[nabilanft]

Hi All,

I'm currently doing my thesis about extracting Neodymium from its oxide using CaH2.
Based on papers that I read, reaction between Nd-oxide and CaH2 will produce Nd metal, CaO, and H2 gas.

My question is, how to remove CaO? As I know, CaO can dissolve in acetic acid or any weak acid but I don't know what pH of the acid.
Can you give me an example like paper that have an explanation about this?
Please respond it ASAP. Thank you 

[Arkcon]

I'd like to welcome you, nabilanft: to the chemical forums, but I'd like to ask you to trouble yourself to read our Forum Rules{click}.  You agreed to these rules as a condition of signing up for our forum, and they apply to you, whether you agree with them or not, or even if you're unaware of them.  You have violated several of our rules upon arrival.  Lets try to work with your question, a little bit at a time, together.

Hi All,

I'm currently doing my thesis

Interesting.  It seems you're at an upper level assignment.

about extracting Neodymium from its oxide using CaH2.

An interesting application.  Is it an important one?  Is this typically how this materiel is produced?  Is neodymium oxide common?  Is it often found in pure form?  Probably not an important concern for the question you've posted, but worthwhile for you to review for the entire thesis.  Just a suggestion.

Based on papers that I read, reaction between Nd-oxide and CaH2 will produce Nd metal, CaO, and H2 gas.

Great.   This is also an interesting application.  For the fun of it, why not write it out as a balanced equation.  That's a high school level problem.  You should be able to solve that sort of problem, before working on a thesis.

My question is, how to remove CaO? As I know, CaO can dissolve in acetic acid or any weak acid

What reactions of CaO do you know?  Can you look up some of its properties?  What reaction will you get?  Draw that one for us.  Why do you select acetic acid?

but I don't know what pH of the acid

OK.  There's a problem right here.  What do you mean "pH" of the acid.  What pH do you get with "the acid."  What other "pH" is possible, and why?   Use the definition of this terms in a high school text book to solve this problem.  Warning: you may not have success.  That is because you are using the definitions incorrectly.
 

Can you give me an example like paper that have an explanation about this?

Please try to realize that not everything in the world is in a peer-reviewed paper.  Basic high school chemistry concepts don't need to be vetted that way.  Chemistry, by Pauling is something you can acquire, and quote, but it shouldn't be necessary.  Any text book will do.

Please respond it ASAP. Thank you 

Please don't use the term 'ASAP' -- its insulting.  Its a 1980's movie quote, barked at someone, just to prove the speaker is a jerk.  Even my current supervisor or manager wouldn't bark at me 'ASAP' and no poster on this forum is remotely my boss.

I'm sorry to not help you more directly, but that's what we do here on the Chemical Forums.  We try to help you help yourself, not dump an answer to make ourselves look smart.  Start by trying to understand the problem and its solution more fully.  You have significant gaps, and its made the problem harder for you.

People first reduced metallic ores to metal in early pre-history.  You may not be trying to make the first copper knife, but your problem is basically not much different.

[Enthalpy]

[...] CaO can dissolve in acetic acid or any weak acid but I don't know what pH of the acid. [...]

CaO dissolves in water as well. And at least neutral hot water corrodes Nd, but once Ca(OH)₂ is dissolved maybe not.
You might want to check Wikipedia at CaO and Neodymium.