Fig. 3

SEM backscattered electron images of different areas and mineralogical assemblages of slags from the Baidian site. The chemical composition of mineral phases numbered in the images were listed in the Supplementary Material (Table S1). a Metal-rich grain containing Ba- and Sn-rich inclusions in crucible BH20:043; b-d The matrix of slag BH20:044, showing the presence of iron silicates, magnetite (Mag), iron-rich tin-calcium silicates, and calcium-rich pyroxene (Px) embedded in the matrix; e Tin oxide, copper- and lead-rich silicates in slag BH20:045; f Lead silicates in the centre of slag BH2:09