ANFO
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ANFO (/ˈænfoʊ/ AN-foh)[1] (or AN/FO, for ammonium nitrate/fuel oil) is a widely used bulk industrial explosive. It consists of 94% porous prilled ammonium nitrate (NH4NO3) (AN), which acts as the oxidizing agent and absorbent for the fuel, and 6% number 2 fuel oil (FO).[2] The use of ANFO originated in the 1950s.[3]
ANFO accounts for an estimated 90% of the 2.7 million tonnes (6 billion pounds) of explosives used annually in North America.
Chemistry
The chemistry of ANFO detonation is the reaction of ammonium nitrate with a long-chain
The fuel component of ANFO is typically diesel, but kerosene, coal dust, racing fuel, or even molasses have been used instead. Finely powdered aluminium in the mixture will sensitise it to detonate more readily.[7]
Explosive properties
ANFO is highly insensitive, making it a
ANFO is technically a
Industrial use
In the mining industry, the term ANFO specifically describes a mixture of solid ammonium nitrate prills and diesel fuel. Other explosives based on the ANFO chemistry exist; the most commonly used are emulsions. They differ from ANFO in the physical form the reactants take. The most notable properties of emulsions are water resistance and higher bulk density.
While the density of pure crystalline ammonium nitrate is 1700 kg/m3, individual prills of explosive-grade AN measure approximately 1300 kg/m3. Their lower density is due to the presence of a small spherical air pocket within each prill: this is the primary difference between AN sold for blasting and that sold for agricultural use. These voids are necessary to sensitize ANFO: they create so-called "hot spots".[a] Finely powdered aluminium can be added to ANFO to increase both sensitivity and energy;[10] in commercial usages however, this has fallen out of favor due to cost.
ANFO has a bulk density of about 840 kg/m3. In surface mining applications, it is typically loaded into boreholes by dedicated trucks that mix the AN and FO components immediately before the product is dispensed. In underground mining applications, ANFO is typically blow-loaded.
AN is highly
Regulation
In most jurisdictions, ammonium nitrate need not be classified as an explosive for transport purposes; it is merely an
ANFO under most conditions is
Ammonium nitrate is widely used as a
Disasters
Unmixed ammonium nitrate can decompose explosively, and has been responsible for several industrial disasters, including the following:
- 1921 Oppau explosion in Germany
- 1947 Texas City disaster in Texas City, Texas
- 2004 Ryongchon disaster in North Korea
- 2011 Oslo, Norway
- 2013 West Fertilizer Company explosion in West, Texas
- 2015 Tianjin explosions
- 2020 Beirut explosion
Environmental hazards include eutrophication in confined waters and nitrate/gas oil contamination of ground or surface water.[13]
Paramilitary use
ANFO was used in 1970 when protests by students became violent at the University of Wisconsin–Madison, who learned how to make and use ANFO from a Wisconsin Conservation Department booklet entitled Pothole Blasting for Wildlife,[6][14] resulting in the Sterling Hall bombing.
ANFO used to be widely used by the FLNC (National Liberation Front of Corsica), along with f15 explosive. Five containers of 500 kilograms (1,100 pounds) each were used to blow up the Tax Office building in Bastia on 28 February 1987.[citation needed]
The ANFO
A more sophisticated variant of ANFO (ammonium nitrate with nitromethane as the fuel, called ANNM) was used in the 1995 Oklahoma City bombing.[citation needed]
The
In November 2009, the government of the
In April 2010, police in Greece confiscated 180 kg of ANFO and other related material stashed in a hideaway in the Athens suburb of Kareas. The material was believed to be linked to attacks previously carried out by the "Revolutionary Struggle" terrorist group.[citation needed]
In January 2010, President Hamid Karzai of Afghanistan also issued a decree banning the use, production, storage, purchase, or sale of ammonium nitrate, after an investigation showed militants in the Taliban insurgency had used the substance in bomb attacks.[18][19][20]
On 22 July 2011, an aluminium powder-enriched ANNM explosive, with total size of 950 kg (150 kg of aluminium powder), increasing demolition power by 10–30% over plain ANFO, was used in the Oslo bombing.[21][22]
On 13 April 2016, two suspected IRA members were stopped in Dublin with 67 kg of ANFO.[23]
On 6 March 2018, 8 members of the extreme right
References
- prilledammonium nitrate effectiveness in which the interaction of the detonation front with a spherical void concentrates energy. Blasting-grade AN prills are typically between 0.9 and 3.0 mm in diameter.
- ^ "ANFO | explosive". Encyclopedia Britannica. Retrieved 4 May 2019.
- ASIN B0000EGDJT.
- ^ Encyclopædia Britannica
- ^ Edward M. Green (June 2006). "Explosives regulation in the USA" (PDF). Industrial Materials (465): 78. Archived from the original (PDF) on 11 October 2022. Retrieved 3 March 2013.
- ASIN B0000EGDJT.
- ^ a b Mathiak, Harold A. (1965). Pothole Blasting for Wildlife. Wisconsin Conservation Department, Madison, Wisconsin 53701. p. 11.
- ISBN 9788122409741.
- ^ ASIN B000JM3SD0.
- ^ "Explosives – ANFO (Ammonium Nitrate – Fuel Oil)". GlobalSecurity.org. Retrieved 3 March 2013.
- ^ PMID 34640139.
- ASIN B0000EGDJT.
- ^ "Explosives and blasting agents". Occupation Safety & Health Administration. Retrieved 3 March 2013.
- ^ P. Cosgrove. Ammogex Material Safety Data Sheet, Document No: HS-MSDS-03, Irish Industrial Explosives Ltd
- LCCN 2007274127..
- ^ Henry Stanhope (8 November 1974). "The will to blow the lid off Ulster still remains strong". The Times. London.
- ^ "Bombs".
- ^ "石家庄九名制贩爆炸物的嫌犯被刑事拘留" [Shijiazhuang nine suspects of the sale of explosives were detained in criminal detention] (in Chinese). Beijing. 3 April 2001. Retrieved 12 August 2017.[permanent dead link]
- ^ "Afghanistan bans chemical used to make bombs; protesters denounce killings". Times Union. Albany, N.Y. Archived from the original on 7 June 2010.
- ^ "Afghanistan bans chemical used to make bombs". The Guardian. AP Foreign. 22 January 2010. Retrieved 3 March 2013.
- ^ Dexter Filkins (11 November 2009). "Bomb Material Cache Uncovered in Afghanistan". The New York Times. Retrieved 3 March 2013.
- ^ Stina Åshildsdatter Grolid; Unni Eikeseth (25 July 2011). "Slik virket trykkbølgen etter bomben" [Such seemed the shock wave after the bomb] (in Norwegian). NRK. Retrieved 28 July 2011.
- ^ Stigset, Marianne; Kremer, Josiane; Treloar, Stephen (27 July 2011). "Police in Norway Extend Terror Probe Across Europe After Breivik Attacks". Bloomberg.
- ^ Daniel Hickey (13 April 2016). "Two men appear in court charged with possession of 150 kg of homemade explosives". Irish Independent. Dublin. Retrieved 16 April 2016.
- ^ "Ο 'Τσαμπ' της 'Combat 18' και ο 'Λύκος' της Χρυσής Αυγής επιβεβαιώνουν τη λογική των 'συγκοινωνούντων δοχείων'".