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Electric Arc
Reduction &
Dilution
Furnaces

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Electric Arc Reduction & Dilution Furnace

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Description: The Electric Arc Reduction and Dilution Furnace (EARDF) combines high-temperature reduction and impurity dilution in a seamless, two-stage process. The initial electric arc phase reduces tin oxide to molten tin metal, while the dilution stage processes slag to recover residual tin and remove impurities, ensuring maximum recovery and purity.

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Key Advantages:

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  • Automatic feed system for continuous operation

  • Integrated dual-function design for reduction and slag processing

  • Ideal for secondary feed or primary concentrates with low Fe, Ta, Ba, Zr, and other high melting point metals

  • High tin recovery from both ore and slag

  • Reduced energy consumption compared to separate EAF and dilution systems

  • Minimized emissions with closed-system operation

  • Direct slag recycling within the same system

  • Compact footprint for space-constrained facilities

 

Here's how an Electric Arc Reduction and Dilution Furnace (EARDF) fits into the tin smelting process:

 

  1. Dual-Stage Recovery: The EARDF combines the reduction capabilities of an electric arc furnace (EAF) with the slag processing efficiency of a dilution furnace (DF), maximizing tin recovery from ore and residual slag.

  2. Integrated Impurity Management: By reducing tin oxide in the electric arc stage and diluting impurities during slag processing, the EARDF achieves superior separation of tin metal from unwanted elements like iron (Fe), lead (Pb), and copper (Cu).

  3. Streamlined Refining: The EARDF simplifies the smelting process by consolidating multiple steps, producing high-purity molten crude tin and minimizing the additional refining stages.

 

Link to below for how the EARDF fits into the Used Lead Acid Battery Recycle (ULAB) Process​

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4×1250KVA EAF layout.png

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1. Type: DB-EDF-20000 Electric Arc Reduction & Dilution Furnace  

  • Power load: 2700KVA

  • Capacity: 30-40 MT feed/day

  • Gas flow: 3000m3/d; Less smoke emission

  • Feed: Sn>5%

  • Sn in slag: <0.5%

 

EARDF used in Lead Acid Battery Recycling

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Used Lead Acid Battery (ULAB) Recycle Process with and without EARDF:

 

  1. Without EARDF: Process relies on rotary furnaces for both primary and secondary reductions.

    • ​​​​​Primary reduction: ULAB paste and grids are processed with fluxes (lime, silica, soda ash) in rotary furnaces.

    • Remelted lead is processed in kettles to produce refined lead and oxidize the Sb and Sn into a mixed metal dross or separate Sn and Sb drosses.

    • Secondary reduction: The drosses are reduced in a rotary furnace to produce a Pb/Sb/Sn bullion.

      • Produces higher metal losses to slag (~3-5%).

    • Refining​ of the bullion is done via kettles and VDUs to produce a Pb-Sb product and pure Sn.

  2. With EARDF: EARDF replaces rotary furnace for secondary reduction, improving metal recovery rates and minimizing losses to the slag.

    • Primary reduction: ULAB paste and grids are processed with fluxes (lime, silica, soda ash) in rotary furnaces.

    • Remelted lead is processed in kettles to produce refined lead and oxidize the Sb and Sn into a mixed metal dross or separate Sn and Sb drosses.

    • Secondary reduction: The drosses are reduced in a rotary furnace to produce a Pb/Sb/Sn bullion.

      • Produces lower metal losses to slag (<0.5%).

    • Refining​ of the bullion is done via kettles and VDUs to produce a Pb-Sb product and pure Sn.

 

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Rotary Furnace & EARDF Comparison

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