Quartz Powder Sample Preparation

Anand asked Paul if he could you provide a tried-and-true preparation method for dissolving quartz powder. Paul was happy to oblige.

Dear Anand,

Quartz powder is best dissolved by fusion with sodium carbonate. You may want to add some HF to the final solution to stabilize the Si for long-term stability.

The following is a general preparation guide for carbonate fusions:

  1. Make certain that the sample is well mixed with the sodium carbonate.
  2. A five 9's pure sodium carbonate is recommended. This is available through E.M. Science.
  3. Mix the sample with the flux at no more than a 1:20 ratio. Typical sample to flux ratios are in the area of 1:10.
  4. If organic matter is present, there are two options: 1) The sample is mixed with the flux initially and heated slowly to 500 °C for ~2 hours before bringing to full temperature; or 2) the sample can be pre-ashed at 500 °C and then the ash is mixed with the flux.
  5. Use Pt as the crucible container material.
  6. Perform the fusion at 1000 °C in a muffle furnace. Avoid flames--this fusion is difficult to perform in a flame due to the high melting point of the sodium carbonate.
  7. Most fusions are complete in 15 minutes and some require up to 45 minutes.
  8. Dissolve the fuseate in dilute HCl (1:1) (for samples high in Si, the use of some HF may be needed).

Please contact me if you have any further questions.

Serving you in chemistry,

Paul R. Gaines, Ph.D.
CEO of Inorganic Ventures & Fellow Chemist

DISCLAIMER: Advice offered by the chemists at Inorganic Ventures is intended for the individual posing the question. Feel free to contact us to verify whether these suggestions apply to your unique circumstances.