Pilot Crushtec International is launching the Metso HRC™ 8 high pressure grinding roll (HPGR) in southern Africa. While manufactured sand is the primary target market, the HRC™ 8 will also find application in mining, particularly in pre-milling applications to help increase mill efficiency and capacity.
In response to the growing demand for process flexibility, energy efficiency, increased throughput and reduced operating costs in mining, Metso’s HRCTM 8, now available locally from Pilot Crushtec, ushers in a new era in applications where a high degree of size reduction is principal. The machine is ideally suited for several ore types, including chrome, lithium, copper and gold, amongst others.
Part of Metso’s proven HRC family, which is known for its efficiency and energy-saving capabilities in comminution processes, the HRCTM 8 uses a method of inter-particle comminution by in a bed of material between two rotating rollers. The rollers, one of which is in a fixed position and another one floating, generate an extremely high pressure, extruding the feed material down to the desired smaller grain sizes.
Typical applications
In the mining sector, the HRCTM 8 can be deployed as a pre-grinder to help improve mill efficiency, explains Oldemar Meneses, Product Manager, HRC Technology at Metso. “To get the best out of their circuits, mines want to feed their mills with as fine material as possible to increase mill efficiency in terms of both reduction and power ratios, and that is exactly what can be achieved by using the HRCTM 8,” says Meneses.
Francios Marais, Sales and Marketing Director at Pilot Crushtec, says pre-milling is generally a daunting task with conventional solutions such as impact crushers. This is usually the case in abrasive applications where producing fine material has proven to be costly due to the subsequent high wear costs associated with traditional solutions such as impact and cone crushers.
“When it comes to mining, chrome will be a perfect application for the HRCTM 8. In this application, pre-milling – the need to take material down to a minus 5 mm size – has traditionally been done with impactors. While the capital cost of going the impactor route seems favourable, this is outweighed by the exorbitantly high wear costs, especially when dealing with highly abrasive ores,” says Marais.
“We therefore also see a big opportunity for the HRCTM 8 in lithium, a highly abrasive ore, where it will be more effective than traditional cone crushers. With its robustness and longevity of wear components, the HRCTM 8 will significantly reduce the cost of producing a minus 5 mm product,” says Marais.
Key features and benefits
One of the major characteristics of the HRCTM 8 is its versatility. It delivers great performance across applications including mining, industrial minerals, manufactured sand and recycling. The machine offers easy and versatile adjustable product gradation. The production gradation does not depend much on the adjusted space between the rolls, but on the choke feed condition and the constant pressure. Pressure can be adjusted to regulate the product gradation curve. This feature allows the customer to meet any product gradation specification requirements for the desired fine size material.
To remain profitable in the face of declining ore grades, mines are increasingly looking for efficient comminution technology. By using a combination of high pressure and a unique patented roller design, the HRCTM 8 is highly efficient in terms of energy consumption and throughput. The inter-particle crushing concept produces considerably more fines than conventional crushing.
As a result, the required product size is met in one pass, eliminating the need to recirculate the load, thus driving plant efficiency. Based on statistics from Metso’s global installed base of more than 130 machines, the HRC™ 8 provides energy savings of up to 50% compared with conventional crushing solutions.
“The HRCTM 8 provides an optimal crushing force with the use of adjustable hydraulic cylinders and variable speed,” explains Meneses. “One can adjust the speed and pressure of the machine depending on the material conditions and application requirements. Pressure influences the reduction ratio, while speed influences the throughput.”
The HRCTM 8 features Metso’s patented Arch-frame, which eliminates the need for a spring-loaded frame. This design differentiates it from traditional HPGR equipment with its anti-skewing features that eliminate variation in product gradation and prevents bearings from being damaged due to misalignment. The unique design also ensures even pressure distribution across the width of the rolls, resulting in optimal performance and longer wear life.
“By reducing energy consumption and increasing wear life of components, the HRCTM 8 helps lower operational costs,” says Meneses. “Existing customers are particularly happy with the minimal need for maintenance. The robust components and high-pressure rock-on-rock crushing enables long wear life of the manganese. In fact, the requirement for maintenance is low compared with impactors; the machine runs at a very low speed, a maximum of 32 rpm, thus significantly reducing wear on the rollers. Depending on application, some customers are only replacing their manganese once in a year or even after two years.”
Designed for high reduction in a single pass with minimal ultra fines in the final product, the HRC™ 8 is suitable for mining operations. “With a maximum feed size of 32 mm, the machine is rated at 60 to 90 tonnes per hour (tph), depending on feed size,” explains Marais.
“We have brought the first unit into South Africa. We will offer a complete static module on a skid frame with handrails and walkways. Also available from us is a mobile version, which is completely tracked. While Metso has a wheeled option, we will offer the first tracked HRCtm 8 in the world, which will also be beneficial for demo purposes because it allows for easy movement of the machine on and between sites,” concludes Marais.
