Is there any difference with "natural light soda ash"? Will it work with Procion dyes?
Country or region: USA
Message: I was wondering if you could tell me if there is any difference with a product labeled "natural light soda ash"? Do you know if it will work just fine with procion dyes or might it not be "strong" enough? The package does also say "commercial sodium carbonate". So, does this mean that it is the correct formula regardless if it is labeled as "light"? Thanks if you are able to answer.
Light soda ash is perfectly fine. In fact, it is the normal grade of soda ash that is sold by dye suppliers such as PRO Chemical & Dye. This is exactly what you want to use. However, if you had soda ash that was not of the "light" form, I would tell you to go ahead and use that, anyway.
There are two main grades of soda ash, light and dense. Both have the same molecular weight (105.99), have the same solubility (maximum 33.2% at 35.4°C), and produce the same pH when measured by weight (a 1% solution in plain distilled water is supposed to produce a pH of 11.4).
The difference between the grades lies in density and particle size. Looking at FMC's technical data sheets for their light versus dense soda ash, light soda ash weighs 0.77 grams per cubic centimeter, while dense soda ash weighs 1.06 grams per cubic centimeter. You would use the exact same amount of dense soda ash as light soda ash when measuring by weight, but, in theory, you would need less of the dense soda ash than light if you are measuring it by volume, that is, by the cupful.
In actual practice, we always use more soda ash in dyeing than we really need to. Since soda ash is a relatively weak base, not all of it ionizes when it dissolves, and adding more does not increase the pH all that much, so it's fine to overdo it a bit. Even using ten times as much soda ash as you need will increase the pH by only about half a pH unit. Our recipes typically contain considerably more than the minimum needed to raise the pH to the desired level in order to activate the cellulose molecule so that it can attack a fiber reactive dye.
As far as the description "natural" is concerned, most soda ash in the US is mined in the form of the mineral trona. That must be what is meant by "natural", on your soda ash. In the rest of the world, most soda ash is produced by the Solvay process, from salt plus limestone. I don't see any strong reason for us to choose one over the other, other than the overwhelming reason of local availability.
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Posted: Sunday - August 12, 2012 at 11:00 AM
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