Deflocculant - Sodium Citrate

[Norm Stuart]

I wonder if anyone has used Sodium Citrate as a deflocculant?

Digitalfire Deflocculants, including Sodium Citrate

At $5 per pound it's as inexpensive as the Calcium Chloride we use as a flocculant.  It has a big solubility of 92 grams /mL, more than the 81.1 gram / mL of Calcium Chloride, and is far less expansive than Sodium Silicate or Darvan 811.

It combines with soluble hard water Calcium ions (aka flocculating ions) to form insoluble Calcium Citrate, only 0.095 gms / mL remain dissolved- taking the calcium ions out of solution.

The only drawback is Sodium Citrate doesn't have much effect on Magnesium ions, so it won't be a deflocculant if you use Epsom Salts as a flocculant - the resulting Magnesium Citrate has a high solubility level of 20 grams/ mL leaving a lot of Magnesium ions in solution.

[Lawrence Weathers]

John Tillton uses this stuff for his crystal glazes.

[Norm Stuart]

It makes sense that John Tilton uses Sodium Citrate to deflocculate because he uses Bentone-EW to flocculate glazes, and Bentone-EW is "a calcium beneficiated bentonite."

So John's only source of soluble Magnesium ions is from his tap water, which is usually pretty low in comparison with Calcium.  He has a lot of good ideas.

Chemistry of the water in 100 US Cities

Flocculation and deflocculation became a pretty simple idea when I suddenly realized all deflocculants are water softeners.  Flocculating is merely adding hard water ions Ca+2 or Mg+2.

Most do an ion-exchange replacing Calcium and Magnesium with Sodium ions from the Sodium Silicate becoming Calcium Silicate (Wollastonite) or Magnesium Silicate (Talc) while making the water ever so slightly salty.

Darvans are polymer plastics which exchange their Sodium or Potassium atoms for the Calcium or Magnesium.

The advantage of Sodium Citrate is like Darvans, it burns-out, leaving no chemistry behind apart from the Sodium.

Lawrence Weathers said:

John Tillton uses this stuff for his crystal glazes.