NCB ALUMINA ZIRCON REFRACTORY BRICKS IMPROVES LINING PERFORMANCE OF GRASIM CEMENT RAIPUR…..
NCB-AZR bricks were lined in the cooling zone of cement rotary kiln of M/s Grasim Cement, Raipur. M/s Grasim Cement Ltd. is having one rotary kiln of capacity 4300 tpd having six stage double string preheater with SLC.
Earlier the plant was using good quality indigenous High Alumina bricks ( 70 % Al2O3 and 2.5 % Fe2O3 ) in the cooling zone (adjacent to retainer ring) i.e. from 1 metre and 3.4 metre from the outlet of kiln. The plant was not satisfied with the lining performance. Though the average lining life achieved earlier was 6-7 months, however the same was considerably low in the previous three campaigns ( 18 to 56 days owing to retainer ring problem). There was a coating formation over lining, hampering the normal kiln operation and affecting the overall productivity.
NCB undertook the challenge to improve upon the situation, studied the plant operating conditions and recommended the plant to install NCB-Alumina Zircon Refractory bricks which are designed to combat the severe thermal spalling and high hot erosion resistance characteristics, besides other excellent high temperature properties including anti coating characteristics. The installation of AZR bricks was carried out under the supervision of experienced engineers of NCB who supervised the brick installation round the clock to ensure proper installation.
The kiln was lighted in the third week of Dec’2003 and since then plant got trouble free performance. NCB-AZR bricks had successfully completed more than 240 days trouble free operation going well beyond the guaranteed life period of 180 days. At the time of lining replacement, the lining condition was intact and there was no sign of any heavy coating or build up, radial/axial displacements, pittings, spalling and the lining thickness was between 150-180 mm. Under these conditions, it could have easily given life more than one year. Considering the excellent performance of AZR bricks, plant had again installed these bricks at the same location
Photograph showing wear pattern of AZR bricks after 240 days of use

The use of AZR bricks has tremendously improved the overall productivity of the plant. The results obtained during first trial clearly indicated that with the use of AZR bricks in the cooling zone of the CRK, the kiln downtime has been drastically reduced leading to increased production, neat cost of bricks have been reduced, fuel have been saved due to reduction in frequent kiln shutdown/startups and controlled kiln shell temperature.

Repeat Installation of AZR Bricks

After achieving excellent service performance of AZR bricks in the cooling zone of their kiln, Grasim Cement, Raipur again installed these bricks at the same location and the kiln was commissioned in the last week of Sep’2004. The plant got trouble free kiln operation for a record one year and AZR bricks were replaced at the time of annual maintenance. At the time of lining replacement, the lining condition was intact and this time also there was no sign of any heavy coating or build up, radial/axial displacements, pittings, spalling and the lining thickness was between 120-150 mm. Considering the excellent performance of AZR bricks, plant had again installed these bricks at the same location third time successively.