Tag Archives: thickeners

Ukraine iron ore miner cuts electricity consumption, process water use with DELKOR thickeners

As part of its modernisation drive, a mining and processing plant recently installed 3 x 62 m diameter DELKOR high-rate thickeners with a view to reducing electricity consumption by one and a half times for the pumping of tails, as well as rationalising the use of process water.

The project concerns the design, engineering and supply of three DELKOR 62 m high-rate thickeners for the dewatering of iron ore tailings as part of the processing plant’s modernised slurry thickening complex.

This modern complex, of which construction was completed in 2020, has now done away with outdated slurry pump stations, adopting, instead, the efficient process of thickening, hydraulic transport and storage of slurries.

Employing DELKOR’s latest generation feedwell design that comes with improved flocculation together with improved flocculant and slurry kinetics, these elevated thickeners boast large feedwells, which rank as some of the largest ever built, DELKOR says.

Ramesh Mahadevan, Regional Managing Director – DELKOR, had this to say upon successful commissioning of the thickeners: “This project is a very important reference for us in Ukraine. Given current global conditions, working with a new end user is a noteworthy achievement and one for which our entire DELKOR team must be commended.”

TAKRAF, the owner of DELKOR, meanwhile, says there has been strong demand for DELKOR technology in Latin America, noting a recent order for TAKRAF Peru for the supply of 2 x 38 m paste tailings thickeners with a capacity of 455-623 t/h.

The order, placed by a Peruvian entity processing tailings from a nearby iron ore mine, forms part of an expansion to develop a second plant. This will enable the entity to handle more tailings from the mine, according to TAKRAF.

Design requirements for the thickeners include accommodating the process demands for a paste application with a target of 65% +/- 3% solids content for the underflow. This required an equipment configuration that allowed it to operate under an expected yield stress of 200 Pa in the underflow material, the company noted.

FLSmidth high density thickeners optimise recoveries at DRC copper-cobalt mine

FLSmidth says it has delivered a thickener solution to help double production rates at one of the world’s largest copper and cobalt producers in the Democratic Republic of the Congo (DRC).

The order for the solution, which included six of FLSmidth’s high density thickeners, was placed in 2020, with delivery now completed.

The mine already had FLSmidth thickeners on site, with the company’s proposal for the mine’s expanded requirements  based on test work to confirm the characteristics of the material to be treated, according to FLSmidth General Manager Projects and Account Sales, Howard Areington.

“The tests confirmed that we could use a similar design to what we had installed on the mine some years previously,” he says. “This solution included six counter current decantation (CCD) thickeners and one pre-leach thickener, each measuring 31 m in diameter.”

These units deliver high solids underflow to optimise the recovery of dissolved metals, according to FLSmidth. In addition to the steeper floor slope, these thickeners were designed with a high torque ring gear drive design, with high tolerances that make for minimal maintenance over long periods of time, the company says.

“Our high density thickener design ensures consistently high underflow densities which allows the operator to sustain high production rates and better recoveries,” Areington says.

These CCD thickeners are manufactured from LDX2101 duplex stainless steel. This provides mechanical benefits without compromising chemical resistance, allowing the mass of each unit to be reduced, the company explained. The pre-leach thickener, which was not exposed to corrosive conditions, is constructed from carbon steel.

“We also designed and supplied five impurities removal thickeners, which are high rate thickeners, also in LDX2101 stainless steel,” Areington says. “The sizes of these units ranged from 20 to 30 m in diameter.”

Fabrication of the equipment was carried out in South Africa while accommodating the demands of the COVID-19 lockdown, which required careful planning and flexibility. With components and platework delivered to site, the welding and construction was conducted by the mine with installation assistance from FLSmidth and its agent in the region.

FLSmidth’s global thickener collaboration hits the right notes in Africa

The use of FLSmidth thickeners in African mining operations has continued to grow, supported by, the company says, global collaboration across the FLSmidth organisation’s offices in South Africa, China and the USA.

According to Alistair McKay, FLSmidth’s Vice President for Mining in Sub-Saharan Africa and the Middle East, the company is set to deliver six substantial thickener contracts to mines in Mozambique and the Democratic Republic of the Congo in 2020. McKay highlights that Chinese companies have been driving much of the growth in the continent’s mining sector.

“In our work in Africa with Chinese customers, we have found that our Beijing office plays a valuable role in ensuring streamlined communication and efficiency,” he says. “This allows a constructive combination of our local knowledge with the ability of our Chinese colleagues to facilitate relationships with our customers in China.”

This differentiator has enhanced FLSmidth’s acknowledged leadership in thickener technology in the region. The company will deliver 25 new thickeners, including high rate, high density and counter-current decantation thickeners, in southern and central Africa this year.

“The design work for these contracts was conducted by FLSmidth’s centre of excellence in the USA,” McKay says. “Given our established local infrastructure and experience in this product range, the thickeners were cost-effectively manufactured in South Africa and China.”

While the fabrication and platework was completed using local skills, the FLSmidth on-site technical support presence to construct and commission the thickeners at Chinese-owned mines in the DRC will integrate staff from the Beijing office.

“This improved communication between FLSmidth and the customer has negated the risk of any misalignment that could slow the process down,” McKay says. “In fact, our Beijing office has become increasingly involved in the full delivery process, fulfilling the role of the project manager. This is significant as the building of relationships across east-west contracts becomes increasingly important.”

FLSmidth offers full-service capabilities in thickener technology, McKay says, starting with bench or pilot scale test work to characterise customers’ material. This informs the customer’s flowsheet and equipment selection and sizing, and the right technology application for cost-effective, optimised operation, the company says.

Outotec to deliver sustainable plant improvements at First Majestic Silver assets

Outotec has been awarded a contract by First Majestic Silver for the delivery of minerals processing technology for its mill optimisation projects at the San Dimas silver-gold mine and Santa Elena silver-gold mine, in Mexico.

The circa-€15 million ($16.3 million) order has been booked in Outotec’s 2020 March quarter order intake.

Outotec’s scope covers the design and delivery of an AG mill, counter current decantation thickener and a tailings filter for San Dimas, and thickeners and a tailings filter for Santa Elena. The deliveries are expected to take place in 2020 and 2021, it said.

Outotec previously delivered HIGmill® high-intensity grinding mills to First Majestic, with one of these going to the Santa Elena operation (pictured), where it has significantly improved the recovery of silver and gold.

Paul Sohlberg, Head of Outotec’s Minerals Processing business, said: “The energy efficient AG mill and environmentally sound thickeners and tailings filters will enable First Majestic to improve plant operations in a sustainable way.”

Back in January, First Majestic President & CEO, Keith Neumeyer, said the company’s 2020 focus remained on “adopting new innovation projects to modernise our processing plants to achieve higher recoveries, improve efficiencies and reduce operating costs”.

He added: “We have witnessed significant benefits from high-intensity grinding at our Santa Elena operation in 2019 and we plan to install the same technology at San Dimas in 2020.”

The company, at that point, said it expected to increase production at San Dimas by restarting mining operations at the past-producing Tayoltita mine by the end of the March quarter, expecting to ramp up production to 300 t/d by the end of 2020. The Tayoltita mine was the original mining area at San Dimas and known to contain higher silver grades.

It said a new 3,000 t/d HIGmill circuit and AG grinding mill would be installed in the second half of 2020 to further improve recoveries and reduce operating costs.

At Santa Elena, meanwhile, it said it planned to install an AG/SAG grinding mill by the end of the year, with a dual-circuit flowsheet implemented to separate the ultra-fine and coarse particles prior to leaching to further improve metallurgical recoveries and reduce energy costs.

Tenova DELKOR shows off sedimentation specialism at Morocco silver project

Tenova DELKOR says it has successfully supplied and carried out mechanical completion of seven DELKOR thickeners, together with its flocculation system and a DELKOR Pinned Bed Clarifier (PBC) for a silver leaching plant project in Morocco.

The thickeners are to be employed in the counter current decantation circuit of the plant, with the project including the design, fabrication and supply of thickeners, flocculation plant and PBC, supervision of installation and performance guarantee.

The PBC is a unique process for hydrometallurgical plants where solution clarity is important, according to the company. “A technology for polishing feed solutions for solvent-extraction plants, the unit offers low suspended solids counts in overflows, regularly achieving clarities of less than 50 ppm solids, and as low as 20 ppm.”

Benefits of the PBC technology, according to Tenova DELKOR, include low capital expenditure for comparative clarifying technology; no moving parts, virtually eliminating the need for maintenance; robust and stable performance; it is optimised to minimise flocculant consumption, and; a small footprint.

Ramesh Mahadevan, DELKOR India Managing Director, said: “As the industry specialist in sedimentation, DELKOR offers a range of thickeners and clarifiers catering to various applications across the minerals, chemical, industrial and water management industries with designs of up to 100 m in diameter.

“Successful hand over of this important project only serves to strengthen our capabilities in the North African region and is a true testament that.”