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Auf der ACHEMA 2022 waren in Frankfurt 25 Anbieter von Klassierer-, Sortier-, Recycling- oder Aufbereitungsanlagen im engeren Sinne vertreten. Der vorliegende Bericht fasst kurz zusammen, welche Aussteller ihr Portfolio im Bereich der Mechanischen Prozesse vorstellten und was an Neuerungen gezeigt wurde. Schwerpunkte stellten u. a. Plan- und Taumelsiebmaschinen sowie Technologien für schnelle Siebbelagswechsel und zum Entfernen von Körnern außerhalb der Produktspezifikation dar.

Auf der ACHEMA 2022 waren in Frankfurt 38 Anbieter von Zerkleinerungstechnik vertreten. Der vorliegende Bericht fasst kurz zusammen, welche Aussteller vertreten waren und was – vor allem an Neuerungen – gezeigt wurde. Schwerpunkte waren einerseits Maschinen zum Dispergieren verklumpter bzw. sehr feinkörniger Pulver zur besseren Verarbeitbarkeit oder zum Einmischen in Flüssigkeiten sowie andererseits Mahlkörpermühlen zur Fein- und Feinstmahlung.

The use and development of lithium-ion batteries (LIBs) are promoting the technological transformation of individual mobility, consumer electronics and electric energy storage. At their end of life, the complex compounds are disposed by different recycling technologies with defined secondary raw material production. The applied depollution temperatures of the process routes influence not only the recycling efficiency but also the process expenditure, design, medium and costs. Different pretreatment strategies in terms of dismantling depth and depollution temperature are existing. Furthermore, manual and mechanical methods for cell opening are distinguished, which together with the depollution leads to a respective organic solvent evaporation. In this contribution to LIB recycling, the influence of different dismantling depths, achieved by manual cell opening, on the thermal depollution of the LIB cells regarding the mass difference originating by organic solvent evaporation are quantified, in order to determine cell and equipment properties for a safe cell opening. As a result, combinations of thermal depollution and manual cell opening are discussed regarding technical and economic feasibility. The process medium and equipment properties for a safe cell opening are determined. Furthermore, recommendations for future industrial LIB waste management are presented.

This paper highlights on the comminution and to the lesser extent liberation properties of two greisen-type lithium bearing-mica ores (L1, L2) subjected to different breakage devices; cone crusher (CC), roller crusher (RC), rotor beater mill (RBM) and a screen mill (SM). The particle size distributions (PSD) of the products from each device were evaluated to search for an appropriate PSD model using Gates-Gaudin-Schuhmann (GGS) and Rosin-Rammler (RR) functions. To determine an appropriate function, coefficients of determination (R2 ) were used as a criterion. Due to budget constraint, only products from rotor beater mill (RBM) were examined for mineral liberation by an automated scanning electron microscope (SEM) technique. It was found that RBM, RC and SM products were better described by the RR model than the GGS model with higher R2 values of 0.97 to 1.0. However, cone crusher products for L1 were better described by GSS model, while that for L2 were better described by RR model. In terms of the spread of size distribution as indicated by RR model parameters, RC products were more uniformly distributed compared to those from other devices, for both ores. Also the RBM products were more scattered than those from other devices. The results indicate that the composition of individual ores affected the comminution products PSDs as different PSD model parameters were obtained for samples comminuted by same devices. The modal mineralogy indicated that both ores are rich in quartz, topaz, zinnwaldite and muscovite. Furthermore, the result indicates that, for both ores, the zinnwaldite phase is more enriched in the fraction < 250 µm. Moreover, better liberation of zinnwaldite is observed for L1 compared to L2. This could be explained by differences of the two ores in three aspects; the nature of mineral association, reduction ratio of the fractions analysed and the spread of the size distribution.

The Ergun equation is commonly used to predict velocity-pressure drop behaviour in packed beds. For many particular systems, the measurements deviate significantly from this relationship. Because of this, the equation is often treated as a purely empirical relationship, and its factors as fit parameters. This paper shows that the physics-based model underlying the Ergun equation should be treated by careful investigation of the included parameters. It is shown that discrepancies between experiment and theory for particle collectives in the millimetre range and above are caused by insufficient methods to determine the specific surface area. This effect is especially large for coarse particles with very rough surfaces. As a 2D measurement method, dynamic image analysis can not provide a good measure of specific surface area. It does not account for both macroscale particle shape and microscale surface roughness, which is confirmed by an analysis of 3D particle measurements from X-ray microscopy.

The determination of the grain size distribution of blasted rock exceeds the capability of an analytical sieving machine which only gives reliable results within a range of 63 μm to 125 mm. Other sophisticated methods are often not available for particle size measurement in coarse-grained applications in medium scale mining. Therefore, an alternative low cost method to investigate the grain sizes of blasted rock is introduced which can cover a range from 63 μm at the lower end without an upper limit. Three different options to examine blasted dolomite grains are investigated and combined with sieve analysis to determine a complete sieving equivalent grain size distribution. Comparison with results of a technical sieving shows that this method gives a good approximation of the size distribution, improving the possibilities for design of mineral processing equipment.

Following the proposal of deriving statistical entropy maps from multidimensional separation curves, an extension is proposed to allow to compare the separation efficiency of various separation processes. This is achieved by integrating the entropy map weighted by the mass distribution of the particles in the feed. This proposal has several advantages: its straightforward extension to multidimensional partition curves, its scalar value (which allows for a natural ranking of processes), its flexibility to adapt to each and every feed, and its non-parametric character. A typical dynamic air classification process of an iron ore is presented as an example.

The increasing importance to predict the storage and flow behavior of granular materials and the need to optimize the processing leads towards ever more complex discrete element models. To parametrize these models, simulation parameters are often iteratively varied until the macroscopic particle behavior corresponds to experimental findings. However, this technique is not always practicable and does not consider the microscopic particle behavior. To study local and microscopic phenomena using the discrete element method, a parameter identification procedure is developed, which solely needs standardized and simple experiments and no supplementary parameter adaptation process. The experimentally identified parameters can be directly transferred to a complex discrete element model, in this case: a ring shear cell. After this the results have been compared to measurements. The validation displays that the developed parametrization procedure is sufficient to identify the model parameters experimentally and makes the numerical parameter adaptation unnecessary. Additionally, all identified parameters are related to physical quantities which facilitates the interpretation of the simulation. Hence, the presented parameter identification procedure extends the actual parametrization technique and especially helps to develop discrete element models where an alignment with experiments is impossible, or local and microscopic phenomena play a key role.

Within the scope of the evaluation and optimization of a grinding circuit, the breakage and mineral liberation characteristics of three low grade sulphide gold ore blends have been investigated by Bond tests, batch grinding tests, and mineral liberation characterization. The tests were conducted in a size range from 0.063 to 2 mm. It was found that the breakage of all blends follows a first-order behaviour for all feed sizes. The work index was correlated with the quartz content and the breakage rate deceleration parameter, which both showed a linear relationship. The correlation between breakage function fineness parameter and first-order rate constant also satisfied a linear relationship .The breakage parameters established from batch grinding and grindability studies indicate differences in the breakage behaviour of the three ore blends. However, the mineral liberation properties of the valuable phase in three blends show minor differences.

The stress behaviour of particle beds describes the relationship between the forces acting on the particle bed and the total energy input supplied. The stress behaviour is closely related to the compaction of the particle bed, which has to be distinguished into a purely elastic and purely plastic deformation. The elastic deformation can be characterized by the elasticity E of the particle bed as a material-specific parameter which is different to the E -modulus of solids. The description of the purely plastic deformation of a particle bed allows to deduce a model of the stress behaviour.

Im Gemengesilo eines Glaswerks kann es aufgrund von Zeitverfestigung zu Anbackungen von Material kommen. Diese meist im Wand- und Austragsbereich auftretenden Verfestigungen beeintrachtigen die Fliesfahigkeit des Gemenges und die Produktqualitat. Begunstigt wird die Bildung von Anbackungen insbesondere durch den Einsatz von Soda bei gleichzeitig hohem Feuchtegehalt. Der Einfluss des Mischprozesses auf die Zeitverfestigung eines Standardgemenges fur Behalterglas wurde mit Scherversuchen untersucht. In the batch silo of glass production, caking of material may occur due to time consolidation. These consolidations mostly grow near the wall and the discharge area and impair the flowability of the batch and the product quality. Caking is favored in particular by using sodium carbonate in combination with a high moisture content. The impact of the mixing procedure on the time consolidation of a standard glass batch of container glass was investigated using shear tests.

In the comminution of heterogeneous bulk mixtures, the comminution behavior of the individual components plays a major role. The present study discusses the linkage between breakage of single ore components and their influence to the breakage characteristics of a defined bulk mixture. Thus, five components were identified from a heterogeneous gold ore material from Buzwagi Gold Mine in Tanzania by washing and manual sorting. The components were characterized in terms of particle size by sieving and composition by XRD. The breakage properties were determined by standard Bond test, batch grinding, and single particle tests. The breakage characteristics were linked to the composition of the components and the bulk sample. The study reveals differences in breakage behaviour of the components as well as their influence in the breakage characteristics of a heterogeneous bulk mixture.

The recycling of spent lithium-ion batteries (LIB) is becoming increasingly important with regard to environmental, economic, geostrategic, and health aspects due to the increasing amount of LIB produced, introduced into the market, and being spent in the following years. The recycling itself becomes a challenge to face on one hand the special aspects of LIB-technology and on the other hand to reply to the idea of circular economy. In this paper, we analyze the different recycling concepts for spent LIBs and categorize them according to state-of-the-art schemes of waste treatment technology. Therefore, we structure the different processes into process stages and unit processes. Several recycling technologies are treating spent lithium-ion batteries worldwide focusing on one or several process stages or unit processes.

In the present work, aluminum matrix composite (Al–Al 2 O 3 ) was produced using mechanical alloying in a planetary ball mill. Aluminum granular in size (1–3 mm) with high amount of alumina particles ( x 50 = 7.6 μ m) were milled up to 500 minutes in a planetary ball mill to indicate the effect of hard particles on the alloying acceleration. The results revealed that high amount of alumina particles promoted the work hardening and decreased the time of mechanical alloying. Further, the particle size analysis indicated that prolonging the milling time caused the particle size to drop from an initial value of 1–3 mm to about 10 μ m during the milling. The X-ray diffraction results demonstrated a continuous decrease in crystallite size in Al phase from 350 to 60 nm. Hardness tests illustrated that hardness increased as a function of milling time. The results verified that the produced composites have a homogeneous distribution of alumina particles in the aluminum matrix. The results showed that the aluminum matrix composite can be produced from the granular Al (mm in size) with micron sized Al 2 O 3 by mechanical alloying process.

In particle bed comminution energy is dissipated by several microprocesses which accompany the flow of particles, their compaction, and breakage. It is unknown how much energy is associated with each microprocess and what the ratios are between the energies dissipated by the different microprocesses. Based on an experimental study, a model has been developed to calculate a critical compaction velocity and the energy dissipated by flow losses. The critical compaction velocity describes the probability of the deaeration of a particle bed. Since the flow losses consume less than 0.1% of the total energy input, this microprocess can be considered negligible compared to others.

Das Beanspruchungsverhalten von Gutbetten beschreibt den Zusammenhang zwischen der Kraft, die auf ein Gutbett wirkt, und der Energie, die dem Gutbett insgesamt zugefuhrt wird. Es ist eng mit der Verdichtung des Gutbetts verknupft, wobei hier eine rein elastische und eine rein plastische Verformung zu unterscheiden ist. Die elastische Verformung kann durch die Elastizitat E des Gutbetts als materialspezifische und vom E-Modul des Feststoffs unabhangige Kenngrose charakterisiert werden. Die Modellierung des Beanspruchungsverhaltens baut auf dem plastischen Verformungsverhalten auf. The stress behavior of particle beds describes the relationship between the forces acting on the particle bed and the total energy input supplied. The stress behavior is closely related to the compaction of the particle bed, which has to be distinguished into a purely elastic and purely plastic deformation. The elastic deformation is characterized by the elasticity E of the particle bed as a material-specific parameter which is independent of the E-module of solids. The modeling of the stress behavior is based on the plastic deformation behavior.

Im vorliegenden Beitrag werden Ergebnisse zum Beanspruchungsverhalten des idealen Gutbetts vorgestellt. Entgegen den bisherigen Modellvorstellungen zeigen Kalkstein- und Quarzfraktionen kleiner 100 μm einen deutlichen starkeren Einfluss der Gutbetthohe auf die Energieabsorption als grobkornige Materialien. Als Ursache wird die zunehmende Steifheit des Gutbetts bei geringer Gutbetthohe und feinkornigeren Partikeln gesehen. This paper presents experimental results of the stress behavior of an ideal particle bed. Contrary to the current model ideas limestone and quartz fractions below 100 μm show a significant higher influence of the particle bed height as coarse-grained materials. The cause of this higher influence is interpreted by an increasing rigidity of the particle bed depending on its height as well as the fineness of the particles.

The confined particle bed comminution of fine materials is of huge economic importance for comminution technology and, therefore, also of fundamental interest for comminution science. This paper presents some experimental results on energy absorption, compression, increase of fineness and energy efficiency proving the effect of stress velocity for compressive stresses at different stress intensities (pressures) and for the two materials limestone and quartz. Our results show that an increasing stress velocity leads to a higher energy absorption in the particle bed, but also to lower compression, comminution and energy efficiency. These effects are not only explained by friction but also by flow losses for which a flow model is presented.

Die Gutbettbeanspruchung fur die Feinzerkleinerung hat in der Zerkleinerungstechnik eine grose wirtschaftliche Bedeutung und ist fur die Zerkleinerungswissenschaft von grundsatzlichem Interesse. Da die Gutbettbeanspruchung sowohl die Merkmale einer Verdichtung als auch die der Zerkleinerung tragt, ist fur ein Erfassen der in ihr vorherrschenden Mikroprozesse eine Betrachtung beider parallel ablaufender Prozesse notwendig.

A model is presented to evaluate mineral processing on basis of gangue recovery and valuables recovery. It combines mineralogical limiting curves with upgrading curves in the Fuerstenau diagram. These curves are used to assess mineral liberation and mineral beneficiation compared with the ideal result. Two new parameters (ratio of separation and ratio of liberation) are calculated based on a comparison of areas enclosed by the mineralogical limiting curve, the upgrading curve, the curve representing a total liberation of valuables, and the curve representing a perfect mixture of valuables and gangue. An assessment of the success of mineral processing is possible using these parameters. The assessment shows whether the quality of a separation product is influenced by the separation process itself or by the achieved liberation of the feed. A series of experiments on the magnetic separation of a greisen-type ore proves the applicability of this model to mineral processing. SEM-based image analysis and ICP-OES measurements have been used to obtain the necessary data.

Predicting silo-vibrations is not yet universally possible but only to a very limited extent. A mechanism of excitation of silo vibrations can be found in oscillating shear stresses between the bulk solid and the inner silo wall, the so-called “wall-stick-slip” effect. So if this wall-stick-slip occurs during shear experiments in shear testers, the probability of silo-vibrations in silos will be high. However if there is no slip-stick effect observed, this will not consequently exclude silo-vibrations. The influences on a stable stick-slip were studied in wall friction experiments with a rotational shear tester and in a specially developed silo model based on a lambdameter. The examined parameters are normal stress, shear velocity, wall roughness and particle shape. Plastic pellets which are known to honk (PET, PA) and plastic pellets that do not honk (PE) are considered [1]. It is shown that the silo model based on a lambdameter is more suitable for initiation and measurement of stable wall-stick-slip of granular media than the conventional rotational shear tester. The industrial experiences in respect of silo vibrations are proved in the silo model for all tested types of plastic pellets. So, if the origin of silo vibrations is wall-stick-slip, the silo model based on a lambdameter gives a better opportunity for predicting silo vibrations. This paper gives a summary on the results obtained with the new method.