Utility model coal washability curve

Currently, there are two types of coal washability curves widely used both domestically and internationally: the H-R washability curve and the M curve. To meet the needs of modern coal preparation technology development, this paper, while fully acknowledging the historical significance of these two curves, addresses certain issues in their application—such as coordinate setting, curve function and distribution, graphing methods, and data reading—and proposes a utility model coal washability curve. Compared to existing curves, the structure of this utility model coal washability curve is entirely different: it uses density as the fundamental variable, with clear principles, concise structure, flexible setup, easy graphing, and smooth curves, making it not only consistent with human intuition but also convenient for data reading. To verify the validity of the applicability of this new curve, the author tested several representative types of coal, including extremely difficult-to-wash coal with small density grade differences.The results show that the utility model coal washability curve can meet the requirements for coal washability evaluation. Additionally, the paper offers suggestions for improving the existing coal washability grade evaluation rules.