What is the difference between electrorefining and electrowinning

Electrowinning processes can also be used for wastewater treatment and general recycling. The principle is still the same, any impure material can be leached into a conducting solution, then the DC voltage is applied through the solution and the desired material can be extracted of course, there are certain limitations such as metal concentration, temperature, acidity levels, chemical components, and more. When it comes to wastewater treatment, electrowinning is a win-win situation.

Less soluble metals make their way to landfill along with the recovery of valuable metals which can be sold to offset the processing cost. Electrowinning can be used as a processing step for the recycling of non-ferrous metals.

Non-ferrous metals can be recycled infinitely without losing any of their properties. This feature makes electrowinning an ideal process to recover pure metals from complex, mixed metal feeds.

In many cases, it is cheaper to recycle metals instead of mining ore, processing it and extracting pure metals. And this is especially true considering continuously decreasing metal grades in existing mines and deposits. Deciding on what process to opt for will depend on the situation. Electrorefining is used when an anode is cast from impure metal. Electrowinning is employed when the metal is already dissolved into solution, or when it is more feasible to employ a hydrometallurgical digestion step as opposed to casting impure anodes.

Electrowinning can also be done on a smaller scale and for more niche applications. Both electrowinning and electrolytic refining can produce very high purity metals exceeding For the most part, electrowinning is a rather straightforward and simple process. Electrical current is provided by rectifier to cathodes and anodes in such way that difference in electrical potential creates a movement of cations towards the cathode.

As time goes by the positively charged ions will plate on the cathodes. It is important to note that as metal builds-up on the cathode the deposition of metal in solution will decrease and the plating will slow down. Once the metal deposition decreases to a rate that is not sufficient for electroplating, the cathodes with pure metal deposited will be harvested. In the case of waste water treatment, the solution wastewater will be cleaned or significantly purified of non-ferrous metals and can be further treated by chemical precipitation or reused within the industrial process.

Electrowinning was mostly unchanged until 20 years ago with the advent of advanced electrowinning technologies that use cylindrical cells with high flow rate to enhance the rate of mass transfer, overcoming issues associated with depletion zones and enabling production of high-purity metals even in presence of impurities.

The advent of cylindrical electrowinning cells has expanded the applicability of electrowinning beyond just metal refining to recycling, waste, and wastewater treatment, and even into hi-tech industries like semiconductors. While electrowinning is mostly used to recover non-ferrous metals such as copper, nickel, tin, cadmium, or precious metals like gold, silver, and platinum, it also has a usage in industries that require wastewater treatment. An electrowinning facility can operate 24 hours a day, 7 days a week and offers some great benefits:.

Given all this electrowinning technology remains a core process in mining, refining, and metal finishing industries, providing great financial and environmental benefits. Get the best of Water Online delivered straight to your Inbox! Sign in or Sign-up. Browse all BookRags Study Guides. Copyrights Electrorefining and Electrowinning from Gale. All rights reserved. Toggle navigation.

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