company said.

Baloyi explained: “Taking ferrochrome samples from a number of mines over a period of two to three years, we conducted extensive test work on these at our well-equipped testing facility in Spartan, near Johannesburg,” he says. “Leveraging this data with our in-house engineering design capacity, we were able to develop the optimal solution and locally manufacture the new spiral concentrator.”

Multotec said: “The institutional knowledge within Multotec has been developed over more than four decades, including valuable expertise in fluid dynamics. Hands-on experience in test work and design allows the development of prototypes that solve customers’ specific challenges – followed by scaled-up local production of equipment to match market demand.”

The economic benefits of the Multotec SC25 spiral for ferrochrome producers are substantial, as some plants were losing the value of their 1 to 3 mm material to the tailings storage facility, according to the company. Many of those who used jigs to treat this fraction were also finding that efficiencies were low.

Refentse Molehe, Process Engineer at Multotec, said ferrochrome is not the only commodity the company has successfully tested.

“We have even seen improved recovery in heavy minerals below 1 mm size, alluvial chrome, manganese slag, and there is potential in industrial recycling,” Molehe said.

Multotec makes an impact in the Pilbara with Ceradox screen panel

Multotec has combined Hardox blocks and alumina ceramic tiles to come up with a new high impact screen panel that, it says, cuts plant downtime and boosts mine productivity.

The Ceradox panel boasts more than double the wear life of traditional rubber panels, according to Multotec, with the innovation developed during 2019 in response to a request from an iron ore mining customer in Australia’s Pilbara region.

Three months of testing delivered results that exceeded expectations, according to Multotec Screening Product Manager, Shawn Faba.

“The customer needed a panel with an extended wear life, so that they only needed to conduct replacements during the regular maintenance shutdown every 12 weeks,” Faba said. “Our testing demonstrated that the panels were lasting 24 weeks and longer.”

Through a close collaboration between Multotec South Africa, Multotec Australia and the customer, a solution was developed and proved for a demanding application on scalper screens, it said.

Faba explained: “Designed for the impact area of the scalper screen, the Ceradox panel must withstand the impact of material up to 300 mm in size falling from a discharge height of up to 3 m. It must also resist high levels of abrasion from the ore.”

The resulting design leverages the impact strength of the Hardox blocks and the abrasion resistance of the ceramic tiles, embedded in Multotec’s proprietary rubber formulation, helping absorb the energy of the falling material, according to the company. The panels are manufactured locally at Multotec’s high-volume facilities in Gauteng, South Africa, which include a rubber mixing plant run by experienced specialists.

Faba noted that the 305 mm square Ceradox panels can be manufactured to different thicknesses from 50 mm to 100 mm.

“With our local manufacturing capability, we can achieve short lead times and deliver to anywhere in the world,” he said.

Multotec says it already supplies about 35% of the screening media to the iron ore mines in the Pilbara area.

Multotec continues to service miners during COVID-19 outbreak

Multotec has reaffirmed its support for customers during the COVID-19 outbreak, saying it will continue to provide assistance, especially to operations declared as essential services, throughout this tumultuous period.

As a global company serving six continents, the mineral processing original equipment manufacturer has operations in Canada, Chile, Australia, Europe, China, Ghana, Zambia, Botswana, Mozambique and South Africa.

Multotec CEO, Thomas Holtz, said: “We certainly find ourselves in challenging times and the global COVID-19 pandemic is giving us the opportunity of modifying the way we do business across the world.”

With South Africa currently in lockdown, Multotec is producing only ‘essential services’ products there, but expects to return to full production at the end of the lockdown on April 17, 2020, Holtz said.

“Our manufacturing facilities in China are fully operational, while our facilities in Canada, Chile and Australia are in various stages of operational capacity,” he says. “We have committed to working on weekends and over public holidays over the next months to ensure any order backlogs are caught up and there is the least possible disruption.”

Holtz highlighted that where some countries’ mining and power generation operations have been declared by their governments as essential services, Multotec is providing full product and service support from its local bases in these locations.

“The safety of our staff and customers is an absolute priority and every precaution is being taken to ensure the continued health of all our stakeholders,” he says. “At the same time, please be assured that – as far as possible and using various means – we continue to provide full technical and sales support to all our customers, wherever they may be.”

Multotec has taken the worldwide travel restrictions as an opportunity to run online training workshops in multiple languages with many customers in remote locations, it says. There are also informative training videos available on the company’s YouTube channel.

Multotec renews power commitment in South Africa

Mineral processing original equipment manufacturer Multotec says it has installed renewable power at one of its facilities in Spartan near Johannesburg, South Africa.

The investment saw 684 photovoltaic solar panels being installed in November 2019, creating a 223 kW generating system. It serves Multotec’s most energy-intensive works – its injection moulding facility – providing almost 20% of the daily electricity demand, the company says.

According to Multotec’s Group Manufacturing Executive, Werner Stessl, the impact of the system is both economic and environmental.

“Multotec is committed to environmental sustainability and we value the fact that this installation is likely to save about 30,000 kg of carbon dioxide emissions each month,” Stessl said. “This is the equivalent of planting about 100 trees a month.”

He says the organisation has been carefully monitoring its rising electricity costs and sought a responsible solution that would leverage the latest renewable energy technology. In collaboration with solar power experts Energy Capital, a thorough investigation of its energy consumption and available opportunities was conducted.

“After months of planning and research, it was established that we could run a battery-less system which would valuably augment our current municipal supply,” Stessl said. “After some structural engineering to prepare our designated roof areas, the panels were efficiently placed and linked up by mid-November last year.”

To date, the system has more than met Multotec’s expectations, which were contractually guaranteed by the service provider, it said. The detailed upfront investigation showed that the installation could be repaid by energy savings within about four-and-a-half years. System performance – right down to the electricity generated by each PV solar panel – can be monitored daily on an online dashboard, he says.

The local municipality has also begun to benefit from Multotec’s initiative, as there is usually ‘overflow’ power generated at weekends the moulding facility does not need. This excess electricity is now channelled back into the main grid by Multotec, at no cost to the municipality.

Multotec builds integrity with hydrocyclone solution at Zambia tailings facility

An innovative hydrocyclone solution from Multotec is allowing a large Zambian copper mine to develop a safe and cost effective tailings storage facility (TSF), the South Africa based company says.

The TSF faced a number of specific challenges, according to Frikkie Enslin, Senior Applications Engineer responsible for cyclones at Multotec, including its extensive planned capacity and the area’s flat topography. The mine’s process plant pumps some 10,000 m³/h of tailings to the TSF, requiring its final circumference to reach about 19 km.

“The flat area around the mine meant there was no suitable topography to provide a natural dam,” Enslin says. “It was therefore vital to create strong walls to retain the slurry from the plant, so that the integrity of the TSF could be assured.”

Simple gravity separation and sun-drying had proved unable to create material firm enough to constitute walls, according to Multotec. In the early days of the plant’s operation, it was shown material being deposited by means of plain spigoting could still not be walked on even after a month of drying in the sun. By contrast, Multotec’s 250 mm GV hydrocyclones were able to deliver an underflow discharge that could be walked on in just two days, the company said. After a week, the material could withstand the weight of an excavator.

The sheer volume of slurry being pumped into the TSF, however, created its own challenge. The hydrocyclones had initially been mounted on metal cradles, which were inundated within a couple of hours. Extracting the cyclone and cradle from the mud for the next placement was difficult and very time consuming.

“The customer needed a solution that would keep the cyclone above the slurry level for longer, and would be easier to move,” he says. “To do this, we designed a cyclone cradle that could be attached to a long wooden pole, giving much greater height, allowing the customer to leave the cyclones in the same position for a much longer time.”

With Multotec’s experience and facilities for custom design and manufacture, the hydrocyclones were then modified to be lighter. This made them easier to handle and manoeuvre, it said.

“Constructed with a lighter metal, these tailor-made units are industry leaders in terms of being lightweight and are rubber-lined to ensure long wear life,” he said. “We also made some innovative improvements to the vortex finders and the cone sections, which are now metal spun.”

Other changes were made to speed up the changing of a spigot, and the moving of the hydrocyclones from one point on the TSF wall to the next. The design now includes a threaded spigot coupling and quick-release connections on the cyclone.

The solution has been so successful to date that over 250 of Multotec’s modified GV hydrocyclones have been installed.

“Just as we collaborated closely with the customer in developing this solution, so we continue our partnership in monitoring the performance of our hydrocyclones as the project goes on,” Enslin says. “An expert applications engineer from our Johannesburg head office visits the site regularly, while our Zambia office in Chingola offers solid technical and field service support. We don’t just sell process equipment, but rather process solutions.”

Multotec’s MATO boosts conveyor refurbishment capacity

Multotec’s conveyor belt lacing subsidiary, MATO, has recently expanded its offering with the addition of new service and repair facilities.

Andrew Frank, Operations Manager at MATO Products, highlighted the recent completion of a new spray-painting booth, which has doubled the firm’s capacity to finish refurbished items.

“To keep up with market demand, we have expanded our spray booth significantly in terms of size and throughput capability,” Frank said. “It can now accommodate components up to a length of 2.2 m and provide a more productive environment for operators.”

This allows for all repair and finishing work – even on the longer diagonal belt cleaners – to be spray-painted in-house, he says, improving turnaround time, quality control and cost to customers.

“We pride ourselves on the functionality and longevity of our products,” he said. “We base this on our technical quality in repairing and refurbishing equipment to ‘as-new’ specifications. Upgrading our facilities ensures that we continue doing this as cost effectively as possible, as our customer base grows.”

Complying with the highest standards of health and safety, the new spray booth is equipped with the latest filtration technology, according to the company. This ensures fumes and chemicals are filtered before air is expelled from the building. A powerful fan unit enables an extraction capacity of 18,000 cu.m/h.

Known as a leader in conveyor belt lacing, MATO also offers a range of belt cleaning solutions.

Multotec-manufactured SAG mill trommel screens beating the competition

With mining companies looking to improve productivity and reduce downtime in the process plant, Multotec is promoting the use of its locally manufactured SAG mill trommel screens as a viable alternative to vibrating screens in SAG mill scalping applications.

“Many designers and mill operators believe that the benefits of simplicity and the ability to handle throughputs in excess of 3,500 t/h of solids make trommels the preferred equipment for this application,” the company said.

A key component ensuring optimal performance of SAG mill trommels is the screen panel, which enables this equipment to classify large volumes of mill product, according to Francois Fouche, Senior Screening Specialist at Multotec.

The company has developed a special range of rubber compounds used to manufacture the compression moulded rubber screen panels that are considered the highest wearing items in the trommel.

“We have achieved excellent results from our compression moulded screen panels with wear life extending over six months in 4,500 t/h hour SAG mill applications,” Fouche stated.
With nearly four decades of experience supplying locally manufactured trommel screens and, Multotec, today, has the process capability to size SAG mill trommel screens with diameters up to 5.5 m, it said.

“The company also designs its trommel screens to suit each customer’s unique requirements and confidently offers process and mechanical guarantees,” the company said.

Fouche said: “Considering the size and complexity of large SAG mill trommel frames, Multotec is able to apply the latest finite element analysis techniques during the design phase to ensure we reduce fatigue stresses and ensure structural integrity.”

Multotec, given the arduous duty, covers all frame surfaces exposed to the milled product with a wear resistant material, typically rubber.

Fouche said the operational performance of a SAG mill trommel is another key consideration for Multotec: “As adequate retention time is required for the efficient removal of the fine fraction, we need to reduce the high velocity of the slurry that exits SAG mills.

“We are able to achieve this with various configurations of weir bars. The design of a set of scrolls is an integral part of the design process as these regulate the flow of solids through the trommel screen.”

Multotec has supplied a number of trommel screens for 38-40-ft (11.6-12.2 m) SAG mills that required 500-600 mm high weir bars to create sufficient retention time. It can also supply a range of rubber shell plates and lifter bars to protect the SAG mill trunnion against wear.

“Providing long term customer support is one of the major advantages that Multotec offers,” Fouche says. “Our experienced competent field service crews maintain the screening media and provide condition monitoring on the trommels.”

The Multotec field service maintenance crews can also focus on wear rate indication and monitor the wear resistant lining of the steel structure, and in doing so provide a complete maintenance solution.