Copper Turnings

1. Based on Different Machining Sources
   Turnings can be categorized into swarf, turning material, milling material, drilling material, grinding material, hacksaw material, etc. Turnings from various sources differ in size and thickness.
   The following image shows grinding material with a high metal recovery rate:

2. Based on Different Packaging Methods
   These can be divided into:
   ① Loose Pure Copper Turnings or Copper Alloy Turnings:
   This packaging method involves ton bags or plastic film packaging without compression. The advantage of this packaging method is that it allows for a direct visual inspection and judgment of the oil and water content. When stored, oil and water can drain or evaporate. The downside includes: the material is fluffy and occupies a larger volume in containers; there is more loss during transportation due to breakage; and it is inconvenient for transportation and feeding during use.
   The following image shows loose turnings swarf:

② Compacted Pure Copper Turnings or Copper Alloy Turnings:
The advantages of this packaging method are: 1. It saves shipping space. 2. It reduces material loss from scattering. 3. It facilitates feeding. Its disadvantages include: 1. It is prone to have contaminants mixed into the compacted blocks, such as other metal impurities like aluminum, stainless steel, or other metallic materials like plastic, rubber. After packing, these cannot be identified through visual inspection from the exterior. 2. Oils and moisture are not easily expelled.
The following image shows compacted purple copper turnings swarf:

The advantages and disadvantages of this packaging method are essentially the same as those for compacting.
The following image shows compacted copper turnings swarf:

Purple copper turnings are a byproduct generated during copper processing and an important type of industrial waste. They typically occur in the following machining processes:
1. Turning: Turning is the most common process for producing turnings, involving the fixation of pure copper or copper alloy materials on a lathe, where the rotating workpiece is machined by a stationary cutting tool to manufacture parts with desired shapes and dimensions.
2. Milling: During milling, pure copper or copper alloy materials are fixed, and a rotating milling cutter moves along the surface of the workpiece to remove material. This process also generates pure copper or copper alloy turnings.
3. Drilling and Boring: In drilling or boring processes, the workpiece is fixed, and a drill bit or boring tool rotates and enters the material to remove material from pure copper or copper alloy to create holes, also generating turnings.
4. Planing and Broaching: Planing and broaching involve the removal of pure copper or copper alloy material using linear cutting motions to achieve flat or specific shapes, processes that also produce pure copper or copper alloy turnings.
5. Grinding: Although grinding typically produces finer powders, in some coarse grinding or specific types of grinding processes, larger fragments or turnings of pure copper or copper alloys may also be generated.
6. Thread Production: When manufacturing threads, whether by rolling or cutting, pure copper or copper alloy turnings are produced, especially during the cutting of threads.
The following images illustrate the production process of purple copper swarf:

1. Inspection Through Images or On-Site Visits
   Carefully examine the impurities and oil and water content. Purple copper turnings often inevitably mix with oil and water during the machining process. During inspections, the presence of oil and water can be observed by checking the surface of the material and the surrounding floor for leaks. Loose turnings packaged in plastic film are likely to have more oil and water, requiring particularly careful observation.
2. Metal Material Verification
   Purple copper turnings, which can be directly used without downgrading, have higher value than mixed pure copper turnings or copper alloy turnings. When suppliers provide offers, they should clearly specify the elemental composition of the metal. If it is a mixed material, the proportions of different raw materials should be clarified as much as possible, which helps buyers assess the goods and subsequently enhances their value.
3. Tracking Past Shipment Information
   Purple copper turnings from a particular factory or supplier are often stable industrial waste. Under the condition that major changes do not occur in the machining process, there will not be significant changes in the metal type of the turning products. And if there are no major changes in capacity, the output of the turning products will not significantly vary either. Therefore, after a trial shipment, turnings are suitable for long-term orders with formula pricing. At the same time, the metal recovery rate and oil and water content data from downstream companies that have previously processed the same turning products can accurately reflect the quality of the goods.

After purple copper turnings are generated and before they are reused, they must go through a series of processing and pretreatment processes. The following are common steps in these processes:
1. Collection and Separation: During the machining process, turnings should be collected periodically or using automated means. To enhance recycling efficiency, purple copper turnings should be collected separately from other metal turnings.
2. Cleaning and Drying: To reduce oil and water content and improve recycling value, collected turnings typically require cleaning to remove adhering cutting fluids or oils. After cleaning, the turnings may be dried through heating or the use of centrifuges.
3. Compaction or Briquetting: To facilitate transportation and handling, dried turnings may be compacted using a press into smaller blocks or briquettes to reduce volume and prevent scattering.
Purple copper turnings are generally directly sent to smelting plants for smelting. Unlike aluminum alloys, they have a high metal recovery rate and do not require extensive treatment in the smelting process. During smelting, the copper will be melted and converted into a liquid state, while non-metallic impurities are removed.

The primary detection method for purple copper scrap is visual inspection. Experienced professionals can visually estimate the metal recovery rate and oil and water content of purple copper scrap within ±1% accuracy. In addition to visual inspection, the detection methods for purple copper scrap also include crucible testing. Furthermore, for metal parts with uncertain copper content, portable spectral analysis can be used for detection.

The primary goal of matching is to seek direct use without downgrading. Pure and consistent purple copper turnings are suitable for manufacturers of specialized products due to their stable supply and elemental content, eliminating the need for extensive processing and pretreatment. If they contain other metal impurities, mixed copper alloys, or have excessive oil and water content, they can only be provided to factories with corresponding pretreatment equipment for utilization after pretreatment. If the quality of the goods is poor and downgrading use is difficult and costly, these mixed copper turnings are often processed into various crude copper ingots or copper bars, significantly reducing their value.

Purple copper swarf inevitably contains oil and water, and the oil and water content range should be clearly specified.
In transactions, special attention should be given to the consistency of the images provided and the actual goods, as well as the consistency of the reported location and the actual shipping location. Due to the great variation in purple copper scrap, prices are heavily dependent on images, origins, and other information.