Studies on the cleaning potentialities of non-coking coal by washability study

Coking coal is the primary prerequisite source for the production of iron and steel through blast furnace route. Efforts have been made to correct the imbalance between need and availability of coking coal. This can be done by blending coking coal with either non-coking coal or semi-coking coal. To search for the above possibility systematic investigation of coals is required. Before going for any beneficiation studies for upgrading the coal (to reduce the ash level), washability study of the sample is required. The washability study of coals is performed through sink-float test in laboratory. Sink-float tests are widely used for coal analysis, to predict the theoretical yield and ash contents of clean coal obtainable in an ideal gravity concentrator at different specific gravities. It is a common practice to plot a series of ‘washability curves’, from the sink-float data of a coal sample in order to generate many useful information relating to its amenability for producing clean coal of desired quality. In this article a systematic investigation of washability study of non-coking coal from eastern region is studied through laboratory sink float test. From the washability study it has been found that 17% to 20% ash level can be achieved with a yield of ~30 to 33%%. Based on the data a suitable beneficiation scheme can be suggested

Significance of coal quality on thermoplastic properties: a case study

The amount of coking coal in all over the world is scarce while it is an essential commodity for steel making; in an economical way, no alternative of coking coal is found out till now. Though, so many researches have already been there to understand its properties specifically its plasticity behavior, it requires a deeper understanding concerning the coal plasticity. Hence, to compare and correlate, five coking coals were chosen from different countries which are used for metallurgical purposes throughout the world. Basic characterization, i.e. proximate and ultimate analyses and petrography were done with the measurement of plasticity, dilation, and swelling properties of the studied samples. Detailed petrographic studies reveal the interrelationship between the different kinds of macerals and the fluidity of coking coals. The vitrinite group of macerals has a positive relationship while the inertinite and the liptinite group of macerals have both positive and negative correlation with the plasticity of a particular coal. Hence, this study focuses to build a profound understanding about the role of all the macerals and other characteristics of coal, i.e. volatile matter, rank, etc., in coal plasticity