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Surface water and groundwater are polluted with pharmaceuticals, detergents, pesticides, and many other substances. Application of ferrates seems to be a perspective option for wastewater treatment as ferrates are not only powerful oxidizing agents but also an excellent disinfecting and coagulating agents decomposing many stable inorganic, organic, and biological compounds. Final products of their decomposition do not include carcinogenic or toxic products. In this paper, stability of electrochemically prepared potassium ferrate encapsulated in packaging materials printed on a 3D printer was monitored. In the experiment, electrochemically prepared potassium ferrate with different purity (21.4 %, 63.5 % and 67.3 %) was used. Stability of potassium ferrate was monitored for one month and that of other ferrates for three months. Different storage conditions of ferrate samples were also compared. Storage conditions had a significant influence on the ferrate stability.

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.

For a correct estimation of the energy demands of particulate systems mixing it is necessary to know the stress in the particulate material situated in front of the mixing element. Despite the theoretical knowledge of the overall stress in front of the homogenizer blade, so far there is no experimental verification in the literature, due to the current absence of a suitable measuring system. This study focuses on an understanding of the distribution of the force interactions between the particulate material and the blade along its height during the mixing process. The theoretical background of this process results from the theory of equilibrium limit of the particulate material, and this state may by described by Mohrʼs circle theory. The Novosad model is the theoretical model which enables an approximate calculation of the force acting on the blade. This model takes into account the effect of the mechanical and physical properties of the particulate material. By modifying the fundamentals of the Novosad model, it will be possible to identify the force distribution along the height of the blade. For the verification of this theoretical study, a new patented measuring system was designed and implemented in the homogenizer blade.

This article deals with the presentation of modern applications for processing powdered, primarily hazardous, waste to an agglomeration form appropriate for subsequent processing by classical methods, for example in the construction, automotive and consumer goods industries. The aim of the research work was to set appropriate operating conditions in order to appreciate currently non-processable wastes resulting from the intensive production of often extremely expensive materials. Technologies which enable returning powder waste back into the primary production cycle were developed and experimentally tested, thus saving raw material resources. When necessary for the fixing of fine airborne particles with a problematic compacting curve (hard to compress, repulsive due to the surface charge) extrusion processes using a patented technology enabling controlled modification of shear forces in the extrusion zone were successfully applied. A new type of axial extruder allows the elimination of the liquid phase and as a result prevents the clogging of the extrusion chamber. In the case of need for granulation of sensitive materials (for example pharmaceuticals not allowing the addition of any kind of agglomerating fluid or reacting strongly in the contact of the two phases), a process of compaction between rolls with different profiled surface was successfully applied. The developed high technologies and the resulting products thus represent a major contribution to environmental protection in the context of not only the work but also the communal environment.