Fireplace brick issues

[flakeybricks]

Hi, I've got a brick fireplace that has no stove in it. I've noticed that the bricks near the bottom have white residue and are flaking. (Pictures attached)

Can anyone help with the cause, is this something that can be fixed and if so what do I need to do?

Thanks, Adam 

[flakeybricks]

Looks like the photos didn't upload...

[flakeybricks]