scholarly journals A high temperature, high pressure reaction-screening apparatus

1985 ◽  
Vol 90 (3) ◽  
pp. 255 ◽  
Author(s):  
T.J. Bruno ◽  
G.L. Hume
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
High Pressure Reaction ◽  
High Temperature High Pressure

scholarly journals High-T, High-P Hydrothermal Synthesis of Uranium Silicates and Germanates

2014 ◽  
Vol 70 (a1) ◽  
pp. C759-C759
Author(s):  
Kwang-Hwa Lii
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Hydrothermal Synthesis ◽  
Alkali Metals ◽  
Spent Nuclear Fuel ◽  
Mixed Valence ◽  
Oxidation States ◽  
Uranyl Silicates ◽  
High Pressure Reaction ◽  
High Temperature High Pressure

Most uranium minerals can be classified as oxidized species in which U is fully oxidized to U(VI), and reduced species, in which U occurs primarily as U(IV). Uranyl silicates are an important group of uranium(VI) minerals in the altered zones of many uranium deposits [1]. Uranyl silicates have also received attention because they form when spent nuclear fuel interacts with water containing silicon under oxidizing conditions. One naturally occurring uranium(IV) silicate exists, namely coffinite (USiO4), which is the most important ore mineral for uranium after uraninite. Numerous synthetic uranium(VI) silicates and germanates containing organic amines or alkali metals as countercations have also been reported [2]. In contrast to the uranium(VI) compounds, the chemistry of materials containing uranium(V) is considerably less developed owing to the tendency of U(V) to either oxidize to U(VI) or disproportionate to U(IV) and U(VI). We have synthesized a pentavalent-uranium silicate and a germanate by a high-temperature, high-pressure hydrothermal method in gold ampoules contained in a high-pressure reaction vessel at ca. 600 °C and 170 MPa [3a,b]. Following the synthesis of the U(V) compounds, a number of mixed-valence uranium silicates and germanates have been synthesized, for example, a mixed-valence uranium(IV,V) silicate, Cs2K(UO)2Si4O12 [3c], a uranium(IV,VI) germanate, Cs8U(UO2)3(Ge3O9)3·3H2O [3d], uranium(V,VI) silicates and germanates, A3(U2O4)Ge2O7 (A = Rb, Cs) and [Na9F2][(UO2)3(Si2O7)2] [3e,f], and a uranium(IV,V,VI) silicate, Na7UO2(UO)2(UO2)2Si4O16 [3g] in which three oxidation states of uranium co-exist in one compound. In addition, tetravalent-uranium compounds, Cs2USi6O15 and Cs4UGe8O20 [3h,i], were also synthesized. All members in the family of uranium silicates and germanates with the oxidation states of uranium from +4 to +6 have been observed. In this presentation the high-temperature, high-pressure hydrothermal synthesis, crystal structures, and XPS spectroscopy of these interesting compounds will be reported.

Homogeneous carbon doping of magnesium diboride by high-temperature, high-pressure synthesis

2014 ◽  
Vol 104 (16) ◽  
pp. 162603 ◽  
Author(s):  
M. A. Susner ◽  
S. D. Bohnenstiehl ◽  
S. A. Dregia ◽  
M. D. Sumption ◽  
Y. Yang ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Magnesium Diboride ◽  
Carbon Doping ◽  
High Pressure Synthesis ◽  
Pressure Synthesis ◽  
High Temperature High Pressure

High temperature-high pressure synthesis of a new phase of LaCuO3

1989 ◽  
Vol 137 (4-5) ◽  
pp. 205-206 ◽  
Author(s):  
A.W. Webb ◽  
E.F. Skelton ◽  
S.B. Qadri ◽  
E.R. Carpenter ◽  
M.S. Osofsky ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
High Pressure Synthesis ◽  
Pressure Synthesis ◽  
New Phase ◽  
High Temperature High Pressure

scholarly journals Sealed rotors for in situ high temperature high pressure MAS NMR

2015 ◽  
Vol 51 (70) ◽  
pp. 13458-13461 ◽  
Author(s):  
Jian Zhi Hu ◽  
Mary Y. Hu ◽  
Zhenchao Zhao ◽  
Suochang Xu ◽  
Aleksei Vjunov ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Mas Nmr ◽  
Material Synthesis ◽  
Widespread Application ◽  
High Temperature High Pressure

Perfectly sealed rotors were designed for the widespread application of in situ MAS NMR in catalysis, material synthesis, metabolomics, and more.

The Feasibility for Potassium-Based Phosphate Brines To Serve as High-Density Solid-Free Well-Completion Fluids in High-Temperature/High-Pressure Formations

SPE Journal ◽  
2018 ◽  
Vol 24 (05) ◽  
pp. 2033-2046 ◽  
Author(s):  
Hu Jia ◽  
Yao–Xi Hu ◽  
Shan–Jie Zhao ◽  
Jin–Zhou Zhao
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Oil And Gas ◽  
Pressure Coefficient ◽  
High Density ◽  
Well Drilling ◽  
Well Completion ◽  
Oil And Gas Resources ◽  
Completion Fluids ◽  
High Temperature High Pressure

Summary Many oil and gas resources in deep–sea environments worldwide are often located in high–temperature/high–pressure (HT/HP) and low–permeability reservoirs. The reservoir–pressure coefficient usually exceeds 1.6, with formation temperature greater than 180°C. Challenges are faced for well drilling and completion in these HT/HP reservoirs. A solid–free well–completion fluid with safety density greater than 1.8 g/cm3 and excellent thermal endurance is strongly needed in the industry. Because of high cost and/or corrosion and toxicity problems, the application of available solid–free well–completion fluids such as cesium formate brines, bromine brines, and zinc brines is limited in some cases. In this paper, novel potassium–based phosphate well–completion fluids were developed. Results show that the fluid can reach the maximum density of 1.815 g/cm3 at room temperature, which makes a breakthrough on the density limit of normal potassium–based phosphate brine. The corrosion rate of N80 steel after the interaction with the target phosphate brine at a high temperature of 180°C is approximately 0.1853 mm/a, and the regained–permeability recovery of the treated sand core can reach up to 86.51%. Scanning–electron–microscope (SEM) pictures also support the corrosion–evaluation results. The phosphate brine shows favorable compatibility with the formation water. The biological toxicity–determination result reveals that it is only slightly toxic and is environmentally acceptable. In addition, phosphate brine is highly effective in inhibiting the performance of clay minerals. The cost of phosphate brine is approximately 44 to 66% less than that of conventional cesium formate, bromine brine, and zinc brine. This study suggests that the phosphate brine can serve as an alternative high–density solid–free well–completion fluid during well drilling and completion in HT/HP reservoirs.

High‐temperature, high‐pressure optical cells

1983 ◽  
Vol 54 (8) ◽  
pp. 993-995 ◽  
Author(s):  
Lawrence R. Holland ◽  
Ronald P. Harris ◽  
Robbie Smith
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
High Temperature High Pressure
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