Study on determination of fluorine in hamartite

The amount of fluorine in hamartite could not determine accurately by using GB7483-87 《Determination of fluorine in water by spectrophotometry with fluorinating agent》.The reason was that the content of fluorine in Sichuan hamartite was much higher,and generally up to 7%～11%.It was easy to form REF_3 sediments. It was very difficult to steam out all of the fluorine in hamartite by using acid digestion.In this work,F was transformed into CaF_2 with the addition of Ca(OH)_2,and the fluorine in the mines could be steamed out completely.The amount of the fluorine in the mines was 9.02%,and CV was 0.44.Recoveries were 97.83%～99.44% by adding standard with 0.5、 1 and 2 times of the fluorine in the mines.This method has high precision,good accuracy and reliability,and it is simple and rapid.So it is a significant supplement to the fluorine measurement of the GB.