3 4 In a German 4 800tpd precalciner kiln residual thickness of RESISTAL B50ZIS in the inlet zone after two years operation was 180 mm annual wear rate 20 mm Fig 4 Mineralogic examination showed that K 2O infiltration and formation of leucite KAlSi 2O6 at the hot face was limited to the Fig 3 Coating in the security zone is limited to