COMMINUTION
the past . She went onto join Gebr . Pfeiffer as a Director of Process Technology more than a decade ago before moving into her current role in November .
On the need for a mining-focused VRM offering , Woywadt said : “ We do have proven duty series for all the other applications like cement industry , lime , gypsum and industrial minerals ; a new MVR duty series has been created for iron ore and non-iron ore applications by adapting the existing proven technology .”
Three different grinding modes can be realised with the MVR Mining series . “ Straight Grinding ” results in one product at a specific grind size , “ De-Dusting ” and “ Selective Grinding ” are realised with a grit extraction system that removes the classifier coarse particles from the process . With these modes , two different products in one process step are available .
Dülfer said a ready-to-integrate plant engineering , including maintenance , concept is available . Experience with very hard and abrasive material from applications with , for example , blast furnace slag and feldspar is being further developed with a focus on even better wear protection and machine availability . “ Attention to the difference of the mining industry compared to the cement industry is key for us ,” he said .
It ' s fair to say the concepts and technologies that Gebr . Pfeiffer proposed some 18-24 months ago have been further developed to address the challenges of the mining environment .
Woywadt said as much when reflecting on a Procemin-Geomet presentation she participated in . At this event , in Santiago , Chile , in August 2024 , Woywadt and her colleague André Cruz showcased how VRMs consume significantly less energy than a tumbling mill circuit , potentially offer improved flotation performance at coarser grinds , produce less fines material , as well as offer a narrower PSD than traditional grinding .
“ We found the recovery was much better using our VRM than that of the traditional AG and pebble mill ,” Woywadt said . “ We were also able to achieve this increased recovery at coarser grinding than the lab-scale rod mill used for testing in direct comparison .”
The example given in Chile last year was from a low-grade porphyry copper ore deposit in Europe , but Woywadt said the company has carried out a series of pilot-scale testing at the company ’ s plant in Germany focused on iron ore with customers during the last few months .
“ We differ in our testing approach in terms of test scope and test quantity ,” Woywadt says . “ Conventional grindability tests require 20-50 kg of material , whereas we carry out extensive and relevant tests with one tonne and sometimes significantly more material . SOPs for iron ore and non-iron ore are in place . The information value of the test includes not only grindability but also specifics about wear and process behaviour .”
Furthermore , grinding tests with iron ore production for DRI in a fluidised bed have been conducted . Preconditions for the material to be handled in the fluidised bed are a maximum feed size of 1-2 mm whereas the fines shall be limited to 10-20 % passing 45 μm . The test series were conducted in the “ De-Dusting ” grinding mode with extraction of the classifier ’ s coarse material from the mill system . The classifier coarse material PSD showed 98 % passing 1 mm and 18 % passing 45 micron , matching the requirements given by the customer , the company says . The yield or recovery of classifier coarse material was 85 % of the feed to the MVR mill . “ These are very promising results despite the already fine feed material that was made available to us ,” Woywadt said .
As a provider of ore grinding solutions , Gebr . Pfeiffer is also interacting with the mining community in combination with NextOre , a magnetic resonance-focused ore sorting and preconcentration technology company .
Back in November 2023 , the two companies announced a strategic partnership to combine Pfeiffer ’ s MVR dry grinding technology with NextOre ' s magnetic resonance sensors and realtime bulk ore sorting . By discharging the reject material , the grinding and separation process handles a lower gross volume of material .
Dülfer says flowsheet integration of MVRs and MR sensor-based solutions have been worked