calcium hydroxide production
TRANSCRIPT
-
7/30/2019 Calcium Hydroxide Production
1/9
Calciumhydroxideproduction
Usingseashellsandcharcoal
Made by plante1999
Introduction
It is know that when calcium carbonate is heated to 850 degree Celsius it decompose to carbon dioxide
and calcium oxide (1), This reaction have been use since very old time for quicklime production. Mixing
the calcium oxide with water would produce calcium hydroxide (2) which has been use as a cement
since early man civilization. A typical lime kiln was made with brick, the fuel was coal/charcoal and the
calcium carbonate was in form of limestone (the name is a little obvious). Air supply was not
compressed as modern variant; the kiln was filled with alternated layer of coal/limestone.
Material required:
Hardwood charcoal/hardwood
Good purity limestone/seashells
16 normal bricks
Hair drier
1.5 inch steel pipe by 2 feet
Glass stir rod(steel could also work)
A polypropylene container
A stainless mesh
Optional:
A stainless steel mug
A thermometer
Ammonium salt
10% Hydrochloric acid, HCl
A steel plate
-
7/30/2019 Calcium Hydroxide Production
2/9
Experimental:
The furnace (the lime kiln)
First a furnace is made fallowing a similar pattern as this one. It is made from normal bricks and the
furnace is made on a steel plate for a better purity of the end product. If the furnace is directly made on
the ground contamination from the dirt of the ground will occur. It is preferable to use a non-oxidized
steel plate since rust could induce iron impurity in your product. One could argue about the fact that
iron oxidizes at high temperature but it is not a problem since the furnace atmosphere will be highly
reducing.
: The Furnace
: The hairdryer
-
7/30/2019 Calcium Hydroxide Production
3/9
The calcium carbonate source:
One could use limestone, which is very common. But limestone could have sulphur and iron impurity
which does make quite a bad quality product. It is know that in early time if limestone couldnt be foundsometime seashells where used instead. Seashells could be picked near a lake/ocean but one could buy
some at the dollar store for a really low price. It is a good idea to test the seashells for calcium,
dissolving one seashell in 10% HCl should make large amount of effervescence and a colorless solution,
if this solution is added to a sodium carbonate and/or sodium sulphate solution a white precipitate
should form.
CaCO3 + 2HCl -) CaCl2 + H2O + CO2
CaCl2 + Na2CO3 -) 2NaCl + CaCO3
CaCl2 + Na2SO4 -) 2NaCl + CaCO3
:The seashells
-
7/30/2019 Calcium Hydroxide Production
4/9
The fuel:
If one live in a countryside he could use wood but he would have been warned that using wood in this
type of furnace is really smelly since wood seam to char and only the carbon produced seam to burn. A
better fuel is hardwood charcoal in large pieces. Hardwood charcoal burn with an hotter temperature
than wood but produce a lot of carbon monoxide gas, In fact when the blower of the furnace is turned
off large amount of blue flame is made proving that the charcoal does not burn completely to carbon
dioxide.
:'' If one live in a countryside he could use wood (the forest near the backyard of my house)
Using the kiln:
First make a layer of charcoal on the bottom of the furnace, add a layer of seashells on top of it, one
handful of seashell is a good proportion, then add a layer of charcoal on top of the seashells. For
starting the furnace it is recommended to use some type of alcohol, lime methanol (wood alcohol). Pour
-
7/30/2019 Calcium Hydroxide Production
5/9
most of the methanol on the bottom of the furnace and light it, when the charcoal/wood seams to burn
by itself start the hairdryer to maximum speed (Check for the cold mode to reduce electricity cost). It
takes about 10minutes to complete a run.
: A better fuel is hardwood charcoal in large pieces.
:The first layer of charcoal
-
7/30/2019 Calcium Hydroxide Production
6/9
:The layer of seashells
:The last layer of charcoal
-
7/30/2019 Calcium Hydroxide Production
7/9
: It takes about 10minutes to complete a run.
Processing/drying:
After the run the shells will be on the bottom of the furnace, simply mixt it with distill water. After a few
minutes the distill water will become cloudy and large amount of heat will be generated, this is an
indication that youre on the right track. Mix the shells in the water to make a paste, the mixture will
heat a lot. At this point one could simply purify it by your own way.
First pour the mixt in a Stainless steel mug and heat the mug to boil off water. Then you will end up with
a powder with some shells pieces. To remove the shells pieces use a Stainless mesh, this will remove
most of the calcium carbonate contamination. You will end up with a white powder.
-
7/30/2019 Calcium Hydroxide Production
8/9
: Temperature rising when the calcium oxide react with water and the newly formed calcium hydroxide
paste.
Testing:
To test the product for calcium hydroxide/calcium carbonate contamination I recommend to use this
simple procedure, it does not show the percentage of carbonate contamination but it does give a good
approximation. First dissolve Somme of your crude product in dilute HCl, if it makes almost no
effervescence and a colorless solution your product doesnt have a lot of contamination from calcium
carbonate/carbon. Then make a solution of ammonium salt and add your crude product to it, a strong
odor of ammonia should be observed.
Description of the crude product: Pure white powders with few small black particles which I suppose are
carbon.
-
7/30/2019 Calcium Hydroxide Production
9/9
:''Pure white powder with few small black particles which I suppose are carbon.''
Quote 1:
CaCO3 -850degree Celsius-) CaO + CO2
Quote 2;
CaO + H2O -) Ca(OH)2
Reference:
Wikipedia
-calcium hydroxide-calcium oxide
-lime kiln
My own work