Steel Grinding Mill

World’s First Trunnion-supported Stainless Steel Grinding Mill

Developments in process engineering are unveiling novel approaches to milling in raffinate circuits. Commodities like copper, phosphate, uranium and even gold have the potential to be processed in a way that introduces acid (or highly acidic process water) immediately into the mill feed as material enters the mill. The grinding mill, therefore the mill operates under extremely low pH conditions (pH = 1-2) and needs to be engineered to the most stringent measures.

New Concept Projects (NCP) have successfully designed, manufactured and commissioned the world’s first trunnion-supported, full stainless steel grinding mill to cope with this application designed by NCP engineers, is the latest iteration of grinding mill technology to be introduced into such a processing stream. The mill was designed to withstand the extreme, low pH conditions of the acid in a raffinate solution.

NCP worked intimately with the client to design and deliver a machine that fitted their exact demands. The end product is a work of bespoke engineering, and a world first. Many aspects of the ancillary equipment were also improved in order to provide robust and lengthened operating life.

Stringent material development and testing was undertaken to ensure that all materials, compounds and surface could withstand the low pH environment. Acid bath testing for materials all the way down to sealant and fastener compounds were conducted.

Key Features include

  • Duplex stainless steel mill shell and ends Stainless
  • Steel girth gear guard
  • Corrosion resistant paint specification for all ancillary equipment such as drive train
  • Specifically designed main trunnion bearings and stainless steel wetted area protection for low pH conditions
  • Fully fabricated, stainless steel feed chute
  • Rubber liners with corrosion resistant fasteners.
  • All sealants and rubber compounds acid bath tested for suitability.
  • NCP’s contract included for the design, manufacturing and supervision of the Mill’s installation and commissioning.