Metal material recycling is one of the most important steps in using resources efficiently and reducing the impact on the environment. Depending on the needs, materials will be separated at the source by sizes and types before going through the recycling process to become a source of production materials. For example, scrap steel is used as the main source of steel production melted by electric arc furnaces (EAF). To facilitate recycling, hard or large materials are cut into small pieces. In this blog post, we will introduce some types of scrap collected at scrap yards to be used as recycled materials for production. We will also discuss internal tests in shredding large scraps and supporting the recycling process with the use of cutting tools.
Types of Scraps
Scrap metal is divided into two categories: ferrous and nonferrous. The distinguishing characteristic between the two types of metals is the presence of iron. Ferrous metals contain iron while nonferrous do not. Therefore, anything that's made out of steel is going to be a ferrous metal.
Another way of classifying steel scrap is to classify it according to the products in which the steel was used before it became scrap. The main steel scrap sources in this sense are automobiles, ships, railroads, construction buildings, machinery, packaging, electric and electronic equipment, etc.
Items and Classification in Scrapyard
There are many types of scraps used for recycling as materials to reproduce new products. Below the table is some main material and items in the scrapyard together with melting points.
|
Classification |
Melting Points (oC) |
Items in Scrapyard |
|
Carbon steel |
1371 - 1540 |
Automobiles, Mild Steel Pipes |
|
Stainless steel |
1510 |
Foundry, Bridges, Storage Tank, Shipbuilding |
|
Cast Iron |
1127 - 1204 |
Rotor Drum, Motor body |
|
Aluminum |
660 |
Aluminum wheels, Furnaces, Ovens, Heaters |
|
Copper |
1063 |
Copper wires, Copper sheets, Electronic equipment |
Application Tool Used to Cut Scraps
There are several ways to shred and cut scraps into small pieces before recycling as materials for production. One of them is using Oxygen Lance to cut those scraps, especially with high hardness or huge size scraps.
Thermic Lance is a steel pipe with inserted wires, or wires and inner pipe that are to be used for fusing the metals and so on. The principle is that harness the oxidation heat of high temperature by providing the pressurized oxygen inside an ignited steel tube. Generally, metal tube contains steel wire that promotes combustion.
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At DLI - we made an internal experiments using Thermic Lance to cut those scraps as below:
1. Experiment to cut Steel Bar:
In this experiment, we use Steel Bar SS400 as the material with a thickness of 80mm. We made an internal test between Type T and Type W to see the effectiveness.
|
Steel bar Length: (mm) |
500 |
|
Thickness (mm) |
80 |
|
Steel grade of cut material |
SS400 |
|
TYPE |
TYPE-T |
TYPE-W |
|
Dimension |
17.3 x 2.1 x 3,000 (mm) |
17.3 x 2.1 x 3,000 (mm) |
|
Oxy pressure (Bar) |
10 |
10 |
|
Cutting time (second) |
117 (1 min 57 secs) |
172 (2 mins 52 secs) |
|
Pipe consumption (mm) |
1480 |
2000 |
2. Experiment to cut Roller:
In this experiment, we use the material that is Roller SKD11 with OD 192mm, with different shapes compared to Steel Bar SS400.
|
Roller OD (mm) |
192 |
|
Steel grade of cut material |
SKD11 |
|
Oxy pressure (Bar) |
10 |
|
TYPE |
TYPE-T |
TYPE-W |
|
Dimension |
21.4 x 1.9 x 3,000 (mm) |
21.4 x 1.9 x 3,000 (mm) |
|
Cutting time (second) |
153 (2 mins 33 secs) |
147 (2 mins 27 secs) |
|
Pipe consumption (mm) |
1455 |
1710 |
Results of those internal experiments show that Type T has a better performance with higher efficiency. So we recommend using type T for cutting general steel scraps in a scrapyard. Type W can be used for higher melting points like stainless steel, or cleaning purposes.
Conclusion
There are many elements that affect the operation and effectiveness of melting and material for recycling production. We want to let you know better about the material scrap type, and melting points, and through our internal experiments consider how to deal with scrap. Please let us know your thoughts and feel free to contact us. We are welcome to support you in enhancing the effectiveness, not only for good performance but also for cost-saving purpose.
