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specimens formed from kyanite, L e.~ it lowers the apparent density and increases the porosity (Fig. 7). In the case of the sillimanite specimens~ the influence of Fe203 on consolidation is more marked than that of the other oxides.Next, bricks were produced from chamotte with a water absorption of 2-4% prepared from original kyanite--sillimanite concentrate fred in a tunnel kiln at 1600~The molding mix consisted to 55% of ehamotte ground to size fraction 3-0.09 mm and 45% of a fne-ground component 35?0 of which was unfired kyanite--sillimanite concentrate and 10% commercial alumina (batch No. 1) or kaolin (batch No. 2). The mixes were wetted to a moisture content of 5-5.5% with a slip of density 1.25 g/cm 3 prepared from an aqueous solution of spent sulfite lye and Polozhsk kaolin. The bricks were formed on a toggle press. The compression strength of the as-molded green products varied 80-100 kgf/em 2 and the porosity of the dried green products was 16-18~.After drying the green products to a remanent moisture content of 1% or less they were fired at 1560-1590~ for 18 h~The properties of the bricks of batches Nos. 1 and 2 were as follows: open porosity 12 and 11%, apparent density 2.63 and 2.55 g/cm 3, cold-crushing strength 1000 and 1300 kgf/em 2, and refractoriness under a load of 2 kgf/cm 2 1620 and 1570~ respectively.

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