About the Lead-zinc Ore

Lead-zinc ore refers to minerals rich in metallic elements lead and zinc. Lead and zinc have a common source of ore-forming materials and very similar geochemical behaviors, as well as similar electronic structures and properties, so they are closely associated in primary deposits.
The main types of lead-zinc ore are sulfide ores, while oxide ores are relatively rare. The primary minerals composing sulfide lead-zinc ores are galena, sphalerite, or marmatite; while those of oxide lead-zinc ores are cerussite, anglesite, and smithsonite. Gangue minerals mainly include calcite, quartz, dolomite, sericite, fluorite, and barite. Lead-zinc ores are often associated with elements such as cadmium, germanium, thallium, indium, gallium, gold, and silver.

Processing Technology

  • Crushing and Grinding

    • Objective: To achieve effective mineral liberation by reducing ore particle size, exposing fresh surfaces of lead-zinc minerals (primarily galena and sphalerite) for subsequent selective flotation separation.
    • Process: Run-of-mine ore first undergoes three-stage closed-circuit crushing to reduce particle size below approximately 15mm. The crushed material is then fed into a closed-circuit grinding system where a ball mill works in conjunction with hydrocyclones for size classification. The circuit ensures consistent grinding to the required fineness, typically achieving 70%-85% passing 200 mesh (74 microns).
  • Lead Flotation Circuit

    • Zinc Depression: Zinc depressants are added during grinding or in conditioning tanks. The most common depressant is zinc sulfate, to form a hydrophilic film on the mineral surface, preventing sphalerite from floating.
    • Lead Collection: Selective collectors, such as xanthates, are added to preferentially collect galena.
    • Process: The pulp enters the lead roughing stage, producing a lead rougher concentrate and tailings. The lead rougher concentrate undergoes multiple stages of lead cleaning (typically 2-4 stages) to produce high-grade lead concentrate. The tailings from lead roughing proceed to the zinc flotation circuit.
  • Zinc Flotation Circuit

    • Activation: An activator is added to the tailings from lead flotation. The most common activator is copper sulfate, which displaces the depressant film on the sphalerite surface, restoring its floatability.
    • Zinc Collection: Collectors (also xanthate types, though potentially different in specific type and dosage from the lead circuit) are added.
    • Process: The activated pulp enters the zinc roughing stage, producing a zinc rougher concentrate and final tailings. The zinc rougher concentrate undergoes multiple stages of zinc cleaning to produce high-grade zinc concentrate.
  • Dewatering

    • The lead and zinc concentrates are sent to their respective thickeners and filters for dewatering, producing the final marketable wet or dry concentrate.

Processing Plant Construction Workflow

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