TY - JOUR

T1 - Characterisation of aluminium black dross before and after stepwise salt-phase dissolution in non-aqueous solvents

AU - Hu, Keting

AU - Reed, Dan

AU - Robshaw, Thomas

AU - Smith, Rachel

AU - Ogden, Mark

PY - 2021/1/5

Y1 - 2021/1/5

N2 - Aqueous leaching to recover salts from black dross is accompanied by hazardous gas generation. The gas-generating phases vary significantly across differently sourced black dross. The challenge for the industry is how to accurately qualify and quantify the problematic components of black dross, especially minor reactive phases. This paper employed XRF, EDX, XRD, Raman and FTIR to analyse two industrial black dross samples from various sources. A novel pre-treatment method before characterisation was devised using water-free glycerol and anhydrous ethanol to remove the major salt components, without reacting the gas-generating phases. The results show that around 80 % of the salts existent in the black dross had been removed successfully through pre-treatment. This method facilitated the determination of minor reactive phases characterised by XRD, XRF and EDX, and had little effect on the characterisation by Raman and FTIR spectroscopy. The ammonia-generating nitride phase was detected by XRD, Raman and FTIR. The FTIR, moreover, allowed the successful identification of carbide. Best practice guidelines for the industrial analysis of black dross has been proposed. The guidelines would provide industry with evidence to include or adjust gas treatment methods and operational parameters when dealing with compositional variability in industrially-sourced black dross.

AB - Aqueous leaching to recover salts from black dross is accompanied by hazardous gas generation. The gas-generating phases vary significantly across differently sourced black dross. The challenge for the industry is how to accurately qualify and quantify the problematic components of black dross, especially minor reactive phases. This paper employed XRF, EDX, XRD, Raman and FTIR to analyse two industrial black dross samples from various sources. A novel pre-treatment method before characterisation was devised using water-free glycerol and anhydrous ethanol to remove the major salt components, without reacting the gas-generating phases. The results show that around 80 % of the salts existent in the black dross had been removed successfully through pre-treatment. This method facilitated the determination of minor reactive phases characterised by XRD, XRF and EDX, and had little effect on the characterisation by Raman and FTIR spectroscopy. The ammonia-generating nitride phase was detected by XRD, Raman and FTIR. The FTIR, moreover, allowed the successful identification of carbide. Best practice guidelines for the industrial analysis of black dross has been proposed. The guidelines would provide industry with evidence to include or adjust gas treatment methods and operational parameters when dealing with compositional variability in industrially-sourced black dross.

KW - Hazardous waste

KW - Aluminium nitride

KW - Aluminium black dross

KW - Characterisation

KW - Salts dissolution

U2 - 10.1016/j.jhazmat.2020.123351

DO - 10.1016/j.jhazmat.2020.123351

M3 - Article

VL - 401

SP - 123351

JO - Journal of Hazardous Materials

JF - Journal of Hazardous Materials

SN - 0304-3894

ER -