Tag Archives: Multotec Process Equipment

Multotec, Clean TeQ bring mine effluent treatment solution to Africa

Environmental, Mining services, Water management, , , , , ,

Multotec Process Equipment and Clean TeQ Water have combined to offer the Africa market a game changing reverse osmosis (RO) technology solution able to truly unlock the significant potential of resin chemistry for effective mine effluent treatment, Vincent Ridgard, Process Engineer at Multotec Process Equipment, says.

Treating effluent on mines often makes use of RO technology, Multotec says, but low recoveries can raise costs substantially. A continuous counter current ion exchange can provide a fit-for-purpose solution, according to Ridgard, who notes that RO was initially designed to remove monovalent salt molecules from sea water.

“However, wastewater on mines also includes divalent and trivalent elements, which cause scaling of membranes in RO systems,” he says. “This means that when a standalone RO plant is utilised to treat these waters, it is operated at lower recoveries to enhance the lifespan of the membranes.”

This results in large volumes of highly concentrated brine streams, he says, which are either recirculated within the system or require very expensive effluent treatment systems. To address these challenges, Multotec offers niche technologies suited to treat divalent and trivalent elements in water on mines.

“Through our close partnership with Clean TeQ Water, in Australia, we offer mines across Africa a continuous counter current ion exchange technology,” Ridgard says. “This uses resin, which is more selective to extracting larger molecules.”

As a result, these systems achieve high recoveries of over 90%, so process water can be re-used within the mine’s process circuits or discharged safely to the environment. The resin-based chemistry removes target species, selectively extracting contaminants through exchanging ionic functional groups engineered on the resin beads.

Ridgard notes that, while these scientific principles are well accepted, there has previously not been a suitable technology to truly unlock the significant potential of resin chemistry. Clean TeQ’s ‘moving bed’ solution – supplied to the Africa market by Multotec – is, therefore, a game changer.

In contrast to the conventional fixed-bed systems, the use of resin transfer mechanisms allows the continuous ionic filtration to handle up to 150 parts per million of solids, whereas conventional systems need a 100% clean liquor. Total suspended solids and total dissolved solids can, therefore, be simultaneously removed.

It also optimises the inventory of resin, a significant cost contributor to the overall plant, and provides high water recoveries. Other benefits include its low power consumption and ability to recover valuable trace metals as a by-product.

Multotec provides Guinea bauxite verification with sampling equipment

Base metals, Mine operation news, Mineral processing, Mining equipment, Mining services, , , , ,

Multotec Process Equipment’s high-precision sampling equipment has found a home in Guinea, with bauxite producers in the West African country using the South Africa-based company’s tools to verify the quality of mined material before it is shipped overseas.

The company has recently provided two tariff sampling plants to a major bauxite producer in the country, including what is possibly one of the largest hammer samplers in the world, it said.

One of the plants is located at the bauxite mining operation itself, while the other is at the export facility where the high-grade bauxite is loaded onto ships.

According to Willem Slabbert, Sampling and Magnetics Specialist at Multotec Process Equipment, the samplers serve a vital role in representatively measuring the quality of the material mined and then exported, as well as its physical characteristics.

“At the mine, the sampling plant gives the mining company and their third-party mining contractor a scientific basis on which to check compliance with their contractual requirements,” Slabbert says.

“Similarly, the plant at the export facility assures the end customer of the quality of bauxite they are purchasing.”

The solution designed for this specific application includes hammer samplers, double-roll crushers, rotating plate dividers, feeder conveyors and barcoded carousels to link the sampling plant’s hourly performance to the indexed samples produced, Multotec explained. There is also protection equipment – a moisture analyser, overbelt magnet and metal detector – and inter-sampling plant conveyors.

“The plants were designed as a holistic solution, to deliver measurements in line with the international standard ISO8685 – ensuring that both sides of a contractual agreement can feel confident in the results,” Slabbert says. “They are also fully automatic and PLC-controlled for maximum efficiency.”

He highlighted that the sampling and materials handling solution was based on extensive test work carried out at Multotec’s facilities in Spartan, near Johannesburg. Crusher tests were also conducted on the specific bauxite, which comprised a substrate material with very hard embedded nodules.

“We identified custom-designed, heavy-duty, double-roll crushers as the optimal solution to deal with the extreme hardness of the nodules in the material,” Slabbert says. “The abrasiveness and stickiness of the Guinean bauxite also required low-friction liners to be designed into each plant.”

Multotec also has a West Africa branch in Ghana to supporting its installations. This branch also sources local components for customers.

Multotec Process Equipment has experience in sampling bauxite in Guinea, says Slabbert, with a sampling plant installed two decades ago for another bauxite producer.

Multotec ready for the mineral processing test

Comminution of minerals, Equipment maintenance, Mineral exploration, Mineral processing, Mining equipment, Mining services, Water management, , , , , , , , , , , ,

Mineral processing specialist, Multotec used a recent media visit to talk up the testing facilities at the heart of its Technology Division.

The South Africa-based company can carry out a range of testwork with its specialised equipment in Spartan, Gauteng, according to Multotec Technology Manager, Faan Bornman.

“Much of our testwork comes from customers who are in the early stages of project development,” Bornman says.

“They need to understand more about how their minerals or material will separate under given conditions. Often there is not a mathematical model that can predict accurately what they can expect.”

Testwork can reduce project risk significantly, providing a solid foundation for the subsequent design and optimisation of process facilities, Multotec says, with Bornman noting that physical testwork is usually the best way of finding out how particles will behave in a process plant.

The equipment available to Multotec customers includes laboratory-scale wet high-intensity magnetic separators, cyclone rigs, filtration equipment, centrifuges, spiral rigs and a screening research rig. There is even capacity to test water purification methods on mine effluent.

“Extensive test work is especially relevant when a customer is wanting to mine and treat less traditional minerals like lithium or graphite,” Bornman says. “As demand grows for commodities like these, we have had customers bring samples to test how our equipment would perform. In these tests, we trial various methodologies and scientifically record and compare the results.”

The R&D laboratory prepares samples and conducts particle size analysis using equipment such as pressure filters, drying ovens, sieves, shakers, sizers and separating funnels. When chemical analysis is required, samples are sent to outside laboratories.

Bornman said his division also receives enquiries from existing customers when they face challenges: “We research the application of different methodologies to customer material, often leading to the development of a new product or improvements to our existing products,” he said.

“In addition to providing a solution for the customer, we are also able to contribute to the efficiency of the industry as a whole, with an updated and commercialised product.”

Screening

When it comes to tests on mineral screening, a test rig – located at Multotec’s Spartan headquarters – delivers two primary benefits, according to Chris Oldewage, Technology Manager at Multotec Manufacturing. First, it facilitates the in-house development process of screening media products. Second, it allows screening media to be tested against customer requirements to ensure the right solution is delivered.

“The ongoing research and development behind our screening media products give the industry opportunities to optimise efficiencies and recoveries,” Oldewage says. “However, changing anything on a plant brings risk of unexpected downtime. Our screening test rig can considerably reduce operational risks by proving any changes before they are implemented on site.”

In the controlled environment provided by the screening test rig, customers can view the actual performance of screening media products with material from their mining operations, Multotec says, with the company’s testing protocols generating the data necessary for detailed process analysis. This facilitates well-informed subsequent decisions, the company said.

The screening rig is made up of three test platforms: a vibrating screen, a sieve bend and a static drain screen platform. The vibrating screen can conduct classification tests, wet and dry dewatering tests, product development tests and plant screen simulations. The static drain screen and sieve bend screening test platforms are wet classification, drainage and dewatering tests.

Multotec Process Engineer, PJ Pieters, said accurate scaling of a customer’s on-mine process is vital for achieving representative and relevant test results.

“We gather a range of key data from customers on our test work questionnaire,” Pieters said. “This includes their material tonnages, volumes of water, screen sizes in operation and aperture sizes on panels among other information.”

This ensures sample sizes are representative and the tests accurately reflect what is taking place in the mine’s processes. Tests, meanwhile, are conducted in triplicate runs to ensure a sound scientific basis for the findings.

Oldewage said: “By removing the risk that mines face in trying new solutions, our testing capability smooths the way for valuable innovation to improve screening performance.”

The screening test facility at Multotec also includes a small Lucotec screen and a small wedgewire trommel screen, both for small-scale verification test work.

Cyclones

Multotec’s large scale cyclone rig, meanwhile, can test the performance of a range of cyclone sizes, up to 450 mm diameter. Tests related to classification, desliming and dewatering, as well as dense medium separation using density tracers, can be conducted.

Among the benefits to customers is the ability to test large volumes of samples, as the rig includes a 1,750 litre sump and a 6/4 pump, Multotec said. Flexibility is provided by a variable speed drive connected to the pump, to vary the flow rates as required by the cyclone size.

Dry samples usually need to be blended before testing, and wet samples may need to be dried before blending. The resulting samples from the test must also be scientifically prepared for particle size and chemical analysis. The precision at each stage is vital, as bulk samples as large as 200 kg may need to be reduced to as little as 100 g.

The rig’s infrastructure also includes two Multotec vezin samplers, which are compliant with the highest design standards to provide reliable samples, according to Multotec. “These help to minimise the common errors of manual sampling and ensure that the integrity of the sample is retained,” the company says.

In addition to using the test rig to analyses the customer’s process flowsheet – with Multotec engineers identifying where its range of classification and other products can add value – the company also uses the cyclone test rig for its own product development.

“This on-going process has resulted in a range of cyclones that are lighter, more cost effective, environmentally-friendly and energy efficient,” the company said. “They all contribute to helping customers lower their cost per tonne in a low footprint, sustainable plant operation.”

Spirals

Multotec says its spiral test rig has been adapted in response to the industry’s need to re-treat chrome dumps and upgrade ultra-fine chrome.

Again, located at the company’s headquarters in Spartan, the rig allows eight to 10 different spirals to be erected at a time.

Jeantelle Rust, R&D Engineer at Multotec Process Equipment, said: “With the drive to process tailings in the chrome sector, we have been running tests on a more compressed spiral with a reduced pitch. This reduces the velocity of the very fine particles.”

This configuration works particularly well when dealing with fine material, hence its application in tailings, Rust said. The spiral could offer a cost-efficient way of separating ultra-fine chrome material and recovering valuable product, according to the company.

Rust said: “Such a solution presents an attractive commercial proposition to industry and will also address environmental concerns presented by tailings dumps.”

Using a “mouth-organ product box”, the material being tested on the spiral rig is split into eight product fractions, not just the usual three for product, middlings and tailings. This helps optimise the mass balance for reporting purposes, according to the company.

The spiral test rig has also been used to evolve designs that deal with coarser material, Multotec said. “Customers were looking for a solution to the ‘beaching’ of coarse coal product on the spiral’s surface, for instance,” it explained.

Rust said: “We were able to modify the angles and diameter of the trough to address this challenge. Our ability to make small adjustments to the equipment, and to test material repeatedly at full scale, is the key to finding practical solutions.”

Multotec has also conducted research for producers of mineral sands where head grades were steadily dropping. This necessitated the treatment of larger tonnages, requiring higher capacity spirals.

“Space constraints on the customer’s site meant that adding spirals to their process was not an option,” Rust said.

“Wider spirals were thus tested for higher throughput, with different angles to minimise losses.”

 

Multotec on the front line of West Africa mineral sampling scene

Environmental, Mineral exploration, Mining services, , ,

Multotec Process Equipment says the growth and diversification of West Africa’s mining sector is making the precision of mineral sampling a “vital priority”.

For over two decades, Multotec has been active in the West Africa market, with its samplers at over 30 sites in countries including Ghana, Liberia, Burkina Faso, Guinea, Sierra Leone, Mali and Guinea-Bissau. A range of commodity sectors use the equipment for both slurry and dry sampling applications, among them gold, bauxite, iron ore and heavy minerals.

Multotec has also presented representative sampling training courses explaining the practical aspects of implementing the Theory of Sampling (TOS).

Willem Slabbert, Process Manager at Multotec Process Equipment, said: “In bulk minerals like bauxite – where our sampling plants have been in operation with a major West African producer for 17 years – the sampling protocol and ‘correctness’ of equipment design is key to ensuring bottom-line success.”

He highlighted the importance of reproducible and accurate sampling – cumulatively termed representative – at the interface between the mine and port, and on the ship-loading conveyor to the client.

The sampling, which must comply with ISO standards and best practice as prescribed by the TOS, confirms the mine is supplying product to the end-customer’s contractual specification. “Any imperfection in the sampling process can lead to unnecessary contractual disputes and potential financial losses for the mine or client,” Slabbert says.

Multotec supplies wet slurry samplers to several gold mines in West Africa, who rely on good gold accounting and reconciliation at their processing plants. The equipment is popular among large gold producers as well as the smaller entrants, according to the company.

“With a comprehensive range of Two-In-One, primary and ancillary samplers, we are able to tailor each installation to the customer’s specific application,” Slabbert says. “This means accommodating variables like throughput rates and slurry densities, including accounting for grade variability from various mine sources feeding a single processing plant, in many of the West African deposits.”

For brownfield projects, Multotec can design solutions to suit and fit the structural constraints of the customer’s existing infrastructure.

Local service support is available from Multotec’s Ghana branch as well as regional agents and service providers operating in other countries. This ensures a point of contact as first line of support and, drawing on its expertise across a range of disciplines, Multotec can put specialists, engineers, design draughtsmen and millwrights to work on projects throughout the West African territories.