the refractory lining must must not wetted by the molten aluminum, have a good mechanical stability, and dont react with fluxes
You need a refractory material made of as pure as possible alumina and with the lowest possible porosity. There are many Al2O3-based refractory bricks on the market, but the higher the Al2O3 content and lower porosity, the more expensive they are.
Refractory clay-based materials with high porosity are corroded, as well due to aluminum melt, but even more through molten flux.
Thank you Mr. Vadim Velotski But I think aluminum will react with aluminum metal beginning from 700 Deg C, this is one . the second I need continuous layer lining on the cast iron crucible , not brick ... with regards
Alumina (Al2O3) not react with metallic aluminum, therefore Al2O3-based refractory materials are suitable for contact with molten aluminum. Alumina will slowly dissolve only in the flux melt.
In order to protect a crucible made of cast iron from the molten aluminum, there are ceramic pastes (paints) which must be reapplied after each melt on the inside of the crucible.
There is no way to apply a permanently stable ceramic layer on the surface of metal crucibles.
you can see that aluminum molten wet alumina and react with it in the following papers
The material needed would depend on what you expect to be contained in the furnace. If this is just molten aluminum then alumina based refractory material would be suitable. However, if slag or matte will be generated, you will have to determine the functional pH of the non-metallic melt. If the slag and/or matte is basic then alumina should still work fine. If however the melt is acidic then you will have to use a different material, you may want to look into chromium-magnesite based refractory material. In any case, both types of material is available in bricks, sheets, and mortar powders. Also, try not to stockpile the stuff. Refractory material quality is very sensitive to air moisture and temperatures, so if you have to stockpile it then find someplace cool and dry.
Hope this helps
Dear friend,
The corrosion of refractories against aluminum melt can be divided into 3 section:
Section 1: Wetting of the refractory surface with the melt and infiltration into the refractory matrix through pores
Section 2: Corrosion of the matrix and surrounding the aggregates of the refractory
Section 3: Corrosion the aggregates and washing them into the melt.
Therefore:
The solution for section 1: The utilization of anti-wetting agents in the composition of refractory.
The solution for section 2: Lowering the porosity level and the pore size distribution of the matrix
The solution for section 3: Increasing the chemical compatibility of the refractory with the melt. It can be chosen by ellingham diagram
Moreover, you can read our article on the topic:
Maybe this RG discussion can be found of some help: https://www.researchgate.net/post/Does_chemical_reaction_occur_between_steel_and_aluminum_molten_If_yes_how_much_is_it_How_can_the_amount_of_reaction_be_reduced
Mr. Emmanuel Sandel ... I feel you talk general ... the raw material is aluminum profiles and UBC
Thank you Carlos ... we all can benefit the discussion .... more light can be spotted on .... regards
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