Magnesium combustion

In new research projects, non-combustible magnesium alloys are being developed. Investigations of the effect and mechanism of elements that may suppress the combustibility of magnesium are continuing. Calcium has been mentioned as an alloying element. 

The combustion of magnesium is a bit easier to talk about than the combustion of a hydrocarbon fuel, so I shall deal with magnesium first and then move on to the more familiar reaction of the combustion of hydrocarbons. I ll pretend that in its combustion, magnesium combines only with oxygen its additional reaction with nitrogen when it bums in air doesn t add much new and complicates the discussion. 

Other methods for analyzing combustion products can be substituted for chromatography. Gravimetry can be used, for example, after a series of absorption on different beds, as in the case of water absorption in magnesium perchlorate or CO2 in soda lime infra-red spectrometry can be used for the detection of CO2 and water. 

The deterrnination of hydrogen content of an organic compound consists of complete combustion of a known quantity of the material to produce water and carbon dioxide, and deterrnination of the amount of water. The amount of hydrogen present in the initial material is calculated from the amount of water produced. This technique can be performed on macro (0.1—0.2 g), micro (2—10 mg), or submicro (0.02—0.2 mg) scale. Micro deterrninations are the most common. There are many variations of the method of combustion and deterrnination of water (221,222). The oldest and probably most reUable technique for water deterrnination is a gravimetric one where the water is absorbed onto a desiccant, such as magnesium perchlorate. In the macro technique, which is the most accurate, hydrogen content of a compound can be routinely deterrnined to within 0.02%. Instmmental methods, such as gas chromatography (qv) (223) and mass spectrometry (qv) (224), can also be used to determine water of combustion. 

Detergents are metal salts of organic acids used primarily in crankcase lubricants. Alkylbenzenesulfonic acids, alkylphenols, sulfur- and methjiene-coupled alkyl phenols, carboxyUc acids, and alkylphosphonic acids are commonly used as their calcium, sodium, and magnesium salts. Calcium sulfonates, overbased with excess calcium hydroxide or calcium carbonate to neutralize acidic combustion and oxidation products, constitute 65% of the total detergent market. These are followed by calcium phenates at 31% (22). 

Uses. Magnesium alkyls are used as polymerization catalysts for alpha-alkenes and dienes, such as the polymerization of ethylene (qv), and in combination with aluminum alkyls and the transition-metal haUdes (16—18). Magnesium alkyls have been used in conjunction with other compounds in the polymerization of alkene oxides, alkene sulfides, acrylonitrile (qv), and polar vinyl monomers (19—22). Magnesium alkyls can be used as a Hquid detergents (23). Also, magnesium alkyls have been used as fuel additives and for the suppression of soot in combustion of residual furnace oil (24). 

Reactivity. Bromine is nonflammable but may ignite combustibles, such as dry grass, on contact. Handling bromine in a wet atmosphere, extreme heat, and temperatures low enough to cause bromine to soHdify (—6° C) should be avoided. Bromine should be stored in a cool, dry area away from heat. Materials that should not be permitted to contact bromine include combustibles, Hquid ammonia, aluminum, titanium, mercury, sodium, potassium, and magnesium. Bromine attacks some forms of plastics, mbber, and coatings (62). 

Aero-derivative gas turbines eannot operate on heavy fuels, thus if heavy fuels was a eriteria then the frame type turbines would have to be used. With heavy fuels, the power delivered would be redueed after about a weeks of operation by about 10%. On-line turbine wash is reeommended for turbines with high vanadium eontent in their fuel, sinee to counteract vanadium magnesium salts have to be added. These salts cause the vanadium when combusted in the turbine to be turned to ashes. This ash settles on the turbine blades and reduces the cross sectional area, thus reducing the turbine power. 

Combustible dusts include metal dust (e.g., aluminum, magnesium, and their commercial alloys), carbonaceous dust (e.g., carbon black, charcoal, and coal), flour, grain, wood, plastics, and chemicals. 

Group E. Atmospheres containing combustible metal dusts, including aluminum, magnesium, and their commercial alloys, or other combustible dusts whose particle size, abrasiveness, and conductivity present similar hazards in the use of electrical equipment. 

Farge combustion works Farge glass works Farge paper pulp works Head works Fime works Magnesium works Manganese works Metal recovery works Mineral works Nitrate and chloride or iron works... 

Magnesium-based additives are commonly employed to treat boiler furnace area fouling and corrosion conditions. They are injected into heavy fuel oil or other combustible material. Cerium is superior in action to magnesium salts, however, because an equivalent weight of cerium increases the melting point of the deposit more than that of magnesium. 

Assess whether the combustion of magnesium is spontaneous at 25°C under standard conditions, given... 

The high temperatures of coal char oxidation lead to a partial vaporization of the mineral or ash inclusions. Compounds of the alkali metals, the alkaline earth metals, silicon, and iron are volatilized during char combustion. The volatilization of silicon, magnesium, calcium, and iron can be greatly enhanced by reduction of their refractory oxides to more volatile forms (e.g., metal suboxides or elemental metals) in the locally reducing environment of the coal particle. The volatilized suboxides and elemental metals are then reoxidized in the boundary layer around the burning particle, where they subsequently nucleate to form a submicron aerosol. 

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