Tag Archives: filter presses

Jord International addresses pressing issues for BMA Caval Ridge

Jord International has recently taken up a challenge from BHP to come up with a safer solution to filter press maintenance at the Caval Ridge metallurgical coal mine, in Queensland, Australia, as part of the New South Wales-based company’s expanding remit to unlock new technologies for the wider mining industry.

The plant and systems designer, developer and service provider was awarded the project, part of BHP’s Supplier Innovation Program challenge, earlier this year. It has seen Jord design and construct the first concept prototype in tandem with the maintenance team at the mine.

The prototype comprised a belt cartridge installer within a self-contained steel frame that holds a new belt and removes the old, damaged belt. The first commercial belt installer is expected to be in use by July, according to BMA.

Craig Samuel, Jord’s Mechanical Engineer for Aftermarket and Reliability, said the filters the company worked with at BMA Caval Ridge are 3 m wide x 5 m long, with the product path through the filter around 14 m long. While the solution was designed for Caval Ridge specifically, he said it could have applications on any site or with any commodity using filter presses.

“The idea came from the understanding of how the filter belts are installed, and a cartridge-style installer just made sense considering Caval Ridge has a readily available crane to move the cartridge around,” Samuel told IM. “The mechanics of the installer required some out-of-the-box ideas to develop a continuously variable speed ratio between the new belt roll and the old belt roll.”

Samuel said he expected the belt change time to be cut in half with this new solution.

Jord has already applied for another BHP Supplier Innovation Program challenge that could leverage a dust management and cleaning innovation, but the company has also been investing in research and development to commercialise new minerals beneficiation technologies for more efficient and effective liberation of ore, according to Kevin Barber, Jord’s General Manager of Resources.

“Our goal is to unlock new technologies that provide step-change improvements to current processes in the industry,” he said of these new technologies. “It’s about using less energy, using less water and removing some of the environmental challenges with particular focus on tailings. We’re finding alternative ways of dealing with problematic ores and resources.”

Tenova TAKRAF proves dry stack tailings credentials at Uzbekistan gold mine

Tenova TAKRAF says it recently installed three DELKOR overhead filter presses at a gold mine’s processing plant in Uzbekistan as part of its wider tailings dewatering system.

The system comprises three DELKOR overhead filter presses each processing around 120 m3/h of gold tailings. Each machine contains 177 mixed membrane filter plates with a size of 2 m x 2 m, and includes a high-pressure cloth washing system.

These filter presses form an important part of Tenova TAKRAF’s complete Dry Stack Tailings (DST) technologies solution, which covers processes from sedimentation to filtration and material handling, the company said.

The supply also included several pieces of ancillary equipment, including belt conveyors for cakes discharged from the filter press (each machine is equipped with a cake breaker), pumping skids for membrane inflation, filter cake washing pumps and high-pressure cloth washing pumps.

“The entire scope of supply, including the slurry feed pumps, is fully controlled and managed by state-of-the-art software,” the company said.

It added: “The complexity of the dewatering process required by this project clearly highlights DELKOR’s filter press potential across the dewatering spectrum. In fact, the filter press cycle includes filter cake squeezing, filter cake washing and filter cake air blowing, with the filter cakes washed with process water in order to remove unwanted residual cyanides from the dewatered cakes.

“Importantly, the required residual moisture content within the dewatered cakes was achieved immediately during start-up.”

Marco Zeni, Tenova DELKOR Project Manager, said: “Notwithstanding demanding site conditions, installation and commissioning, together with the required operational training, was successfully completed. With this project, we take another important step towards firmly establishing DELKOR also as a provider of filter presses to round up the filtration product portfolio and once again demonstrating that: it pays to talk to a specialist.”

Weir Minerals Africa optimising pump performance for filter presses

With mining companies focused on reducing and recycling as much water as possible while recovering valuable minerals and metals, filter presses are becoming a much more common sight in the concentration process.

Weir Minerals Africa says these “mission-critical” filter presses demand a carefully selected pump to ensure optimal performance and uptime.

Marnus Koorts, Product Manager for Slurry Pumps at Weir Minerals Africa, says the high pressures associated with operating a filter press often lead the pump to underperform.

“The operation of a filter press involves a wide spectrum of pressure and flow conditions within each cycle,” Koorts says. “This ranges from high-flow, low-pressure conditions when slurry is initially being pumped into the press, to low-flow and high pressure when full.”

He emphasises it is not enough to simply specify a pump for the average of this range of conditions. Rather, it is vital to establish the minimum and maximum values on the spectrum, and to specify accordingly.

“Filter presses in the market can demand pressures of up to 45 bar,” he says. “In many cases, therefore, the application requires high-pressure pumps such as the Warman AHPP high pressure range.” These pumps offer multi-stage high pressure operation to 1,000 psi and are used in slurry transportation and tailings management operations.

Koorts continued: “Where lower pressure requirements are present, the newer technology of the Warman WBH could be used as it is generally a more efficient pump with longer wear life of spare parts.” The Warman WBH pumps, also used in slurry transportation and tailings management applications, come with a wide variety of impellers and shaft seals and maintains efficiency through ‘one point adjustment’ during the wear cycle, according to Weir.

Failure of pumps to deliver enough pressure to a filter press results in the solid-liquid separation process being inefficient, according to Weir, with the selection of the right pump an important starting point in ensuring optimal operation.

The next key aspect of the customer’s selection, Koorts says, is the choice of sealing arrangement. This aspect of the pump can often lead to issues in the plant, when valuable product is lost through leakage.

“An expeller seal is not usually recommended, as the pressure it generates to seal the pump is generally not sufficient in a filter press application,” he said.

Weir said: “The stuffing box option can be used under certain conditions. However, the pressure of the surface water needs to be higher than the pressure inside the pump. This means that it would usually be suitable on a low-pressure pump for a low-pressure filter press.”

Koorts added: “When the filter press requires a higher pressure, then the plant will have to provide a water line with a higher pressure to feed the gland, or it will not seal properly.”

The preferred sealing option is a mechanical seal for these applications. While this is more costly, it offers substantial savings by preventing product being lost and downtime being incurred, according to Weir.

A further consideration is the level of corrosive aspects of trace elements in the slurry. This can lead to rapid corrosion of mild steel pumps. This is why many applications require stainless steel options.

Comprehensive technical backup needs to underpin each step in this process, Koorts said. For Weir Minerals Africa, this begins with its local manufacturing process, which includes foundries for casting components, through to local componentry manufacture and assembly capability.

“This quality control and capacity feeds into our spares availability and service exchanges for refurbished pumps,” he says. “The result is quick supply through our strategically located branch network with 12 offices in South Africa and eight through the rest of Africa.”