Cast Iron Borings

Spontaneous Heating and Pyrophoricity

DOE-HDBK-1081-94

PYROPHORIC METALS

laying the sand around the perimeter of the fire, fine dry sand can be used to

isolate incipient fires of aluminum dust.

Cast Iron Borings

Cast iron borings or turnings are frequently available in the same machine shop

as the various combustible metals. Clean iron borings applied over a

magnesium chip fire cool the hot metal and help extinguish the fire. This agent

is used by some shops for handling small fires where, with normal good

housekeeping, only a few combustible metal chips are involved. Contamination

of the metal chips with iron may be an economic problem. Oxidized iron chips

must be avoided to prevent possible thermite reaction with the hot metal, and

the iron chips must be free from moisture.

Sodium Chloride

Alkali metal fires can be extinguished by sodium chloride, which forms a

protective blanket that excludes air over the metal so that the metal cools

below its burning temperature. Sodium chloride is an agent that is used for

extinguishing sodium and potassium fires. It can also be used to extinguish

magnesium fires.

Soda Ash

Sodium carbonate or soda ash (not dry chemical) is recommended for

extinguishing sodium and potassium fires. Its action is similar to that of sodium

chloride.

Lithium Chloride

Lithium chloride is an effective extinguishing agent for lithium metal fires.

However, its use should be limited to specialized applications because the

chemical is hygroscopic to a degree and may present problems because of the

reaction between the moisture and the lithium.

Zirconium Silicate

This agent has been used successfully to extinguish lithium fires.

Dolomite

If zirconium or titanium in the form of dry powder becomes ignited, neither

can be extinguished easily. Control can be effected by spreading dolomite (a

carbonate of calcium and magnesium) around the burning area and then adding

more powder until the burning pile is completely covered.

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Pyrophoricity