Bridging Fundamental Science With Real-World Applications

How The Process Works

Paktunc D, Coumans JP, Carter D, Zagrtdenov N, Duguay D. (2024) Mechanism of the Direct Reduction of Chromite Process as a Clean Ferrochrome Technology. American Chemical Society, Engineering Au, 4, 125-138.

Step 1 - Pelletization & activation

Step 2 - Controlled carbothermic reduction in rotary hearth

• Incongruent dissolution of chromite in molten salt

• Transport of Fe and Cr species and reduction on carbon particles

• Shrinking cores of chromite and carbon particles

• Alloy formation

• Residual refractory spinel and ferrochrome alloy particles as final products

• Each pellet behaving as mini reactors

Step 3 - Recovery of alloy particles by conventional mineral processing

Step 4 - Cleaning & refining alloy/slag particles

• Alloy particles are readily separated and recovered from the furnace products through conventional classification and gravity separation techniques

• Addition of a cleaner circuit such as MGS, LIMS and/or Falcon will enhance the grade-recovery figures.

Red: alloy Green: spinel Yellow: forsterite

DRC product as seen under an SEM-based Mineral liberation analyzer

see technical paper for the details

Pilot Validation

• Large-scale demonstration tests were carried out at federal research facility in Canada.

• 1-1.5 kg charges making 2 to 4 pellet high stacks to assess heat transfer limitations and to determine optimum pellet bed height in furnace.

• Multi-layer pellet reduction success.

• Results confirm consistent alloy formation and chromite conversion in stacked pellet beds of up to four layers.

• High metallization achieved in 4‐pellet‐stack test.

• Recovery figures reaching 90% for alloy grades of ~95% for rougher concentrates.

• The process has reached TRL-7.

Photos of reduced pellets from 4 pellet-high stack

top layer

bottom layer