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Electrowinning: A Complete Guide

Electrowinning, also called electroextraction, is the electrodeposition of metals from their ores that have been put in solution via a process commonly referred to as leaching.

The process involves passing an electric current through a solution containing metal ions, causing the metal to plate out onto an electrode.

Electrorefining uses a similar process to remove impurities from a metal. Both processes use electroplating on a large scale and are important techniques for the economical and straightforward purification of non-ferrous metals. The resulting metals are said to be “electrowon”.


How Does Electrowinning Work?

In electrowinning, an electrical current is passed from an inert anode (oxidation, made out of lead (Pb)) through a leach solution containing the dissolved metal ions so that the metal is recovered as it is deposited in an electroplating process onto the cathode (reduction, stainless steel, aluminium (Al), titanium (Ti)).

In electrowinning, the anode consists of the impure metal (e.g., copper) to be refined. The impure metallic anode is oxidized and the metal dissolves into solution. The metal ions migrate through the acidic electrolyte towards the cathode where the pure metal is deposited. Insoluble solid impurities sediment below the anode often contains valuable rare elements such as gold, silver and selenium.

The electrodes used in electrowinning are typically made of steel or other metals, and they are coated with a layer of metal that is being recovered. The electrical current is passed through the electrodes, causing the metal ions to plate out onto the electrodes. The metal is then collected from the electrodes and processed further.

What Metals Can be Recovered Using Electrowinning?

Electrowinning can be used to recover a wide range of metals, including:

  • Copper

  • Gold

  • Silver

  • Nickel

  • Zinc

  • Cobalt

  • Cadmium

  • Lead

  • Mercury

Electrowinning is also used to recover metals from spent electrolytes. Spent electrolytes are solutions that have been used in electroplating or other industrial processes and contain metal ions. Electrowinning can be used to recover the metals from these solutions, making the process incredibly useful.

How is Electrowinning Used in the Mining and Electroplating Industry?

Electrowinning is commonly used in the mining industry to recover metals from solutions containing metal ions. The process is used to recover metals from leach solutions, which are solutions containing metal ions that have been extracted from ore using a leaching process. The leach solutions are then treated with electrowinning to recover the metals.

Electrowinning of Gold and other Precious Metals

Electrowinning of Gold is a method used to extract gold from its ore. It's a complex and accurate process in which a continuous electric current is applied to the gold bearing ore. The process involves the electrolysis of a solution of chloride salts to produce pure gold. Electrowinning can be a costly process, but it's essential for producing many gold-based items.

Electrowinning is a way to separate pure gold from other metals. The electrowinning process used to extract the gold from the ore material. It consists of passing an electric current through a solution of chloride salts, which causes the gold to form tiny particles.

These particles are then collected and transferred to a refining tank where the gold remains in its pure form. The electrowinning unit uses transformers, copper circuit boards and copper wiring to generate an electric current strong enough to separate gold from other metals. 1

Electrowinning Efficiency

Electrowinning has high metal recovery rates, with some processes achieving up to 99% metal recovery. Electrowinning can be used to recover a variety of metals, including copper, gold, silver, nickel, zinc, and lead.

However, the efficiency of electrowinning depends on several factors, and the process can generate wastewater that requires treatment. Despite these limitations, electrowinning remains an important process for recovering metals from various sources.

As technology continues to advance, it is likely that new and improved electrowinning processes will emerge, further improving the efficiency and sustainability of metal recovery.

What are the Advantages of Electrowinning?

Electrowinning has many advantages over other methods of metal recovery, including:

  1. High metal recovery rates, up to 99%

  2. Low operating costs

  3. Minimal environmental impact

  4. Ability to recover metals from a wide range of solutions

  5. High purity of recovered metals

For more information about electrowinning kindly get in touch with our team.

Electrowinning Electrodes

Electrowinning is based on the electrochemical deposition of metals such as nickel, copper, zinc, cobalt and manganese on cathodes in highly concentrated metal salt electrolytes by using custom designed electrodes.

Depending on your business needs, we can customize electrodes anode coatings for the specific metal winning process.

The custom-made electrodes for electrowinning results in market-leading performance, including higher purity of the deposited metal, lower oxygen overpotential, increased process efficiency, higher durability and stability due to better corrosion resistance.

The latest generation of PREDEST anodes are manufactured out of titanium and coated with a mix of precious metal and nonprecious metal oxides. This prevents the high overpotential requirement and degradable nature of earlier anodes that were made of graphite and lead alloys.

Our custom-made electrowinning anodes are an effective alternative to sacrificial anodes, providing significant energy saving benefits as well.


Electrowinning FAQs

What is the Difference Between Electrowinning and Electrorefining?

Electrowinning and electrorefining are both methods of extracting metals using an electrical current. The main difference between the two processes is that electrowinning is used to recover metals from solutions containing metal ions, while electrorefining is used to purify metals that have already been extracted.

What is the Efficiency of Electrowinning?

The efficiency of electrowinning depends on a number of factors, including the composition of the solution, the current density, and the temperature.

Generally, electrowinning has high metal recovery rates, with some processes achieving up to 99% metal recovery. However, the efficiency can vary depending on the specific process and conditions.

What are the Main Advantages and Disadvantages of Electrowinning?

Unlike traditional smelting processes, electrowinning does not produce significant amounts of air pollutants such as sulphur dioxide or particulate matter. The process also has minimal water usage, which is important in regions with limited water resources. 2

However, the process can generate wastewater that contains metal ions and other contaminants. This wastewater must be treated before it can be discharged to the environment to prevent contamination of water sources.

What metals can be recovered through electrowinning?

Electrowinning can be used to recover a variety of metals, including copper, gold, silver, nickel, zinc, and lead.

How does electrowinning compare to other metal recovery processes?

Electrowinning is generally considered to be a more efficient and environmentally friendly process than traditional smelting processes. It also has lower operating costs and requires less energy input.

Is electrowinning used in any other industries besides mining?

Yes, electrowinning is also used in other industries, such as the recycling industry to recover metals from electronic waste and other sources.


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