I would like to know about the potential uses for spent Nitric-HF acid (6:1 Ratio) which is an acid mix typically used to etch silicon wafers for the production of microchips. What industries or companies can use spent Nitric-HF acid?
Tom Mackey - Theodore, Alabama 2000
The Si etching reaction can be expressed as follows: Si + 4HNO3 +
6HF --> H2SiF6 + 4NO2 + 4H2O Silicon is oxidized by rthe nitric acid and the resulting silicon oxide is dissolved by the HF acid.
Hexafluorosilicate and water are generated in the solution. The NO2 is gasified and treated. One possible use for the spent acid is fertilizer, but many fertilizer producers cannot handle the residual HF.
Tom Mackey - Theodore, AL. 2000
(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)
Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.
If you are seeking a product or service related to metal finishing, please check these Directories: