7/30/2019 Calcium Hydroxide Production

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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

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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

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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

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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

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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

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:The layer of seashells

:The last layer of charcoal

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: 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.

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: 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.

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:''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