Water Environment Federation (WEF) Discussion ForumsWater Environment Federation (WEF) Discussion Forumshttp://www.wef.org/TechnicalDiscussions/jfuller@wef.orgSun, 12 Oct 2008 10:52:15 GMT20http://www.wef.org/TechnicalDiscussions/Topic8728-14-1.aspxFluorides are easily treated by the addition of CaCl2/Ca(OH)2 at about pH 9. The precipitation is fairly simple - what can be problematic in my experience (I've treated about 80,000 gallons of fluoride bearing buffered oxide etch) is the flocculation. Most of my troubles came from getting gooky, hard to filter solids cakes out of the filter press. The choice of flocculant is critical.</P><P>The fluoborate ion will likely need to be hydrolyzed before it can be effectively precipitated.</P><P>Please e-mail me, or reply in this forum, as you prefer, if I can be of further assistance.</P><P>E-mail links are on my site, at:</P><P><A href="http://www.dedalusenviro.com">http://www.dedalusenviro.com</A>Wed, 26 Mar 2008 16:33:24 GMTDedalushttp://www.wef.org/TechnicalDiscussions/Topic8728-14-1.aspxHello,<br><br>Has anyone got experience with semiconductor wastes containing HBF4? or removing fluorides from HBF4 wastes?<br>thank you.<br><br>bosqueTue, 25 Mar 2008 05:51:33 GMTadisco