Optimising Ambient Setting Bayer Derived Fly Ash Geopolymers.

Area of Science:

• Materials Science
• Industrial Chemistry
• Environmental Engineering

Background:

• The Bayer process generates significant red mud waste, while coal combustion produces fly ash.
• Both industrial byproducts require extensive impoundment, posing environmental challenges.
• Geopolymers offer a potential alternative to traditional cement, utilizing waste materials.

Purpose of the Study:

• To investigate the feasibility of creating geopolymers from Bayer process liquor and fly ash.
• To optimize geopolymer production for ambient curing conditions, enabling large-scale application.
• To demonstrate the versatility of this geopolymerization process with different fly ash sources.

Main Methods:

• Combining Bayer liquor (a byproduct of alumina extraction) with fly ash.
• Oven curing to establish baseline compressive strength.
• Optimizing mix design and curing conditions for ambient temperature hardening.
• Testing geopolymer compressive strength using fly ash from two distinct power stations.

Main Results:

• Geopolymers with compressive strength exceeding 40 MPa were achieved after oven curing.
• Successful ambient curing of Bayer liquor-fly ash geopolymers was demonstrated.
• Geopolymers were successfully produced using fly ash from two different power stations, indicating process versatility.

Conclusions:

• Bayer liquor and fly ash can be combined to create effective geopolymers.
• Ambient curing optimization allows for practical, large-scale production of these sustainable materials.
• The geopolymerization process shows versatility with different fly ash sources, supporting broad industrial application.