Zinc Refining by the Wet Method
Zinc refining is a process used to separate the valuable fraction from the non-valuable fraction of raw zinc. The process involves the use of a variety of wet methods. The primary wet method process used for zinc refining is the froth flotation process. This process uses a combination of air bubbles, oil, and a chemical reagent to separate the valuable particles from the non-valuable particles. The valuable particles typically contain a higher percentage of zinc, while the non-valuable particles are typically composed of other metals such as lead and iron.
The froth flotation process is usually conducted in an agitated tank, and begins with crushed ore being added to the tank. This ore must first be ground to a fine powder and suspended in water. The chemical reagent is then added and the mixture is stirred, aerated, and heated. As the agitation and stirring continue, the chemical reagent works to attract and associate with the particles that contain high concentrations of zinc. An inverse reaction forces other particles to form clumps and sink to the bottom of the tank.
The air bubbles collect the particles that are associated with the chemical reagent, forming a foamy surface. This foamy surface is referred to as “froth” and it is skimmed off the top of the tank by a rotating scraper. The froth is then sent through a series of filtering devices which collect the valuable particles, while allowing the non-valuable particles to pass through and be discarded.
The valuable particles are then collected and sent to a furnace, where they are smelted and refined, and the final product, refined zinc, is ready for use in numerous products and applications. The froth flotation process is simple and economical, and as such it is the most common type of zinc refinement process in use.
The wet method for refining zinc is beneficial for a variety of reasons, including its safety and its ability to provide a very pure end product. In addition, the wet method also significantly reduces pollution and emissions, due to its low-emission process. As a result, the wet method is an increasingly popular choice for refining zinc.
