AT42287B - Method of manufacturing for melting vessels u. Like. Suitable masses. - Google Patents

Description

  

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 but cause dangerous and harmful reactions between water and silicon through their decomposition in liquid metal, through which silicon can be brought into the metal and this can be made oxide-brittle.



   All of these evils will be completely remedied by the following new kind of glow.



  By adding water, you can turn pure, amorphous alumina hydrate into semi-fist-sized, rounded pieces, which dry well and thus become solid and heat-conductive and, as a result of the additional water drawn off, remain so porous that all chemically bound water can be removed without any problems, even in high embers. The alkaline additions contained in the alumina hydrate are dissolved by the water, partially evaporate with it or concentrate due to the capillarity of the shaped bodies on their surface, where they become one with the alumina
Water no longer absorbing compound that can be easily removed. Corresponding annealing vessels are fully filled with these dried pieces, covered and gradually heated in a suitable oven to a high level of white heat, approximately up to 16,000, and left there for about 1 hour.

   If this heat level is exceeded, the
Alumina is solid and lean and requires a higher amount of binding clay when manufacturing crucibles, which should be avoided because of the silicon content of the latter. One leaves the heated one
Alumina to prevent air from entering, cool when closed and then grind the pieces to a fine powder that is passed through a 1 to 1 mesh size sieve and is now ready for use. The following should be noted with regard to the exclusion of air during cooling: The annealing vessels are covered after filling. As soon as the vapors begin to escape, air is displaced, which is easily possible between the gap in the loosely fitted lid.

   If no more vapors are formed, the temperature has meanwhile become so high that the lid is glazed together with the edge of the vessel and forms the most favorable air seal. Up to this point all vessel walls are glazed and form a good seal.

 

Claims (1)

PATENT CLAIM: Process for the production of melting vessels u. Like. Suitable masses of pure, amorphous aluminum oxide and binding clay, optionally with the addition of burnt magnesite. Dolomite or the like, characterized by the representation of aluminum oxide in such a way that pure, amorphous alumina hydrate is formed into smaller pieces by adding water, which are dried and then gradually heated to high white heat (1600 ")) in closed vessels and in this heat are left for at least 1 hour, after which they are allowed to cool in the absence of air, pulverized and mixed with the binding clay, optionally with the addition of the basic substances.