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Precipitation and Crystallization Processes in Reprocessing, Plutonium Separation, Purification, and Finishing, Chemical Recovery, and Waste Treatment
Published in Reid A. Peterson, Engineering Separations Unit Operations for Nuclear Processing, 2019
Calvin H. Delegard, Reid A. Peterson
The process began with MnO2 removal by filtration. Because some Pu(VI) was present in the feed solution, reduction to Pu(IV) then occurred using 0.05 M ammonium sulfite, (NH4)2SO3, in the presence of 0.2 M ammonium sulfate, (NH4)2SO4. The sulfate aided in later precipitation of the plutonium peroxide by forming larger and more readily settling crystals. A minor adjustment to achieve 2.0 M HNO3 was then done followed by the slow addition of 30% H2O2 (~9.8 M) to make the final solution 10% H2O2 while maintaining 20°C to minimize iron-catalyzed decomposition of peroxide to oxygen gas and water. The precipitate was allowed to digest, growing the Pu2O7 particle size. The suspension was then cooled to ~5°C, settled, decanted, and washed with three 5-L portions of 0.4 M H2SO4 with settling and decantation between the ensuing washes. The decantates were recycled to the Crossover step (Figure 3.3) to conserve Pu values. The Pu solution concentration under these conditions, and those of the subsequent second precipitation strike, was about 0.02 g/L or ~8 × 10−5 M.
Properties of the Elements and Inorganic Compounds
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
Ammonium hydroxide Ammonium hypophosphite Ammonium iodate Ammonium iodide Ammonium iron(III) chromate Ammonium iron(III) oxalate trihydrate Ammonium iron(III) sulfate dodecahydrate Ammonium iron(II) sulfate hexahydrate Ammonium lactate Ammonium magnesium chloride hexahydrate Ammonium mercuric chloride dihydrate Ammonium metatungstate hexahydrate Ammonium metavanadate Ammonium molybdate(VI) tetrahydrate Ammonium molybdophosphate Ammonium nitrate Ammonium nitrite Ammonium nitroferricyanide Ammonium oleate Ammonium oxalate Ammonium oxalate monohydrate Ammonium palmitate Ammonium pentaborate tetrahydrate Ammonium pentachlororhodate(III) monohydrate Ammonium pentachlorozincate Ammonium perchlorate Ammonium permanganate Ammonium peroxydisulfate Ammonium perrhenate Ammonium phosphate trihydrate Ammonium phosphomolybdate monohydrate Ammonium phosphotungstate dihydrate Ammonium picrate Ammonium polysulfide Ammonium salicylate Ammonium selenate Ammonium selenite Ammonium stearate Ammonium sulfamate Ammonium sulfate Ammonium sulfide Ammonium sulfite Ammonium sulfite monohydrate Ammonium tartrate Ammonium tellurate Ammonium tetraborate tetrahydrate Ammonium tetrachloroaluminate Ammonium tetrachloropalladate(II) NH4OH
Groundwater Cleanup and Remediation
Published in David H.F. Liu, Béla G. Lipták, Paul A. Bouts, Groundwater and Surface Water Pollution, 2019
David H.F. Liu, Béla G. Lipták, Paul A. Bouts
Hypochlorite is used in drinking water and municipal wastewater systems for the treatment and control of algae and biofouling organisms (U.S. EPA 1985b). In industrial waste treatments, hypochlorite is used for the oxidation of cyanide, ammonium sulfide, and ammonium sulfite (Huibregts and Kastman 1979). Sodium hypochlorite solutions at concentrations of 2500 mg/l are also used for the detoxification (by oxidation) of cyanide contamination from indiscriminate dumping (Farb 1978). However, because the principal products from chlorination of organic contaminants are chlorinated organics which can be as much of a problem as the original compound, hypochlorite treatment is limited.
Recovery of Cobalt from Secondary Resources: A Comprehensive Review
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Michael Chandra, Dawei Yu, Qinghua Tian, Xueyi Guo
The application of more benign organic acids has been investigated in order to reduce the environmental impact from inorganic acid usage. The organic acids that have been studied recently are citric acid (C6H8O7) (Maroufi et al. 2020; Yu et al. 2019), malic acid (C4H6O5) (Li et al. 2010; Zhang et al. 2018), tartaric acid (C4H4O) (Nayaka et al. 2016; Chen et al. 2019), aspartic acid (C4H7NO4) (Li et al. 2013), and ascorbic acid (C6H8O6) (Li et al. 2012) to leach spent LIBs. However, organic acid is generally more expensive than inorganic acids while having a slower dissolution rate. Besides, it treats lower S/L ratio feed, which leads to low treatment capacity. These drawbacks may prevent the utilization of organic acid leaching in large-scale applications (Yao et al. 2018). Leaching cathode materials in alkaline solution, although uncommon, has shown potential promising results (J. Wang and Guo 2019). Wu et al. (2019) reported the utilization of ammonia as a leaching reagent, ammonium bicarbonate as pH buffer, and ammonium sulfite as a reductant. Ammonia leaching is relatively selective for Li, Ni, and Co as they form stable metal ammonia complexes. Lithium and cobalt leaching efficiencies were 60.53% and 80.99%, respectively, under optimum conditions (1.5 M ammonia, 1 M ammonium sulfite, 1 M ammonium bicarbonate, solid/liquid ratio = 20:1 (g/L), t = 3 hours, T = 60°C).
Dynamic disorder in the high-temperature polymorph of bis[diamminesilver(I)] sulfate—reasons and consequences of simultaneous ammonia release from two different polymorphs
Published in Journal of Coordination Chemistry, 2021
Laura Bereczki, Lara Alexandre Fogaça, Zsolt Dürvanger, Veronika Harmat, Katalin Kamarás, Gergely Németh, Berta Barta Holló, Vladimir M. Petruševski, Eszter Bódis, Attila Farkas, Imre Miklós Szilágyi, László Kótai
The small difference found between the decomposition reaction heat in air and inert atmosphere rules out the ignition of evolved ammonia with the oxygen in air [20]. The thermal decomposition of 1-LT proceeds via formation of a 1-HT intermediate. Thus, the structural motifs of 1-HT play a key role in the nature of the decomposition process. The extension of the lattice in the direction of the a axis weakens/breaks the N-H…O-S hydrogen bonds, thus decreasing the number of redox centers (N-H…O-S), and results in a small extent of redox reactions. The reaction between the free gaseous ammonia and the solid silver sulfate occurs at a much higher temperature (∼420 °C) than the decomposition temperature of 1-LT (<200 °C). Thus, the redox reaction takes place in the solid phase and has a quasi-intramolecular character. The ammonium sulfite intermediate may also be formed in the solid phase, because no gaseous S2 forms in the gas phase [42]. Although the silver sulfate–ammonia reaction results in an ammonium sulfite intermediate [41], the ammonium sulfite sublimate can be formed from gaseous SO2, NH3 and H2O because the ammonium sulfite decomposes at a remarkably lower temperature than what is required for the reaction between silver sulfate and ammonia.
A review on the heterogeneous oxidation of SO2 on solid atmospheric particles: Implications for sulfate formation in haze chemistry
Published in Critical Reviews in Environmental Science and Technology, 2023
Qingxin Ma, Chunyan Zhang, Chang Liu, Guangzhi He, Peng Zhang, Hao Li, Biwu Chu, Hong He
These mechanisms indicate that the formation of sulfite can also stabilize the surface ammonium through the formation of ammonium sulfite. This is consistent with the results of product analysis, in which the formation of NH4+ on oxides was increased by 1–2 orders of magnitude by coexisting SO2 (Yang et al., 2016). In addition, these mechanisms also indicate that the pre-adsorbed ammonia can increase the adsorption sites for SO2. Kinetic measurements demonstrated that NH3 increased the observed uptake coefficient of SO2 by about 1–4 times at various RH values on α-Fe2O3 and γ-Al2O3 (Yang et al., 2019).