Pushpa International

Borsi, durg, Chhattisgarh

Chemical & physical propertiescrystal form alpha alumina trigonal systemchemical nature amphotericreaction with acids subject to mild attack by aqua andor hydrofluoric acidreaction with alkalis very slight with strong hot solution onlyoxidation-reduction effects nonetrue density(gcm3) 3.97hardness knoop(kgcm2) 2000-2200mohs 9.0color dark browncolor after firing light bluemelting point 2000 cmax. Usable temperature 1900 cspecific heat (calg c) 0.26 (20-29 c)coefficient of thermal conductivity(calcm2.sec.c) room temperature 900 c0.047 0.013electrical resistivity (wcm) 30 c 300 c 900 c 1600 c1016 1013 105 104coefficient of liner expansion (x10-6) 7-9(0-1600c) chemical composition (% by weight)grit item 10 90 100 180 220-220 230 400 500 -1200al2o3 94.5 97.0 9305 min. 92.5 min. 91.0 min. 89.0 min.Tio2 1.5 3.8 1.5 3.8 1.5 -3.8 4.0 max 4.0 max magnetic matters contents (% by weight)grit no. magnetic matters content16#-30