Ball Mill Resurfacing
A valued client had a ball mill with severe corrosion on the internal shell that was so widespread and severe that wear linings could not be reinstalled.
IND was contracted to fill all corrosion and restore the substrate surface to within 0.5mm variation of the original design and provide a smooth surface for wear liners to be reinstalled onto.
During a seven-day shutdown, we completed pit filling of all significant washouts with Belzona 1111, 1812 and 1311 restoring the mill’s structural integrity and internal surface curvature.
Following our restoration, rubber liners were able to easily apply their lining over the smooth service and trunnion liners were then installed over the top of the rubber lining.
Corrosion Assessment
The mill was extremely pitted on the internal surface with some pitting going all the way through the shell and many other areas more than 10mm in depth.
Surface Preparation & Quality Assurance
The mill’s internal surface was thoroughly blasted to ISO 8502 Class 2.5 with a surface profile above 75μm. Quality assurance inspections were conducted to assess the presence of surface chloride contaminants, surface profile and environmental conditions, with all tests confirming the surface was ready for Belzona application.
Lost Substrate Repair
Once the surface was adequately prepared, a selection of Belzona repair composites was applied to the mill surface.
Belzona 1812 was applied to the most serious areas, particularly the washout in-between the main mill substrate and the removable ends.
Belzona 1111 was the primary metal filler utilised to fill the majority of pitting and to redesign the mill surface back into its original shape.
Belzona 1311 was used as a fine filler to bring remaining trouble areas back to the required profile.
This task used appoximately150kg of Belzona product in total.
Once all pitting was filled, our team sanded and profiled all excess coatings back and re-shaped the holes used to fasten the wear liners to the mill. The end result was a near new mill surface with no deviations or pitting beyond 0.5mm. We also conducted a final whip blast which achieved a surface profile over 75μm on the surface of the Belzona coating and substrate steel which allowed rubber lining to be applied.
