Hydroxylamine nitrate

A dilute solution of hydroxylamine nitrate and nitric acid was left in a vented tank for four years. Evaporation caused the concentration of the... 

That the acid has the formula H2N202, and not HNO, is shown by its formation from hydroxylamine and nitrous acid. On mixing dilute solutions of hydroxylamine sulphate and sodium nitrate, the hydroxylamine nitrate loses water, thus HO-NH2 + 0=N—OH = H20 + HO—N=N—OH the silver salt is thrown down on addition of silver nitrate. 

J.C. Oxley, K.R. Brower, "Thermal Decomposition of Hydroxylamine Nitrate" SPIE, 872 (1988) 63-69. 

Thus, a large excess of U(IV) is required to reduce Pu(IV), diluting the enrichment of the recovered U. Further, the reactions described by Eqs. 7 and 8 will reduce the efficiency of the separation process and may ultimately lead to incomplete separation of U and Pu due to lack of reducing agent, so increasing the cost of the procedure. Alternative methods to reduce Pu include the use of hydroxylamine nitrate with hydrazine as stabiliser or the electroreduction of Pu(III) [66] in situ. Nonetheless, the current use of U(IV) as a reductant for... 

Hydrazine and hydroxylamine nitrate (HAN) are two other common additives for revised PUREX flowsheets. In the presence of hydrazine/ HAN, Pu(III) is converted to Pu(IV) in UV-irradiated nitric acid solutions. In the dark, Np(V) is reduced to Np(IV) by both HAN and hydrazine, but the rates are slow [97,98] ... 

The mixture of uranium and plutonium is treated with a suitable reducing agent [iron(ii) sulfamate, hydrazine, or hydroxylamine nitrate] under these conditions, is not reduced and stays in the kerosene layer, but Pu is reduced to Pu +, which is only weakly complexed by TBP and so migrates into the aqueous phase. 

W. Gerhertz, ed., Ullmann s Encyclopedia of Industrial Chemistry , 7thedn., Wiley-VCH, Weinheim, 2003, chapters Ammonia Ammonium Compounds Hydrazoic Acid and Azides Hydrazine Hydroxylamine Nitrates and Nitrites Nitric Acid, Nitrous Acid and Nitrogen Oxides Nitrogen. 

Although the redox potentials for aqueous solution indicate that uranium(IV) should reduce plutonium(IV), anions and other complexing agents can change the potentials sufficiently that uranium(IV) and plutonium(IV) can coexist in solution (25). Since one of the products of photochemical reduction of uranyl by TBP is dibutyl phosphate (DBP), which complexes plutonium(IV) strongly, experiments were done to test the photochemically produced urani-um(IV) solutions as plutonium(IV) reductants (26). Bench-scale stationary tests showed these solutions to be equivalent to hydroxylamine nitrate solutions stabilized with hydrazine (27). 

Hydroxylamine salts were found to be good reductants of plutonium, under certain conditions ( 5). Interest in these reducing agents stemmed from the desire to avoid the introduction of metallic cations in the separated plutonium product. Hydroxylamine sulfate was used on a large scale at the Savannah River Plant (j>). While partitioning was satisfactory, the objectionable presence of sulfate ions led to the adoption of hydroxylamine nitrate (HAN). The reaction mechanism and kinetics of the HAN reduction of plutonium have been studied extensively The... 

Figure 2. Prereduction partitioning scheme HAN, hydroxylamine nitrate N2Hh...

At the present time the titanium column shown in figure 4 is installed in a Pu-test cycle at Karlsruhe with a throughput of about 400 g Pu/h, where the electro-reductive Pu backextrac-tion can be tested and compared with the competitive procedure using hydroxylamine nitrate (HAN) as reducing agent. 

The flows and acidities required for recovery of Th with the solvent stream from Contactor III are such that hydroxylamine nitrate cannot prevent the oxidation of Pu(III) which occurs predominantly in the organic phase in the settlers, and Pu losses are sustained. 

Figure 4. Aqueous Pu with hydroxylamine nitrate and hydarzine...

Figure 5. Aqueous Pu with mixtures of ferrous or ferric nitrate and hydroxylamine nitrate...

Plutonium trifluoride. Plutonium trifluoride can be converted directly to plutonium metal, or it is an intermediate in the formation of PUF4 or PUF4 -PUO2 mixtures for thermochemical reduction, as described in Sec. 4.8. The stabilized Pu(III) solution, produced by cation exchange in one of the Purex process options for fuel reprocessing, is a natural feed for the formation of plutonium trifluoride, as is shown in the flow sheet of Fig. 9.9 [03]. A typical eluent solution from cation exchange consists of 30 to 70 g plutonium/liter, 4 to 5 Af nitric acid, 0.2 Af sulfamic acid, and 03 Af hydroxylamine nitrate. The sulfamic acid reacts rapidly with nitrous acid to reduce the rate of oxidation of Pu(III) to about 4 to 6 percent per day. Addition of ascorbic acid to the plutonium solution just before fluoride precipitation reduces Pu(IV) rapidly and completely to Pu(III). 

Hydroxylamine nitrate (HAN) requires addition of hydrazine as a holding reductant, to prevent destruction of hydroxylamine by the nitrous acid present as a result of radiolysis, in the reaction... 

Feed enrichment, 5 w/o U specific power, 50 MW/MT burnup, 40,000 MWd/MT. A, aqueous O, organic 30 v/o TBP in dodecane S, solvent, do-decane V, vapor HAN, hydroxylamine nitrate FP, fission products [0] concentration not stated, but known to be small (assume zero) ( ), calculated by material balance. 

Figure 10.29 Principal steps in Purex process for LMFBR fuel. F.P. = fission products HAN = hydroxylamine nitrate ...

Reduction with hydroxylamine. No comparable rate data for reduction of Np(V) by hydroxylamine are available. Barney [B2] reported that the initial rate of reduction of Pu(IV) by 0.1 M hydroxylamine nitrate (HAN) was about one-fourth the initial rate of reduction of Pu(lV) by U(IV) at 25°C. If the same ratio applies to reduction of Np(V) by HAN or U(IV), a reaction time of around (4X35) = 140 min might be required. Use of hydroxylamine would have the advantage of not requiring reduction of uranium to U(IV) and its subsequent recycle. 

R7. Richardson, G. L, and J. L. Swanson Plutonium Partitioning in the Purex Process with Hydrazine-Stabilized Hydroxylamine Nitrate, Report HEDL-TME-75-31, June 1975. 

Fig. 13. Pu(IV) extraction by di(2-ethylhexyl)-phosphoric acid effect of nitric acid and sodium nitrate concentration. 0.01 MD2EHPA Q M D2EHPA diluent, Amsoo 125-82. Plutonium reduced with hydroxylamine nitrate, reoxidized and stabilized with 0.1-0.5 M NaNOg-... 

The Pu was eluted from the colunm with 4 ml of 1.0 hydroxylamine nitrate. 

The Pu was then backwashed from the organic phase with 3 half-volume 1 hydroxylamine nitrate washes, precipitated with ammonium hydroxide, washed once with water, and dissolved in 20 X of concentrated nitric acid. The solution was then diluted to 100 X with 1 M nitric acid. 

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