• To participate in the 911Metallurgist Forums, be sure to JOINLOGIN
  • Use Add New Topic to ask a New Question/Discussion about Grinding.
  • OR Select a Topic that Interests you.
  • Use Add Reply = to Reply/Participate in a Topic/Discussion (most frequent).
    Using Add Reply allows you to Attach Images or PDF files and provide a more complete input.
  • Use Add Comment = to comment on someone else’s Reply in an already active Topic/Discussion.

Dry Grinding Hard Ore (2 replies)

Bill Rico
10 months ago
Bill Rico 10 months ago

Looking at dry grinding material of extreme hardness holding a BWi of 27kWh/t from an F80 of 6-8mm to a P80 of 16um in an air-swept compartmented ball mill. There are operating plants doing this to 75um, is 16um too fine? Only considering milling technologies due to project requirements. Any experiences would be appreciated.

Marshal Meru
10 months ago
Marshal Meru 10 months ago

My last project (Roche Bay Magnetite Project, Nunavut, Canada is characterized by required grinding size (liberation size) P80 of -0.025 mm, but your ore hardness is higher the RB ore. The use of the BM, from your F80, 6-8 mm to P80, 0,016 mm, requires a high power consumption. You know that. If the base case is a new plant, you can think to the Metso VMs or ISA Mills, depending on your production capacity. If you can ensure F80 6 mm, you can successfully use the VMs. Please note, you can reduce the power consumption of 35%...45% in comparison with BM. I have developed the laboratory and pilot tests with METSO on its Pennsylvania Grinding facility and the results are excellent. In addition, the VM CAPEX and OPEX are significantly lower than BM CAPEX and OPEX. The range of the VM production capacities is very large, the VM300 can meet the requirements of the large production capacities. I can facilitate the contact with Metso Grinding Dept., US, PA. FYI, recently, Metso developed a new concept of VM Liners, that considerably reduces the OPEX (maintenance costs). If you expect to improve an existing BM circuit, the task of your BM is difficult (from 6-8 mm to 0,016 mm. You are obliged to add a grinding phase, characterized by low power consumption, before the BM, in order to have a BM feed of 1-1.4 mm, but be carefully with the screening plant efficiency. I do not know if your process is dry or wet. Good Luck!

Zander Barcalow
10 months ago
Zander Barcalow 10 months ago

If you expect to keep the dry process, as mentioned, the BM F80 is «coarse» under incidence of the required P80, and you are obliged to help the BMs. You can think to the HPRG equipment or study the dry fine grinding equipment supplied by ThyssenKrupp Polysius, Germany. Another aspect: Did you think to the final electrostatic separation? You can recuperate the fine particles. Look to the SNIM Flowsheet, Mauritania, and magnetite ore. I worked on it.

Please join and login to participate and leave a comment.