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Passivation/Pickling of Titanium

I am in the process of temporarily decommissioning a Titanium Grade 17 autoclave used for Pressure acid leaching of Nickel laterite ore.
There is a Iron/Sodium Alunite scale that is present on the autoclave walls and will likely have to be removed.

Removal will consist of mechanical descaling such as sandblasting.
I am trying to determine if any passivating/pickling or any form of cleaning is necessary after scale removal for the titanium to protect it while it sits unused for a 3 month period ?

I would appreciate any advice.

Regards, Ronan Gillen Process Engineer

Ronan GIllen
nickel producer - Kalgoorlie, Western Australia, Australia
2003

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Because you are grit blasting off iron containing material it is likely that some of it will get imbedded into the titanium surface in the process. If this is the case, you should passivate it using any of the ASTM A967 processes before storage just to make sure you do not have any rusting in those areas. It may be overkill, but it would be a shame to have pits of iron particles rusting on you. The titanium itself will quickly form a tough oxide layer that will not be a problem.

Lee Kremer
Stellar Solutions, Inc.

McHenry, Illinois

2003