5 replies to this topic

[spectrum]

Would appreciate advice on a safe method of rendering compositions containing Potassium Chlorate inert by chemical means. The composition is wetted with water - it's a match-head composition - but would need converting to a state whereby if it were allowed to dry, it would NOT leave an explosive substance - "self sustaining burning".

 

Any process should therefore be conducted whilst wet and leave a residue which is "dead" when dry. The process should be safe of course. No enthusiasm really for Manganese Dioxide and clouds of Oxygen. 

 

 

[Rob.L.]

Have you thought about dissolving out the potassium chlorate in warm water as this is most likely to leave any other components as solids? It may take a while or be impossible, particularly if you have a binder.

 

It may be that after washing the residue with warm water several times you could introduce potassium or sodium chloride in excess so that the 'fuel' contains so little oxidising material as to render it stable?

 

Without knowing the composition,  may be you could introduce an excess of sodium chloride or potassium carbonate, which being hygroscopic may prevent it from drying out as well as 'diluting' the components?

 

I am guessing you are doing this professionally so perhaps a controlled burn at a suitable site may be possible?

 

With no other detail it is possible that the above my be inappropriate.

 

Regards. Rob. L.

[spectrum]

Thanks Rob. I did consider overloading the fuel balance to render any dried residue ineffective and as you rightly say, using a hygroscopic diluent to see that it struggled to dry at all - I was thinking Calcium Chloride.

 

Also thought about introducing a reducing agent, say Magnesium, to reduce the Chlorate and create an inert Oxide but have safety concerns on this one although if wet I can't see it cooking off to ignition point - the atmosphere might be a bit fruity of course!

[digger]

OK here you go, a few different method from the old cape Canaveral site

 

All the chemicals below work by reducing the Chlorate ion. The Sulphites have the same reducing power in dilute acidified solutions as Sulphur Dioxide. All the Sulphite and Sulphur Dioxide reactions take place in a similar manner. You can test for the presence of Chlorate in your product as per US Patent No. 2,392,769
Use K compounds if you need to keep Na out of your final product.

 

Sodium Metabisulphite

The solution should first be acidified to pH 3 or so using Sulphuric or HCl acid, the Sulphite added and the solution heated strongly or boiled

The Sodium Metabisulphite reactions take place according to:

First, the Metabisulphite dissociates:

Na2S2O5 + H2O <----> 2Na⁺ + 2H⁺ + 2SO3^2-
The Sulphite then reacts with Chlorate:

3SO3^2- + ClO3 ^- => 3SO4^2- + Cl^-
The overall reaction is:

3Na2S2O5 + H2O + 2NaClO3 => 3Na2SO4 + 3H2SO4 + 2NaCl
There is more info. here on dissociations.

You can then neutralise the solution using Sodium Hydroxide which will give you more Sodium Sulphate and water.

H2SO4 + 2NaOH ==> Na2SO4 + 2H2O

 

Sodium Bisulphite

Similar to Metabisulphite

 

Sodium Sulphite

Similar to Bisulphite

 

Sodium Disulfite

Similar to Bisulphite

 

Sulphur Dioxide

See US Patent No. 2,392,769
The chemical equation would be:
SO2 + H2O ===> 3H2SO3 + ClO3 ^- ===> Cl^- + 3SO4^2-
Sulfur dioxide gas can be generated by a number of means including adding HCl to Sodium Bisulfite and gently heating.

 

Ferrous Sulphate + H2SO4

This is cheap and easy to obtain. The reaction products should not be a problem. The Sulphate should be dissolved in the acidified water (the acid will stop Iron Hydroxide form forming, it is also necessary for the reaction that destroys the Chlorate) first and then added to the solution that is being treated.
6FeSO4 + NaClO3 + 3H2SO4 ====> 3Fe2(SO4)3 + NaCl + 3H2O
Keep the pH below 3 for the reaction to proceed and the solution should be heated/boiled.

 

Ferrous Ammonium Sulphate + H2SO4

Same as Ferrous (II) Sulphate but it is more expensive and harder to get. Does not oxidise in air as Ferrous (II) Sulphate does and won't form Hydroxide when added to water. Keep solution below pH 3 for destruction reaction to proceed. Heating or boiling should be used.

 

Strong acids

HCl is the best acid to use. Wouters page explains the process and is thus:
Acid is added to the solution to be treated and the solution is boiled. Yellow gas is released (the more Chlorate the more gas) as the Chlorate is destroyed.

2KClO3 + 4HCl ===> 2KCl + 2H2O + 2ClO2 + Cl2

This yellow gas is ClO2 and is explosive at concentrations above 10%. It is also very toxic, as is the Chlorine gas, and should not be inhaled under any circumstances. If using HCl, any excess acid can be gotton rid of by boiling. There should not be large amounts of Chlorate present (as with all the other methods) when adding acid. The solution is them basified with NaOH (or appropriate hydroxide or carbonate if you are concerned for the final colour that the produce will make when burned) and the presence of Chlorate should be checked for using some of the sensitive tests for Chlorate. HCl acid can be purchased at the builders providers and is used for cleaning cement

Edited by digger, 20 February 2017 - 06:06 PM.

[spectrum]

Thanks Gareth. You didn't rate the Sodium Hydroxide idea we discussed earlier?

[digger]

Nope, looked into it, not really a goer