Efficient beneficiation of difficult-to-wash Indian low volatile coking coal fines through Magotteaux flotation

Abstract

The scarcity of Indian coking coals emphasizes the need for more efficient cleaning processes. Conventional gravity methods struggle with fine coal, prompting a shift toward flotation techniques. This study explores the potential of Magotteaux flotation, a modern technique, to enhance cleaning efficiency for Low Volatile Coking (LVC) coal fines. Comprehensive studies on difficult-to-wash LVC coal fines using Magotteaux flotation cell with a single reagent system are lacking. The characteristics of the LVC coal, including physical properties, washability, XRD, and SEM were conducted, followed by milling the coal into three size fractions (−500 μm, −250 μm, −150 μm) to evaluate the efficiency of Magotteaux flotation. Key process variables such as feed size, collector dosage, air flow rate, and impeller speed were optimized using the RSM-CCD method. The optimized conditions achieved a clean coal ash content of 22.2%, with 75.7% combustible recovery and 30.5% separation efficiency. Further, a two-stage cleaning process reduced the clean coal ash content to 19.2%, demonstrating the effectiveness of Magotteaux flotation for processing LVC coal fines. The research highlights Magotteaux flotation as a key player in efficient LVC coal fines processing, contributing to sustainable and effective coal cleaning.