In the recent past, it was realised that the gross coke yield was going down as a result of lower oven throughput in the stamp charged batteries of Tata Steel. The basic reason for this being the net reduction in the ash content of the coal blend used due to the incorporation of higher percentage of low ash imported coals and reduction in the ash content of captive coals through washing. The coals having higher ash content improves the bulk density, as the specific gravity of ash is higher than that of pure coal. Moreover, the ash components have affinity for water and pure coal repels water, which in case of pure coal, works against the holding together of the blend. Hence, lower the ash content, less is the bulk density of cake under identical stamping energy and lower the bulk density, less is the oven throughput. In order to maximise the oven throughput and productivity, a study was conducted in the laboratory mainly to assess the effect of various blend constituents and their ash content on the bulk density of coal charge. The effect of ash content on the coal cake stability has also been dealt with. This study, in short, is a useful tool for selecting the right type of coals and designing the optimum blend for stamp charging to achieve maximum throughput and productivity.In addition, studies were also carried out to assess the effect of addition of various binders on coal cake stability at lower moisture level which would also help in achieving higher throughput and productivity.

Disposal of waste plastics is a serious global issue, and hence it is imperative to explore methods to recycle them for efficient utilisation. The coke making process is considered to be a promising area to which the thermal decomposition of waste plastics is applicable, because the process involves coal carbonisation at a high temperature under a reducing atmosphere. As an outcome of the research work carried out on a laboratory scale followed by plant trials at Tata Steel, it was found that waste plastics recycling process using stamp charged coke ovens is feasible to recover coke, tar, light oil and gas from general waste plastics mixed in coal by carbonisation in coke ovens. It has also been established in the laboratory that waste plastics up to 1% can be used in coke making without any deterioration in coke strength. Plant trials have also indicated that co-carbonisation of waste plastics with coal is a possible solution for its disposal.

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Coke reactivity index (CRI) and coke strength after reaction (CSR) are the most important parameters used to assess the blastfurnace coke quality. The present work describes the possibility of estimating CSR for coke from ash chemistry of coal blends. For development and validation of the regression model, data obtained from the Tata Steel's coke oven battery numbers 8 and 9 were utilized. It was found that CSR is greatly influenced by coal ash chemistry.