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HPGR to Increase Plant Capacity (12 replies)
Although I do not have direct experience on operation of HPGR, but I feel throughput can be increased based even in three stages depending on mineralogical characteristics and suitable process design.
I don't have that specific experience, but you might use simulation software to predict the performance of such a system. I've used simulation for such studies with the IDEAS software.
It is important that one does not look at the HPGR in isolation, but at all the materials handling and ancillaries associated with HPGR operation to make a balanced decision. Often reliability issues with ancillaries and energy use in materials handling can negate many of the positives of HPGR's if the complete systems engineering is not properly done and optimized.
We have real data for exactly this scenario; we operate three plants on essentially the same ore body - a very hard ore and one primary crusher product feeds two of the plants - one has 4 stage including HPGR closed with dry screening and the other three stage contract crushing - thus can compare a) three stage crushing of ROM ore and b) three stage crushing/HPGR. The effect on milling is profound with the HPGR product having a P80 of 40% increase in sustainable throughput rate - i.e. tph to the primary ball mill.
The plants are at the Mogalakwena operation of Anglo Platinum in Limpopo province S Africa. the main Concentrator plant primary gyratory accepts feed from an open pit operation - the product from that crusher is fed to the main plant with capacity of 7.5 mtpy and a contract crusher /transporting by road, 100 km to a smaller leased plant; being used for both production and for technical investigations, with capacity of 700 ktpy. The ore, Plat reef, is a very hard, pyroxenite, PGM ore body with grade typically 3-4 gpt PGM, associated with copper, nickel and iron sulphides. More details can be found on our website - i.e. Anglo Platinum
For achieving liberation of very hard banded hematite quartzite ore similar to taconites to P80 < 5mm, HPGR besides 3 stages of crushing was recommended on testing by the manufactures of HPGR. The overall grinding energy was naturally more but the hematite separation is much better.
But, can we operate HPGR circuit dry without causing environment problems (dust pollution)?
Slight description about ore or minerals can help to give a predictive view.
Gents the Freeport Grasberg concentrator has also run quaternary crushing with HPGR in the 4th stage on one of their lines for some years now. 4 stage crushing will have ball mill F80 benefits that should increase throughout, in addition to the higher fines content of a HPGR product for a similar F80 compared to 3 stage cone crushing. Comparison of before and after Bond work index values must also consider any artificial impacts of higher fines content in the HPGR product vs. a lab crushed baseline. If this is not accounted for in design you might overstate the throughput gains by double dipping.
Thank you for links presented. Very useful.
I'm currently involved in similar reengineering project in Mongolia.
Hope to present the results soon.
Mineral processing plant throughput boost by additional HPGR circuit installation as a 4th stage after conventional 3 stage crushing?Does any one have a real experience in application such a decision? There are a lot of benefits for a downstream process discussed in literature, but nothing about possible upstream problems.