Font Awesome icons disappear after refresh in Chrome
I guess you are on a Windows machine, right?
This is an old problem with Chrome. See this posting on CSS Tricks. The next to last post should be the answer to your question. Or in short: Use the PUA (Private Use Area) for encoding.
The Unicodes (PUA codes) for each icon are listed in the Font Awesome CSS file - see: Font Awesome uses the Unicode Private Use Area (PUA)... (around line 190).
I got the same problem in latest verion of chrome (33.0.1750.152)Working solution for me: move styles from body to head section.