Recycling of bismuth oxides

OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 23 No. 3 2021 Ta b l e 4 Results of melting of bismuth oxides at a temperature of 1150 °C Optimization of the charge composition Product, Q-ty, g Experiment No 6: Content (β), % / Distribution (ε) of the component, % Bi Pb Zn Sb As Sn Alloy 67.3 7.06/89.0 81.64/99.0 0.03/0.4 1.15/32.2 ‒ 0.17/7.2 Slag 44.8 0.06/0.5 1.81/1.0 6.72/46.9 1.24/23.1 1.55/39.9 1.17/33.6 Dust 20.8 2.69/10.5 ‒ 16.29/52.8 5.16/44.7 5.03/60.1 4.43/59.1 Product, Q-ty, g Experiment No 8: Content (β), % / Distribution (ε) of the component, % Bi Pb Zn Sb As Sn Alloy 68.3 7.32/93.6 80.55/99.7 0.02/0.2 1.07/30.4 ‒ ‒ Slag 91.3 0.08/1.4 1.23/2.0 3.31/47.0 0.61/23.1 0.65/34.1 0.46/27.2 Dust 36.4 0.73/5.0 ‒ 3.39/52.7 3.07/46.5 3.15/65.9 3.12/72.8 Product, Q-ty, g Experiment No 9: Content (β), % / Distribution (ε) of the component, % Bi Pb Zn Sb As Sn Alloy 68.3 7.32/93.6 80.55/99.7 0.02/0.2 1.07/30.4 ‒ ‒ Slag 91.3 0.08/1.4 1.23/2.0 3.31/47.0 0.61/23.1 0.65/34.1 0.46/27.2 Dust 36.4 0.73/5.0 ‒ 3.39/52.7 3.07/46.5 3.15/65.9 3.12/72.8 Operating time of bismuth lead Product, Q-ty, g Experiment No 9: Content (β), % / Distribution (ε) of the component, % Bi Pb Zn Sb As Sn Alloy 67.5‒74 4.32‒8/ 59.9‒96 52.3‒86.7/ 70.1‒97 0.03‒0.34/ 0.4‒3.7 2.5‒2.9/ 71.3‒84.8 0.28‒0.76/ 11.2‒29.6 0.7‒0.93/ 30.4‒44.3 Slag 73‒91 0.03‒1.2/ 0.5‒20.4 0.3‒15.3/ 0.4‒25.3 0.08‒13.3/ 3.6‒78.2 0.23‒1.47/ 7.1‒55.7 0.67‒6.68/ 28.4‒48.3 0.76‒5.42/ 41‒54.9 Dust 36‒55.5 ‒ ‒ ‒ ‒ ‒ ‒ Ta b l e 5 Composition of slags in the Na 2 O-SiO 2 binary system Content in the charge, mass.% Content in the slag, mass.% Estimated value Actual value Oxides Na 2 CO 3 SiO 2 C Na 2 O SiO 2 Na 2 O SiO 2 100 15 11 7 46.5‒78.2 21.8‒53.5 ‒ ‒ 22 13 3 42.4‒75.2 24.8‒57.6 15 26 5 26.9‒78.2 21.8‒73.2 25 75 33 12.5 43.3‒75.9 24.1‒56.7 65.6 34.4 66 25 27.6‒61.2 38.8‒72.4 44.7‒60.8 39.2‒55.3 Similar considerations can be applied to the composition of slag in systems Na 2 O-SiO 2 -MgО and Na 2 O- SiO 2 -FeО. Consideration of multicomponent phase diagrams leads to similar results. Increasing SiO 2 consumption to 26 % of the oxides while maintaining the proportion of Na 2 CO 3 at 15 % (Experience No. 7) leads to separation of the metallic and slag phases. In the resulting bismuth lead (60 % of oxides), containing 8.2 % Bi and 93.4 % Pb, 90–92 % of these metals are extracted. The slag (62 % of oxides) with a low bismuth content (0.11 % wt.) is characterized by a large proportion of lead (up to 23.4 % wt.).