Co-hydrothermal carbonization of polyvinyl chloride and moist biomass to remove chlorine and inorganics for clean fuel production

Hydrothermal carbonization of food waste after oil extraction pre-treatment: Study on hydrochar fuel characteristics, combustion behavior, and removal behavior of sodium and potassium.

Comparison of ultrasound-assisted and traditional caustic leaching of spent cathode carbon (SCC) from aluminum electrolysis

Chemical and biological leaching is practiced on a commercial scale for the mining of metals from ores. Although bioleaching is an environmentally-friendly alternative to chemical leaching, one of the principal shortcomings is the slow rate of leaching which needs to be addressed. The application of ultrasound in bioleaching, termed sonobioleaching, is a technique which has been reported to increase the rate and extent of metal extraction. This article reviews efforts made in the field of sonobioleaching. Since bioleaching is effectively a biological and chemical process, the effects of sonication on chemical leaching/reactions and biological processes are also reviewed. Although sonication increases metal extraction by increasing the metabolite production and enhanced mixing at a micro scale, research is limited in terms of the microorganisms explored. This paper highlights some shortcomings and limitations of existing techniques, and proposes directions for future research.

https://www.mdpi.com/2079-9276/7/1/3/pdf/1

A Review of the Application of Ultrasound in Bioleaching and Insights from Sonication in (Bio)Chemical Processes

Ultrasonic-assisted coal beneficiation: A review.

Ultrasonic coal washing to leach alkali elements from coals.

Alkali vapors present in the flue gas generated during coal-based combustion form fouling deposits as they condense. An additive added to coal can trap alkali elements in ash, therefore suppress the growth rate of fouling deposits, and increase thermal efficiency of a coal-fired thermal power plant. Laser-induced breakdown spectroscopy (LIBS) technique is proposed and demonstrated to screen potential additives to trap alkali elements in ash. Five additives—namely, kaolinite, alumina, silica, magnesia, and pumice—were analyzed for their effectiveness on four Indian coals for retaining/confining alkali elements in ash during coal combustion. Ratio analysis based on LIBS emission intensity values clearly shows that kaolinite and pumice are promising additives to trap sodium. Similarly, kaolinite, pumice, and silica exhibited good potassium retention.

V. Midhun Reddy

Papers

Ultrasonic coal washing to leach alkali elements from coals.

Suitability of laser-induced breakdown spectroscopy in screening potential additives to mitigate fouling deposits