Hypothetically, I have a chemical tank that was brought out of service and the solid deposits at the bottom of the tank primarily contain aluminum chloride. The whole system never sees water, and the aluminum chloride is generated upstream in the process as a by-product (anhydrous under tank conditions).
It's time to clean this solid out, and water flushing seems to be an easy solution. However, previous experience tells us, extensive heat and HCl (aq) and HCl (g) generation during the flooding process, corrodes the tank material and the welded joints, inner pressure rings, etc.
I want to use an alternative solvent to dissolve the aluminum chloride without generating HCl. Ideally, I would like to clean out the tank afterward with water, to get rid of the solvent and remaining solids. My first initial screen takes me toward polar aprotic solvents with high vapor pressure.
What does this community think?
Edit: After some comments, I think I should clarify. There are some other factors, such as solvent toxicity, carcinogenicity, $$ cost (tank is quite large), safe disposal of solvent at that scale, getting rid of the solvent completely from the tank, etc. might reduce the chances for some candidates.