Manufacture of refractory products

23.20
Manufacture of refractory products
This class includes the manufacture of intermediate products from mined or quarried non-metallic minerals, such as sand, gravel, stone or clay.

This class includes:
- manufacture of refractory mortars, concretes etc.
- manufacture of refractory ceramic goods:
  • heat-insulating ceramic goods of siliceous fossil meals
  • refractory bricks, blocks and tiles etc.
  • retorts, crucibles, muffles, nozzles, tubes, pipes etc.
This class also includes:
- manufacture of refractory articles containing magnesite, dolomite or chromite