Method for making carbon blocks highly resistant to thermal shock

摘要

The invention relates to a simplified production process with which it is possible to obtain carbon blocks, in particular anodes intended for aluminium production using the Hall-Héroult electrolysis process, which have high thermal shock resistance. This process comprises a grain size distribution adjustment operation of a carbon aggregate which includes:a) separating an initial ungraded carbon aggregate AC into a first fraction F1 made up of grains whose sizes are smaller than X, and into a second fraction F2 made up of grains whose sizes are X or greater, X lying between 0.2 and 2 mm;b) crushing B1 the first fraction F1 and part P1 of the second fraction F2 such as to obtain a powder F comprising a controlled proportion of ultra-fine grains;c) mixing the remaining part P2 of fraction F2 and said powder F in proportions with which it is possible to obtain crude carbon blocks whose so-called "Gr/S" ratio between the proportion PGr of grains larger than 0.3 mm and the proportion PS of grains between 30 mum and 0.3 mm in size is at least equal to 4 and baked carbon blocks of high density.