Tag Archives: Multotec

Multotec spirals helping assess heavy minerals potential in Cameroon

Exploring for heavy minerals in Cameroon, a multinational mining company is gaining valuable results and insights through the use of an on-site pilot plant from South Africa-based process equipment leader Multotec.

The pilot plant was designed and assembled at Multotec’s extensive design, manufacturing and testing facilities at Spartan near Johannesburg, South Africa, and shipped to the remote site in central Africa last year. The containerised plant includes a range of Multotec’s own equipment including screen panels, cyclone rig and spiral rig.

According to Faan Bornman, Technology Manager: Research and Development at Multotec’s Technology Division, drill samples from the prospect area are passed over the screen to remove oversized material, with undersize going into a sump to be mixed with water to the correct density. The undersize material reports to the cyclone for desliming – the removal of very fine particles – delivering an underflow with an optimal size range of between 38 microns and 1 mm. This is fed to the spiral rig for concentration, with the spiral delivering a concentrate, middlings and tailings. The process allows the project to assess its economic heavy minerals portion, which is concentrated towards the inner section of the spiral.

“Multotec’s HX5 and 117HM spirals were employed to suit the customer’s requirement, with the new 117HM spiral showing great recovery in mineral sands,” Bornman says. “With the HX5 handling up to 5.5 t/h and the 117HM 2.3 t/h, these spirals also offer different recoveries and grade in the various heavy minerals.”

The equipment in this pilot plant is vital to achieving an accurate assessment of the deposit’s viability, but the results also give the customer important insights into how the full-scale plant should be designed if exploration proves results provide positive, according to Multotec.

“To ensure that the customer receives optimal value from the pilot plant, we sent a process engineer to site to commission the system,” Bornman says. “During the several weeks that he spent there, he also conducted training with local staff on how to run and maintain the plant.”

Multotec supplies 38 slurry pumps to Kazakh chrome project

Mineral process equipment specialist Multotec’s global reach has recently been highlighted with the supply of slurry pumps to a chrome project in Kazakhstan.

According to Gerhard Hendriksz, General Manager, responsible for slurry pumps at Multotec, an order of 38 slurry pumps was delivered in mid-December 2021 through a collaboration of Multotec’s international business team and the company’s distributor in Kazakhstan.

“The pumps were produced according to the specifications provided by Multotec’s distributor, ensuring the units will deliver the required duty for the end customer,” Hendriksz said. “This includes being designed to withstand highly abrasive operating conditions.”

Certain chrome deposits in Kazakhstan boast some of the world’s highest concentrations of chrome oxide (Cr₂O₃) – up to 62% content – making the slurry particularly abrasive. The pump range Multotec delivered includes models from the HD25 to the MD300, in metal- and rubber-lined configurations to suit their respective duties.

A turnaround time of just 10 weeks was achieved, with Multotec leveraging its local supply chain that included foundry work, machining and other suppliers, as well as collaboration with Multotec’s technical partner, 7D, based in Perth, Australia.

Andre Burger, Production Manager, responsible for pumps at Multotec, emphasised that a close working relationship with the end user and Multotec’s Russian-speaking business team ensured smooth preparation and delivery.

“Our distributor has in-depth knowledge of the customer’s applications and has the engineering expertise to ensure optimal product specification and performance,” Burger said. “Multotec will support the products with aftersales and support services, including availability of spare parts.”

Despite the trade disruptions related to the COVID-19 pandemic, Multotec has continued to perform strongly on the export front. Last year, it earned a place in the Exporter of the Year Awards – presented by the South African Capital Equipment Export Council.

Multotec supplies a complete range of pumps for medium- and heavy-duty slurry applications, including cyclone feed, spirals feed, mill discharge, tailings disposal, filter feed, effluent discharge and spillage. The range caters for flow rates from around 15 cu.m/h up to 2,000 cu.m/h.

Multotec addresses grade control, recovery issues with RAMA sampling system

With its latest sampling system that aligns with metallurgical accounting standards, minerals processing equipment company Multotec says it now offers unprecedented levels of accuracy for effective plant optimisation.

The company’s Realtime Automated Metallurgical Accounting (RAMA™) system promises to deliver significant value by unlocking higher mineral content through improved grade control and recovery, as well as by optimising the consumption of reagents. The system brings together three sampling disciplines – metallurgical accounting slurry sampling, sub-sampling, preparation and analysis – into one solution, it says.

“By integrating our advanced samplers with a sample preparation system that meets metallurgical accounting standards, we can feed online analysers with a fully representative and accurate sample,” Modisaotsile Nyokong, Process Manager at Multotec, says. “While analysers can be accurate instruments, they cannot provide meaningful results if they are fed with inaccurate samples.”

Nyokong highlights that the RAMA online analysis feed preparation system extracts regular and full sample increments from slurry flow streams according to AMIRA P754 metal accounting standards, best practice standard and Theory of Sampling (TOS). This eliminates more than 80% of the total sampling error and allows real time process control to be conducted to the highest standard, according to the company.

“Samples are extracted from the production flow using automated mechanical samplers which are TOS compliant,” he says. “This is achieved by taking full cross-cut samples that are representative of the flow stream.”

The analysed slurry is therefore unbiased, presenting an accurate reflection of all the key parameters such as particle size, slurry density, settling velocity and mineral grade, Multotec claims. Nyokong explains that process control samplers – including pressure pipe, poppet and shark fin type samplers – have traditionally been used to feed online analysers. However, these primary samplers do not comply with the TOS, with the result that poorly represented samples are analysed with high levels of precision – a futile exercise.

“Our advantage with the RAMA system lies with feeding representative samples to online analysers, using correct sampler designs,” Nyokong says. “This produces real-time results that represent the flow stream and are free of error or statistically significant bias.”

Multotec’s slurry sample preparation solution prepares and treats each analysis stream in its own line, making it ideally suited to analysers that deal with streams individually. This avoids cross-contamination. Where multiple streams are analysed through the same analyser source and detectors, some cross contamination of streams can occur with different grades or mineral properties – undermining the accuracy of the result.

Over an analyser multi-stream cycle, the RAMA system can collect composite samples for each stream, according to Willem Slabbert, Sampling and Magnetics Product Specialist at Multotec. This means the analyser does not measure the instantaneous off-take stream ‘sample’ from the traditional in-line continuous discharge like process control samplers – which is only done about 30 minutes apart.

“Rather, it measures the performance of each stream through multiple composite samples taken over the 30-minute interval,” Slabbert says “This reduces the grade or quality variability per flow stream, and gives the plant manager a more representative monitoring of minimum and maximum process conditions – with precise values.”

The problem with ‘snapshot’ sampling of process control samplers is that stream properties can fluctuate before and after the analysis., meaning the fluctuation is not captured in the results. By contrast, the RAMA system’s composite sample accounts for all process variations over the analysis period, according to Multotec.

Slabbert reiterates that sample analysis results are only as good as the sample presented for analysis, pointing out that this applies as much to online analysers for process control as it does to conventional laboratory analysis for metallurgical accounting.

“RAMA is also a cost saving solution, as separate process control samplers are no longer required,” he says. “The samplers’ purpose in our system is doubled up for both metal accounting and for process control – without the need for any compromise.”

Configured in a containerised and modular design, RAMA is a compact and mobile system. This allows for easy installation and retrofitting into any plant operation, where it can feed any type of online analyser. It can also be readily transported and commissioned, with flexibility for expansion where necessary. Layout options are available for plants that have primary and secondary sampling with a subsequent containerised sample preparation stations, as well as for those with primary sampling only and separate secondary sampling preparation.

The RAMA system allows analysers, for the first time, to be fed with representative samples taken from the production flow stream, according to the company.

Multotec added: “The innovative combination of existing equipment with proven track record into a modular, containerised solution will bridge the gap between metallurgical accounting accuracy and accurate process control.”

Slabbert concluded: “The advantages of this novel combination of sampling global best practices into process control applications will unlock value for both analyser calibration as well as optimal, dynamic process performance.”

WEC Projects, Multotec combine for Mali gold mine modular wastewater treatment plant

WEC Projects, in conjunction with its partner, Multotec, has designed and custom engineered a wastewater treatment plant for a gold mine in Mali, West Africa.

The plant, used to remove arsenic from the mine’s wastewater stream, incorporates a modular design which simplifies the logistics and reduces the costs of transport and installation, according to WEC Projects.

The international mine operator is a client of Multotec, an engineering company specialising in mineral processing plant design and installation. The company approached WEC Projects, a local EPC contractor in the water and wastewater treatment industry, to jointly develop a customised solution to remove toxic arsenic from the mine’s wastewater. A multi-stage removal system was required to meet the strict standards for the mine’s discharge. However, the system also required a modular design which would facilitate the transportation, installation and commissioning of the plant.

Wayne Taljaard, Managing Director of WEC Projects, said: “The mining industry in Africa presents some very unique challenges, not the least of which are the remote locations of many of the mines and the difficulties experienced in getting staff and equipment to sites where road, power and water infrastructure is often lacking, hence the requirement by Multotec for a modular solution that would allow for rapid transport to site and to simplify its installation and commissioning.

“The COVID-19 pandemic added to the difficulties for us and the client, causing delays that reduced the time frame for delivery.”

In the treatment process, the mine’s wastewater undergoes primary solid/water separation using coagulation and flocculation and the primary clarifier. From there it enters a two-stage chemical precipitation and secondary clarification process to reduce the arsenic levels. The final stage sees the sludge undergo dewatering before disposal. The treated water, although not potable, is then reused by the mine for process applications.

The plant has a processing capacity of 150 cu.m/h and is capable of reducing the arsenic levels from around 13 mg per litre to less than 0.1 mg per litre.

Taljaard added: “The project, incorporates a number of unique features in addition to its modular design, including nine custom-designed, proprietary lamella clarifiers and a multi-stage arsenic removal process capable of treating the wastewater to the mine’s discharge standards. WEC Projects has completed a number of water and wastewater treatment projects throughout Africa. Our ability to provide a customised and modular solution for Multotec underscores our ability as a major player in the industry both in South Africa as well as across the continent.”

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.