The “Titanium Canon” – An Introduction to Metal Combustion

Posted: June 29, 2015 in Fire Investigation, Fire Protection, Fire Science
Tags: , , , , , , ,

by: Jason A. Sutula

Most people do not think about metals burning when they think about combustion and fire. Yet, metals can combust, especially when the metals are being used within an industrial process or themselves being processed at higher temperatures. Fortunately for the process safety, mining, and other industries, much research on metal combustion has been done over the years. One of the first studies on the burning of metal dusts was published in 1955 by Titman (Titman, 1955).

Titman examined small metal particles and the influence they had on the explosive mixtures of gases. Additionally, the metal dusts themselves were determined to have explosive properties. The hazards of metal dust combustion are similar in nature to those of organic dusts, which were discussed in a previous post of mine (The Creamer Canon). Since metals have a high affinity for oxygen and have the material property of high heats of oxidation, they are capable of producing high temperatures and the liberation of energy in very rapid fashion.

Another seminal, systematic study was conducted by Harrison and Yoffe in 1961 and published in the Proceedings of the Royal Society of London (Harrison and Yoffe, 1961). Harrison and Yoffe conducted their experiments using wires of various metals. These metals included aluminum, iron, magnesium, molybdenum, titanium, and zirconium.

Harrison and Yoffe demonstrated that the process of metal combustion was much more difficult to initiate when the metal was in wire form as opposed to dust. Their results indicated that the explosive hazard associated with the metal dusts were not as much of a concern with larger chunks of metal. Additionally, Harrison and Yoffe discovered that the mode of burning for each metal was determined by the relative melting and boiling points of the metal and the metal oxides (which is formed as the product of the combustion reaction).

Today’s embedded YouTube video selection demonstrates the energetic reaction produced by titanium powder burning. The reaction of the individuals involved is eerily similar to that of the Mythbusters crew as seen in the Creamer Canon video. In addition to providing a means to educate us through videos on the internet, combustible metals do have many other useful purposes. One such is the use of metal dusts to ensure a specific color in commercial firework displays. Titanium, Aluminum, and Magnesium powders are used to make a vibrant white color in the pyrotechnic stars. With that in mind, an argument can be made that the Chinese were actually the first researchers who began walking the path of understanding metal combustion. Have a happy and fire safe 4th of July!

Titman, H., Trans. Inst. Min. Engrs., Lond., 115, 1955.

Harrison, P.L., and Yoffe, A.D., “The Burning of Metals,” Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 261, No. 1306, pp. 357-370, 1961.

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