SAS Offers for Commercial Sphere

Improvement of aluminium quality and of energetic and environmental characteristics of aluminium electrolysis.

Code: IMC-S-00-0071-UACH

Institute of Inorganic Chemistry

Contact Person:


Electrolytic production of aluminium belongs to the most energetically demanding processes, because 12,5 - 16 MWh of electric energy is consumed per one ton of produced aluminium. The modern production technology of primary aluminium installed after reconstruction in Žiar nad Hronom represents the primary aluminium production carried out on the present knowledge level. However, even such a modern technology needs further development and improvement. There are three principal groups of problems that should be solved :

  • Improvement of the energetic efficiency of aluminium electrolysis. In spite of the present 93 - 95 % current efficiency, the total energetic efficiency attains 30 - 40 % only. The electrolysis is at present carried out at the temperature of approx. 960 °°C, whereby the substantial part of energy is consumed for heating the cells and covering the heat loss into the surroundings. One of the ways how to decrease the non-effective energy consumption is the total decrease of the electrolysis temperature using a bath of modified composition, or the usage of suitable additives into the electrolyte.
  • Increase of the produced aluminium purity. The produced primary aluminium is contaminated mostly by sodium, partially by calcium or lithium. Besides these impurities, the current efficiency influences negatively next impurities e.g. phosphorus, vanadium, and iron. For it’s further processing aluminium must be refined. The solution of produced aluminium purity problems involving refination is the next important issue in the energetic consumption decrease process.
  • Improvement of the existing technology, cell output increase, processing of used cells, introduction of inert electrode materials, etc. The above mentioned topics are together closely related and it is not possible to solve them individually. It is obvious that it is a very demanding task. The technological parameters of electrolysis and process control are characteristic for every producer. The research results are mostly confidential in character and are not disclosed. With regard to the facts, relatively limited energetic sources, and because the plant in Žiar nad Hronom, where the newest knowledge in this field should be applied and underwent substantial reconstruction recently, the submitted project is of strategic importance for Slovakia.


Several advanced solutions which realization would lead to an important contribution to the Slovak economy exist at present. They are in the form of lower electric energy consumption and due to the lower cost and higher aluminium quality its better market use.


Improvement of such demanding technology, as the aluminium production is, is possible only in the framework of close co-operation. The proposed project should exploit the up-to-date results and further continue in technologic innovations as well as in teaching and training qualified personnel, which is in Slovak conditions an important task.