High altitude HPGRs – CITIC Heavy Industries reports on successful installation at Zijin’s Julong copper mine
In the traditional mineral processing circuit, the crushing of very hard rock pebbles – that are on the one hand too large to be crushed by mill balls and on the other by larger ore fragments in the SAG mill – is completed by a cone crusher, and the crushed material then needs to be sent back to the SAG mill.
However, this model has shortcomings: after being treated by the cone crusher, some larger particle sizes usually still remain and the problem is more prominent for ores with a lot of high-hardness material such as found in lenses and certain horizons. These hard-to-grind particles circulate and accumulate in the system, which not only reduces grinding efficiency and causes a lot of energy wastage, but also restricts the SAG mill production capacity. They can end up being sent back to the mill several times, which also causes creation of too many fines from the fresh ore material.
Luoyang-based CITIC Heavy Industries is one of the global OEMs supplying HPGRs as a solution to this problem – where the HPGR can be positioned after the SAG mill in place of a cone crushing bank or following the cones – to make sure the pebbles are ground sufficiently – and they achieve this thanks to greater power, wear resistance and compressive forces to ensure effective inter-particle comminution. One of its largest installations being at Zijin Mining’s huge Julong copper mine in China’s Tibetan plateau at 4,300 m altitude with the associated challenges on top of this – low atmospheric pressure and large temperature fluctuations.
CITIC says its GM200-180 HPGR was tailored for the project and supplied in 2023 since when it has achieved 24-hour continuous and stable operation through a series of adaptation and optimisation of the design, verifying the reliability and adaptability of the equipment under extreme working conditions. In this case the HPGR is positioned after the SAG mill and cone crusher.
The OEM says following installation, production capacity increased by 23%. “The actual production capacity of the crushing system before the project transformation was 130,000 t/d. After the addition of the HPGRs, the production capacity jumped to 160,000 t/d, exceeding the design target, effectively releasing the potential of the SAG mill, and helping the customer expand the production scale and improve the efficiency of the resource development.”
Comprehensive energy consumption was reduced by 14.5%. Through the in-depth application of the lamination and crushing principle of high-pressure grinding, the unit energy consumption of the system was reduced from 18.8 kWh/t to 16.08 kWh/t, of which the unit energy consumption of SAG milling was reduced by 25%, and the unit energy consumption of ball milling was reduced by 16.2%, significantly reducing customer production and operation costs and achieving greener and lower-carbon production.
The application of the HPGR also allowed enlargement of the size of the discharge of the front-end cone crushers, reducing the operating load of the crusher, and reducing the wear of the liner, greatly improving the service life.
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