Aluminum diecast

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Cast aluminum, also known as aluminum alloy casting, is a type of aluminum alloy produced through the casting process. The production process involves pouring molten metal into a mold, where it cools and solidifies into a specific shape. Cast aluminum is widely used in various industries due to its good fluidity and plasticity, making it an ideal material for manufacturing complex-shaped parts and products. The main metal component of cast aluminum is aluminum (Al), but it often contains other metal elements as alloying elements to enhance its physical and chemical properties. The aluminum content of cast aluminum is often lower than that of wrought aluminum. In particular, some non-standard low-grade cast aluminum scrap, such as aluminum pots, may have an aluminum content of only 70%-80%. Common alloying elements include:
1. Silicon (Si): Enhances the casting performance and mechanical properties of aluminum. The high proportion of silicon can significantly improve the fluidity and fillability of the metal in the mold. This is also the main difference between cast aluminum and wrought aluminum. The silicon content typically ranges from 2% to 13%.
2. Magnesium (Mg): Increases strength and corrosion resistance, usually with a magnesium content of 0.3% to 1%.
3. Zinc (Zn): Improves strength but reduces ductility, with a typical content of up to 3%.
4. Copper (Cu): Enhances hardness and strength but reduces corrosion resistance, typically with a content of 1% to 5%.
5. Manganese (Mn): Improves corrosion resistance and toughness, with a content of up to 1.5%.
Common mixed cast aluminum is shown in the figure below:

The proportion of these alloying elements will be adjusted according to the intended use and required mechanical properties of the cast aluminum. Common cast aluminum products include:
* Automotive parts, such as engine blocks and wheel hubs
* Mechanical equipment parts
* Kitchen utensils, such as aluminum pots and pans
* Artistic products
Cast aluminum and wrought aluminum are often referred to as "raw aluminum" (cast aluminum) and "recycled aluminum" (wrought aluminum) in China. According to the definition of the Institute of Scrap Recycling Industries (ISRI) in the United States, mixed cast aluminum scrap is classified as "Tense," which refers to "mixed cast aluminum scrap." This type of scrap includes clean aluminum castings, possibly from automotive or aircraft parts, but excludes ingots. The scrap should not contain iron, brass, dirt, or other non-metallic substances. The oil content should not exceed 2% of the total weight.

Common Classification

The most commonly used indicator to distinguish mixed cast aluminum scrap is the "impurity content," which refers to the amount of metals and non-metals other than aluminum alloy in the scrap. For example, "2% impurity mixed cast aluminum" or "30% impurity mixed cast aluminum." The price of the scrap directly correlates with the level of impurities.
There are also classifications based on the type of cast aluminum alloy. The main classification systems for cast aluminum alloys include:
1. American Aluminum Association (AA) standard: This is an internationally widely used classification system, which uses four-digit numbers to identify different alloys, such as A356 and A380.
2. European standard (EN): Uses the EN numbering system, usually starting with "EN AC-" followed by four digits, such as EN AC-46000 and EN AC-43100.
3. Japanese Industrial Standards (JIS) standard: Such as ADC12, AC4H, and AC8A.
4. Chinese GB/T standard: Such as ZL102 (equivalent to AlSi12), ZL104 (equivalent to AlSi10Mg), and ZL109 (equivalent to AlSi12CuNiMg).
Common types of cast aluminum include A356, A380, and ADC12. Some mixed cast aluminum scrap may have a single metal alloy number, which can increase its value.

Common Sources

Mixed cast aluminum scrap is commonly sourced from two main areas:
1. Production factories: Mainly residual products, such as defective engine blocks, mechanical parts, or edge materials from processing.
2. Used and discarded products: For example, automobile repair shops, mechanical repair shops, and other industries that generate large amounts of discarded cast aluminum scrap.

Value Points

The value of mixed cast aluminum scrap lies in its ability to be efficiently recycled. First, the impurities in the scrap should not be excessive, especially metal impurities like steel and iron, which can significantly affect the aluminum recovery rate and product quality. High levels of iron can not only reduce the price of the aluminum ingot but also lead to the loss of aluminum during the refining process, resulting in a loss of 1%-2%. The presence of non-metallic impurities, such as rubber and plastic, can also cause environmental pollution.
Second, if the scrap is entirely composed of the same type of cast aluminum alloy, its value will be higher. For example, factory-produced residual products with the same A356 alloy number can be efficiently recycled.

Processing Methods

Mixed cast aluminum scrap contains various impurities and requires appropriate processing methods to remove them. The most commonly used method is manual disassembly, where workers manually disassemble, crush, and separate the scrap to remove attached metals and non-metallic impurities. Mechanical crushing can also be used, followed by various separation methods, such as magnetic selection, flotation, and X-ray screening, to separate the cast aluminum from other metals or impurities. Selling crushed cast aluminum is also a common practice, which is referred to as "Twitch" in the ISRI classification.

Detection Methods

The most commonly used detection method for cast aluminum scrap is to test for iron content. This involves randomly sampling some scrap, typically 100-500 kg, and then separating and calculating the iron content. Alternatively, the scrap can be melted and the iron content calculated after removing the iron slag.

Matching Direction

Cast aluminum scrap is widely applicable to various factories that produce cast aluminum ingots. Almost all recycled aluminum companies have a demand for cast aluminum scrap, making its usage extremely broad. Some cast aluminum scrap with high impurity levels can be matched with buyers who have manual disassembly or mechanical crushing and separation capabilities. Polished crushed cast aluminum that meets Chinese import standards can command a higher price than other crushed cast aluminum scrap.

Special Attention

Cast aluminum is often confused with Tense, Trump, and Irony Aluminum in international trade. Different countries and markets have varying standards for cast aluminum, so it is essential to carefully inspect the goods during transactions.

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