Improving Health and Productivity of Calcining Kiln Through Several Innovations in Refractory Maintenance Practices at Rourkela Steel Plant

Abstract

Calcined Lime is one of the most important ingredients in both primary and secondary steel making for removal of impurities to make clean steel. Lime quality depends on limestone characteristics, calcination process and kiln health. Refractory performance of lime kilns plays crucial role in enhancing the productivity and product quality of lime kilns. After the capacity expansion of hot metal production from 1.9 to 4.2MT in RSP, 2 new vertical twin shaft lime kilns, supplied by M/s. Cimprogetti, Italy, were introduced in 2012–13. However, maintaining quantity and quality of produced lime remained a challenge due to frequent refractory failure in these kilns. RSP employed several innovative repair methodologies and introduced design changes and applied superior materials to substantially improve the life of these kilns. These interventions resulted in reducing overall down time of kilns, thereby improving calcined lime quality and productivity for steel making. Frequent thermal imaging along with design modification helped to prevent sudden pre matured failure in kilns. As a result, consistent better life of more than two years could be achieved. Good recative lime with LOI less than 5.2 and Reactivity more than 320 could be produced in line with enhanced steel production of SMS-II.