Precious metals in urban waste. (30th May 2016)

• Record Type: Journal Article
• Authors: Prichard, Hazel M.; Wedin, Francis; Sampson, Jean; Jackson, Matthew T.; Fisher, Peter C.
• Is Part Of: Water and environment journal. Volume 30:Number 1/2(2016)
• Page Start: 151
• Page End: 156
• Publication Date: 2016-05-30
• Subjects: gold -- incinerator ash -- palladium -- platinum -- silver -- sewage sludge -- urban‐mining; Sewage -- Periodicals; Water-supply -- Periodicals; Environmental management -- Periodicals; Water-supply engineering -- Periodicals; Pollution -- Periodicals; 628.1
• DOI: 10.1111/wej.12166
• Languages: English
• ISSNs: 1747-6585

Abstract

Abstract: Samples of incinerator ash from sewage operations in the UK have been analysed and all contain concentrations of over 1 ppm gold (Au), ranging up to 7 ppm, showing a remarkable consistency of enrichment for all the 9 incinerators sampled. Samples analysed from 2005 to 2007 and in 2014 all have elevated values showing a consistency of high Au grades over time as well as between incinerators. One dried sewage sample also has elevated Au values averaging 721 ppb. Rounded grains of Au, 2–3 microns in diameter, have been located in the incinerator ash. Our results indicate that this ash produced from incinerated sewage contains Au, with associated platinum‐group elements (PGE) and silver (Ag). This forms a polymetallic resource which may be economic to recover and recycle. Tests to extract these precious metals from the ash are ongoing.