Dealkalization processes of bauxite residue: A comprehensive review

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Bauxite residue is a highly alkaline waste product of alumina refining.
• Its long-term storage presents significant environmental challenges and hinders sustainable aluminum production.
• Increasingly stringent environmental policies worldwide highlight the need to address bauxite residue's alkalinity.

Purpose of the Study:

• To review the composition and characteristics of bauxite residue.
• To detail the Bayer process, focusing on alkaline substance formation and release.
• To analyze and evaluate various global dealkalization methods for bauxite residue.

Main Methods:

• Review of global literature on bauxite residue management techniques.
• Analysis of the Bayer process, including alkaline substance formation and release mechanisms.
• Evaluation of phase transformation, merits, limitations, and application status of dealkalization processes.

Main Results:

• Bauxite residue's alkalinity is a major environmental and industrial challenge.
• Several dealkalization processes exist, each with unique mechanisms, advantages, and disadvantages.
• No single method is universally applicable due to residue variability and resource availability.

Conclusions:

• Effective management of bauxite residue alkalinity requires a context-specific approach.
• Selection of dealkalization processes should consider residue characteristics, regional resources, and future applications.
• Tailored strategies are crucial for the sustainable development of the aluminum industry.