Elements of Technology, Raw Materials, and Processing

Within the last 30-40 years, the processing of carbon cathode blocks has become more complex and sophisticated. Many types of cathode carbon blocks have appeared, and it is not easy to understand the different changing properties of carbon materials. 

There are several grades of carbon cathode bottom blocks with different characteristics (Table 2.3). All producers of carbon cathode blocks have standard grades, yet there are minor differences in properties among the grades of various producers  

2 Refractories and Carbon Cathode Materials for Aluminium Reduction Cells 

Anthracite is a fossil carbonaceous material containing minor amounts of inorganic salts—sodium oxide, potassium oxide, calcium carbonate (carbon specialists call it ash ), and organic compounds (called volatiles). 

The deposits of anthracite around the world differ, and not all anthracite materials may be used for the production of cathode blocks. The mineralogy of anthracite is not easy, and specialists in carbon define fusenite, inerterite, micrinite, and liptinite structures, all differing in the morphology of their stmcture. After the calcination, the influence of these structures in raw anthracite on properties is not great, so for an aluminium producer, the structures of raw anthracite are interesting only from an educational point of view (Fig. 2.22). 

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