Improvised Gas Mask


Step 9: Quench Some Coals

Picture of Quench Some Coals
I looked into my fire and saw some good coals glowing inside. So I knocked it apart, grabbed some good coals with tongs made from two sticks, and quenched them in water.

I was wondering whether my charcoal would be "activated" or not. After some reading I decided
my wasteful way of making it pretty much guaranteed it would be "activated". That means no hydrocarbons left in the pores and all the carbon being short chains with their little arms out ready to grab molecules.

Here's a 1919 blurb explaining making activated charcoal and soda lime fillers in WW1. from WAR GAS INVESTIGATIONS WAR WORK OF THE BUREAU OF MINES (google books)

Many different substances were carbonized, and the resulting charcoal tried for a gas-mask absorbent. Different kinds of wood were tried, also nut shellsincluding coconut shellslamp black, carbon black, blood, seaweed, and ivory nuts. The first coconut charcoal came from Dr. H. B. Lemon, of the University of Chicago, and by December, 1917, nut shells formed the basis of most of the charcoal used in gas masks.

In preparing highly efficient charcoal the main idea is to clean thoroughly the pores of the charcoal of any hydrocarbon residues, which greatly reduce the absorptive power. One method of cleaning is to let the charcoal cool in air so as to absorb as much oxygen as possible, and then reheat it to a comparatively low temperature. Oxidizing with steam has certain advantages, the charcoal being ground to about 8 to 14 mesh and steam treated.

Soda Lime.
Soda lime, a mixture of caustic soda and calcium hydroxide, is used in gas masks to remove acid vapors or gases from the air. A great deal of study and experiment was given to the making of a suitable product, and by December, 1917, through the efforts of the bureau, a factory, capable of producing 800 pounds a day of this material was actively at work. The soda lime finally produced was much superior to that made by the English.

Here's another version of the same story from THE CHEMICAL WARFARE SERVICE Clarence J. West (google books)

the preparation of active charcoal resolved itself into two steps: the formation of a porous, amorphous base carbon at relatively low temperatures, and the removal of the absorbed hydrocarbons from the primary carbon and the increase of its porosity. The first step involves the destructive distillation of a material (cocoanut shell was found the most suitable wood) at relatively low temperatures, in thin layers so that the deposition of inactive carbon from the cracking of hydrocarbons, would be avoided. The second step is much more difficult, and was finally accomplished by oxidation with air, steam or carbon dioxide steam, all of which were used in the manufacture of gas mask carbon.

In addition to the use of cocoanut shell (Dorsite), other sources were developed, such as anthracite coal (Bachite), and a synthetic product made by carbon manufacturing process
from lampblack, powdered coal and other suitable materials (Carbonite).

Soda Lime. Charcoal alone is not a satisfactory all-round absorbent because it has too little capacity for certain highly volatile acid gases, such as phosgene and hydrocyanic acid and also because an oxidizing agent is the best means of handling certain gases. It has, therefore, been found that the use of an alkaline oxidizing agent in combination with the charcoal is advisable. The material actually used was a soda lime containing sodium permanganate. The ratios used were 60 per cent. 6-14 mesh cocoanut shell charcoal and 40 per cent. 8-14 mesh soda lime permanganate granules. The last mixture suggested, which would have had a distinctly greater all round efficiency, was composed of 75 per cent. specially impregnated cocoanut charcoal and 25 per cent. soda lime containing no permanganate.

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where do we buy soda lime?
-max-3 years ago
what do you mean by: "After some reading I decided
my wasteful way of making it pretty much guaranteed it would be 'activated' "?
nickademuss5 years ago
you could also get activated charcoal from your pet shop, its used in the water filters, you may need to smash it a bit to make it pack in closer to your filter. I would also recommend, sealing off your filter when not in use, it will keep absorbing contaminants in the air just sitting around. Interesting idea....

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