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Hydrothermal synthesis can be defined as a method of synthesis of single crystals that depends on the solubility of minerals in hot water under high pressure. The crystal growth is performed in an apparatus consisting of a steel pressure vessel called an autoclave, in which a nutrient is supplied along with water. A temperature gradient is ...
The resulting compression heat is dissipated by heat exchangers; it is used to preheat raw gases. The actual production of ammonia takes place in the ammonia reactor. The first reactors were bursting under high pressure because the atomic hydrogen in the carbonaceous steel partially recombined into methane and produced cracks in the steel ...
A second heat treatment at a suitable temperature is then required to age the material. The elevated temperature allows the dissolved elements to diffuse much faster, and form the desired precipitated particles. The quenching is required since the material otherwise would start the precipitation already during the slow cooling.
A catalyst is required to make the process operate at feasible temperatures. Heating the water can be achieved through the use of water concentrating solar power. Hydrosol-2 is a 100-kilowatt pilot plant at the Plataforma Solar de Almería in Spain which uses sunlight to obtain the required 800 to 1,200 °C to heat water. Hydrosol II has been ...
Heat treating furnace at 1,800 °F (980 °C) Heat treating (or heat treatment) is a group of industrial, thermal and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as ...
The oxidation reactions occur in superheated water at a temperature above the normal boiling point of water (100 °C), but below the critical point (374 °C). The system must be maintained under pressure to avoid excessive evaporation of water. This is done to control energy consumption due to the latent heat of vaporization. It is also done ...
Pure water has a charge carrier density similar to semiconductors [12] [page needed] since it has a low autoionization, K w = 1.0×10 −14 at room temperature and thus pure water conducts current poorly, 0.055 μS/cm. [13] Unless a large potential is applied to increase the autoionization of water, electrolysis of pure water proceeds slowly ...
Starch gelatinization is a process of breaking down of intermolecular bonds of starch molecules in the presence of water and heat, allowing the hydrogen bonding sites (the hydroxyl hydrogen and oxygen) to engage more water. This irreversibly dissolves the starch granule in water. Water acts as a plasticizer.