Leading mineral process company, Multotec Process Equipment, will be providing a continuous ion exchange (Clean-iX®) metals processing scavenging equipment to a customer in the Democratic Republic of Congo.

The equipment, using Clean-iX® ion exchange technology from Melbourne-based metals recovery and industrial water treatment specialists Clean TeQ, will treat up to 20 million litres a day of a raffinate stream, removing contaminant metals and improving the quality and environmental rank of the raffinate before it is processed further.

The technology is built on the foundations of batch ion exchange, a process that has been used in the industry for over 50 years. The Clean-iX® process allows the extraction of metals from clarified leach liquors using a ‘moving packed bed’ column, maximising adsorption; this method of extraction has higher efficiency than conventional technologies.

As a leading provider of high-quality mineral processing equipment and solutions to the mining, mineral processing, petrochemical and power generation industries, Multotec has an exclusive technology distribution agreement with Clean TeQ for the African continent.

Carien Spagnuolo, senior process engineer at Multotec Process Equipment, says the group leverages its extensive sales and service network in African countries to bring customers leading edge technologies from around the world, especially for niche applications or difficult to treat waters.

“The DRC contract confirms the rapidly increasing global interest in the application of continuous ion exchange technology for metallurgical scavenging and water purification,” she says. “The installation is expected to offer another valuable reference for the efficacy and cost effectiveness of the process, for which there is a large potential market.”

In metals recovery and purification, Multotec is able to draw on Clean TeQ’s Clean-iX® technology. There is also a suite of water purification technology from Clean TeQ that includes Continuous Ionic Filtration (CIF®), DeSALx® for desalination and sulphate reduction, and HiROx® for high recovery reverse osmosis.

The DRC project is the second contract awarded in the past 12 months in which Multotec has applied Clean TeQ’s technology offering. Multotec is also currently implementing a proprietary continuous ionic filtration wastewater treatment solution at a mineral processing plant in the Middle East. Multotec was the principal bidder with overall responsibility for delivering the complex wastewater management and effluent treatment systems for the pyro-metallurgical mineral processing facility.


The correct time to change mill liners is when the efficiency of the mill drops and not when you think the lining is completely worn. Spike Taylor, managing director of Multotec Rubber, explains that the efficiency of the mill liner relates directly to recovery efficiency of the downstream equipment, and that plant operators need to adopt a far more proactive approach in this regard.

“A further ramification of waiting too long to change out the mill lining is that the fresh feed rate will decrease significantly because of the higher recirculating load, and this will have an obvious impact on production throughput in a plant,” Taylor says.

One of the major costs associated with operating a minerals processing plant is the cost of power or kW.hr/t, and this is significant because when the efficiency of the closed circuit mill is reduced it means that the material is essentially being treated more than once. This is a major additional cost factor, but often one that is not apparent.

Sam Hearn, global sales and business development manager at Multotec Rubber says that often when speaking to plant operators, a hurdle that needs to be jumped is the misconception that the mill liner is an expensive purchase.

“Once we have engaged with the plant engineers and drawn to their attention that the liners only cost between 10 to 20% of the operating cost of a mill, and that the cost of power is far greater we have their attention,” Hearn says. Power is a monthly expenditure for a plant and in most cases is not directly allocated to the mill’s operating costs, yet power accounts for about 60% of the total operating cost for that mill.

Hearn says that if it is accepted that the power cost is 60% and the liner cost is 10%, then the balance of the mill’s operating costs can be attributed to the grinding media. “This is an area which can be adversely affected by liner profile and charge trajectory so Multotec takes special care to ensure the design is correct,” he explains.

Worn liners allow more slippage of the charge and this results in an acceleration of the wear rate which can lead to the predicted life not being achieved with sudden replacement requirements so more frequent liner measurements need to be taken as the liners near the end of their life.

Multotec Rubber has a sound reputation with its customers where the use of its MultoScan system has been implemented. Using the MultoScan measurements and the SCADA data that the company receives from customers, it is possible to generate an accurate report on the performance of the mill. This enables Multotec’s technical team to engage with the mill operator directly in terms of mill performance and costs.

“In many instances, it is possible to make recommendations based on this data motivating for an earlier mill liner change out as this can dramatically reduce operating costs and increase overall plant efficiency,” Hearn explains.

What is most important in this scenario is Multotec’s ability to use the data generated to accurately determine the actual payback period for the new lining. As an example, Hearn talks about one customer where Multotec found that by replacing the mill lining ahead of the plant’s replacement schedule it was possible to increase the efficiency of the entire plant with a payback period of only days. In this instance, using available data it was easy to distinguish that even though the lining appeared to have an acceptable remaining life, the efficiency of the milling circuit was well below plant design requirements.

“Achieving these increased efficiencies is what is attracting our customers as they can clearly see the advantage in replacing the mill linings at the most cost advantageous stage. And being able to assist our customer using accurate data to make informed decision such as this is a major differentiator for us and them,” Taylor concludes.

The introduction of MultoScan several years ago made it possible for plants to accurately measure mill liner profiles. Using this information end users can easily and accurately predict the lifespan of the liner and the point at which the mill will become inefficient. The automatic measurement and display of the charge level is valuable in confirming that the operation of the mill is correct and this value is essential in calculating the trajectory.

Highly skilled technicians take the data acquired by MultoScan and leverage Multotec’s Hawkeye proprietary programme to interpret and analyse the data. Significantly there is no time lag on the information analysis which makes the level of responsiveness possible unprecedented, and allows customers immediate feedback on the condition of the liners and any immediate issues can be addressed on the spot.

Another very important advantage is the repeatability of the results which is considered an enormous benefit as there is virtually no room for human error. MultoScan also reduces the time spent in the mill taking readings, decreasing mill stoppage time, another significant cost saving for mines.

Having access to accurate information on the liner profile will allow maintenance crews to set the trigger point for the liner inventory. This will, in turn, allow plants to reduce the liner stockholding drastically optimising the inventory; another cost saving.


Being locally registered in Mozambique and well-staffed with 26 highly trained and qualified Mozambican nationals, Multotec Services Mozambique Limitada has secured supply contracts for processing equipment with some of the country’s major role players.

“We were the first mineral processing company to establish a facility in Tete province – back in 2011,” says Thinus Kruger, Multotec’s regional manager for east Africa. “We now have a solid presence with our full range of mineral processing solutions, as well as maintenance and fabrication services.”

Kruger emphasises that the company’s global strategy is to be located close to customers, not just in-country but as near to operational sites as possible.

“Our branch is situated within 20 to 100 kilometres of all our major customers, making for fast response times in terms of maintenance and support services and for the delivery of emergency spares,” he says.

Multotec Services Mozambique’s customer base now includes four major coal players, a graphite mine and a heavy minerals mine, as well as mineral separation plants and harbours. So well equipped is the branch that it is also used as a base for servicing customers in Zimbabwe and Madagascar. Among the full fleet of vehicles to enhance customer service is an eight-tonne crane truck for collection and deliveries, a personnel transporter, double-cab vehicles for service support, two forklifts, an equipped standby trailer, and a rugged HDPE welding trailer for overland installations of HDPE pipes.

Situated just off the main road between Tete and Moatize, the Multotec facility is just 10 km from the airport and 15 km from customs, and boasts a 1,000 square metre fabrication workshop with a bending break, guillotine, pedestal drill, power saw and a variety of welding machines.

“Leveraging the local team’s combined 60 years of experience in mineral processing, our company in Mozambique offers long term maintenance contracts, supply contracts and fixed price agreements to suit customer requirements,” says Kruger. “We also conduct small to medium-scale steel fabrication and specialise in the manufacturing of steel chutes, launders, steel pipes and general fabrication work, including carbon steel, stainless steel, aluminium and welding and installation of HDPE pipes.”

The range of work carried out for customers encompasses service exchanges and refurbishment on cyclones, the retro-fitting of belt cleaners, samplers and cyclone clusters, and preventative or reactive maintenance of screening and other process equipment.

Quality of services is ensured by ongoing investment in local employees through training on-site and advanced training in Multotec’s South Africa-based training centre, which hones employees’ skills in installing and maintaining Multotec products, as well as in the ceramic lining of equipment.

Refurbishment of cyclones forms part of Multotec Services Mozambique’s market offering.

This focus on skills has allowed the company to develop a depth of expertise that – in addition to a commercial manager, accountant and human resources officer – also includes a metallurgical process specialist, an engineering and fabrication specialist, ten artisans or technicians, four HDP pipe welders and nine artisan assistants and installers. The company’s capacity is enhanced by technical support from the Multotec head office in South Africa.

“We regularly fly our Multotec equipment specialists to Mozambique to assist with on-site training for our customers, as well as to conduct audits on their installed Multotec equipment,” says Kruger.

He expects that employment numbers in the company are likely to rise over the coming year as business grows, and a full bursary is being provided for a local university student in the field of teaching education.


Multotec Process Equipment’s custom designed version of the innovative Conturbex screen worm centrifuge has allowed a customer to almost double its production of dewatered sodium sulphate, while improving plant availability.

Gerrit du Plessis, product specialist in solid liquid separation at Multotec Process Equipment, explains that this design of centrifuge has a number of benefits in this application.

“The centrifuge rotates at a high speed of over 2,000 rpm to ensure effective dewatering, while the product is moved forward across the screen by a scroll mechanism,” says Du Plessis. “This distributes the product evenly, which minimises the possibility of vibration due to uneven loads around the screen.”

He emphasises that vibrations can cause machine stresses if material gathers unevenly on the screen, potentially leading to mechanical failure and unplanned downtime.

“Another important feature is that the product has a relatively short residence time in the machine – only about two seconds – which allows it to absorb variations in feed rates,” he says. “This is significant because it can manage lower solids concentration streams, meaning fewer line blockages and lower energy consumption; this assists the continuity of the whole plant operation.”

Multotec worked closely with the customer to establish the operational and process parameters of the plant, to ensure that the Conturbex centrifuge machine would be fit for purpose.

“We also arranged for the customer to visit existing installations in the country where these units were operating in similar applications, as the screen worm unit is relatively new technology in this application,” says Du Plessis. “This allowed the customer to gain the necessary confidence in the technology by talking to companies where it was already employed.”

So successful was the outcome of the new installation that the customer ordered two more of these machines for their plant.

Du Plessis highlights a further advantage in the design of the screen worm centrifuge, being the formation of thin layers of the solids on the screen.

“As it travels from the small diameter to the large diameter, the layer of solid matter remains loose and is constantly becoming thinner due to the increasing surface area of the screen,” he says. “This allows further dewatering without requiring high G-forces that would need greater energy inputs.”

The demanding conditions in the crystalline streams of these process plants, where there are high temperatures along with extremely corrosive and abrasive conditions, requires that Multotec utilise specialised, abrasion resistant materials to ensure long operational life and durability.

“Our capability in high quality design and precision engineering is also vital, as centrifuge technology is based on high-speed rotating equipment and fine tolerances,” he says.

Gerrit du Plessis, product specialist : solid liquid separation at Multotec Process Equipment.


In its efforts to promote South Africa’s skills growth and continuous product improvement, the Multotec Group recently donated one of its SC20/7VC small diameter seven-turn spirals to the University of Pretoria (Tukkies). The spiral will support research and development as well as effective and experiential learning among students.

According to Wynand Roux, lecturer in the Department of Material Science and Metallurgical Engineering, proper research needs the involvement of industry players like Multotec. Significantly, the organisation has a long standing relationship with Tukkies that has included providing both funding and equipment donations.

“Ongoing interaction with equipment suppliers affords our students the opportunity to undertake projects aimed at providing innovative solutions and new technology for the mining and metallurgical sectors,” says Roux. “Having access to equipment like Multotec’s spiral certainly assists in bridging the gap between theory and practice, and allows students to better understand what this sort of equipment can achieve.”

Post graduate student Bernard Fundikwa, who is doing his Master’s degree in the department, says the equipment is used by both undergraduates – for practical work – as well as by post graduate students who are conducting research.

Rikus Immink, managing director of Multotec Process Equipment and himself a Tukkies graduate, says the donated spiral has a shallower angle and is equipped with a mouth organ product box and three sliding splitters.

“This particular spiral offers the ability to process a variety of minerals, coarse or fine and ranging from low density to high density ores, which could include mineral sands, heavy minerals and rare earth minerals,” says Immink. “The through angle is designed such that it falls between the high-grade spiral and fines spiral, and can be used for pre-concentration or for cleaning purposes.”

Attending the handover ceremony with Multotec group CEO Thomas Holtz, Immink reiterates that the company is proud to be associated with the University of Pretoria, and looks forward to future research projects that will be conducted using the spiral.

From left, Thomas Holtz, Multotec ceo, Professor Roelf Mostert, HOD of Material Science and Engineering, Rikus Immink, managing director of Multotec Process Equipment, Professor Sunil Maharaj, dean of Faculty of Engineering, Built Environment and Information Technology and Wynand Erasmus, general manager gravity concentration at Multotec Process Equipment.


Unreliable and time consuming methods of monitoring the condition of mill liners are now a thing of the past, as mines can now ensure higher efficiencies by tracking liner wear in real time.

With the introduction of MultoScan by Multotec Rubber, milling plants can accurately measure a mill’s liner profile and predict the point at which the mill will start becoming inefficient. The automatic measurement and display of the charge level confirms that the operation of the mill is correct.

According to Matthew Fitzsimons, technical manager at Multotec Rubber, wear rates of liners are not linear, as the increased slippage of the charge on worn liners tends to exponentially increase the wear rate.

Data generated by the MultoScan is analysed and interpreted by highly skilled technicians using Multotec’s Hawkeye proprietary programme, so there is no time lag, allowing plants much quicker responsiveness.

“When combined with critical mill operating parameters, this data can help predict the point where the liner becomes inefficient and hence when the mill itself will become inefficient,” says Fitzsimons. “Customers can receive immediate feedback on the condition of the liners, so any urgent issues can also be timeously addressed.”

The traditional way of monitoring liner wear was the time consuming and often inaccurate pin-gauge method. The MultoScan now provides an effective alternative, while also being much more affordable than the highly sophisticated but expensive monitoring technology in the market.

Repeatability of the MultoScan results means that there is hardly any room for human error in this system. It also saves mines significantly in terms of the time value of mill stoppages for taking manual wear readings.

Further savings can be harnessed by reducing the stockholding of liners that mines need to keep; this is due to better information on the liner profile, giving maintenance crews the ability to set the trigger point for the liner inventory as and when they need it.

Fitzsimons highlights the potential that MultoScan offers, as individual plants can map key performance indicators of their mills and link these to the liner profile condition, extending the capability of the monitoring system by allowing mines to select specific criteria.

Field trials have proven how well the system works in some of Africa’s most arduous milling conditions; more recently, the technology has even been exported to Australian customers.

He emphasises the commercial value that plants can leverage by optimising their mill performance through access to this pioneering technology, alongside Multotec’s market-leading technical expertise and support.

Data generated by the MultoScan is analysed and interpreted by highly skilled technicians.