Sciencemadness Discussion Board

soda lime

Magpie - 14-3-2006 at 15:01

I needed some soda lime to remove CO2 from air so have made my own using the formulation shown in Wikipedia. It is: 75% Ca(OH)2, 20% H2O, 3% NaOH, and 1% KOH. I ground the NaOH, KOH, and a little of the Ca(OH)2 in a mortar and pestle to intimately mix then mixed this with the rest of the Ca(OH)2 in a sealed plastic bag. I then added the water and again mixed in the sealed bag. Then I made a pellet (with my homemade pellet press) and set the pellet out in the room for an hour or so. When I tested it w/10% HCl it fizzed.

Has anyone else tried making their own soda lime?

Marvin - 15-3-2006 at 13:27

Tried, no. That is a very odd method for sodalime.

It ought to be made by slaking quicklime with a concentrated solution of sodium hydroxide.

Magpie - 15-3-2006 at 14:12

Yes, I suppose it is odd, and not very efficient. I can see now that your method would likely be better. I'll give it a try.

Excluding atmospheric CO2 from your materials would still take some care.

Magpie - 16-3-2006 at 11:24

Marvin I again made some soda lime using the Wikipedia formulation shown in my 1st post. Only this time I first mixed 0.8 g NaOH and 0.27g KOH with 10 mL water. Then I mixed this with 15g CaO in a mortar with pestle. What I got was a difficult to mix, almost dry, clumpy aggregate.

One advantage I can see to this method is that the product is irregular and mostly pea-sized which is what I want for my air-purifying tube.

Let me know the correct procedure (as you know it). I want to learn how to do this correctly, hopefully getting small BB sized particles.