Hank Yarn Mercerization
Exactly similar to fabric mercerization, yarn mercerization involves the same caustic impregnation under tention followed by washing and neutralization.
Now there are multiple hank mercerization machines are available in the market that perform almost all operations up to washing automatically.
The mercerized yarn, of course posses better lusture, tensile strength, abosrbency and better color yield during dyeing.
The actual cautic soda and mercerizing wetting agent concentrations are similar to fabric mercerization and you can refer those pages for better understanding.