Eggshells as a catalyst

[Glycer-rides]

As posted on t'otherside, an interesting paper here on the use of calcinated eggshells.

http://www.sciencedirect.com/science/art...0314000441

"The present study revealed that the calcination–hydration–dehydration treatment is a sufficient method to increase the catalytic activity of waste shells possessing calcium carbonate as their main constituent. The experimental results showed that the methyl ester conversion for commercial CaO was 67.57% whereas it was found to be 94.52% for the CaO obtained from the calcination–hydration–dehydration treatment of egg shell at a 5 wt% catalyst (based on oil weight), a methanol to oil ratio of 12:1, a reaction temperature of 65 °C and a reaction time of 1 h. The synthesized biodiesel was compared with the ASTM standards of biodiesel and the properties density, kinematic viscosity, flash point and cloud point conformed to the ASTM D6751 specifications".

(The 12:1 ratio is the molar ratio btw, I've seen 9:1 and 6:1 mentioned elsewhere)

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[photoman290]

i haven't had time to read the paper yet, but calinating egg shells will involve heat. how much and at what temperature will be important.

[dgs]

i haven't had time to read the paper yet, but calinating egg shells will involve heat. how much and at what temperature will be important.

They were subjected to a temp of 900degs C for 2 1/2 hours.

[photoman290]

thought so. that is the range i assumed. that is the the temperature well 880c if i remember that removes the chemically bonded water from hydrated lime to turn it back to calcium oxide, or quicklime. not a easy thing to do at home unless you make a calcinator.

[Head Womble]

I've visited a quick lime kiln and they're very impressive, I think this one was running at 1400° (large scale commercial unit).

Not the sort of thing you would have at home.

[kamaangir]

You can get electric heat treating ovens that can handle those and higher temps. Not hard to build one at home either. If it needs an oxygen free environment you can always have some inert gas being injected in the oven.

[photoman290]

i a sure you can find an oven on a lab equipment site  cheaply enough. the question is would it be worth the trouble. a pottery kiln is another option,if you can find one.

[dgs]

With the cost of KOH at around one pence per litre for processed bio, it certainly isn't worth it.

However for experimental or interest reasons, its whatever takes your fancy.