A more appropriate solution would be to implement a way to hide the navigation label text but keeping it available as screen reader text on the link.

The reason is that you’d essentially be allowing the creation of empty links. This is fine for visitors that can see the page and see the icon, but when you can’t see and need to rely on assistive tech to tell you what something is then an empty link can be very problematic. Because now, you know nothing apart from the fact that it’s a link.

And so, by providing a way to simply hide the label from sight, you will have a link that is just an icon but that will also have a textual alternative available for screen readers.

For more information, please refer to the following:
https://www.w3.org/TR/UNDERSTANDING-WCAG20/navigation-mechanisms-refs.html
https://webaim.org/techniques/hypertext/link_text#text
https://fontawesome.com/v4.7.0/accessibility/