I have a problem with the anodic oxidation process in a fixing bath due to the presence of silicates. The solution would be eliminate or make them inert. How can I do?
Silicates react with HF forming SiF4 or H2SiF6 respectively. SiF4 is volatile and could be eliminated by destillation (caution - glassware would be attacked, too. All exeriments have to be performed in plastics or recoveres vessels). For some aplications it could even be sufficient to mask the silicate with fluoride.
I also remember some experiments that used polyols as glycerine as polydentated ligands for silicates but do not know if the effiicency would be sufficiently high as to enmask larger amounts.
Si(OH)4 or condensation products of it should be slightly acidic, most salts of it (like Na2SiO3) are basic. Maybe ion exchange resin (basic, acidic or a combination of both types) could remove the silicates?