Abstract: A bearing part for a gas bearing comprising two bearing parts, said bearing part formed of a granite-like or metal substance with pores or gas leakage channels and means for injecting a gas between the bearing parts (2, 3) for forming a gap (7) therebetween. The pores (10) in the surfaces of the granite material of these bearing parts are sealed by a non-brittle, transparent, mechanically, machinable pore sealing material (9, 12) for forming gas bearing parts having a non-porous surface. Examples of pore sealing materials (9, 12) for sealing the pores of the bearing parts and bearing part material are polyurethanes, acrylic polymers, epoxy resins, silicone resins, polyvinylidenefluoride resins, aramide resins etc. Preferably the pore sealing material consists of a polymer being curable at low temperatures, particularly below 30.degree. C.

Abstract: A method of converting particles liberated in chemical or physical processes, such as fly ash, metal processing sludge particles obtained in the preparation of metals or metal compound, or particles of electroplating sludge, are made harmless by preheating these particles to at least 600.degree. C. and then mixing same with a molten slag material, whereafter the mixture is solidified and broken.Preferably, the particles are preheating to their softening point or are molten.Noxious products, such as metals, being present in said particles cannot be leached out from the broken solidifed composition.