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- bluish-white color when freshly cut -
11,34g/cm3, melting point 327C
(10,69g/cm3) - boiling point 1740C (vaporizes
at 550C) - bad heat and electrical conductor -
very soft, highly malleable
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- výroba pláštu zemních kabelu - radiation
shields - bullets and shot - lead-acid
batteries - alloys PbSb, solder -
PbSn,antifriction alloy - PbSnSb-
compounds carbonate, oxides
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only in compounds
galena - PbS
cerussite - PbCO3
anglesite PbSO4
- galena is the most important and widely used -
the main impurities Cu, Zn, Sb, Fe, As, Sn, Ag,
Bi a big amount
of gangue
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only in compounds
galena - PbS
cerussite - PbCO3
anglesite PbSO4
- selectivecollective (PbZn) concentrate 40-70
Pb - other source(40) waste batteries etc.
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Pb is produced mainly by pyro. way
- Reduction smelting 90 - ISP 5 - Others
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Roastingremoval of S, conversion of sulphide
into
oxide
Sintering coarsening agllomerate
Reduction smelting
Purification of lead bullion
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- Done together on a (Dwight-Lloyd)sintering
machine - providing Pb content under 2
(mixing raw concentrate with returned
agglomerate) - partial removal of Sn and Sb as
As2O3 a Sb2O3
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Obtain as much as possible lead bullion
Dissolve as much as possible noble metals in Pb
Move all gangue and Zn into slag
Separate Cu off Pb in form of matte
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1. zone under 400C, drying and warming of
charge .2. zone (reduction) 400-900C, removal
of water, decomposition of carbonate sulfate,
reduction of oxides, sulfidization of Cu3. zone
(melting) above 900C, streaming down liquid Pb
to crucible, dissolution of Au, Ag, Cu, As, Sb,
Sn etc. into lead bullion
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- charge coke, air, sinter, CaO
PbO CO Pb CO2PbO.SiO2 CaO PbO
CaO.SiO2PbO.Fe2O3 PbO Fe2O3PbSO4 PbO
SO3PbS 2PbO 3Pb SO2PbSO4 4 CO PbS 4
CO2PbSO4 Pb 2PbO SO2PbSO4 SiO2 PbO.SiO2
SO3
Main reactions
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continuous taping, the principle of connected
vessels
Construction of the furnace
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- lead bullion90-96 Pb, 0,2-2,5 Cu, 0,5-5 Sb,
0,1-0,8 As, 0,1-1,5 Sn, 0,06-0,5 Ag
- slag25 - 32 SiO2, 34 - 40 FeO, 10 - 16 CaO,
5 - 8 Al2O3 MgO, Pb, ZnO ( 30)
- BF gas CO, CO2, SO2, vapor, N2, dust (3-50
g/m3, 40-80 Pb, toxic)
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- removal of dross and Cu- removal of As, Sn,
Sb,- removal (recovery) of noble metals- removal
of Bi
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removal of dross - stirring at 500C -
physical impurities ascending to the surface of
lead melt (difference in specific gravity)
- withdrawing as dross
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removal of Cu - limited dissolution of Cu v Pb
at low temp., higher affinity of Cu to S
than that of Pb - 1. step lowering or
increasing temperature of the melt just
above of melting point of Pb - 2. step (350C)
adding elemental S to form Cu2S (under
0,002)
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removal of Sn, As, a Sb - higher affinity with
oxygen, comparing to Pb - oxidation with air or
with sodium nitrate - oxidation with air
500C to remove Sn, 700C-800C to remove As,
Sb
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removal of Sn, As, a Sb - oxidation with sodium
nitrate (Harris refining) fused sodium
hydroxide, 500C oxides As, Sb, Sn have
acidic character, reaction with oxides
of alkli metals to form arsenate,
antimonate (V),
stannate
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removal of Sn, As, a Sb - oxidation with sodium
nitrate (Harris refining) 2NaNO3 Na2O
2.5 O2 N2 2As 2.5 O2 AsO5 Sn
O2 SnO2 2Sb 2.5 O2 Sb2O5 As2O5
3Na2O 2Na3AsO4 Sb2O5 3Na2O 2Na3SbO4
SnO2 Na2O Na2SnO3     
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recovery of noble metals (Parkes method) -
de-silvering lead by adding metal Zn to form
inter- metallic compound (higher melting
point, lower specific gravity) - 500C,
stirring, cooling almost to consolidation,
formation of foam containing noble metals (Ag,
Au..) - removal of Zn by vacuum
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removal of Bi atd1.) Kroll-Betterrs method
(under1Bi) - adding Pb-Ca (3- 4 Ca) and Mg
metal - slow cooling from 400C to 360C,
foam forming atd2.) electrolytic refining (Bi
gt1) - electrolyte PbSiF6 H2SiF6
(fluorosilicate and fluorosilic
acid) - Pb cathodes - Bi and noble metals
report into do anode slugde
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