Obiettivo THE RESISTANCE TO EROSION OF GLASS-CERAMIC MATERIAL, COUPLED WITH THE FAVOURABLE TENSILE STRENGHT AND HARDNESS, MAKES THIS MATERIAL PARTICULARLY USEFUL FOR INDUSTRIAL APPLICATIONS WHICH INVOLVE WEAR DUE TO EROSION. CONVENTIONAL GLASS-CERAMICS ARE MADE BY COOLING A MELT TO THE GLASSY STATE AND THEN CRYSTALLISING IT IN A CONTROLLED MANNER BY REHEATING. IN THE USSR GLASS-CERAMICS ARE MADE IN THIS WAY, USING BLAST-FURNACE SLAG AS THE CHIEF CONSTITUENT. IMPERIAL COLLEGE IS DEVELOPING A NOVEL PROCESS FOR THE PRODUCTION OF A GLASS-CERAMIC MATERIAL ("SILCERAM") FROM MOLTEN BLAST-FURNACE SLAG BY HEAT TREATMENT. THIS INVOLVES DIRECT COOLING FROM THE MELT INSTEAD OF THE TWO-STAGE REHEATING TREATMENT FOR CONVENTIONAL GLASS-CERAMICS. THE NUCLEATION AND GROWTH OF CRYSTALS TAKE PLACE DURING A CONTROLLED COOLING FROM THE MELT, THUS AVOIDING THE REHEATING FROM COLD GLASS REQUIRED BY THE CONVENTIONAL PROCESS. IT ALSO SHORTENS THE HEAT TREATMENT TIME LEADING TO ADDITIONAL ENERGY SAVINGS. A PILOT-PLANT FOR THE PRODUCTION OF GLASS-CERAMIC CASTINGS HAS BEEN DESIGNED, CONSTRUCTED AND COMMISSIONED. THIS CONSISTS OF AN OIL-FIRED TILTING TANK FURNACE CAPABLE OF MELTING 100 KG BATCHES, A HEAT TREATMENT KILN, CASTING AND MOULDING EQUIPMENT AND FACILITIES FOR STORING RAW MATERIALS AND FINISHED PRODUCTS. PHYSICAL AND MECHANICAL PROPERTY DETERMINATIONS HAVE BEEN MADE IN THE LABORATORY WITH THE NEW MATERIAL. THE VISCOSITY OF THE MOLTEN MIXTURE USED FOR "SILCERAM" PRODUCTION HAS BEEN DETERMINED AS A FUNCTION OF TEMPERATURE OVER A RANGE BETWEEN 1250 AND 1600 DEGREES C. THE DATA SHOW THAT THE MELT HAS ADEQUATE FLUIDITY AT 1450 DEGREES C, BUT HAS RAPIDLY INCREASING VISCOSITY AS THE TEMPERATURE FALLS TO THAT OF THE TREATMENT KILN (900 - 950 DEGREES C) WHICH IS NECESSARY IF THE SHAPE IS TO BE RETAINED DURING CRYSTALLISATION. (THE VISCOSITY AT 1350 DEGREES C IS 5.95 NSM EXP-2). THESE INVESTIGATIONS HAVE SHOWN THAT THE NEW MATERIAL IS ATTRACTIVE AS AN EROSION-RESISTANT CERAMIC FOR INDUSTRIAL APPLICATIONS. IT COULD BE USED AS A LINING FOR CONVEYORS OR PIPES WHICH CARRY EROSIVE GAS-ENTRAINED SOLIDS. TESTS UNDER INDUSTRIAL CONDITIONS (COMPARATIVE TESTS OF THIS KIND DEPEND UPON THE PREVAILING CONDITIONS, SUCH AS PARTICLE VELOCITY, SIZE AND NUMBER DENSITY AND ANGLE OF IMPACT) HAVE SHOWN THAT THE NEW MATERIAL ERODED 1.5 TO 3.5 TIMES SLOWER THAN CAST BALAST (A MATERIAL IMPORTED FROM OUTSIDE THE EEC WHICH CURRENTLY DOMINATES THE MARKET). SINCE THE COST PER TONNE IS CLOSE TO THAT OF CAST BALAST, THERE IS AN ADVANTAGE ON A COST PLUS PERFORMANCE BASIS. A SERIES OF TRIALS HAS ENABLED THE BEST CONDITIONS FOR CASTING TO BE ESTABLISHED; THE PILOT PLANT WHICH WAS DESIGNED AND COMMISSIONED DURING THIS PROJECT HAS BEEN USED TO OPTIMISE MELTING, CASTING AND HEAT TREATMENT CONDITIONS. IF, HOWEVER, PRODUCTION IS TO BE CARRIED OUT IN AN INDUSTRIAL PROCESS, FURTHER INFORMATION ON MELT AND REFRACTORY BEHAVIOUR WOULD BE REQUIRED. Programma(i) PRE-ENNONUC 2C - Energy research and development programme (EEC), 1979-1983 Argomento(i) Data not available Invito a presentare proposte Data not available Meccanismo di finanziamento Data not available Coordinatore Imperial College of Science, Technology and Medicine Contributo UE Nessun dato Indirizzo Prince Consort Road SW7 2BP London Regno Unito Mostra sulla mappa Costo totale Nessun dato
