Difference between recoverable amount and residual value?

Residual value is the estimated worth of an asset at the end of its useful life to the business – this is often a “scrap” amount (or so little that it is taken to be $nil).

An asset has a recoverable amount which changes with time. For an asset “in use”, its recoverable amount derives from that use. If recoverable amount is less than carrying amount, the asset is impaired (unless it can be sold for more). The amount for which an asset can be sold before the end of its useful life is not the same as residual value.