Reactive metal-water explosions

In casting or processing reactive metals such as titanium, tungsten, and molybdenum, incidents have occurred in which molten metal contacted water. In some instances, explosions have resulted. There have been no published papers describing such accidents.  

Few in-depth studies have been made for any single accident in no case were the energetics developed to yield information on TNT equivalents nor were overpressures determined. The accidents were at industrial or government production plants and rarely was there an opportunity for an immediate on-site inspection after an incident. 

When accidents are analyzed, the initial event is usually the failure of 

In an accident report prepared by Robert Beall, he concludes  

Of imp Mtant consideration is the fact that water leaks in arc furnaces of this type have occurred occasionally in the various melting establishments without any serious explosion resulting therefrom. In a few reported instances, steam buildups have been noted but not of serious consequence. It must be pointed out that the affair here reported required the coincidental occurrence of a water injection, intimate mixing with molten metal, and very possibly, tamping of the mixture by the falling electrode. Such a chain of circumstances can lead to a powerful explosion rather than the customary quiet extinguishing of the arc. 

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Reactive metal-water explosion No solid r ctive metals in stored radioactive materials or equipment Extremely unlikety. 

Chemical Reactivity - Reactivity with Water Reacts vigorously to form toxic hydrogen fluoride (hydrofluoric acid) Reactivity with Common Materials When moisture is present, causes severe corrosion of metals (except steel) and glass. If confined and wet can cause explosion. May cause fire in contact with combustible material Stability During Transport Stable Neutralizing Agents for Acids and Caustics Flush with water, rinse with sodium bicarbonate or lime solution Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Reaction with cold water is of moderate vigour, but violent with hot water, and the liberated hydrogen may ignite [1], The powdered metal reacts explosively with water [2], The reactivity of lithium and other alkali metals with various forms of water has been discussed in detail. Prolonged contact with steam forms a thermally insulating layer which promotes overheating of the metal and may lead to a subsequent explosion as the insulating layer breaks up [3],... 

For small-scale experiments, the LNG and liquid refrigerant cases are analyzed using a model which assumes that the volatile liquid (or some part of it) is superheated to a temperature at which homogeneous nuclea-tion occurs. Such nucleation is very rapid and the event resembles an explosion. An attempt is made to employ this same model to explain R s in the water-smelt, water-aluminum, and water-reactive metal cases, but data to make definitive conclusions are lacking. 

Sodium is extremely reactive. It reacts explosively in water as it releases hydrogen from the water with enough heat to ignite the hydrogen. The resulting compound of this reaction is sodium hydroxide (2Na + 2HjO —> 2NaOH + H T). Due to its extremely electropositive reactivity, there are few uses for the pure metallic form of sodium. Because of its reactivity, hundreds of sodium compounds are found on the Earth s surface. 

Bromine pentafluoride is a highly reactive compound combining explosively or with ignition with most elements and their compounds. Spontaneous explosion or flaming can occur when mixed with water, organic compounds, metal powder, metal hahdes, metal oxides, metal sulfides and chlorine (upon warming) (Patnaik, P. 1999. A Comprehensive Guide to the Hazardous Properties of Chemical Substances, 2nd ed. New York John Wdey). 

Barium Perchlorate — Fire Hazards Flash Point (deg. F) Not flammable but can aggravate fire intensity Flammable Limits in Air (%) Not flammable Fire Extinguishing Agents Not pertinent Fire Extinguishing Agents Not To Be Used Not pertinent Special Hazards of Combustion Products Not pertinent Behavior in Fire Increases the intensity of fires. Containers may burst or explode Ignition Temperature (deg. F) Not pertinent Electrical Hazard Not pertinent Burning Rate Not pertinent. Chemical Reactivity Reactivity with Water No reaction Reactivity with Common Materials When mixed with combustible materials or finely divided metals, can become an explosive... 

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