BALL MILLED BAUXITE RESIDUE AS A REINFORCING FILLER IN PHOSPHATE- BASED INTUMESCENT SYSTEM

• Adiat I. Arogundade

  English

  Author

• Puteri S

  English

  Author

Bauxite residue (BR) is an alumina refinery waste with a global disposal problem. Of the 120 MT
generated annually, only 3 MT is disposed via utilization. One of the significant challenges to sustainable
utilization has been found to be the cost of processing. In this work, using ball milling, we achieved material
modification of bauxite residue. Spectrometric imaging with FESEM showed the transformation from an
aggregate structure to nano, platy particulates, leading to particle size homogeneity. BET analysis showed
surface area was increased by 23%, while pH was reduced from
10.8 to 9.1 due to collapsing of the hydroxyl surface by the fracturing action of the ball mill. Incorporation of
this into a phosphate-based fire retardant, intumescent formulation led to improved material dispersion and the
formation of reinforcing heat shielding char nodules. XRD revealed the formation of ceramic metal phosphates
which acted as an additional heat sink to the intumescent system, thereby reducing char oxidation and heat
transfer to the substrate. Steel substrate temperature from a Bunsen burner test reduced by 33%. Therefore, ball
milling can serve as a simple, low-cost processing route for the reuse of bauxite residue in intumescent
composites

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