X-ray fluorescence sorting of non-ferrous metal fractions from municipal solid waste incineration bottom ash processing depending on particle surface properties

Abstract

A heavy non-ferrous metal fraction (< 50 mm) of municipal solid waste incineration bottom ashes from wet-mechanical treatment was separated by screening, magnetic separation and eddy-current separation into ferrous metals, non-ferrous metals and residual sub-fractions. The non-ferrous metal fractions were divided and subjected to (i) a washing process, (ii) dry abrasion and (iii) no mechanical pre-treatment to study the effect of resulting different surface properties on a subsequent X-ray fluorescence sorting into precious metals, zinc, copper, brass, stainless steel and a residual fraction. The qualities of the X-ray fluorescence output fractions were investigated by chemical analyses (precious metal fraction and the residual fraction), pyrometallurgical tests and subsequent chemical analyses of the metals and slags produced by the melting processes (zinc, copper, brass and stainless steel fraction). Screening directs brass and stainless steel primarily into the coarser fractions, while copper and residual elements were rather transferred into the finer fractions. X-ray fluorescence sorting yielded zinc, copper, brass, stainless steel and precious metals fractions in marketable qualities. Neither a negative nor a positive impact of mechanical pre-treatment on the composition of these fractions was identified. Solely the yield of the brass fraction in the grain size 16–20 mm decreased with increasing mechanical pre-treatment. The pre-treatment also had no impact on yield and quality of the products of pyrometallurgical tests.

Recovery of Molybdenum, Chromium, Tungsten, Copper, Silver, and Zinc from Industrial Waste Waters Using Zero-Valent Iron and Tailored Beneficiation Processes

“…The high Cu and Zn content is in agreement with the role of these elements as main alloying element in brass. With respect to further recycling it has to be mentioned that both elements can be co-processed in copper plants [18] and also Ag is recovered there [19].…”

Elemental analysis of residual ash generated during plasma incineration of cellulosic, rubber and plastic waste

“…Both ash streams can be potentially hazardous depending on the type of waste feed (Gidarakos et al, 2009; Mandal et al, 2018). It is also evident from the literature that various elements have been detected using several analytical techniques during plasma incineration of municipal and medical wastes (Bakkali et al, 2013; Gomez et al, 2009; Pfandl et al, 2020; Rani et al, 2008). The X-ray florescence studies for overall composition of incombustible elements showed presence of heavy metals, such as Zn (Anastasiadou et al, 2012; Gidarakos et al, 2009; Wei et al, 2011), which is potentially hazardous for human health and environment due to leachable tendency (Benassi et al, 2019; Leelarungroj et al, 2018; Parmar and Thakur, 2013; Sawell et al, 1988; Shi and Kan, 2009; Vaishaly et al, 2015; Zhang et al, 2008).…”

Heavy metal recovery from the fine fraction of solid waste incineration bottom ash by wet density separation

“…Conversely, prior studies regarding valuable metal separation from MSW BA considered several techniques, often consequential from processing techniques of mined minerals [35]. Whereas, despite innovative methods, such as acid washing [36], microwave-assisted leaching [37] and X-ray fluorescence sorting [38] were proposed from recent studies, to our knowledge, an alternative approach to separation of valuable metals from BA through gravimetric shaking table remains still overlooked. Thereby, the aim of the present study is the investigation of valuable metals recovery from MSW incineration BA using a wet shaking table device to compliment the to-date underexploited 0/2 mm fraction of dry BA treatment facilities.…”