Making fertilizer less explosive - 1405
- *Abstract
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Overview
Ammonium nitrate is a commonly used and widelyavailable component of fertilizer. Unfortunately, ammonium nitrate is a highly volatile and unstable material with explosive hazard characteristics. Ammonium nitrate mixed with fuel oil creates a powerful explosive, ANFO, which is a weapon of choice for acts of terrorism due to relatively low cost, availability, ease of assembly, and magnitude of destructive force released upon detonation.
In order to make ammonium nitrate fertilizers safe for consumer use, the explosive potential of the ammonium nitrate must be somehow controlled. Prior attempts to control the explosive potential of ammonium nitrate have included addition of desensitizing agents, the substitution of alternative nitrogen sources, and the dilution of ammonium nitrate with inert or thermally stable materials. Each of these methods has significant shortcomings, and so, until now, no practical means existed forrendering ammonium nitrate’s explosive capabilities inert while maintaining itsproperties as a fertilizer.
Invention
UK researchers are developing a formulation for coating ammonium nitrate with the fly ash which is generated in large quantities as a byproduct during coal combustion. In the United States alone, the annual production of fly ash is on the order of tens of millions of tons, and most of it is disposed of as waste. Therefore, there is plentiful supply of material that could be used in our coating process.
Ammonium nitrate particles are coated with Class C fly ash, a Class F fly ash, flue-gas desulfurization waste, and/or atmospheric fluidized bed combustion waste. Any coating method may be used, such as spraying, immersion, and disk pelletization, as long as a substantially even coating of a suitable thickness is achieved. Detonation tests showed that the coatings coatings were effective in stopping the propagation of the explosive.
Applications
- agriculture
- homeland security
- energy sectors
Advantages
- independently shown to reduce the explosivity ofammonium nitrate
- designated as a Qualifying Anti-TerrorismTechnology (QAT) by the Dept of Homeland Security
- potentially eliminates requirement to store andtransport AN as a Class 5.1 oxidant
- utilizes a low-cost coating and coating process
- two-year field studies of corn, wheat, andfescue crops demonstrated nutrient efficacy and benign environmental impact
- provides additional soil nutrients (calcium and sulfur) and a pH buffering component forthe ammonium nitrate
- maintains a suitable particulate size foragricultural fertilizer application equipment
- reduces land-fill space currently being used todump coal combustion by products
- coal ash is non-toxic and low-cost
IP Status: U.S. Patent No. 7,785,553
Publication
Taulbee, Darrell & T Thurman, James & Schwab, Greg. (2009). Reducing the Explosion Potential of Ammonium Nitrate Fertilizer by Coating with Coal Combustion By-Products. Available at http://www.flyash.info/2009/078-taulbee2009.pdf
- 國家/地區
- 美國
