Tag Archives: magnetic separation

Primero completes WHIMS project at Fortescue’s Christmas Creek iron ore op

Primero Group says it has completed the construction of a Wet High Intensity Magnetic Separation (WHIMS) processing plant at Fortescue Metals Group’s Christmas Creek iron ore mine in Western Australia.

The plant is expected to improve product grade and mass recovery from the desands unit at the Christmas Creek Ore Process Facility #2.

The flowsheet is based on a simple and robust configuration, where wet screen undersize at a nominal -1 mm is treated in open circuit through a low intensity magnetic stage, followed by a vertical WHIMS stage to produce a concentrate stream and a tailings stream, which can be integrated with the existing process and auxiliary equipment. The vertical WHIMS project entails the redirection of the wet screen undersize stream from the existing scrubbing circuit to feed the brownfield magnetic separation plant.

“We can proudly say that despite the impacts of COVID-19 and the fast-tracked nature of the project, the plant was successfully delivered and commissioned in less than 12 months – meeting all safety and project key performance indicators,” the company said.

Primero put the project’s success down partly to the “enhanced opportunity for collaboration early contractor involvement (ECI) provides”.

It added: “A flexible approach to project development that ensures the needs of all project stakeholders can be met prior to detailed design and implementation in a lump sum engineering procurement and construction (EPC) environment. This constructive, relationship-based contracting continued throughout construction, commissioning and now operation – demonstrating the power of the ECI contracting model when coupled with Primero’s unique, vertically integrated EPC capability.”

Steinert to bolster sorting system test capacity in Pulheim

Steinert is to introduce additional sorting lines for mining and waste recycling at its new test and development centre in Pulheim, Germany, the company says.

The new lines are being installed in an effort to better achieve the company’s aspiration of “test before you buy”, allowing it to “respond with ever more accuracy to the sorting aims of extraction, purity and profitability for each sorting task”, Steinert said.

Steinert’s sorting solutions are used throughout the mining industry as a way of pre-concentrating material ahead of milling.

The metal sorting line of the new test and development centre will official go into operation on September 22. This milestone will be marked with a virtual event held on that day.

By opening the new building, the company is trebling its testing capacity, allowing it to be more flexible in responding to customer demands, it said.

“The processing sequence deployed in the sorting systems is the same as that used in a real industrial plant,” Peter Funke, CEO of the Steinert Group, said. “We are delighted that even more customers can try out our technology, from magnetic separators to sensor-based sorting systems, such as X-ray transmission, X-ray fluorescence and near-infrared (NIR),”

The research and development team is also moving to the same building in Pulheim, seven kilometres away from STEINERT’s headquarters in Cologne, allowing customers to derive even more benefits from the latest developments, the company said.

Bunting ups the Electro Overband Magnet stakes for Agnico’s Kittilä gold mine

The largest Electro Overband Magnet ever built at the Bunting manufacturing plant in Redditch, England, is destined for installation at the Agnico Eagle-owned Kittilä gold mine, in northern Finland.

Over a 12-month operating period, the Overband Magnet will lift and separate damaging tramp metal from around 2.7 Mt of conveyed ore, protecting crushers, screens and other up-stream process plant, according to Bunting.

One of the world’s leading designers and manufacturers of magnetic separators for the recycling and waste industries, Bunting has European manufacturing facilities in Redditch, just outside Birmingham, and Berkhamsted, both in the UK.

The Electro Overband Magnet uses high-strength magnetic forces to lift and then automatically discard tramp ferrous metal present in conveyed ore, Bunting says.

“In operation, the large Electro Overband Magnet is suspended in a crossbelt orientation across the non-magnetic head pulley of a conveyor transporting mined ore,” the company explains. “Any tramp ferrous metal entering the deep and strong magnetic field is attracted to the face of the electromagnet and lifted up and onto the surface of a continuously-moving self-cleaning rubber belt.

“Reinforced and heavy-duty rubber wipers on the belt catch the captured metal, transferring it to the side and away from the conveyed ore. As the wipers move the ferrous metal out of the Overband Magnet’s magnetic field, it drops under gravity into a collection area.”

This latest Electro Overband Magnet is part of a major plant expansion and upgrade at Kittilä, Bunting said. This will see ore production go from 1.6 Mt/y to 2 Mt/y, with gold output expected to rise by 50,000 oz/y to 70,000 oz/y when completed.

When initially contacted, Bunting engineers worked closely with the mine operator to design a bespoke Overband Magnet for the difficult application, it said. Design considerations included the width of the conveyor, the volume of conveyed ore, and the size and shape of the tramp ferrous metal. With these details, the Bunting design team calculated the minimum magnetic field and force density for optimum separation using an in-house developed Electro Overband Magnet Selection program.

These criteria provided the basis for the design of the electromagnetic coil by the Bunting-Redditch engineering team.

The final design is a model 205 OCW50 Crossbelt Electro Overband Magnet, with the 17 kW electromagnetic coil, generating the strong magnetic field, cooled using recirculated oil. Efficient cooling of the electromagnet is critical as the magnetic force decreases proportionally to the rising temperature of the coil, Bunting said.

The Overband Magnet is 4.2 m long, 3 m wide and 2.2 m high, and weighs just over 13 t.

The Electro Overband Magnet is designed for positioning in a crossbelt orientation over the non-magnetic head pulley of a 1,600 mm wide conveyor, inclined at 12° and travelling at 0.75 m/s. The conveyed ore has a particle size range of between 70-400 mm, Bunting said, varying in conveyed capacity between 450-765 t/h (equating to 2.7 Mt/y).

“The tramp iron ranges widely in size and nature and includes steel rebar (2,400 x 20 mm diameter), cable bolts (600 x 15 mm diameter), steel mesh, and broken drill bits,” Bunting said. “With a maximum working gap of 600 mm (distance between the magnet face and the bottom of the ore conveyor), the Electro Overband Magnet is designed to lift and separate the tramp metal through a splayed burden of up to 500 mm. This requires a substantially deep and strong magnetic field and related force density.”

Adrian Coleman, General Manager of Bunting’s Redditch facility, said large mining projects, such as this, often require bespoke solutions.

“Over 40 years, we have gained considerable experience in designing and building large Electro Overband Magnets,” he said.

“However, this was the largest we have ever manufactured at Redditch, presenting many challenges, which were overcome. And the design and manufacturing process all took place during the COVID-19 crisis.”

Bunting ups the mineral separation ante with ElectroStatic Separator

Bunting has launched a new separation device that, it says, significantly broadens the company’s separation capabilities, opening new opportunities for optimising mineral reserves.

The development of the ElectroStatic Separator comes in response to enhanced material separation requirements in the recycling, plastics and minerals industries, Bunting said.

It uses tungsten electrode wire to generate electrostatic charges to separate dry liberated particles, exploiting the difference in electrical conductivity between various materials in a feed material to produce a separation.

“The separation depends on a number of key material characteristics including conductivity, moisture content and size range,” Bunting said. “In many applications, often due to the fine particle size, the ElectroStatic Separator is the only technology that enables a separation (eg -2 mm granulated cable scrap).”

The technology also replaces less environmentally friendly separation processes such as froth flotation in mineral processing applications (eg separation of rutile from silica sand), according to the company.

In operation, the technology uses the difference in conductivity between insulators (eg plastics) and conductors (eg copper and aluminium) to obtain a separation on an earthed roll. A vibratory feeder evenly feeds a material mix onto the top of a rotating earthed metal roll, with the rotating roll transferring the material under an electrode bar inducing an electrostatic charge. Non-conductive materials (ie insulators) adhere to the earthed roll via an image force, while the conductors lose their charge quickly and, under centrifugal force, are discharged, according to Bunting. This enables a separation.

ElectroStatic Separators provide material segregation in plants processing minerals, producing plastics, and recycling secondary metals, the company says, with differences in conductivity found in recycled materials and minerals sufficient to enable excellent levels of separation.

“Indeed, this includes the separation of metals with different conductivity,” the company said.

The mineral processing industry commonly uses ElectroStatic Separators in conjunction with high intensity magnetic separators such as Bunting’s own Rare Earth Roll Magnetic Separator and Induced Magnetic Roll Separator, it said. This combined separation process is used when processing beach sands, for example.

The new separator is available as a single or double staged system in feed widths of 500 mm, 1,000 mm and 1,500 mm to suit a specific application.

The Bunting Centre of Excellence in the UK includes a laboratory-scale model of the new ElectroStatic Separator, according to the company.

Bunting expands Permanent Overband Magnet range

Bunting has released a new model Permanent Overband Magnet that, it says, is specifically developed for use on mobile plant such as crushers and screens used in mining, quarrying and recycling.

The PMax model is a lighter and more compact design that meets specific requirements of reduced maintenance time and lighter weights, it said. It has been released alongside the Easibelt Permanent Overband Magnet for recycling and bulk handling terminal applications. These models come on top of the classic PCB model in the Overband range.

The design of the Overband Magnet is simple with two pulleys mounted on a frame either side of a permanent magnetic block, according to Bunting. It is positioned above a conveyor, either over the head pulley, or more commonly across the belt. In operation, conveyed material passes under the Overband where the strong magnetic field attracts, lifts and then automatically discards tramp ferrous metal.

The PMax is 15% lighter than the standard PCB model across the range and 12% shorter in length, according to Bunting. These reductions result in a 14% higher magnetic force to weight ratio. It operates at a maximum working height of 300 mm (above the conveyor) on belts with widths between 600 and 1,500 mm.

The reduction in weight and size is achieved through adopting new manufacturing processes, including investing in new production plant, the company said. The new design release was in response to customer requests across Europe, it added.

Adrian Coleman, the General Manager of Bunting-Redditch, said: “Our PCB model has been an industry-standard for several decades and remains the optimum design for many applications. However, the PMax is specifically designed as a lower weight option for mobile plant, whilst the Easibelt offers significantly reduced maintenance time.”

Eriez makes a case for DVMF tech in hard-rock lithium sector

Eriez says it’s high-intensity Dry Vibrating Magnetic Filter (DVMF) technology holds the key to removing very fine iron-bearing contaminants from hard-to-flow powders, such as lithium, to produce higher quality end-products.

In a recently published white paper, the separation technology leader says the DVMF technology has been validated as the most effective separation process for hard-rock mining lithium applications.

‘Hard Rock Mining: High-Intensity Dry Vibrating Magnetic Filter (DVMF) Removes Fine Iron-Bearing Contaminants Found in Lithium and Other Hard-To-Flow Powders’ was written by Eriez Mining and Minerals Processing Director, Jose Marin.

According to the paper, the DVMF is ideal for both lithium producers and users, with typical DVMF applications including fine sand, glassmaking, talc, clays and various other finely divided industrial minerals and chemical products.

The DVMF uses a high-intensity electromagnet and flux converging matrix, which amplifies the magnetic field and provides high-gradient collection sites for the magnetic material as the feed materials filter through, according to Eriez.

The canister is attached to dual high-frequency, low-amplitude vibratory drives and these drives deliver a strong vibratory action to the canister assembly, which enhances the fluidity of very fine powders, resulting in a smooth and even flow of product through the matrix grid.

On the DVMF’s hard-rock lithium separation credentials, Marin explained: “Eriez 5,000 gauss strength DVMFs reduce contamination to parts per billion, rather than parts per million. These results are a real breakthrough in terms of magnetic contaminant removal in hard-rock mining.”

To learn more about Eriez DVMFs and download this white paper, click here.

Vale exploring dry stacking/magnetic separation to eradicate tailings dams

Vale has confirmed a Reuters news report from last week stating that it would spend an additional BRL11 billion ($2.5 billion) on dry iron ore processing over the next five years.

The company said it has invested nearly BRL66 billion installing and expanding the use of dry processing, using natural moisture, in iron ore production in its operations in Brazil over the last 10 years and it would carry on this trend.

“By not using water in the process, no tailings are generated and, therefore, there is no need for dams,” the company said, added that about 60% of Vale’s production today is dry, and the goal is to reach 70% in the next five years.

Dry processing is used in the mines of Carajás, Serra Leste and the S11D Eliezer Batista Complex (pictured), in Pará, Brazil, and in several plants in Minas Gerais. In Pará, in the Northern System, about 80%, of the almost 200 Mt produced in 2018 was through dry processing. The main Carajás plant, Plant 1, is in the process of conversion to natural moisture: of the 17 plant processing lines, 11 are already dry and the remaining six wet lines will be converted by 2022.

Serra Leste’s treatment plants, in Curionópolis, and S11D, in Canaã dos Carajás, also do not use water in ore treatment, according to Vale. In S11D, for example, the use dry processing, using natural humidity, reduces water consumption by 93% when compared to conventional iron ore production.

In Minas Gerais, dry processing increased from 20%, in 2016, to 32%, in 2018. Today, this type of processing is present in several units, such as Brucutu, Alegria, Fábrica Nova, Fazendão, Abóboras, Mutuca, Pica and Fábrica. “Over the following years, the objective is to roll it out at other locations in Minas Gerais, such as the Apolo and Capanema projects, which are currently under environmental licensing,” the company said.

Vale said: “Dry processing is linked to the quality of the iron ore extracted from mining. In Carajás, as the iron content is already high (above 64% Fe), the ore is only crushed and sieved, so it can be classified by size (granulometry).

“In Minas Gerais, the average content is 40% iron, contained in rocks known as itabirites. To increase the content, the ore is concentrated by means of wet processing (with water). The tailings, composed basically of silica, are deposited with water in the dams. The high-grade ore resulting from the process can then be transformed into pellets at the pelletising plants, increasing the added value of the product.”

The mills that operate dry processing in Minas Gerais depend on the availability of ore with higher levels – about 60% Fe – still found in some mines in the state. “In order to achieve the necessary quality, and be incorporated into Vale’s product portfolio, it is necessary to blend with Carajás ores, carried out at Vale’s distribution centres in China and Malaysia. The process allows Vale to offer excellent quality ore which can be tailored to meet the needs of our clients,” the company said.

The blending of the product with natural moisture does not eliminate the need for humid concentration of the low-grade itabirite used in the production of pellets. However, to reduce the use of dams, Vale plans to invest approximately BRL 1.5 billion on dry stacking technology in Minas Gerais between 2020 and 2023. This technique filters and reuses waste water and allows the latter to be stored in piles, thus reducing the use of dams. The goal is to achieve up to 70% of the waste disposed in the coming years, but success depends on the improvement of technology and external issues, such as environmental licences, Vale said.

“Today, Vale doesn’t have a dry stacking operation that can deal with the production quantity especially in a region with high rainfall indices, such as the Ferriferous four-side, in Minas Gerais. The available dry stacking technology is used on a small scale around the world – up to 10,000 t/d of tailings produced – in desert regions or with low rainfall. In Minas Gerais, Vale’s tailings production quantity is, on average, 50,000 t/d per unit,” Vale said. In 2011, the company developed a pilot project on the Cianita stack in Vargem Grande, after an investment of BRL100 million.

The studies were completed in 2018 and the technicians evaluated the geotechnical behaviour of piles under rainy conditions. The next tests will be applied on an industrial scale at the Pico mine in the municipality of Itabirito, Vale said.

“Another solution that has been studied is the dry magnetic concentration of iron ore based on the innovative technology developed by New Steel, a company acquired by Vale at the end of 2018 for BRL1.9 billion,” Vale said. “The dry magnetic concentration eliminates the use of water in the concentration process of the low-grade ore, which disposes the waste generated in sterile piles, similar to what happens in dry stacking. This technology, however, is in the industrial development stage and is not yet ready to be applied on a large scale.”

Master Magnets Disc Magnetic Separator gets to work on Nigeria coltan project

Master Magnets has manufactured and despatched a Disc Magnetic Separator to Nigeria for use in the processing of coltan.

The magnetic separator is used in a process to extract primarily tantalum from coltan, which is a combination of columbite and tantalite.

For this new project, tests were undertaken in the Master Magnet test facility in Redditch, England. The tests confirmed the level of separation, capacity and the magnetic separator configuration.

Once completed, the samples were returned to the client in Nigeria for analysis. On receiving confirmation the separation matched their processing requirements, an order was placed.

The origins of the Disc Magnetic Separator date back to the early 1900s. Although manufacturing techniques have significantly changed and more advanced machines have been incorporated, the basic function design remains virtually the same. The separator is widely used to ensure an accurate separation of dry minerals that have varied magnetic susceptibilities.

Typically, a Disc Magnetic Separator features up to three high-intensity electromagnetic discs, each set at a different height from a feed conveyor:

  •  Disc one – this will be set the furthest from the feed material. The objective is to extract only the most magnetically susceptible particles;
  • Discs two and three – the second and third discs are set at lower gaps. This increases the magnetic force at each disc and enables the separation of different grades of magnetic material.

The magnetic intensity can be further adjusted by varying the current of each coil. This allows each disc separator to be designed and set-up for an individual mineral ore.

For this latest project, the test work recommended a model MDS3-375 Disc Magnetic Separator. This featured three high-intensity electromagnetic discs, (with six electromagnetic coils) each set at a different height from a 380 mm wide feed conveyor.

The tests had determined the MDS3-375 Disc Magnetic Separator could process between 500 kg/h and 600 kg/h.

Master Magnets says it is one of the world’s leading designers and manufacturers of magnetic separators for the mineral processing sector. The company’s manufacturing and test facilities are based in Redditch, UK.

Over several decades, it has developed an extensive portfolio of high intensity magnetic separator for purifying and concentrating minerals. Laboratory-sized versions of many of the designs are found in their Technical Test Facility.

Eriez looks to non-ferrous metal recovery growth with European expansion

Eriez Europe has opened a new 326 m² manufacturing facility dedicated to rotor manufacturing, light fabrication assembly and additional product line assembly, expanding the existing European manufacturing headquarters in Caerphilly, South Wales.

Complementing Eriez’ Eddy Current Separator (ECS) manufacturing sites in North America and Asia, the expansion of the South Wales facility adds a third rotor manufacturing site to the company’s global network, strengthening Eriez’ ability to provide consistent levels of customer service excellence worldwide, the company said.

Eriez Europe, which has been manufacturing separation technologies for the past 50 years, will manufacture and stock a range of global ECS rotors on-site, enabling customers to have quick access to process-critical spare rotors should they be required.

“The investment at Eriez Europe includes a high-speed balancing machine and a filament winding machine to facilitate the intricate manufacture of Eriez’ advanced range of ECSs, designed to recover non-ferrous metals from a wide variety of waste streams,” the company said.

The new facility will increase annual production capacity of ECS rotors by a third, promoting globalisation of the Eriez brand and ensuring the best possible service is provided for new and existing customers alike, Eriez said.