SonoAsh employs a unique, patent-protected, process in the beneficiation of coal ash – sonication. Sonication is the application of low frequency, high energy transmission of mechanical energy through shear vibration.
The “sonicator” technology was developed by Placer Dome with an expenditure of $10 million between 1985 – 1995 for application in the mining industry. It has since been successfully deployed to continue application development, with a $60 million expenditure, for PCB soil destruction (2004 – 2007) and heavy oil de-asphalting (de-asphalting IP sold in 2012 plus royalty stream). An additional $4 million to pursue the concept and IP for coal ash beneficiation.
The SonoAsh process is a wet process. A raw coal ash slurry flows through the sonication chamber where the high-intensity soon-mechanical energy fractures and de-agglomerates the coal ash. The fractured ash is then separated using well-proven mineral processing technology known as froth flotation.
Sonication + froth flotation can be used to recover coal ash that has been disposed of in impoundments or landfills. Older coal ash storage sites can thus be reclaimed so that the construction of new disposal sites can be avoided or postponed. Since dry fly and coal ash is not required for sonication + froth flotation processing, the ash producers do not need to alter their conventional wet ash handling practices.
Ash in slurry form can be transported cost-effectively via slurry pipelines, enhancing the flexibility of location of both source material and end product.
The SonoAsh process is particularly suitable for processing impoundment coal ash due to it being a wet process.
The unit operations of the SonoAsh process include mature mineral processing processes:
1. Raw material stage: dredging and pumping for impoundment coal ash, pumping only for fresh ash (delivery of coal ash is customer responsibility), SonoAsh will then screening and crushing if required (wet and dry)
2. Pre-sonicator stage: blending into a slurry with correct solids/liquid ratio for sonication
3. Sonication stage: low-frequency technology developed and central to the SonoAsh approach
4. Froth flotation stage: separation of the carbon and non-carbon particles employs flotation. However, the key performance issues of flotation alone, lack of fine particle size, and oxidized carbon particles are overcome through sonication.
5. Dewatering, drying, and packaging using standard mineral processing equipment