THE USE OF DEM SIMULATION FOR CONFIRMING THE PROCESS OF PARTICULATE MATERIAL MIXING

At the present time in the research of particulate materials, computer methods that work independently with individual particles are coming to the forefront. One such method is the Discrete Element Method – DEM, which is already widely used. Its usage, however, is complex, mostly due to the input data – what the properties of the researched material are, plus their interaction in processes. And despite the progress, it is still always necessary to validate the experimental equipment and to verify the individual simulations by an experimental measuring or by theoretical knowledge. This study focuses on the verification of the simulation of the mixing of a particulate material with the help of the DEM method, whereby simulations are compared with an experimental measurement and theoretic calculations. The theoretical calculation was carried out by the Novosad model, while the experimental material was granulated polyethylene with strictly defined mechanical-physical properties

STUDY OF SAMPLES STRENGTH OF MATERIAL FORMED BY THE PROCESSES OF COMPACTION, EXTRUSION AND TUMBLING GRANULATION

In a period of industrial expansion, protection of the environment is often neglected during the mass manufacture of products. One of the problems of our society that is necessary to face at present is the provision, processing and then usage of waste composed of fine particles that are extremely dangerous for mankind. This study looks at the processing of the fine dust resulting from the manufacture of brake pads. The selected technologies for the process of dust treatment were compaction, extrusion and tumbling granulation, and their consequent comparison with the strength of a break and disintegration of agglomerates from fine dust. The experiments were performed on a unique equipment that made it possible to process such dust in the form of larger units and thus reduce their dustiness, with this dust being reintroduced into the technologies for repeat processing or used for energy processing, in a cement kiln, for example

MODIFICATION OF POWDER MATERIAL BY COMPACTION PROCESSING

There are different criteria for assessing the appropriateness of an agglomeration technology in the deployment processing of dry, fine and dirty dust burdening in the communal and working environment. Besides the benefit of the environment components, the agglomeration technology offers the possibility of re-processing the material as the primary raw material within a wide range of industries. Preliminary tests have shown that the compressed material remains in the memory from the previous compression. For returning the already processed material into a primary production, it is essential that it is reformed without the need for additional materials, a requirement that can be problematic. This article deals with the modification of a powder material (powder dust from the manufacture of friction components) and the investigation of its properties before and after the compaction processing

THE DEVELOPMENT OF A NEW ADSORPTION-DESORPTION DEVICE

The aim of this work was to construct a new adsorption-desorption device based on the principle of separation of volatile organic compounds, e.g., ethanol. As an adsorbent, it is possible to use granulated activated carbon (GAC) in the adsorption and desorption process. In this study, two kinds of GACs were used and marked as GAC1 and GAC2. A particle size distribution and water vapour sorption for the selected GACs were measured. An experiment with distilled water was performed as a preliminary study of the new device’s functionality. After the determination of the time necessary for the adsorption and desorption, the experiments were carried out with a model mixture (5% v/v ethanol-water mixture), which resulted in a product with the ethanol content of 39.6 %. The main advantage of this device would be the potential competition of conventional distillation

DESIGN OF PARTICULATE MATERIAL COMPACTOR ROLLS DIAMETER

At present, in a period of an industrial expansion great emphasis is placed on the environment. That means aiming for a reduced energy consumption, and also lessening dustiness from very fine powder material. This category also includes particulate material agglomeration processes. Because this process is very energy-intensive, it is necessary to correctly design these devices. The aim of this paper is to focus on a theoretical design of a production compactor with the rolls diameter for an experimental particulate material, based on Johanson’s theory and experimentally measured material properties. The material used for experimental measurements was an NPK-based industrial fertilizer consisting of several components. The results of this paper is the dependence of the ratio of the maximum compression pressure to the initial compression pressure from the rolls diameter of the proposed compactor

ANALYSIS OF STATIC ANGLE OF REPOSE WITH RESPECT TO POWDER MATERIAL PROPERTIES

This paper investigates the Angle of Repose (AoR) of powder materials with respect to their morphological and rheological properties. Glass beads, sand, flour and semolina of different particle sizes were used as the experimental materials. The investigated material was analysed with respect to particle shape and size. The rheological properties of the material were obtained by a shear cell test. The AoR was analysed in terms of cohesion, bulk density, particle size and circularity. More cohesive materials such as the flour samples exhibited the largest AoR > 40°, indicating their poor flowability. Glass bead samples with a high circularity value had significantly lower AoR than the flour. The Angle of Internal Friction values were not dependent on those of the AoR. Using a dimensional analysis, a mathematical model was developed to determine the AoR values based on the material properties. By the application of this model, highly accurate calculation of the value of AoR is made possible

Modifying the properties of finely ground limestone by tumbling granulation

Calcium carbonate in the form of finely ground limestone is a material that has found its application in a wide range of industries, in the chemical, rubber, agricultural, and paper industries, is used for desulfurization of boilers and other. In civil engineering, ground limestone is used for the production of building materials, plaster and mortar mixtures, as a filler in concrete mixtures, in road construction, and as an essential component of mastic asphalt. This paper deals with examining the modification of the properties of finely ground limestone by the tumbling agglomeration method. It has been shown that the components of concrete with a round grain have a positive effect on the pumping of concrete in comparison with an elongated grain or the rough surface of crushed stone. The experiments will be carried out on a granulation plate using a variety of granulation liquid. The agglomerates and their properties were compared with untreated finely ground limestone, with a focus on detecting changes in compressibility, density and particle size. The output of this paper is a description and graphical representation of the changes in the properties of ground limestone before and after the agglomeration process