ANFO (or AN/FO , for ammonium nitrate/fuel oil ) is a widely used large industrial explosives. His name is commonly pronounced as "an-fo".
It consists of 94% porous prilled ammonium nitrate (ANN), which acts as an oxidizing agent and absorber for fuel, and 6% of fuel 2 oil (FO).
ANFO has found extensive use in coal mining, quarrying, metal mining, and civil construction in applications where low cost and ease of use may outweigh the benefits of other explosives, such as water resistance, oxygen balance, higher detonation rate, or performance in small diameter columns. ANFO is also widely used in avalanche mitigation.
It accounts for about 80% of 2.7 ÃÆ' - 10 9 Ã, kg (6 ÃÆ'â € "
The press and other media have used the term ANFO loosely and incorrectly in describing the IEDs, in the case of fertilizer bombs (see Hazardous use below).
The use of ANFO originated in the 1950s.
Video ANFO
Chemistry
ANFO blasting chemistry is a reaction of ammonium nitrate with a long chain alkane (C n H 2n 2 ) to form nitrogen, carbon dioxide, and water. In an ideal stoichiometric balanced reaction, ANFO consists of about 94.3% AN and 5.7% FO by weight. In practice, little excess fuel is added, since underdoses produce reduced performance while overdose only produces more post-explosive smoke. When the detonation condition is optimal, the gas mentioned above is the only product. In practical use, such conditions are impossible to achieve, and explosions produce moderate toxic gases such as carbon monoxide and nitrogen oxides (NO x ).
ANFO fuel components are usually diesel, but kerosene, coal dust, racing fuel, or even molasses have been used instead. The powdered aluminum powder in the mixture will make it sensitive to blow up faster.
The ANFO is classified as an explosive agent, which means that decomposition through detonation rather than deflagration at a speed higher than the speed of sound in the material but can not be detonated by a blasting cap. 8 without sensitizer. ANFO has medium speed compared to other industrial explosives, measuring 3,200 m/s with a diameter of 130 mm (5 in), unconstrained, at ambient temperature.
ANFO is a tertiary explosive, which means that it can not be removed by a small explosive number in a typical blasting cap. A larger secondary explosive number, known as a primer or booster, should be used. One or two dynamite sticks are used historically; The current practice is to use Tovex or pentolite booster reinforcement (TNT/PETN or similar compositions).
Maps ANFO
Industrial use
In the mining industry, the term ANFO specifically describes a mixture of solid ammonium nitrate and diesel fuel. Other explosives based on ANFO chemistry exist; the most commonly used is the emulsion. They differ from ANFO in the physical form of the reactants. The most prominent emulsion properties are higher water resistance and bulk density.
While the pure crystalline ammonium nitrate density is 1700 kg/m 3 , each explosive AN explosive level is about 1300 kg/m 3 . Its lower density is due to the presence of a small spherical air pocket in each prill: this is the main difference between AN sold for blasting and sold for agricultural use. These voids are needed to make ANFOs sensitive: they create what is called a "hot spot". Fine powder aluminum can be added to ANFO to increase sensitivity and energy; However, this has fallen due to lack of cost.
ANFO has a mass density of about 840 kg/m 3 . In surface mining applications, it is usually added to the borehole by a special truck that mixes the AN and FO components immediately before the product is delivered. In an underground mining application, ANFO is usually blow-loaded.
AN is very hygroscopic, easy to absorb water from the air. In a humid environment, the water absorbed interferes with its explosive function. AN is completely soluble in water; thus, can not be loaded into drill holes containing standing water. When used in wet mining conditions, considerable effort must be taken to remove the puddles and install the liner in the borehole; generally more productive than using waterproof explosives such as emulsions.
Regulatory treatment
In most jurisdictions, ammonium nitrate does not need to be classified as an explosive for transport purposes; it is just an oxidizer. Mines usually prepare ANFO in place using the same diesel fuel that drives their vehicles. While many fuels can theoretically be used, low volatility and diesel costs make it ideal.
ANFO under the most blasting conditions are hat-sensitive, so it is classified as a blasting agent and not high explosive.
Ammonium nitrate is widely used as a fertilizer in the agricultural industry. It is also found in instant cold packs. In many countries, purchases and their use are limited to buyers who have earned the right license.
In popular culture
Discovery Channel shows ANFO's MythBusters commonly used (with the help of professional detonation), especially in episode 26: "Salsa Escape, Cement Removal" and episode 125: "Knock Your Socks Off" as well as the final series when they are not just blew up recreational vehicles, but created the most iconic explosion in the event's history when they used 5,01 pounds of ANFO to blow up a cement truck.
It was used by Jim Caviezel's character in the 2006 DÃÆ'Â © jÃÆ' Vu film in the domestic terrorist attacks.
In the book The Third Day, The Frost by John Marsden, ANFO is used to blow up Cobblers Bay.
In the sub-plot of the Executive Order by Tom Clancy, the anarchists made a truck bomb full of ANFO but caught before reaching their targets.
In the book Battle Royale by Koshun Takami, students are trying to bomb school using ANFO.
In the movie The Dark Knight by Christopher Nolan, The Joker uses compounds to hold the two hostages, and tries to get people on every ferry blow up other ferries.
In the novel of Stephen King Desperation, novelist Johnny Marinville prevents other groups going ahead, and starts blowing up the Pit and this inside with the ANFO, sacrificing himself..
This is often mentioned and used by the Vic protagonist at NOS4A2 by Joe Hill.
Disaster
Unmixed ammonium nitrate can decompose explosively and be responsible for several industrial disasters, including the 1922 Oppau explosion in Germany, the Texas City disaster of 1947 in Texas City, Texas, the 2004 Ryongchon disaster in North Korea, and the explosion of the Western Fertilizer Company 2013 in West, Texas. Environmental hazards include eutrophication in restricted waters and contamination of kerosene or surface water of nitrate/gas.
Malicious use
The ANFO was first used evil in 1970 when student protests became violent at the University of Wisconsin-Madison, who learned how to make and use ANFO from a Wisconsin Conservation booklet titled Pothole Blasting for Wildlife , which resulted in the Sterling Hall bombing.
The ANFO is used for widespread use by the FLNC (Corsica National Liberation Front) in Corsica, along with the explosive f15, against the French invaders and symbols. Five containers of 500 kilos each were used to blow up the Tax Office building in Bastia on 28 February 1987.
An ANFO car bomb was adopted by IRA Temporary in 1972 and, in 1973, the Troubles consumed 47,000 pounds of ammonium nitrate for the majority of bombs. The Ulster Volunteer Force (UVF) also uses ANFO bombs, often mixing in gelignite as a booster. The IRA detonated an ANFO truck bomb at Bishopsgate in London in 1993, killing one and causing damage worth  £ 350 million. It is also seen being used by groups such as the Colombian Revolutionary Armed Forces and ETA. In 1992, Shining Path conducted the Tarata bombing in Lima, Peru, using two ANFO truck bombs.
More sophisticated ANFO variants (ammonium nitrate with nitromethane as fuel, called ANNM) are used in the bombing of Oklahoma City 1995.
The bombing of Shijiazhuang (Chinese: ???????????????????????????????????????????????????????????????????????????????????????????????? ??????????????????????????????????????????????????????????????????). others were injured when, in a short time, several ANFO bombs exploded near four apartment buildings.
Improvisation of bombs made with AN farming classes is less sensitive and less efficient compared to explosive class variations. In November 2009, the prohibition of ammonium sulfate, ammonium nitrate, and calcium ammonium nitrate fertilizer was applied in the former Malakand Division - consisting of Upper Dir, Lower Dir, Swat, Chitral and Malakand districts of North West Frontier Province (NWFP) of Pakistan - by government of NWFP, following reports that the chemical was used by militants to make explosives.
In April 2010, police in Greece seized 180 kg of ANFO and other related material hidden in a hideout in the outskirts of Athens, Kareas. The material is believed to be linked to attacks previously carried out by the terrorist group "Revolutionary Revolution".
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 Taliban militants had used the substance in a bomb attack.
On July 22, 2011, ANNM explosives of enriched aluminum powder, with a total size of 950 kg (150 kg of aluminum powder), increased destruction by 10-30% above ordinary ANFO, used in the Oslo bombing.
On April 13, 2016, two suspected IRA members were suspended in Dublin with 67 kg of ANFO.
On March 6, 2018, 8 members of the far-right neo-Nazi group «« Combat 18 Hellas »were arrested in Athens, Greece accusing some of the attacks on immigrants and activists with their 50 kg ANFO.
ANNM
Ammonium nitrate and nitromethane (ANNM) are one of the most powerful types of improvisation of AN-based explosives. The relative effectiveness factor of ANNM varies depending on the mixture, but does not exceed 1.0 (ANNM AL = R.E.F. from 1.0-1.1). ANNM usually contains 60:40 (kinepak) mixture of AN and NM (60% ammonium nitrate, 40% nitromethane by mass), although this produces a wet slurry. Sometimes, more AN is added to reduce liquidity and make it easier to store and handle, as well as providing a balanced mix of oxygen. ANNM is also more sensitive to shock than standard ANFO and therefore easier to detonate. When ANNM erupts, the main product is H 2 O, CO 2 and N 2 , but NOT x and gas Other toxic must be formed due to negative oxygen balance. The balanced equation is as follows:
3NH 4 NO 3 2CH 3 NO 2 - & gt; 4N 2 2CO 2 9H 2 O
Depending on the detonation impulse (eg detonator # 6 versus detonator # 10), the detonation product can be ascertained to be chemically unstable.
References
External links
- An ANFO video is used in the open pit
- Video showing ANFO 5 kg charge billing
- Securing Ammonium Nitrate: Using Lessons Gained in Afghanistan to Protect Affairs from IED: Hearing before the Subcommittee on Cyber ​​Security, Infrastructure Protection and Security Technology from the Domestic Security Committee, House of Representatives, One Hundred Twelve Congresses, Second Session, July 12, 2012
Source of the article : Wikipedia
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