Recovery of copper, antimony and lead tin from crude tin electrolysis anode slime

  Rough tin electrolytic anode mud treatment process

Recycling copper :
(1) in the anode mud after drying reverberatory furnace, oxidizing roasting, copper → CuO, tin → SnO ₂ at a temperature of 700 ~ 750 ℃, and volatile part of arsenic, antimony.
(2) baking for 40 to 60 mesh sand, 5% to 7% dilute sulfuric acid leaching of copper, the liquid: solid = 2: 1, stirred for 2h, the leaching temperature is 80 ~ 90 ℃. Copper enters the solution as CuSO ₄ . After leaching, the liquid contains copper 4.5 to 6 .5g /L ; the leaching residue component (%) is: 0.2 to 0.4Cu, 32 to 45Sn , 6 to 15Bi , 21 to 26Pb .
(3) replacing the copper-containing solution to obtain an iron powder with copper powder.
Recycling bismuth:
(1) a dilute sulfuric acid leach residue after the copper, with 8% to 10% diluted hydrochloric acid leaching liquid: solid = 2: 1, the leaching temperature is 90 ~ 95 ℃, stirred for 2 ~ 3H, bismuth into solution was BiCl ₃ , the leachate contains 铋 40 ～ 50g The leaching rate of /Lo 铋 is generally 70 %.
( 2 ) The hydrazine-containing solution is hydrolyzed to obtain a BiOCl precipitate. The volume ratio of the water added to the hydrazine solution is 8 to 10 : 1 . The mixture was hydrolyzed and stirred, and allowed to stand for 24 hours after hydrolysis . The obtained BiOCl precipitate contains 65% to 72% Bi , which can be used as a raw material for producing electrolytic ruthenium.
( 3 ) The steps and technical conditions for producing electrolytic ruthenium from BiOCl :
The BiOCl precipitate is slowly added to 10 % to 12 % hydrochloric acid to dissolve into BiCl ₃ : liquid: solid = 3 : 1 , and stirred at room temperature, a small amount of potassium chlorate may be added to ensure complete dissolution of the hydrazine. Adding glue at the end of dissolution 0.2g /L and sulfuric acid 3g /L to speed up clarification and lead removal.
The crude BiCl ₃ solution is replaced with an iron plate to obtain a sponge crucible; an iron plate can also be used as a cathode and an anode to control current density. 110A /m ² , allowing the electrowinning and displacement to occur simultaneously, accelerating the formation of the sponge.
The sponge crucible is melt cast into a rough anode. The sponge is covered with caustic soda or caustic potash at 35 0 ~ 400 °C The temperature of the molten bismuth into crude, and then cast into anodes which component (%) is: 9 7 ~ 99Bi, 0.1Sn, 0. 8 ~ 1.3Cu, 0.8Pb, 0.05Fe.
Rough electrolytic refining: using HCl-BiC1 ₃ electrolyte (hydrochloric acid 16 0 ~ 165g /L , Bi ³⁺ 11 0 ～ 150g /L) , cathode current density 90A /m ² , electrolyte temperature 1 5 ~ 30 °C The same name 50mm The cathode is purely ruthenium and the periphery is coated with paraffin. The cathode deposits are dense and fine. After casting into ingots, the composition (%) is: 99.95Bi , 0.001Sn , 0.002Cu , 0.002Pb , 0.001Fe , 0.001As , 0.002Sb .
( 4 ) The direct yield of the whole process is 78 % to 81 %.
Recycling lead and tin:
(1) hydrochloric acid residue of the secondary component (%) after leaching bismuth: 4 0 ~ 48Sn, 22 ~ 28Pb, 1 ~ 2Bi. Reverberatory furnace smelting reduction with tin, lead, bismuth, reduced to metal. The ratio of smelting ingredients is: secondary filter residue 100kg , Pulverized coal 1 0 ~ 12kg, sodium carbonate 4 ~ 5kg Limestone 3kg Fluorite 3kg . The melting temperature is 120 0 to 1300 °C, and the produced alloy contains 45 % to 55 % Sn , 40 % to 47 % Pb , and 4 % to 6% Bi . This alloy has a low tin grade and a high lead content and is a coarse solder.
( 2 ) Rough solder electrolytic refining. Silicon hydrofluoric acid electrolyte, the component (g · L ^-1) was: total acid ^{16 0 ~ 180, Sn 2+ 15} , Pb 2+ 10, HBF 4 12 ~ 15, gelatin 0.15, β - naphthol 0.15. The conditions controlled during electrolysis are: current density 6 5 to 70 A · m ^-2 , electrolyte temperature 3 2 ~ 36 °C , Cell voltage 0. 2 ~ 0.35V. The obtained cathode deposit has a smooth surface and contains 55 % to 60 % Sn and 40 % to 45 % Pb as qualified solder.
Impurities such as antimony and arsenic remain in the anode slime. This anode mud is the raw material for the tadpole.