EcoFriendly bulk lining materials

RUSAL created an innovative technology to install the basements of aluminium cells (ITME). The technology comprises unique bulk lining materials (BLM) created by LLC RUSAL ETC based on lignite semi-coke, which is capable of being recycled, barrier materials based on burnt clays (porcellanite), and graphite foil. The assembly technology is mechanised and is carried out using specially designed types of equipment – installation, vibration compression and recycling units equipped with regulatory and technical documentation. LLC RUSAL ETC started its development in 2005. In this period, an original installation for BLM vibration compaction was created, and laboratory tests of new carbon-based thermal insulation materials were conducted.  In 2006, the Sayanogorsk Aluminium Smelter launched 1, in 2011 – 3, and in 2014 – 21 S-175 type pilot cells.  Since 2015, ITME technology has been implemented as part of S-175 cell relining in Sayanogorsk, since 2016 – during the relining of all cell types at the Novokuznetsk Aluminium Smelter, since 2017 – S8BM(E) has been implemented in Krasnoyarsk, and since 2020 – during S-8BM(E) cell relining at the Bratsk Aluminium Smelter.  Application of the developed innovative BLM installation technology reduces the costs of basement materials by 38-60%; decreases the labour costs for basemen installation by 75-80%; and reduces the quantity of waste by 25-30%.

Along with installation technology, various BLM cell designs were developed as part of the project (S-175, S-255, RA-400, S8BM(E), etc.). To date, the total number of BLM cells operating at all  RUSAL smelters exceeds 1,300 units.  Analysis of the technical and economic indicators of BLM cells, as well as the results of more than 10 autopsies, show that the current efficiency and energy consumption of the pilot cells and control group cells are quite close. However, BLM cells have got a number of specific advantages. The results of autopsies show that bulk lining materials based on lignite semi-coke are able to compensate for the forces aimed at lifting the furnace bottom when aluminium and fluoride salts leak into the basement. In this case, the aluminium melt locally leaking into the basement forms a composite low-heat conducting material with lignite semi-coke, which contributes to the preservation of thermal balance, thereby increasing the service life (according to expert estimates by 5-10%).  Due to the high density of the upper barrier layer and the foil layers used for BLM cells, there is a decrease in the consumption of aluminium fluoride (by at least 10 %).  At the same time, up to 80% of BLM based on lignite semi-coke can be reused.  The technical solutions developed in the field of installation technology, structures and operation methods of cathode units for primary aluminium production cells are protected by more than 20 patents (including 8 international ones: USA, Canada, China, Australia, Kazakhstan).