Electrowinning – an introduction

Electrowinning is a process used to recover metals from a solution or an electrolyte, by means of an electrolytic chemical reaction. This occurs when an electric current passes from a cathode that's negatively charged to a positively charged anode through a metal-containing solution. During this process, the electrons reduce the metal ions in the solution to form a solid metal deposition on the cathode. The quality of the metal produced can vary depending on the individual process and may require further processing or refining.

Nickel powders are widely used in industrial applications worldwide, such as rechargeable batteries, manufacturing and powder metallurgy. In some cases, nickel powders are used to add a magnetic feature to a particular material. Nickel can be used in electroplating and coinage industries as well. But there is more to nickel powder, and there is something that you have probably never heard about until now.

What is Metal Finishing?

Metal finishing is a type of surface finishing that can be defined as the deposition of a metallic coating onto a product either to enhance performance, function or aesthetic qualities while providing overall added value. While it's not obvious on a daily basis, many objects have been subjected to metal finishing for use in our normal lives. These include parts in a car, aircraft, fencing, medical and dental devices, industrial machinery or even beautiful pieces of art. The term finishing is based on the fact that it's normally the last step of the manufacturing process (save for any heat treatment).

While Elon Musk compares AI to “summoning the demon” and Bill Gates doesn’t “understand why some people are not concerned” that artificial intelligence slowly but steadily becomes a part of our daily lives.

Our mobile phones are equipped with Siri, Cortana or Google Now that assist us with daily tasks. Self-driven cars are already on our roads, driving thousands of miles with ZERO accidents (or at least they are not the reason for the accidents).

Retailers like Amazon and Target use a self-educating software that can anticipate your needs and offer you the next product to buy even before you know you need it.

How about these online customer support chats? Did you know that most of them are machines hiding behind human names? Many of them have the ability to learn and to adapt to the tone of questions in order to search company websites and present the right information to the customer.

Acid mine drainage: we’ve all heard of it, and its negative reputation. But what if we told you that it’s not all bad? What if this environmental pollutant was recovered and transformed into a profit-turning resource? [Bejan & Bunce, 2015] There are varying methods of dealing with acid mine drainage (AMD), but only some of them are economically viable and effective long-term. This blog post is going to dive into some of the solutions for the treatment of AMD, and how emew technology provides one of the most promising alternatives, specifically for copper recovery from acid mine drainage.

What are the Factors that Affect Anode Life?

In electrowinning, metals ions dissolved in an electrolyte are deposited in a reduced metallic form at the cathode. The conversion of the metal from an ionic (dissolved, positive charge) to metallic form (solid, no charge) at the cathode requires a supply of electrons into the electrolyte solution which is supplied from the anode.

Electrowinning is a very convenient and robust way to directly recover dissolved metals such as copper, silver, gold, nickel, cobalt, and tin from their aqueous states in a particular electrolyte.  Not surprising then when talking about metal recovery that we tend to focus most of our attention on those metals that we are interested in with the aim of recovering them from solution.  That is after all the objective of the metal recovery process.  What is less often talked about however are the impurities that can affect metal recovery with electrowinning.  This blog post will identify those impurities that are most detrimental and discuss their effect on the electrowinning of some commonly recovered metals from aqueous solutions. 

As the world is advancing towards clean, sustainable energy sources, businesses in traditional resource industries can be faced with a moral dilemma – to sacrifice margins in favour of clean initiatives or continue using conventional equipment and carbon-based energy sources that ensure revenue maximization.

The electro-refining of copper is a multi-step process that starts with copper concentrate that is smelted to produce impure copper anodes, which are then electrorefined to produce LME Grade A copper cathode (+99.99%).  A simplified block flow diagram of copper refining is shown below.

Silver refining is a critical part of any precious metals refinery.  Often the higher value metals such as gold and the Platinum Group Metals (PGM’s) are associated with silver, which must be recovered separately as a by-product.