There is disclosed a method of burning a ceramic shell mold for use in precision casting for curing the ceramic shell mold. The ceramic shell mold is positioned within a heating compartment while a mass of sand within the heating compartment is fluidized so as to submerge the ceramic shell mold thereinto. Thereafter, particles of the sand are heated to a predetermined curing temperature, which sand particles then heat the ceramic shell mold enveloped by the sand particles.

1.A method of burning a ceramic shell mold for use in precision casting, which ceramic shell mold has a shaped cavity, defined therein, and at least one opening leading into said shaped mold cavity, said burning method being carried out by the use of a heating kiln of a type comprising heating and combustion compartments divided by a ceramic filter, said heating compartment being positioned immediately above said combustion compartment and accommodating therein a mass of sand, and a source of heating medium of elevated temperature, said burning method comprising the steps of:

positioning said ceramic shell mold from top into the mass of sand within the heating compartment while said mass of sand is fluidized by the application of compressed air flowing upwardly through the ceramic filter at a pressure within the range of 1.0 to 2.5 kg/cm.sup.2 , said ceramic shell mold being positioned such that the opening leading into the mold cavity projects outwardly from the top level of said mass of sand within said heating compartment;
interrupting the supply of the compressed air; and supplying the heating medium composed of a blast of hot gas from the combustion compartment into the heating compartment through said ceramic filter to heat said mass of sand and, in turn, said ceramic shell mold at a predetermined curing temperature for a predetermined time, said gas pressure being such as to avoid fluidization of the sand particles during this curing time.

2. A method as claimed in claim 1, wherein the burning of said ceramic shell mold is carried out by the effect of heat-exchange in contact with particles of said gaseous sand which are heated by said heating medium upwardly flowing through interstices among said sand particles.

3. A method accordng to claim 1, wherein the pressure of the blast of hot gas during the curing time is introduced under a pressure of 0.5 to 1.0 kg/cm.sup.2.