Extinguishing Titanium Fires

PYROPHORIC METALS

DOE-HDBK-1081-94

Spontaneous Heating and Pyrophoricity

base cutting lubricants. Consequently, water-based coolants should be used in ample

quantity to remove heat, and cutting tools should be kept sharp. Fines should be

removed regularly from work areas and stored in covered metal containers. To

prevent titanium dust explosions, any operation which produces dust should be

equipped with a dust collecting system discharging into a water-type dust collector.

Descaling baths of mineral acids and molten alkali salts may cause violent reactions

with titanium at abnormally high temperatures. Titanium sheets have ignited upon

removal from descaling baths. This hazard can be controlled by careful regulation of

bath temperatures.

There have been several very severe explosions in titanium melting furnaces. These

utilize an electric arc to melt a consumable electrode inside a water-cooled crucible

maintained under a high vacuum. Stray arcing between the consumable electrode and

crucible, resulting in penetration of the crucible, permits water to enter and react

explosively with the molten titanium. Indications are that such explosions approach

extreme velocities. The design and operation of these furnaces require special

attention in order to prevent explosions and to minimize damage when explosions do

occur.

Extinguishing Titanium Fires

Tests conducted by Industrial Risk Insurers (IRI) on titanium machinings in piles and

in open drums showed that water in coarse spray was a safe and effective means of

extinguishing fires in relatively small quantities of chips.

Carbon dioxide, foam, and dry chemical extinguishers are not effective on titanium

fires, but good results have been obtained with extinguishing agents developed for use

on magnesium fires.

The safest procedure to follow with a fire involving small quantities of titanium

powder is to ring the fire with a Class D extinguishing agent and to allow the fire to

burn itself out. Care should be taken to prevent formation of a titanium dust cloud.

Alkali Metals Sodium, Potassium, NaK, and Lithium

Properties

Sodium

At room temperature sodium oxidizes rapidly in moist air, but spontaneous

ignitions have not been reported except when the sodium is in a finely divided

form. When heated in dry air, sodium ignites in the vicinity of its boiling point

(880 C or 1,616 F). Sodium in normal room air and at a temperature only

Pyrophoricity

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