Burning Rate Studies. V. Effect of Acid Concentration on the Consumption Rate of Various Fuels with Nitric Acid

1957 ◽  
Vol 61 (4) ◽  
pp. 388-394
Author(s):  
A. Greenville Whittaker ◽  
Harry Williams
Keyword(s):  
Nitric Acid ◽  
Burning Rate ◽  
Acid Concentration ◽  
Consumption Rate

Recovery of Heavy Metals from the Spent Catalyst of the Hydrotreating Unit (HDT) for the Use of the Impregnation of Supported Catalysts

2018 ◽  
Vol 792 ◽  
pp. 133-139 ◽  
Author(s):  
Toapanta Germania ◽  
Caterine Donoso ◽  
María José Cárdenas ◽  
Amón Bolívar ◽  
Vladimir Ortiz
Keyword(s):  
Heavy Metals ◽  
Nitric Acid ◽  
Acid Concentration ◽  
Supported Catalysts ◽  
Nitric Acid Concentration ◽  
Added Value ◽  
High Tech ◽  
Spent Catalyst ◽  
X Ray ◽  
Spent Catalysts

Spent catalysts contain metals that have a high added value. From all metals, lanthanum has attracted a lot of attention due to the growing demand in the high-tech. The spent catalyst of the hydrotreatment unit is a material composed of lanthanum-enriched matrix of amorphous aluminosilicates. The experiment was carried out with a spent catalyst with a constant particle size of 90 μm. The treatments were obtained applying of two level factorial design to investigate the effect of following factors: temperature (20 - 60 °C), nitric acid concentration (3 - 6 M), leaching time (1 - 4 h) and percent solids (10 - 20 %). The research is carried out in two steps process: pretreatment of the catalyst and leaching with nitric acid. The leaching results show a yield of lanthanum of 99.44% using the following conditions: temperature (20 °C), nitric acid concentration (3M), leaching time (1 h), percent solids (20%) and 300 rpm. The principal analysis of the spent catalyst was carried out using the X-Ray Fluorescence (XRF) technique, 3.08%, while the percentage of lanthanum recovery in the extract, washing and refining was carried out using the Inductive Coupling Plasma (ICP) technique.

Selective separation of silver(I) by novel substituted thiourea

2007 ◽  
Vol 95 (8) ◽  
Author(s):  
Aslam Khan
Keyword(s):  
Experimental Data ◽  
Nitric Acid ◽  
Acid Concentration ◽  
Organic Phase ◽  
High Selectivity ◽  
Nitric Acid Concentration ◽  
Equilibration Time ◽  
Acid Solutions ◽  
Nitric Acid Solutions ◽  
Species Effect

The extraction of silver(I) from nitric acid solutions using naphthyl substituted thiourea such as 1-naphthylthiourea (ANTU) has been studied. Different variables: equilibration time, aqueous pH, chloride and extractant concentrations and organic phase diluent that could affect the extraction system were evaluated at 28.0 ± 2.0 °C. It was found that silver is quantitatively extractred by ANTU over the entire studied range of nitric acid concentration. Extraction of silver by ANTU is fast and equilibration was achieved in less than five minutes. Experimental data relating to silver have been analysed to determine the stoichiometry of the extracted species. Effect of foreign ions on the extraction of silver was carried out. Recycling capacity of the extractant was also studied. Thiourea and EDTA solutions were found suitable for > 99% stripping of extracted silver(I). The reagent has been found to have high selectivity for silver against copper, cadmium, nickle, cobalt, halfnium, zircomium and europium.

Research Progress of Red Oil Explosion Accidents in Nuclear Fuel Reprocessing Plant

2017 ◽  
Author(s):  
Chunlong Zhang ◽  
Hui He ◽  
Shangui Zhao ◽  
Fengli Song ◽  
XinHua Liu
Keyword(s):  
Nitric Acid ◽  
Nuclear Fuel ◽  
Acid Concentration ◽  
Preventive Measures ◽  
Nitric Acid Concentration ◽  
Purex Process ◽  
Nuclear Fuel Reprocessing ◽  
Explosion Accidents ◽  
Reprocessing Plant ◽  
Fuel Reprocessing

Since Westinghouse Savannah River Company (WSRC) of America first applied PUREX process in 1954, PUREX process is always the top priority in nuclear fuel reprocessing plant. And this process is based on liquid to liquid extraction with TBP as the extractant. TBP is irreplaceable in the development of PUREX process in nuclear fuel reprocessing, its advantages are well recognized. However TBP does have some disadvantages such as formation of red oil, which will appear in the system of high nitric acid concentration and heavy metal nitrate, once the red oil forms, it can lead a exothermic runaway decomposition in reasonable conditions, such as exceeding a certain temperature (typically 130°C) or high acid concentration. If gas products and energy released from the decomposition reaction could not be exported in time, it will lead to vessel overpressure and caused violent explosion accidents. By now, it has happened 6 times so-called red oil explosion accidents worldwide, resulting in different degrees of equipment and construction damage and environmental contamination. From 1953 to now, research related to red oil has never stopped. WSRC, Hanford Company, Oak Ridge National Laboratory and Los Alamos National Laboratory of America have conducted many studies, as well as some research institutions from Russia, UK, France and India. Defense Nuclear Facilities Safety Board of America issued a technical report in 2003, preventive measures for red oil explosion were established in this report, and these measures provided good practice experience and reference for other countries, and the temperature condition (⩽130°C)and nitric acid concentration (⩽10M)for preventing red oil explosion are employed in some countries which has built the reprocessing plant. Nevertheless, research conclusions and knowledge of red oil vary from country to country. Especially, Kumar and Smitha etc. conducted several experiments in adiabatic condition in recent years, and investigation on stability of TBP - nitric system was made, the results indicated that the red oil runway reaction will happen even in lower temperature and lower nitric acid concentration in contrast with the reported value, and they thought it would need a further study to assess the validity of present preventive measures, and to rebuild the safety limits for preventing red oil explosion in the operation of nuclear fuel reprocessing plants. In this paper, related research results of red oil explosion accidents were combed, and the characters of study work of different periods were summarized, and definition, formation conditions of red oil, pathway of runaway reaction, control and preventive measures for preventing red oil explosion of different countries were analyzed and compared, as well as the new viewpoints of recent literatures. And some research ideas for future investigation based on present work were also proposed.

Separation and purification of Th from U by ammonium molybdophosphate from nitric solutions

2002 ◽  
Vol 90 (5) ◽  
Author(s):  
A. M. I. Ali ◽  
H. G. Nowier
Keyword(s):  
Nitric Acid ◽  
Acid Concentration ◽  
Nitric Acid Concentration ◽  
Acid Solutions ◽  
Separation And Purification ◽  
Retention Capacity ◽  
Nitric Acid Solutions ◽  
Ammonium Molybdophosphate ◽  
Saturation Capacity

SummaryAmmonium molybdophosphate(AMP) was synthesized and characterized. The AMP was found to be insoluble in water or nitric acid solutions of different concentrations. The sorption of Th and U from nitric acid by AMP has been investigated. The effect of shaking time on the sorption of Th was studied. The effect of nitric acid, Th concentration and AMP on the sorption of Th were also studied. Studies on the retention capacity of AMP showed that its capacity decreased by increasing the nitric acid concentration of Th. The saturation capacity was found to be 120 mg Th/g

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