Ammonium nitrate solids

In the dual-pressure process, low to medium pressure gases (0.3 to 0.6 MPa) containing nitrogen oxides are compressed to 1.1 to 1.5 MPa for efficient absorption in water to make nitric acid. Because of the potential for unreacted ammonia from the converter to combine with nitric acid to form ammonium nitrate, additional operating and safety precautions are necessary to deal with the accumulation of ammonium nitrate solids. One reported solution is a periodic injection of steam to parts of the compressor (see Figure 9.3)104. 

Ammonium nitrate, solid (nitrogen concentration of 23% nitrogen or greater) 33 2000 X ... 

Ammonium Nitrate and Urea. Almost half of the total fertilizer nitrogen application in the United States is as ammonium nitrate or urea, in either solid or solution form. The breakdown for the year that ended June 30, 1990 (Fig. 11.2) is ammonium nitrate solid 7 percent urea solid, 21 percent and urea-ammonium nitrate solutions, 20 percent. The history and the technology of ammonium nitrate and urea production from synthetic ammonia are covered in detail in Chapter 28. The production of nitric acid from synthetic ammonia, which is a prerequisite to the production of ammonium nitrate, also is covered completely in Chapter 28. The production plants for all these materials are, like synthetic ammonia plants, highly sophisticated, involving all facets of modern engineering. 

Solid particulates are captured as readily as hquids in fiber beds but can rapidly plug the bed if they are insoluble. Fiber beds have frequently been used for mixtures of liqmds and soluble sohds and with soluble solids in condensing situations. Sufficient solvent (usually water) is atomized into the gas stream entering the collector to irrigate the fiber elements and dissolve the collected particulate. Such nber beds have been used to collect fine fumes such as ammonium nitrate and ammonium chloride smokes, and oil mists from compressed air. 

Exothermic Decompositions These decompositions are nearly always irreversible. Sohds with such behavior include oxygen-containing salts and such nitrogen compounds as azides and metal styphnates. When several gaseous products are formed, reversal would require an unlikely complex of reactions. Commercial interest in such materials is more in their storage properties than as a source of desirable products, although ammonium nitrate is an important explosive. A few typical exampes will be cited to indicate the ranges of reaction conditions. They are taken from the review by Brown et al. ( Reactions in the Solid State, in Bamford and Tipper, Comprehensive Chemical Kinetics, vol. 22, Elsevier, 1980). 

Ammonium nitrate decomposes into nitrous oxide and water. In the solid phase, decomposition begins at about I50°C (302°F) but becomes extensive only above the melting point (I70°C) (338°F). The reaction is first-order, with activation energy about 40 kcal/g mol (72,000 Btii/lb mol). Traces of moisture and Cr lower the decomposition temperature thoroughly dried material has been kept at 300°C (572°F). All oxides of nitrogen, as well as oxygen and nitrogen, have been detected in decompositions of nitrates. 

Unloaded silica does not recover HPA from aqueous solution. The surface of silica gel modified with quarternary ammonium salts (QAS) gets anion-exchange properties. The aim of the work is the elaboration of solid-phase reagents on the base of ion associate of HPA with QAS immobilized onto silica surface for the determination of phosphoms and organic reductants. Heterocyclic (safranine and lucigenine) and aliphatic (trinonyloctadecyl ammonium iodide and tetradecyl ammonium nitrate) compounds have been examined as QAS. 

Reduced molibdophosphoric HPA was found to be well recovered by silica modified with tetradecyl ammonium nitrate. It was assumed as a basis of phosphoms determination in the range of 0.5-5 pmole using solid-phase spectrometry. 

Nitrous gases originating from the combustion units in nitric acid plants carry small amounts of unreacted ammonia, NH3. The ammonia may react with the nitrous gas to form microscopic particles of ammonium nitrate that adhere to solid surfaces. Within a short time, there is a growing layer of ammonium nitrate salt covering the internal surface of the nitrous gas compressor (Figure 4-27). This layer can obstruct the flow passages because it tends to increase the power consumption, provoke excessive vibrations, and even present a safety hazard since ammonium nitrate explosions can occur. 

Solutions. Two substances on the list, ammonium nitrate and ammonium sulfate, are qualified by the term solution," which refers to the physical state of these chemicals. Solid, molten, and pelletized forms of these chemicals are exempt from threshold and release determinations. Only facilities that manufacture, process, or otherwise use these chemicals in the form of a solution are required to report. Supplier notification applies only if the chemical is distributed as a solution. 

E. Posnjak, F.C. Kracek, Molecular Rotation in the Solid State. The Variation of Crystal 1 Structure of Ammonium Nitrate with Temperature , JACS 54, 2766-86 (July 1932) 4) D.P. 

Brown A.C. McLaren, On the Mechanism of the Thermal Transformations in Solid Ammonium Nitrate , ProcRoySoc 266A, 329—43 (1962) 27) Anon, Department of the Army... 

Composite proplnts, which are used almost entirely in rocket propulsion, normally contain a solid phase oxidizer combined with a polymeric fuel binder with a -CH2—CH2— structure. Practically speaking AP is the only oxidizer which has achieved high volume production, although ammonium nitrate (AN) has limited special uses such as in gas generators. Other oxidizers which have been studied more or less as curiosities include hydrazinium nitrate, nitronium perchlorate, lithium perchlorate, lithium nitrate, potassium perchlorate and others. Among binders, the most used are polyurethanes, polybutadiene/acrylonitrile/acrylic acid terpolymers and hydroxy-terminated polybutadienes... 

Ammonium nitrate, a colorless Ionic solid used as a fertilizer, explodes when it is heated above 300 °C. The products are three gases molecular nitrogen, molecular oxygen, and steam (water vapor). Write a balanced equation for the explosion of ammonium nitrate. 

As discussed in Section 3-, whenever an ionic solid dissolves in water, the salt breaks apart to give a solution of cations and anions. Thus, in any aqueous salt solution the major species are water molecules and the cations and anions generated by the salt. For example, a solution of potassium chloride contains K and Cl ions and H2 O molecules as major species. Likewise, the major species in a solution of ammonium nitrate are NH4 , NO3, and H2 O. 

It oxidised violently when it was heated with potassium nitrate. When it was submitted to a pressure of 70 bar and sodium nitrate was present, it detonated violently. With ammonium nitrate in the molten state it combusts, whereas in the solid state it detonates when exposed to impact. 

When ammonium nitrate, NH jNOj, dissolves in water, it absorbs heat. Consequently, its standard enthalpy of solution must be positive. This means that the entropy change caused by ammonium nitrate going from solid to solution must increase for the process to proceed spontaneously. This is exactly what one would expect based on the concept of entropy as a measure of randomness or disorder. 

Solid ammonium nitrate is an orderly, crystalline substance, a state considerably less random than a solution of ions in water. In this case, the positive entropy change outweighs the enthalpy change. That is TAS > AH. The Gibbs free energy change is negative, so the process will proceed spontaneously. 

Many of the cold packs sold in stores use this endothermic process. A cold pack usually contains a flimsy plastic bag of solid ammonium nitrate inside a larger package filled with water. When punched, the inner bag ruptures. This releases the ammonium nitrate, which dissolves and produces a chilled pack to relieve pain and swelling in aching joints. 

Another reaction between NH3 and N02 has to be considered, especially at low temperatures. NH3 and N02 form ammonium nitrate (NH4N03), which deposits on the catalyst in solid or liquid form at T < 180°C (m.p. 170°C), thereby reducing the DeNO performance (Figure 9.11) [32,33,37-41]. 

Ammonium nitrate is the cheapest source of oxygen available for commercial explosives at the present time. It is used by itself in conjunction with fuels, or to give more sensitive explosives in admixture with solid fuels and sensitisers such as nitroglycerine and TNT. It is, therefore, a compound of particular importance for the explosives industry. 

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... 

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