Method of producing a spinel type ceramic sintered body

Claim 1

A method of producing a spinel ceramic sintered body consisting essentially of a dense, reacted sintered body, the major mineral composition of which is composed of a quartz and a spinel solid solution in which Al, Fe and Cr are in mutual solid solution based on analysis of the chemical composition and X-ray diffraction, said sintered body having a thermal conductivity falling within the range of 1.3-2.5 kcal/mh °C., and a specific electric resistance within the range of 10 2 -10 7 Ωcm, comprising (a) providing a powder of a chrome slag discharged as waste from sodium chromate production containing Cr 2 O 3 :2-18 wt %; CaO: 0-15 wt %; Fe 2 O 3 : 10-45 wt %; Al 2 O 3 : 5-20 wt %; MgO: 5-20 wt % as the major ingredients and an aluminum silicate powder containing at least a clay having the composition expressed in terms of mole ratios: ##STR1## wherein R represents collectively Al, Fe and Cr, and mixing the resultant mixture to prepare a ceramic base material, (b) molding said ceramic base material and drying the resultant product to form a green molded body, (c) burning said green molded body in a hot atmosphere at a temperature between 1150°-300° C.

Claim 2

A method of producing a spinel ceramic sintered body consisting essentially of a dense, reacted sintered body, the major mineral composition of which is composed of a quartz and a spinel solid solution in which Al, Fe and Cr are in mutual solid solution based on analysis of the chemical composition and X-ray diffraction, said sintered body having a thermal conductivity falling within the range of 1.3-2.5 kcal/mh °C., and a specific electric resistance within the range of 10 2 -10 7 Ωcm, comprising (a) providing a powder of a chrome slag discharged as waste from sodium chromate production containing Cr 2 O 3 :2-18 wt %; CaO: 0-15 wt %; Fe 2 O 3 : 10-45 wt %; Al 2 O 3 : 5-20 wt %; MgO: 5-20 wt % as the major ingredients and an aluminum silicate powder containing at least a clay having the composition expressed in terms of mole ratios: ##STR1## wherein R represents collectively Al, Fe and Cr, and mixing the resultant mixture to prepare a ceramic base material, (b) molding said ceramic base material and drying the resultant product to form a green molded body, (c) burning said green molded body in a hot atmosphere at a temperature between 1150°-300° C.