Recyclable materials containing lead, zinc, copper, gold and silver

Lead sludge and lead-bearing filter residues

Sludges, precipitates and filtration residues arising from smelting, metal recovery or solution treatment. Some also contain silver, zinc or copper; assess combined recovery value from actual composition.

Typical materials

• Lead precipitates and dewatered filter cakes.
• Lead-rich residues from hydrometallurgical treatment.
• Silver-bearing lead sludge and filter residues.
• Other lead-bearing intermediates with a clear source and potential recovery value.

Typical appearance

Wet sludge, paste, pressed cakes or dry powder; colour varies with composition, moisture and oxidation. Materials called “lead sludge” can have very different composition and treatment needs.

Supply scenario example

A metal recycler regularly produces lead-bearing filter cake with silver reported in the assay. The supplier can share Pb and Ag results, cake photos, monthly output and location to discuss individual lots or ongoing recovery.

Suggested information: Pb, Ag, moisture, originating process, and known Zn, Cu, As, Cd or other constituents.

Identify battery paste from battery dismantling separately; do not report it as other industrial lead sludge.

Copper sludge and copper-bearing filter cake

Sludges, precipitates and dewatered cakes from copper solution treatment, metal recovery and copper processing. They may be brown, black or blue-green, or granular with fine metal particles.

Typical materials

• Copper precipitates and pressed filter cakes.
• Residues from electroplating, etching-solution treatment and copper recovery.
• Fine sludge, particles and copper-bearing filter material collected during processing.
• Other copper-bearing intermediates with a clear source and measurable composition.

Supply scenario example

A copper recycler presses copper precipitates into filter cakes suitable for bags or drums. Cu content, moisture, process information and whole-lot photos support discussion of purchasing and delivery.

Suggested information: Cu, moisture, originating process, Fe, Ni, Zn, Cl, oil and known impurities.

Describe and sample separately collected copper process materials separately from mixed wastewater-treatment sludge.

Copper wire-drawing sludge and fines

Wire-drawing sludge, copper fines and filtration residues from copper wire production can also be submitted for assessment. Describe oil, moisture, non-metallic inclusions and any separation treatment.

Zinc washing residues and lead-zinc tailings

Tailings, fines, settled solids and filter cakes from washing, desliming, gravity separation or flotation of zinc and lead-zinc ores. Where metals remain, assays and beneficiation tests can support assessment of retreatment or other recovery routes.

Typical materials

• Zinc ore washing sediments and desliming fines.
• Lead-zinc flotation tailings and gravity-separation sands.
• Historical tailings containing Pb, Zn and associated silver.
• Dewatered filter cakes or dry-stacked fine tailings.

Typical appearance

Fine sand, powder, settling-pond sludge or dewatered cake; grey, grey-brown or yellow-brown colours may occur. Colour alone cannot establish metal content.

Supply scenario example

A lead-zinc concentrator has historical washing sludge whose fine particles were not fully recovered in the original circuit. Area-specific assays, stockpile photos, estimated quantities and the original flowsheet help assess possible reuse.

Suggested information: Zn, Pb, Cu, Ag, moisture, particle size, oxide/sulphide character, stock quantity and original beneficiation process.

Tailings with similar total metal content may have different economic value because mineralogy, particle size and recovery difficulty differ.

Mixed metal-bearing intermediates

Materials in which metal separation, purification or final recovery is incomplete. They may contain two or more of Pb, Zn and Cu, with possible gold and silver.

Typical materials

• Lead-copper or lead-zinc mixed middlings.
• Precipitated filter cakes from polymetallic recovery.
• Enriched metal-bearing materials requiring further treatment.
• Intermediate products retaining several valuable metals after separation.

Supply scenario example

A concentrator produces mixed middlings containing lead, copper and silver, without separation into single-metal concentrates. Individual metal results, mineralogy and the original separation process support discussion of further treatment and possible procurement.

Suggested information: Separate Pb, Zn, Cu, Au and Ag results, moisture, particle size and the process that generated the material.

Smelting slag, leach residues and metal-bearing dust

Residues and dust from pyrometallurgical or hydrometallurgical operations that retain recoverable metals. They may be hard lumps, granules, powder or filter cake; value depends on metal content, mineral form and treatment cost.

Typical materials

• Copper-bearing furnace slag and lead smelting residues.
• Zinc leach residues with associated lead and silver.
• Lead/zinc dust-collection residues and other metal-bearing flue dust.
• Silver-bearing residues from smelting or refining.

Supply scenario example

A smelter seeks a recovery route for copper slag or lead-zinc dust. Assays, the generating process, available quantity and packaging condition help assess feasible receiving and treatment arrangements.

Suggested information: Valuable metals, major Fe/Si/Ca constituents, S/Cl/F, moisture and known impurities.

Identify washing tailings, chemical leach residues and high-temperature smelting slag separately; do not label all of them “ore washing residue”.

Gold/silver-bearing materials and anode slimes

Precipitates, dust, filter residues and intermediates from smelting, electrolytic refining, precious-metal processing and gold/silver recovery. They may look like ordinary dark sludge or cake rather than shiny metal.

Typical materials

• Silver-bearing lead sludge and slag.
• Anode slimes from copper or lead electrolytic refining.
• Precipitates and filter residues from gold/silver recovery.
• Gold/silver-bearing dust and residues from precious-metal processing.

Supply scenario example

An electrolytic refiner collects and packages anode slimes by lot, with assays indicating gold, silver and associated metals. Representative sample results, process information, packaging photos and lot quantity support recovery and settlement discussions.

Suggested information: Au and Ag content and units, analytical method, associated Cu/Pb and other metals, moisture and generating process.

Report gold and silver preferably in g/t, stating dry or wet basis. Payability and pricing are agreed after verification assays and assessment of recovery conditions.