In connection with the introduction of an experimental department for the production of aluminosilicate and alumina articles at the Kazogneupor factory, it became necessary to arrange the production of high-porosity alumina with a certain phase composition.Literature data indicate that to obtain coarse-crystalline corundum chamotte it is best to prepare the briquet from finely milled alumina grade GK or other special grades of high purity [i]. It is recommended that GK also be used in the bond part of the batch [2].Since the production volume of special aluminas does not meet the demands of the refractories industry, it was decided to organize GK output for the Kazogneupor factory at the Pavlodarsk aluminum factory (PAZ) with powerful calcination furnaces of diameter 4.5 and length ii0 m.The complexity of producing special alumina, due to the periodicity of the output, the reduced resistance of the lining, and the wear of the pneumatic belts for the powerful furnaces, is exacerbated as a result of their inertia and the vast material flows. Experience with the production of special alumina in large furnaces is not available.It is known that for the production of a-alumina [3]* mineralizing additives are added to the furnace during calcination; these are most frequently fluor-and chlorine-containing compounds which accelerate the phase conversion of the alumina, reducing the temperature of formation of the a-alumina. In this case the fluorine or its compounds contribute to the growth of crystallites of alumina, and the chlorine or its compounds hardly affect their growth. The use of complex mineralizing additives (AIF3 + NH~CI) yields thoroughly calcined alumina with crystallites of the required size. Aggregates of alumina obtained by incorporating chlorine compounds in the furnace are easily broken down during milling into monocrystals.The use of chlorine compounds as mineralizers requires the setting up of a technological unit to prepare them and to introduce them into the furnace, which in existing alumina factories is not always possible. To obtain corundum articles with a granular structure it is possible to use alumina with a more coarsely crystalline form (type GK), and therefore alumina in the a-form (GKOI) for corundum refractories at PAZ was produced with the use of fluorine mineralizers in accordance with TU 48-2853-2--81.The starting material consisted of aluminum hydroxide of the following chemical composition (parts by weight): 0,36% NaaO, 0.020% Fe~O3, 0.019% SiO~, loss on ignition 34.5% (remainder alumina). It should be noted that the hydroxide produced by PAZ has a relatively large size, both in aggregates (on average 65 ~m) and in the composite crystals. St is known that in the process of decomposition of the aluminate solutions, the size of the hydroxide alters cyclically (complete cycle time 40-45 days) from a maximum, averaging 80 ~m, to a minimum, averaging 40 ~m.