The quality of recycled granules depends on what factors?
Many resources used by humans, such as oil, which is the raw material in plastic production, are considered non-renewable resources. Considering the widespread use of petrochemicals and the importance of plastic manufacture, recycling plastic parts is one of the most vital issues. One of the plastic industry’s concerns is recycling used plastic parts into granules and increasing the quality of recycled material granules.
In the following, while introducing granules, the benefits of using them are explained. Efforts are made to answer questions such as recycling into granules and solutions to increase the quality of recycled granules.
What is Granule?
Granule is a specific form of polymer used in various small and large applications. Polymer materials are melted with a device called an extruder after production. This device brings the polymers to a molten form, and the blade at the output of this device grinds the polymer and produces granules.
One of the crucial issues in the plastic industry has always been the recycling of plastic materials. The granulation of recycled plastic plays a significant role in this field. Granulation is one of the most important stages in plastic recycling. By increasing the quality of granules, a significant profit can be achieved, and more functional products can be manufactured.
Advantages of Using Granules
The production of granules is a crucial and sensitive stage and must be precise and high-quality. However, using granules also has its advantages. Some of the benefits of using granules include:
High control over shaping and coloring: The production of granules is an industrial process in which there is high control. This feature allows for monitoring and controlling the shaping and coloring of granules. For this reason, uniform and desirable shapes and colors are observed in granules.
Possibility of additives: One of the important advantages is the possibility of using additives in the granulation process. In this process, additives can be added according to the required needs and applications to increase the quality of the granules.
High uniformity: Using granules leads to the production of products with high uniformity. The reason for this uniformity is the same ability to control and modify the granulation process. The higher the quality of the produced granules, the higher the uniformity.
Granules, despite their valuable advantages, have a precise and relatively complex production process. By precise control and compliance with a set of fundamental principles, the quality of granules increases. Furthermore, increasing the quality of granules paves the way for increased profits and an expanded range of applications for recycled materials.
The most important factors affecting the increase in granule quality can be categorized into two main groups:
- Raw materials entering the granulator.
- Characteristics of the granulation process in the machine.
1) Raw materials entering the machine:
One of the most important factors affecting the quality of granules is the quality and freshness of the raw materials entering the machine. The higher the freshness of the raw materials without exposure to excessive heat and light, the higher their quality. Intense light radiation or excessive heat effects negatively on the structure of the raw materials and reduces their quality.
The moisture content and volatile organic compounds (VOC) in the raw materials have a significant impact on the overall granule production process and final quality. High moisture in the raw materials has a negative effect on the appearance and quality of the granules. This high moisture inside the extruder machine creates unwanted bubbles on the product. Additionally, high moisture can cause “stress” and concentration of stress in the produced product, resulting in decreased product quality.
Other important points for raw materials:
To minimize the moisture in the raw materials special drying devices are used. The raw materials are placed in these drying devices before entering the granulator to reduce their moisture and prevent the mentioned issues. However, the use of drying devices has its specific conditions and considerations.
Another important measure in increasing the quality of recycled material granules is washing. Washing is a crucial stage in granulation because the impurities in the materials affect the final product quality. Various pollutants exist in the raw materials used, such as dirt, grease, or even metallic parts. Cleaning these impurities is necessary, and sometimes multiple washes are required with high pressure and precision.
Sometimes, even after multiple washes, the inner surfaces of recycled materials still contain some impurities. In such cases, washing after milling is necessary.
2) The features of the granulation process in the granulation production line
The second category of factors affecting the quality of granules is the conditions and characteristics of the granulation production line. One of the most important parts of the granulation process is the milling machines. The body shape, sharpness, and quality of the cutting blades and other parts of the milling machine play a prominent role in the quality and increase of the produced product.
The milling machine not only grinds the plastic materials but also separates non-plastic materials (such as metal parts). The better the machine can separate the excess materials, the higher the final quality. Due to the repeated and continuous use of the milling machines, it is necessary to service and inspect these machines at suitable intervals.
One of the most significant advantages of using granules is controlling the production process. The use of automatic machinery in the production process and the employment of skilled and experienced human resources maximize control accuracy. As a result, the quality of recycled material granules increases.
Conclusion
Given the essential need for recycling plastic materials, one of the concerns in this field is recycling plastic components into granules. Using granules has considerable practical advantages, with the most important advantage being the ability to control the production process. Overall, the quality of recycled material granules mostly depends on two major factors:
1) The quality of the raw materials used
2) The conditions governing the granulation process