Yellow brass turnings

1. Based on Different Processing Sources
   They can be classified as chips, turning material, milling material, drilling material, grinding material, hacksaw material, etc. Turnings from various sources differ in size and thickness.
   As shown in the following image, grinding material has a high metal recovery rate.

2. Based on Different Packaging Methods
   They can be categorized as:
   ① Loose Pure Copper Turnings or Copper Alloy Turnings:
   These turnings are often packaged in bulk bags or plastic film without compression. The advantage of this packaging method is the ability to visually inspect and judge the oil-water content, allowing the oil-water to drain or evaporate during storage. The disadvantage is that the material is fluffy, occupying a large volume in a container; there is significant loss during transportation due to its fine nature; and it is inconvenient for transportation and feeding during use.
   As shown in the following image, loose turnings.

② Briquetted Pure Copper Turnings or Copper Alloy Turnings:
The advantages of this packaging method are: 1) it saves shipping volume. 2) it reduces material loss from scattering. 3) it is convenient for feeding. Its disadvantages are: 1) it is easy to have foreign objects mixed in the briquetted blocks, such as other metal impurities like aluminum, stainless steel, or other metal substances like plastics, rubber. After packaging, these cannot be identified from the exterior with the naked eye. 2) oil and water do not easily drain out.

③ Bundled Pure Copper Turnings or Copper Alloy Turnings:
The advantages and disadvantages of this packaging method are largely similar to those of the briquetted method.

Brass turnings, among other copper alloy turnings, are a byproduct of the copper processing industry and an important industrial waste material. They are typically generated in the following processing steps:
1. Turning: This is the most common process for generating turnings, involving the fixation of pure copper or copper alloy materials on a lathe. The stationary cutting tool cuts the material by rotating the workpiece to manufacture parts of the desired shape and size.
2. Milling: In the milling process, pure copper or copper alloy materials are fixed while a rotating milling cutter moves along the surface of the workpiece to cut the material. This process also generates pure copper or copper alloy turnings.
3. Drilling and Boring: During drilling or boring, the workpiece is fixed, and the drill bit or boring tool rotates and enters the material to remove it and form holes. This process also generates turnings.
4. Planing and Broaching: In planing and broaching operations, linear cutting movements are used to remove pure copper or copper alloy material to achieve a flat surface or specific shape, generating turnings in the process.
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 alloy may be generated.
6. Thread Production: When threads are produced, whether by rolling or cutting, pure copper or copper alloy turnings may be generated, especially during the cutting of threads.
The following images illustrate the process of chip production:

1. Through Pictures or On-site Inspection
   Carefully inspect the impurities and oil-water content. Pure copper turnings or copper alloy turnings often inevitably mix with machine oil and moisture. During inspection, observe the presence of oil and water leakage on the surface of the material and the surrounding ground. Some loose turnings packaged in plastic film have a relatively higher oil-water content, which requires close attention.
2. Metal Material Verification
   Single pure copper turnings or copper alloy turnings, because they can be directly reused without downgrading, have higher value than mixed pure copper turnings or copper alloy turnings. When suppliers issue listings, they should clearly specify the elemental composition of the metal. If it is a mixed material, it is helpful for buyers to judge the goods and enhance their value if the proportions of different raw materials are specified as accurately as possible.
3. Trace Past Cargo Information
   The pure copper turnings or copper alloy turnings produced by a particular factory or supplier are often stable industrial waste materials. Under the condition that the processing technology does not undergo significant changes, the metal composition of their turnings products does not change significantly; under the condition that production capacity does not undergo significant changes, the output of their turnings products does not change significantly either. Therefore, after sampling, turnings are very suitable for long-term contracts procured at formula prices. At the same time, the metal recovery rate, oil-water rate, and other data from downstream companies that have previously processed the same turnings can accurately reflect the quality of the cargo.

After generation, pure copper turnings or copper alloy turnings need to go through a series of processing and pretreatment procedures before reuse. The following are common steps in these processes:
1. Collection and Separation: During the processing, turnings should be collected regularly or using automated methods. To improve recycling efficiency, pure copper turnings or copper alloy turnings should be separated from other metal turnings for collection.
2. Cleaning and Drying: To reduce oil-water content and enhance recycling value, collected turnings are typically washed to remove adhering cutting fluid or grease. After washing, the turnings may be dried through heating or the use of a centrifuge.
3. Compaction or Briquetting: To facilitate transportation and processing, dried turnings may be compacted using a press to form small blocks or briquettes, reducing volume and preventing scattering.
Pure copper turnings or copper alloy turnings are generally directly sent to smelting plants for smelting. Unlike aluminum alloys, they have high metal recovery rates and do not require the addition of fluxes during the smelting process. In the smelting process, brass is melted and transformed into a liquid state, with non-metal impurities being removed.

The main detection method for brass scrap is visual inspection. Experienced professionals can visually estimate the metal recovery rate and oil-water content with accuracy within ±1% range. In addition to visual inspection, other detection methods for brass scrap include crucible testing. Moreover, for certain metal pieces with uncertain copper content, portable spectrometry can be used for detection.

The primary aim of matching is to seek direct reuse without downgrading. Pure, single-component pure copper turnings or copper alloy turnings are suitable for specialized product factories due to their stable supply and elemental content, requiring minimal processing and pretreatment steps. If they contain other metal impurities, mixed different copper alloys, or have extremely high oil-water content, they can only be provided to factories equipped with appropriate pretreatment facilities for use after pretreatment. If the quality of the cargo is poor, making it difficult and costly to reuse without downgrading, such mixed copper turnings often can only be downgraded for processing into various crude copper ingots or rods, significantly reducing their value.

Brass chip scrap inevitably contains oil-water, and the range of oil-water content should be clearly specified.
In transactions, particular attention should be paid to the consistency between the offered goods' photos and the actual goods, as well as the consistency between the offered location and the actual shipping location. Due to the immense variability of brass scrap, prices are heavily dependent on images and origin information.