Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: smanga on 01/09/2006 11:39:22

Title: soda lime process of making sodium hydroxide
Post by: smanga on 01/09/2006 11:39:22

Hi guys, It's smanga here I'm new so I don't know exactly hw things work here, but I have a serious problem for an assingment. I want to know the use of carbon in the first step of the soda lime process. If any one knows the answer they can e-mail me at: sma2ngo@yahoo.com

thanx guys hoping to here from you soon!!!

smsk

Title: Re: soda lime process of making sodium hydroxide
Post by: Soul Surfer on 02/09/2006 22:00:13

I am not sure quite what you are looking for, because the soda lime process  is a fundamental chemical process used to make a commonly required industrial chemical sodium hydroxide from naturally avaiable chemicals,  calcium carbonate (limestone)and sodium carbonate (natron from soda lakes or produced via the ammonia soda process).

The carbon used is in the form of carbonate chemicals which are quite common on the earth's surface rather than the carbon that occurs in coal  however the process does require a lot of heat which can also be produced by burning carbon.

A Google search should produce the information you require but I used a rather old fashioned chemistry textbook dating form around 1950.

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Title: Re: soda lime process of making sodium hydroxide
Post by: lightarrow on 03/09/2006 11:00:43

Yes, also according to my book, Soda-lime process, basically, is the reaction:
 
Ca(OH)2 + Na2CO3 --> CaCO3 + 2NaOH.

The CaCO3 (calcium carbonate) precipitates because it's highly insoluble, and NaOH remain in solution. So, the role of carbon is to make an insoluble compound of Ca, leaving NaOH in solution.

Ca(OH)2 is made from CaO and water. CaO is made heating CaCO3 at temperatures higher than 900°C.

The same could be achieved, for example, with Na2SO4 or NaF or Na3PO4 or...:
CaSO4, CaF, Ca3(PO4)2... are insoluble as well.