**2.2 Developed disintegrators, separators and disintegrator milling systems**

The DS series of multi-functional disintegrators were developed at Tallinn University of Technology (TalTech) for the processing of various materials, including polymer materials and plastic scrap [9]. The disintegrators of this series include:


These systems are designed for processing various types of materials and are characterized as follows (**Table 1**):



• increases a material's chemical activity.

#### **Table 1.**

*Characteristics of used disintegrators and classifiers.*

**Figure 2.**

*Schematic representation of disintegrators DSA-2 (a), DSL-115 (b) and DSA-158 (c): Disintegrator equipment: 1 – Rotors; 2 – Electric drives; 3 – Material supply; 4 – Grinding elements; 5 – Output (authors image).*

The developed disintegrators can work in the system of direct, separative (closed) or selective milling (**Figure 2**).

In the direct milling system, all the material passes through the disintegrator, undergoes a series of high-intensity impacts and flies out into the collector of the final product. Direct grinding is intended for the: testing the properties of materials, production of materials with a wide granularity, processing dry, wet or liquid materials, to combine the impact effect with other technological operations, such as mixing, homogenizing, cleaning and drying.

To obtain a product with a very fine grain, it is necessary to use the separative milling mode of disintegration, in which the crushed mass repeatedly passes the disintegrator and a classifier separates the product with the required grain size. Switching from one grinding mode to another requires only one simple operation - changing the classifier. An example of separative milling is the final operation of recycling acrylic waste – pre-crushed scrap is milled into particles of an adjustable size from 2 mm to 50 microns. The resulting powder can be effectively used as a starting material for creating new powder mixtures and for electrostatic spraying as a new coating.

Selective milling is a variant of separation in process, in which small and large particles are sent to different collectors. It allows to separate (enrich) materials with different density, strength, or get rid of microdefects in the structure of the material (**Figure 3**).

**Figure 3.** *Modes of disintegrator milling (authors image).*

The purpose of this option is:

