Removal of silicon from waste HF solution for glass cleaning

The process for removal of silicon from waste HF solution contaminated by HF attack of TV panel glass was described for use in cleaning of the glass. The removal of silicon was carried out by mixing HF solution containing silicon fluoride ion with sodium carbonate, whereby sodium silico-fluoride precipitated. This process made it possible to reuse the waste HF solution for cleaning of the glass. In an industrial practice, the process was applied and resulted in 90 similar to 95wt% silicon removal at reasonable cost.