Department of Mechanical and Industrial Engineering

Overview

The Laboratory for Sustainable Materials Recycling is part of the Institute of Mechanical and Industrial Engineering of Tallinn University of Technology. The Laboratory is home to the Materials Recycling Technology Research Group, which focuses on the recycling of problematic and difficult-to-process materials and the development of new recycling-based products.

The research group is led by Senior Researcher PhD Dmitri Goljandin, who is also the head of the laboratory. The group is an integral part of the Institute of Mechanical and Industrial Engineering and actively contributes to two TalTech research directions: “Wear-resistant composites and surfaces” (supervisor Prof. J. Kübarsepp) and “Innovative materials for industrial applications” (supervisor Prof. I. Hussainova).

The main activity of the research group is related to the development of grinding systems for the processing of various problematic and difficult-to-grind materials. The recycling of materials and the creation of new valuable products play an important role. The development of devices and processes uses or combines intensive grinding with other technological processes to achieve efficient material degradation and property modification. In addition, the focus is on the use of recycled materials in the development of new products, contributing to both sustainability and innovation in the field of materials science and engineering.

The research group has extensive and long-standing experience in solving complex technological problems, including the processing of ceramic and metal waste, composite materials (e.g. hard alloys, complex polymer and metal matrix composites), used car tires, printed circuit board waste and textile waste.

Equipment and capabilities

The laboratory for sustainable materials recycling is equipped with various types of impact grinding and combined separation systems (developed at Taltech), from low-capacity laboratory mills to semi-industrial equipment, for simulating production technological processes and conducting experiments:

• Laboratory multi-purpose disintegrator grinding system DSL-175 with a combined inertial-centrifugal classifier;
• Semi-industrial multi-purpose disintegrator grinding system DSL-115 for direct, separation and selective grinding modes;
• DSA-series industrial dismembrators;
• High-capacity disintegrator mill DSL-350;
• DESI WT – Disintegrator device for studying impact wear of materials.
• Vibroseparators of different capacities;
• Eddy current separator for separating magnetic and non-magnetic metal particles,
• Laboratory shredder mill;
• Roller mill;
• Air-inertial separators and sedimentation chambers;
• SD-15 - experimental module for studying the processes of rapid crushing of rubber composites;
• SD-25 - experimental module for simulating the processing of car tires into rubber crumb with simultaneous separation of textile and metal wire at room temperature;
• Experimental device RP-10 (22 kW) for crushing whole car tires with simultaneous separation of rubber fine crumb with metal parts and textile peel;
• DS - 37/21 Laboratory modular prototype of a rapid grinding and separation system for textile waste;
• Screening device (Vibratory Sieve Shaker RETSCH AS 200 control) for determining the component composition of powder materials;
• Etc.

The laboratory also provides the following services:

• Crushing and grinding of materials in disintegrator mills. Obtaining powders of the required size (2.8 mm to 5µm) from different materials. It is also possible to separate different fractions;
• Obtaining multicomponent high-quality mixtures. Grinding and mixing in one process using disintegrator technology;
• Determination of properties of powder materials: sieve analysis (DIN 66165), laser analysis (ISO13320), specific surface area, bulk and tap density, flowability, internal friction, direct shear test of powder materials.

Figure: Laboratory equipment: belt feeder, disintegrator mill in direct grinding mode, vibrating screens and dust filter.

Figure: Eddy current magnetic separator.

Main areas of activity

Laboratory for sustainable materials recycling

• Offers a wide range of services from studying the properties of powdered materials, grinding/separation/separation/mixing of materials with a wide range of properties and purposes, to the development and implementation of technological processes.
• An important part is participation in applied and scientific Estonian and European projects.
• Carrying out educational activities (thesis and training of young scientists, e.g. Erasmus+ staff mobility, etc.) related to the processing of complex and composite materials.

The main area of ​​activity is the development and implementation of high-intensity separation grinding methods for processing materials for various purposes, as well as the development of equipment and processes using or combining disintegration with other technological processes.

Keywords characterizing the activity: Grinding and recycling of materials. Grinding systems. Disintegrator technology. Obtaining powders of the required size. Selective grinding. Ultrafine grinding of materials. Obtaining high-quality homogeneous/multicomponent mixtures. Studying the impact wear of materials. Reuse and recycling of materials. Development of reprocessing methods for conventional and difficult-to-grind materials (ceramic and metal materials, composite materials: hard alloys, plastic composite materials, printed circuit boards (metal-glass fiber plastic laminated composite material, car tires, etc.).

Figure: Samples of ground recyclable materials.

Collaboration and projects

Over the past five years, the Materials Recycling Technology research group has implemented several research and development projects focusing on the processing of complex waste materials, the development of new circular products and the development of innovative mechanical separation solutions. The most important projects include:

- Epoxy and metal recycling from non-ferrous e-waste. Printed circuit boards contain significant amounts of critical metals such as Cu, Au, Ag, Ni, Sn, Pd and Pt. The recycling of printed circuit boards is a challenge due to the high content of epoxy and bromine, which are hazardous to the environment and health. The aim of this activity is to validate the epoxy separation technology to enable the utilization of raw materials and critical raw materials in recycling furnaces.

- Development of textile waste shredding technology and novel materials to valorize textile waste and support the circular economy. A technology suitable for crushing special types of textile waste has been developed, which allows for more efficient recycling after separate collection of the waste type. In addition, solutions are proposed for using crushed textile waste as starting materials for various materials and products.

- Niobium slag recycling and valorization. The recycling and possible reuse of Nb slag generated during the production of metallic niobium (Nb) at NPM Silmet OÜ was studied. An Nb slag recycling technology was developed using disintegrator technology, as a result of which the metallic Nb remaining in the slag was separated and calcium aluminate (CA) was obtained as the main component. Of the possible areas of use of CA studied, the use of CA as a component of a heat-conducting material turned out to be the most promising. The thermal conductivity and mechanical properties of the obtained heat plates turned out to be better than the properties of an analogous industrially produced material.

- An application study for the use of reed biocomposite materials in biodegradable food containers. The aim of this research is to reduce the generation of plastic waste in nature by replacing single-use plastic tableware with modified reed and reed-reinforced biopolymer composites.

- Finding the possibility & technology for separating aluminum scrap. The aim of the work is to investigate the possibilities (and find a rational method) of separating wood chips from metal chips in the mixture, which would allow more efficient burning of the wood part in boiler houses (aluminum chips do not clog the grates) and increase the price of aluminum scrap by increasing their concentration and purity.

Team and contact

Contact: Dmitri Goljandin
E-mail: dmitri.goljandin@altech.ee
Phone: +372 553 7985
Cooperation requests with Estonian companies. Contact us for a visit and cooperation!

We are looking for companies interested in the following topics:

• Reuse of hard alloy plates in coarse-grained milling elements;
• Possibility of recycling Li-ion batteries;
• Recycling of textile materials (using shredded fibers for pyrolysis, combustion, to create noise-absorbing and electromagnetic shielding composites);
• Recycling of fiber composites (with metal, mineral and plastic matrix) for the purpose of separating and recovering components, including solar panels and glass and carbon fiber plastic composites;
• Processing of peat for the purpose of increasing its value;