Recovery of Gold and Silver from Anode Slime

Recovery of Gold and Silver from Anode Slime Systeme efficient extraction of precious metals from anode mud, with precise separation and recovery of gold, silver, and other precious metals.

What is Anode Slime?

Anode slime is a sludge-like material that adheres to the anode surface, settles at the bottom of electrolytic cells, or remains suspended in the electrolyte during the electrolytic refining process. It is highly enriched with precious metals, rare metals, and other valuable metals. Extracting these metals from anode slime offers significant economic benefits. For example, copper anode slime can be processed to recover copper and extract elements such as gold, silver, selenium, and tellurium.

Anode Slime Treatment Methods

1. Pyrometallurgical Treatment of Anode Slime

Anode slime is a sludge-like material that adheres to the anode surface, settles at the bottom of electrolytic cells, or remains suspended in the electrolyte during the electrolytic refining process. It is highly enriched with precious metals, rare metals, and other valuable metals. Extracting these metals from anode slime offers significant economic benefits. For example, copper anode slime can be processed to recover copper and extract elements such as gold, silver, selenium, and tellurium.

2. Hydrometallurgical Treatment of Anode Slime

This process is suitable for materials with high gold and silver content. Lead anode slime, which oxidizes readily, undergoes natural oxidation or roasting at 120-150°C. This converts copper, arsenic, antimony, and bismuth into their respective oxides. The oxidized slime is then leached in an acidic chloride medium to dissolve base metals (Cu, Sb, Bi, As), further enriching the gold and silver content. The de-based slime undergoes chlorination leaching for gold. Simultaneously, any silver not converted to AgCl during oxidation is oxidized. Silver is subsequently leached using a suitable solvent.

Recovery of Gold and Silver from Anode Slime Process Flow

Full Hydrometallurgical Process for Lead Anode Slime

This process is suitable for materials with high gold and silver content. Lead anode slime, which oxidizes readily, undergoes natural oxidation or roasting at 120-150°C. This converts copper, arsenic, antimony, and bismuth into their respective oxides. The oxidized slime is then leached in an acidic chloride medium to dissolve base metals (Cu, Sb, Bi, As), further enriching the gold and silver content. The de-based slime undergoes chlorination leaching for gold. Simultaneously, any silver not converted to AgCl during oxidation is oxidized. Silver is subsequently leached using a suitable solvent.

Full Hydrometallurgical Process for Copper Anode Slime

Hydrometallurgical treatment of copper anode slime, like traditional pyrometallurgy, involves separating base metals first, followed by precious metal extraction. Some process stages are similar, such as sulfation roasting of copper anode slime and acid leaching for copper removal.

Pyrometallurgical Route

After decopperization and deselenization, the slime undergoes noble lead smelting and chlorination refining to produce doré metal. The doré is then electrolytically refined to produce pure gold and silver.

Hydrometallurgical Route

The predominant flowsheet involves sulfation roasting for selenium volatilization, leaching for copper and silver removal, and chlorination for gold dissolution. The resulting gold and silver are purified chemically, eliminating the need for separate electrolytic refining steps for these metals.

In recent years, hydrometallurgical processes for anode slime have advanced significantly. Treatment has largely shifted from traditional pyrometallurgical routes to predominantly hydrometallurgical flowsheets.

Raw Material

Solid Anode Slime,Liquid Anode Slime,Slag,Electronic Waste

Solid Anode Slime
Solid Anode Slime
Liquid Anode Slime
Liquid Anode Slime
Slag
Slag
E-Waste
E-Waste

Final Product

Solid Anode Slime,Liquid Anode Slime,Slag,Electronic Waste

Gold
Gold
Silver
Silver
Platinum
Platinum
Palladium
Palladium

Advantages

1. High Recovery Rates (>99%)

Direct recovery rates for gold and silver are typically 97-98%, and can exceed 99%, significantly higher than traditional routes.

2. Short Production Cycle

Generally 10-20 days. Gold and silver inventory is lower compared to traditional processes.

3. Suitable for Various Scales

Hydrometallurgical processes are adaptable to anode slime treatment plants of all sizes, particularly small and medium enterprises. Traditional pyrometallurgy requires a certain scale for operational efficiency.

4. Fewer Steps & Shorter Flowsheet

The hydrometallurgical process produces high-purity gold or silver powder directly, which can be melted into anodes for electrolytic refining. Solvent extraction refining of gold chloride solutions can yield Grade 1 gold, completely bypassing the gold electrolysis step.

5. No Intermediate Recycling Streams

The hydrometallurgical process replaces smelting and silver refining furnaces with separate gold and silver leaching steps. This eliminates the production of intermediate recycling streams (accounting for 30-40% of the slime feed), improving direct recovery and reducing costs.

6. Enhanced Comprehensive Utilization

During base metal separation, valuable metals are concentrated at high ratios in specific residues or solutions, facilitating efficient comprehensive recovery.

Technical Parameter

Anode Slime Hydrometallurgical Refining System Technical Parameters
If you have other requrement and want to know more details, please contact us.(The data in this table are for reference only)

ModelCapacity kg/dayPower/kwSize(Length*Width*Height)Project Budget(USD)
PGM-100100-200kg300kw10000*5500*6000mm150000USD
PGM-300300-500kg500kw15000*8500*6000mm200000USD
PGM-500500-1000kg800kw20000*15000*7000mm500000USD
PGM-10001000-2000kg1000kw35000*20000*7000mm1000000USD

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