Difference between revisions of "Armstrong's mixture"

From Sciencemadness Wiki
Jump to: navigation, search
(Preparation)
Line 10: Line 10:
  
 
==Preparation==
 
==Preparation==
Armstrong's mixture can be prepared by '''''very carefully''''' mixing powdered red [[phosphorus]] and [[potassium chlorate]]. This is always done underwater or under a liquid.
+
Armstrong's mixture can be prepared by '''''extremely carefully''''' mixing powdered red [[phosphorus]] and [[potassium chlorate]]. This is always done underwater or under a non-flammable liquid. The mixture is then let to dry in open air.
  
 
==Safety and handling==
 
==Safety and handling==

Revision as of 21:32, 15 December 2020

Armstrong's mixture is a highly sensitive primary explosive, often found in various pyrotechnic toys.

Composition

Armstrong's mixture consists of red phosphorus and potassium chlorate. Other formulae use potassium perchlorate. Sulfur is used to substitute for some or all of the phosphorus to slightly decrease sensitivity and lower costs. Calcium carbonate may also be present in small proportions, as desensitizer. Mixtures, in which the chlorate is replaced by bromate exceed those in sensitivity and are even more unstable and sensitive.

Availability

Armstrong's mixture is found in paper caps in toy cap guns and in party poppers. The amount is very small, a few milligrams, and it's mixed with glue for better stability. Due to the high dangers of this mixture, it's extremely risky to extract this mixture.

Preparation

Armstrong's mixture can be prepared by extremely carefully mixing powdered red phosphorus and potassium chlorate. This is always done underwater or under a non-flammable liquid. The mixture is then let to dry in open air.

Safety and handling

Armstrong's mixture is highly sensitive and can explode if heated or impacted. Due to extreme sensitivity to friction, mixing dry potassium chlorate and red phosphorus will most likely lead to an explosion, hence the ingredients are usually combined in a slurry with water, formed into the final product (for example, single drops onto paper for "paper caps") and allowed to dry. To decrease sensitivity, oil can be added.

References

Relevant Sciencemadness threads