The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Need information for methanol recyling.

2000

We are a gold and silver jewelry manufacturing company and use methanol [affil links], isopropanol and acetone ⇦ this on eBay or Amazon [affil links] Warning! highly Flammable! in our process. We generate about 10 gallons of methanol and about half a gallon each of acetone ⇦ this on eBay or Amazon [affil links] Warning! highly Flammable! and isopropanol as waste. Presently we are incinerating the spent solutions in a burner.

I would appreciate, if somebody knows of any method where I could recycle the solutions by distillation or any other techniques.

Ajit Menon
Landstroms - Rapid City, South Dakota

---

Unfortunately, these are by definition, haz waste. You need a license to treat (incinerate) it.

Recovery by distillation is probably a viable option. This is legal, as it is recovery, rather than treatment.

The biggest problem will be the condensing coil. you will have to run chilled water or similar thru it to get the surface of the coil below the condensing (boiling) temp of each solution. Acetone is very volatile at room temp.

Commercial stills are available.

Safety is an issue. Do some homework on it.

James Watts
- Navarre, Florida
2000

---

All three solvents are infinitely soluble in water and form binary azeotropes (constant boiling mixtures) water. If you pick up water, distillation will not remove it. This is why grain alcohol for consumption never exceeds 180 to 190 proof.

You will not get pure alcohol if there is significant water contamination.

Charles R. Reichert CEF-SE
- Seattle, Washington
2000

What Charles says is true. In a commercial facility or lab, a fractional distillation unit is used. In poor man's language this involves using a longer coil so that a great amount returns to the boiling mixture. It is possible to control the "cut" to 0.1F which gives a great consistency, separating the pure solvent from the azeotrope. I rather doubt if his operation requires "pure" solvents, just clean ones.

James Watts
- Navarre, Florida
2000