Ammonium Nitrate Slurries

Ammonium nitrate slurries can be either prepared in the factory and loaded into cartridges or mixed on site and pumped down the shot-holes. Ammonium nitrate slurries consist of a saturated aqueous solution of ammonium (about 65%) and other nitrates (i.e. methylamine nitrate MAN ). This solution also contains additional amounts of undissolved nitrates together with a fuel. The fuel is generally aluminium powder but water-soluble fuels such as glycol may also be employed. The slurries can be made more sensitive by adding either TNT, PETN, 

Gelatine dynamite 25-55% Nitroglycerine, 1-5% nitrocellulose, woodmeal Inorganic nitrates 

Ammonium nitrate slurries can be either prepared in the factory and loaded into cartridges or mixed on site and pumped down the shot-holes. Ammonium nitrate slurries consist of a saturated aqueous solution of ammonium (about 65%) and other nitrates (i.e. 

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Decomposition of a 70% nitric acid-ammonium nitrate slurry explosive led to overflow, contact with wood and a fire. This spread to detonators, which initiated detonation of the slurry. 

Gulf Oil Corporation Aqueous Ammonium Nitrate Slurry Explosive Compositions Containing Hexamethylenetetramine... 

Ammonium Nitrate Slurry Sensitized with Nitro substituted Alkanols... 

Ammonium Nitrate Slurry Blasting Composition Containing Sulfur—Sodium Nitrate Sensitizer... 

In some chemical granulation processes, the solid raw materials, for example MOP, are partially dissolved in an ammonium phosphate and/or ammonium nitrate slurry and the mixture is then sprayed onto a bed or curtain of material in the granulator which is usually a heated rotary drum, for example, a Spherodizer . In this process, granules are formed primarily by accretion (refer to Chapter 13). 

Water-in-od emulsion explosives have been made as typified by a formulation containing 20% water, 12% oil, 2% microspheres, 1% emulsifier, and 65% ammonium nitrate. The micro droplets of an emulsion explosive offer the advantage of intimate contact between fuel and oxidizer, and tend to equal or outperform conventional water-based slurries. 

Oil-Explosive Combinations. See under Slurry Explosives in Vol 6, E469-R, and under Ammonium Nitrate Blasting Explosives in Vol 1, A341ff... 

Special authorisations are available for manufacture at the site of use of ammonium nitrate/fuel oil and certain slurry explosives provided that the equipment used and its position on the site are suitable. 

In the 1950 s a sudden and dramatic change affected the explosives industry in many parts of the world. This was the introduction in the U.S.A., Sweden and Canada of ammonium nitrate sensitised with fuel oil as a major blasting explosive. A slower but also important change started in the 1960 s with the development of slurry explosives in the U.S.A., Canada and other countries. 

This base is used to the minimum possible extent in the final explosive as the water it contains does not contribute to the power and indeed requires energy for its evaporation. All slurry explosives therefore contain further ammonium nitrate in solid form and also a fuel for combustion. The ammonium nitrate is usually in dense form similar to that used in nitroglycerine explosives as this gives the best physical properties. However, it is common practice to mix the explosive hot so that much or all of the solid ammonium nitrate results from crystallisation during cooling. 

The first and still successful dense slurry was sensitised with TNT and therefore consisted of a suspension of TNT and solid ammonium nitrate in a solution of ammonium and sodium nitrates gelled with cross-linked guar gum. The TNT is preferably in the form of small pellets. No further fuel than the TNT is essential but aluminium can be added for increased... 

Long-term field trials in England have shown that N efficiency of cattle slurry applications declined once the application rate exceeded pasture plant requirements [7], The cattle slurry was reported to be 90% as efficient as ammonium nitrate fertiliser when applied at 300kg N/ha compared with 63% efficient at 600kg N/ha and that the efficiency varied with season of application, being most effective in spring. 

Inorganic oxidizers are widely used as blasting agents in mining and construction explosives and also in improvised explosive devices utilized by terrorists. Ammonium-nitrate-based explosives (e.g., ammonium nitrate and fuel oil — ANFO) have almost completely replaced the majority of dynamites. In addition, slurry and emulsion explosives, which contain mosdy ammonium nitrate and a small amount of other oxidizers, have become widely used. 

Ammonium nitrate (AN NH4NO3) is a white, crystalline material, the crystal structure of which varies with temperature.melting point is 442 K and its heat of fusion is 71.4 kj kg . Though the mass fraction of oxygen of AN is 0.5996, it is highly hygroscopic and absorbs moisture from the atmosphere to form liquid AN acid. This limits its application in propellants and pyrolants. However, AN is widely used as an oxidizer of explosives such as slurry explosives and ANFO (ammonium nitrate fuel oil) explosives. 

The physicochemical properties of explosives are fundamentally equivalent to those of propellants. Explosives are also made of energetic materials such as nitropolymers and composite materials composed of crystalline particles and polymeric materials. TNT, RDX, and HMX are typical energetic crystalline materials used as explosives. Furthermore, when ammonium nitrate (AN) particles are mixed with an oil, an energetic explosive named ANFO (ammonium nitrate fuel oil) is formed. AN with water is also an explosive, named slurry explosive, used in industrial and civil engineering. A difference between the materials used as explosives and propellants is not readily evident. Propellants can be detonated when they are subjected to excess heat energy or mechanical shock. Explosives can be deflagrated steadily without a detonation wave when they are gently heated without mechanical shock. 

Slurry explosives consist of saturated aqueous solutions of ammonium nitrate with sensitizing additives.[i-3] Nitrates such as monomethylamine nitrate, ethylene glycol mononitrate, or ethanolamine mononitrate are used as sensitizers. Aluminum powder is also added as an energetic material. Table 4.15 shows a typical chemical composition of a slurry explosive. It is important that so-called micro-bubbles are present within the explosives in order to facilitate the initial detonation and the ensuing detonation wave. These micro-bubbles are made of glass or polymeric materials. 

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