Oxygen-enriched
Bottom Blowing Furnace Smelting (shorted as bottom-blowing) technology, as an effective
approach of direct lead smelting, has been adopted by major large-scale
smelters since its invention in China about 20 years ago. With the accumulative
knowledge of operation practice, Metalcess can offer you the whole package
service on EPC basis for lead project.
The bottom blowing process can treat lead sulfide ore, lead -zinc sulfide concentrate, lead containing zinc leaching residue and lead-bearing waste material including lead paste from lead acid battery etc.. Lead smelting consists of oxidation and reduction stage, and both can be performed
in two bottom blowing furnaces separately.
The lead material mixed
with flux in proportion is charged into bottom blowing furnace for oxidation
where lead bullion and high lead slag are produced. The high lead slag enters
into the second bottom blowing furnace for reduction to produce lead bullion
and zinc slag. The zinc slag is further charged into the fuming furnace to
recover zinc oxide powder and harmless residue. Off-gas from oxidation stage is
directed to acid-making process and that from reduction and fuming stage are
desulfurized by absorption method. Dust collected from bottom blowing furnaces
returns to feeding system for furnace burden preparing. The lead bullion,
through fire-refining or electro-refining is then casted into standard lead
ingot.
After
optimization, the lifetime of the lance is 2-3 months and campaign life of
oxidation and reduction furnaces are more than three and two years
respectively.
Characteristics
1. Furnace shell heat insulation but without water cooling
jacket ensures better operation safety and lower energy consumption;
2.
Full auto-thermal
reaction possible; flexible and automatic switch between autothermal or
semi-autothermal mode to match with feed material enthalpy value
3. Oxygen content ≥70% used for smelting intensifies
reaction in the bath to achieve higher productivity;
4.
Continuous oxidation process, highly automated
operation, stable SO2 content (12-18%) in off-gas in favor of acid-making;
5.
Short process and low volume of reactor
minimizes facility investment;
6. Fully-insulated process without ladle transfer, minimized fugitive
emission and environment pollution.
7. Feed moisture up to 8% can be directly smelt in the furnace,
reducing investment and operation cost for concentrate drying;
8.
Good
adaptability to raw material, being lead concentrate as low as to grade 30% or
secondary lead material from spent lead acid battery.
