The use of waste ion exchange resins as components of the coal charge for the production of metallurgical coke

In this research an innovative method to utilise waste ion exchange resins (WIER) is investigated. The aim of the study is to evaluate the impact of WIER addition to coke quality. For this purpose, industrial tests were performed with different share of WIER and the resultant cokes were studied by means of standard coke analytical techniques, as well as microscopic examinations. By combining optical and SEM petrographical examination it is revealed that the pyrolyzed IER occurs predominantly as separate spheres within the coke matrix, by having extremely durable sulfur bridge bonds. This observation can explain the improvement of the mechanical strength of the produced coke expressed by "cold" indices of MICUM test. Moreover, the coke parameters related to susceptibility to gasification with CO2, like CRI and CSR parameters, seem to be also affected since the chars created from WIER in the coke matrix are more reactive than the coke matter originated from coal. This first step towards a potential recycling of WIER shows that by the addition of WIER up to 3% the coke quality parameters, such as sulfur content or abrasion (M10), are adversely affected. The coking plants may still accept this small (1-3%) impact of polymer waste in the coal feedstock, without significant impacts in their production yields.