"Salt cake is a by product in the aluminium recycling process using a rotary furnace. Salt cake is a mixture of aluminum oxides and aluminum nitrides, metal and salts (mainly NaCl and KCl, with small amounts of MgCl2 and CaCl2).
The salt cake is a growing environmental problem. It is proving very difficult to dispose in the Europe and is regarded as hazardous waste. The reason is that when saltcake gets wet it gives of gases, e.g. hydrogen, methane, ammonia. Also water leaching out of the land fill would contain chlorides.
The alternative is to try and recycle the saltcake and reclaim the aluminium, aluminium oxide and salt. This is done by grinding up the saltcake and separating out the free aluminium. The residue if then mixed with water, which dissolves out the salts, which are later re crystallised and sold back to the secondary aluminium smelters and aluminium oxide, which may be used in abrasive industry or in the manufacturing of cement.
The current technology has high initial and operating cost and not economical in small volume and that is why there are only few aluminium salt cake recycling facilities exist in the Europe. All the salt cake generated by the aluminium recycling plants have to transport the salt cakes to these facilities, which results a large amount of cost due to transportation and associated CO2 emission.
The project aims to develop an in situ salt cake recycling technology that will utilize the excess of heat from the flue gas from the rotary furnace and able to reprocess salt cake more efficiently and more economically also in small volume.
The process will allow recycling salt cakes in situ at the aluminium recycling plant, without the need for transporting the salt cakes to the salt cake recyclers. This will reduce to cost for transportation, CO2 emission and increase the competitiveness of the European aluminium recycling industry."
Fields of science
Call for proposal
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Funding SchemeBSG-SME - Research for SMEs
30564 Lorqui Murcia