I am 52 still working can use my part superannuation to pay down my mortgage ?
No, you can't.
Once you reach your preservation age you'll be able to start a transition to retirement pension while you are still working and you can draw some money out to pay off your mortgage (or for any reason really). For you that will be age 60. For a transition to retirement pension you can draw up to 10% of your superannuation balance each year.
In the meantime, you might be best to actually salary sacrifice more to super (provided you keep under your concessional contributions caps) and then draw it back out when you reach 60. This is because when you salary sacrifice to super, you'll be paying much less income tax, meaning more money in your overall wealth, then if there is any mortgage remaining when you reach 60, draw it out of super (tax free) and eliminate the mortgage.
If you want to know more, don't hesitate to get in touch.
All the best,
As Glenn has said, unfortunately you'll have to wait a few more years until you can access your super.
The only exception would be if you could satisfy financial hardship (you'll need to talk to your super fund for that). If going down the financial hardship route, tread very carefully.