converting baking soda to washing soda after already dissolved into solution

[rwb500]

@Randy Holmes-Farley ,


I make your DIY two part recipe #1 in 5 gallon buckets now. Instead of baking my baking soda to make washing soda, could I simply dump the right amount of unbaked baking soda into a bucket of water and use a powerhead (with venturi for aeration) to have the same reaction take place in solution? How long would it take? Would I need a heater?

Alternatively, when baking the baking soda, do I really need to spread it as a thin layer? I'm baking a lot at a time now. I would prefer to fill a metal bowl and let it sit in the oven for a few hours.

thank you

 

[Randy Holmes-Farley Verified Community Expert]

Boiling it will help drive off CO2. I’m not sure normal aeration will get the job done.

Baking a lot is ok, but like a turkey, the center will take a while to get to temp,

 

[rwb500]

Thanks Randy. Boiling this solution would be a big pain.

I have decided to experiment with baking large quantities and I will post my results here. my first experiment using an oven and a large steel pot was unsuccessful. It is a relatively wide pot, about 10" wide. The height of the baking soda was about 5".

I baked 4089 grams of baking soda at 375 degrees F (non-convection) in a large steel pot without a lid for 3 hours and 40 minutes. The remaining solid powder weighed 3612 grams. This indicates a conversion rate of 32% (the remaining product should have weighed 2579 grams).

I have now put the same pot on my electric stove at low heat. Nothing happened for an hour but now the powder seems hot all the way through and water vapor is condensing on the loosely fitted lid.

 

[Randy Holmes-Farley Verified Community Expert]

Did you have a lid in the oven? It should not be covered. You want the CO2 to escape.

 

[rwb500]

no lid in the oven. My instant read thermometer battery is dead, but it didn't feel hot in the center. I'm trying the stove to see that heats it more quickly.

 

[rwb500]

Well today I put the same pot of baking soda uncovered on the stove with low-medium heat (3/10 on electric stove) for 3 hours. Moisture was still condensing when I put the lid on it, so I knew it wasn't done. While still hot from the stove I put it back in the oven at 400 degrees uncovered for 2 hours. After all of that, based on the change in weight, it is now about 2/3 converted to sodium carbonate. My conclusion is that heating large quantities of baking soda in a pot is impractical but could be done if you don't mind leaving your oven on for 10+ hours. Maybe in the winter.

 

[Randy Holmes-Farley Verified Community Expert]

That seems sensible. Thick layers of dry solid are a pretty good insulator and so it can take a very long time to heat the interior to the required temp, and it also may tend to slow the escape of CO2 from deep in the layer.