Thank you Winterclock for very useful information. Yes You are right , it is the best of all , others traveling around %3.
What would be needed to extract all water and where I can find the information after 45 degree to 100 degree % 60 alembic process.
And I found some papers suggesting 1500 celcius degrees for some crystals but I found some papers writing about 260 celcius degrees.
I will attach these papers but APUG is slow. I am going to internet explorer to attach them. I will try . I am here.

The Potassium Fluoride – water system
The solubility of potassium fluoride, KF has strong temperature dependence. The salt is much
more soluble than sodium fluoride and it forms two hydrates. The tetrahydrate, KF4H2O is the stable
form in equilibrium with a binary solution at temperatures below 17.7 C. Between 17.7 and
approximately 45 C, the dihydrate, KF2H2O is the stable form. Above 45 C, the anhydrous form of
KF will precipitate from supersaturated solutions.
The eutectic point of KF-H2O solutions is
between -21.8 C and -21.5 C due to the high solubility of KF.