Secondary zinc, also known as recycled zinc, is zinc that is recovered from various scrap materials rather than mined as ore. The specifications for secondary zinc can vary depending on its intended use, the recycling process, and the source of the scrap material. Here are some key specifications and considerations for secondary zinc:
Chemical Composition:
The chemical composition of secondary zinc is crucial to ensure its quality and usability. Typical elements analyzed include:
Zinc (Zn): The primary component, usually required to be of high purity, often above 95%.
Lead (Pb): Typically kept below 1.5% to prevent brittleness.
Iron (Fe): Should be minimized, usually below 0.1%, to maintain ductility and corrosion resistance.
Cadmium (Cd): Generally kept very low, below 0.1%, due to its toxicity and impact on alloy properties.
Copper (Cu): Should be limited, typically below 0.1%, as it can affect the alloy’s mechanical properties.
Aluminum (Al), Magnesium (Mg), and Tin (Sn): May also be present in small quantities, depending on the scrap source and desired properties