It is difficult if not impossible to separate the two.
An individual should try his/her best to separate the two and leave each in their individual silos. But this is difficult and often times they do get intermingled. In such a situation try to filter out the negatives of work and leave them at the work place and only get the positives home and vice versa.
Someone once told me - Associate your work with something you remove or put aside when you return home. So I associated it with with my car keys - once I returned home from work and put my car keys away - I essentially put my work away and 'switched on the HOME mode'.