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Where can we find spent alumina catalyst from hydrodesulphurisation unit? 

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The particle size of ground spent hydrodesulphurization catalyst appeared to be a critical factor on enhancing the metal extraction efficiency.
As a catalyst for ethanol dehydration to ethylene, the obtained alumina nanosheets with easily-accessible surface and more active sites, exhibit a superior catalytic performance to the commercial alumina with a much higher yield at large space velocity.
Therefore, the ordered mesoporous alumina was a promising catalyst support for the carbon dioxide reforming with methane.
The measurements of the activity of the catalyst in hydrodesulphurization (HDS) of thiophene and hydrogenation (HYD) of cyclohexene indicate that titania-modified alumina supports can improve the HDS primary activity of the catalyst.
The recovery and regeneration of alumina from spent catalysts can not only significantly contribute to the total recycling of such hazardous spent catalysts but also provide a new approach for the preparation of γ-Al2O3 with a high specific surface area using spent catalysts as the aluminum sources.
Accordingly, this synthetic strategy provides a facile route to the controlled synthesis of nanostructured alumina catalyst supports with customized pore structures.
Furthermore, it is demonstrated that alumina is superior to active carbon, silica, or zirconium oxide as support for the hydrogenation/dehydration/hydrogenation sequence and a palladium-based catalyst deactivated more rapidly than the platinum catalyst.
Therefore, with anticipated 5% annual increase in catalyst consumption, the generation of spent hydroprocessing catalysts predicted to be 200,000 tons annually.
However, it was found that surface basicity of alumina catalyst plays an important role in catalytic hydrolysis of urea, and the activity of catalyst may be also influenced by the basic strength.

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How to produce alumina?4 answersAlumina can be produced through various methods. One method involves digesting aluminium-bearing materials with hydrochloric acid to produce an aluminium chloride liquor and acid-insoluble solids. The solids are then separated from the liquor, and the liquor is depleted of impurities. Aluminium chloride hexahydrate solids are produced from the liquor, which are then thermally decomposed to produce high purity alumina. Another method involves carbothermal reduction of a solid material prepared from an aluminum mineral-containing acid-soluble substance to obtain a crude alumina product. This product is then subjected to alkali dissolution, seed precipitation, and calcination to produce alumina. Additionally, sintering an aluminum compound in the presence of a molybdenum compound and a potassium compound, where the aluminum compound includes aluminum hydroxide, can also be used to produce alumina. Another method involves treating aluminous material, calcining it, leaching it with hydrochloric acid, and then crystallizing and precipitating aluminum chloride hexahydrate to obtain alumina. Finally, alumina can be prepared by placing aluminum sulfate in a reactor, introducing gas, and heating it to a set temperature for a certain time.
What is the significance of recycled aluminum alloys?5 answersRecycled aluminum alloys have significant advantages in terms of environmental sustainability and economic benefits. They can be used as a material choice for automobile body stamping due to their recyclability and low cost. Additionally, the use of secondary aluminum alloys in various industries allows for more economical and environmentally friendly production processes. However, the quality of recycled aluminum alloys can be affected by the presence of impurities, such as iron, which can negatively impact mechanical properties and corrosion resistance. To overcome these challenges, various techniques, such as ultrasonic melt treatment and microalloying with rare earths, have been explored to improve the properties of recycled aluminum alloys. Furthermore, proper metallurgical processing and modification techniques can be employed to obtain the desired mechanical and service properties of alloys made from secondary raw materials. Overall, the significance of recycled aluminum alloys lies in their potential to reduce carbon dioxide emissions, conserve energy, and provide a sustainable alternative to primary aluminum production.
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Where can I find palladium scrap?9 answers

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