−188.14℃; density 1.696 grams per liter at STP; valence −1. Fluorine is a yellowish, poisonous, highly corrosive gas. It is the most chemically active nonmetallic element and is the most electronegative of all the elements. It is a member of Group 17 (the halogens) of the periodic...
An actual calcium fluoride leach liquor was utilized to evaluate the process #3. An aliquot of 500 ml of leach liquor containing 0.260 mole/L fluoroboric acid, 0.11 mole/L boric acid, and 0.11 mole/L sulfuric acid was treated with concentrated ammonium hydroxide to a pH of near 7 and stir...