Coal-Agglomeration Processes: A Review

This article presents an extensive review of the coal-agglomeration process, including oil-agglomeration theory, characterization methods of coal hydrophobicity, and the main factors affecting the agglomeration-process performance in terms of combustible recovery and ash rejection. Coal rank and oxidation state, coal petrography and composition, coal-particle size, pulp density, and pH, bridging-liquid type and concentration, presence of surfactant and electrolytes, bridging-oil emulsification, and agitation intensity as well as time are among the factors here discussed. A chronological overview of the development and milestones of the coal-agglomeration processes is also provided.