Sustainable and energy efficient leaching of tungsten(W) by ultrasound controlled cavitation [Elektronisk resurs]

• The project aims to use ultrasound controlled cavitation to achieve a more energy efficient leaching process. Locally, collapsing cavitation bubbles cause an extremely high pressure, shock waves and high temperature, which provide an opportunity to perform the leaching process at a much lower temperature than in an autoclave (20 bar overpressure and 220 ° C). The results show that the method works, but that a higher static pressure and thus temperatures are necessary to achieve a leaching recovery rate corresponding to today's autoclave technology. Another process parameter of importance is flow control and the initiation of cavitation bubbles that occur through a geometrically optimized nozzle (orifice plate). Numerical and experimental adaptation of the developed reactor with respect to the leaching conditions (Sodium hydroxide and Scheelite concentrate), required more time than expected. Best test results show that an energy supplement with ultrasonic controlled cavitation of 104 kWh / kg increases the leaching recovery by 21%. The leaching reagent temperature 60° C was determined regarding available reference data and was thought to be close to optimum for intensive cavitation in atmospheric pressure. Optimum temperature relates to the leaching reagent, vaporization temperature, density, boiling point, surface tension, and viscosity. Generally, for leaching is that higher temperatures are required to increase the chemical reaction rate (requires overpressure). The modified reactor principle provides stable results and is possible to scale up. Higher cavitation intensity for shorter finishing time and higher recovery rate require advanced flow induction, multiple excitation frequencies adapted to the optimized reactor geometry, as well as optimal process pressure and temperature. 

Ämnesord

Engineering and Technology  (hsv)

Environmental Engineering  (hsv)

Mineral and Mine Engineering  (hsv)

Teknik och teknologier  (hsv)

Naturresursteknik  (hsv)

Mineral- och gruvteknik  (hsv)

Engineering and Technology  (hsv)

Mechanical Engineering  (hsv)

Fluid Mechanics and Acoustics  (hsv)

Teknik och teknologier  (hsv)

Maskinteknik  (hsv)

Strömningsmekanik och akustik  (hsv)

Engineering and Technology  (hsv)

Materials Engineering  (hsv)

Metallurgy and Metallic Materials  (hsv)

Teknik och teknologier  (hsv)

Materialteknik  (hsv)

Metallurgi och metalliska material  (hsv)

Teknisk akustik  (ltu)

Engineering Acoustics  (ltu)

Process Metallurgy  (ltu)

Processmetallurgi  (ltu)

Indexterm och SAB-rubrik

Ultrasound

Cavitation; Leaching

Scheelite

Vibro acoustic optimization