At American Zinc Products, we produce zinc from waelz oxide (WOX). We use our patented extraction process to extract value from the WOX, which contains mostly zinc with some lead and silver. It is refined into special high-grade zinc (SHG) that is 99.995% pure—turning what would have been industrial waste into a valuable commodity.
Our unique, patented process makes AZP the only zinc plant in the world producing SHG zinc from solely recycled materials.
The Four Main Steps in Our Process
The WOX is delivered by rail from recycling facilities in the form of a dry powder and stored in silos on site. From here it is mixed with solution and pumped into the Leaching phase via a slurry pipeline.
During Leaching, WOX is mixed with weak sulfuric acid and water by an automated process. The purpose is to dissolve the zinc present in the WOX and put it into a clear solution. The clear zinc bearing solution is then sent to solvent extraction (SX) for purification.
The clear zinc bearing solution moves into a row of mixing tanks, where it’s mixed with an organic material that attracts the zinc particles. The zinc and the organic material settle on top of the rest of the solution, just like oil and vinegar separate in salad dressing. After separation, the zinc is removed from the organic material leaving a high purity zinc bearing solution called electrolyte. Meanwhile, the organic material is recycled back to the beginning to extract more zinc and the process repeats.
Now, the zinc needs to be collected from the electrolyte solution. This happens in the cell house, where the solution is pumped into large plastic lined concrete tubs, called cells, filled with a series of cathodes and anodes.
When electricity is supplied to the anodes, the dissolved zinc starts to build up on the aluminum plates of the cathodes. Once it’s thick enough, it’s mechanically removed with our state-of-the-art cathode stripping machine and sent to casting.
Finally, our extracted zinc, now in the form of metal, is ready for the furnace. Here, it’s melted down and cast into 55lb slabs or large 2200lb blocks called jumbos. We also can combine our zinc with other metals to form an alloy depending on customer requirements.