Types Of Mills Research Articles

Quantifying the Value of Log Sorting Based on the Location of Timber Harvest Sites Across Wisconsin

Abstract It is generally understood that sorting logs based on grade generates maximum value for all stakeholders. However, the benefits of sorting logs may depend on the location of a timber sale and distances to manufacturing mills. The objective is to quantify the potential value of log sorting through scenario-based analysis in different areas with divergent forest and mill types. An optimization model was developed to allocate logs from the timber sale to the highest profit-yielding mills. Factors considered by the model included logging and transportation cost, timber sale tract-to-mill distances, mills’ acceptance criteria, and price at the mill gate. Four timber sales from across Wisconsin were selected for the study. Three scenarios were tested, with each scenario yielding different proportions of log sorts. The results showed that log sorting increased profit by up to $41.10 per cord in certain locations but was not profitable in other locations. Study Implications The methods proposed in this study can help foresters and landowners increase the value of harvested timber. Practitioners can use the proposed method to systematically assess the gain or loss in profit associated with log sorting at each timber sale. It also provides directives on the best mill for each log sort to be sent. The proposed method should be adopted to minimize underutilization of timber, especially in areas where profits are marginal.

Effect of different mills on the physical and flow properties of selected black bean flour particle size fractions

AbstractBackground and ObjectivesParticle size and shape can influence inherent flour properties and eventually the quality of the finished food product. The objective of this study was to determine the effect of mill type on the physical and flow properties of selected particle size fractions of black bean flour.FindingsParticle shape differed with mill type and particle size. Disc mill and stone mill produced flour particles with lower circularity and greater elongation than did hammer mill, cyclone mill, and centrifugal mill. Greater particle elongation with a stone mill and disc mill is attributed to compression/shear size‐reduction forces applied to the particles trapped between the rotating/nonrotating stones or discs. Particle circularity increased with an increased particle size, which was reflected by a strong positive correlation between circularity and particle size (r = .93, n = 5) while elongation value was negatively correlated with average minimum particle size (r = −.90, n = 5). Particle circularity had a negative correlation of r = −.93, n = 30; r = −.81, n = 30; r ≈ −.95, n = 30; r = −.94, n = 30 with L*, angle of repose, angle of slide, and compact bulk density, respectively.ConclusionsMill type and particle size interaction significantly affected the physical and flow properties of selected particle size fractions of black bean flour. The results indicate that the large black bean particles were more circular and compact and less convex and elongated compared with small particles.Significance and NoveltyThese findings indicate that mill type affects not only particle size but also particle shape, both of which can affect the flow and functional processing properties of black bean flour.

Effect of the milling method and particle structure on the color tone of (Cr, Fe)2O3 inorganic black masterbatch pigment

(Cr, Fe)2O3 pigment was milled using different techniques into the same particle sizes to investigate the influence of milling processes on its properties. The research showed that milling type resulted in significant color differences, accompanied by the pigment color changing from intense reddish-brown to dark brown. Differences in the morphology of the particles embedded in the plastic matrix led to different light scattering, which is observed as a decrease in the color saturation of the pigment. Particle size distribution (PSD) was characterized by measuring with a laser diffraction particle size analyzer. Pigments were milled down to 4 µm in all milling methods. The very small particles in the pigment affected the light scattering and the color tone. The particle size of the pigment milled by the planetary mill was D10 = 0.035 μ ± 0.1. Color values of the plastic plates were measured according to CIE laboratory analysis. The pigment milled with the planetary mill was lighter, greener, and yellower (ΔL*=4.15, Da*=3.68, Db*=2.96). The pigment milled with the jet-mill was closest to the pigment color after calcination. The pigment milled with ball mill was slightly greener than the values after calcination (Da*=1).

Methane production potential of pulp mill sludges: microbial community and substrate constraints.

Sludges from pulp and paper mills represent a major ecological and environmental cost, and anaerobic digestion represents a method of waste reduction and energy recovery for these mills. This study compared methane production potential and microbial communities across 11 primary- and biosludges from five pulp and paper mills using various mill processes. We measured methane production from sludges in anaerobic batch reactor experiments over 64 days. Sludges were incubated with and without added substrate to test for organic substrate limitation versus inhibition of methanogens. Initial microbial communities and changes to community composition were determined using Illumina MiSeq for metabarcoding of bacterial and archaeal 16S rRNA genes. Mean methane production potential varied greatly between sludges (0.002-79mL CH4 g-1 TS). Among primary sludges, kraft mill sludge produced more methane than other mill types. For these other mills, biosludge produced more methane than primary sludge, which had evidence of methanogen inhibition. Microbial communities and diversity were influenced by the initial community composition, and high methane production was only seen in sludges with high diversity. A number of sludges innately produced substantial methane and may be targets for further modelling and larger scale testing of anaerobic digestion.

Effect of biomass-based carbon capture on the sustainability and economics of pulp and paper production in the Nordic mills

Bioenergy with carbon capture and storage (BECCS) is one of the key negative emission technologies (NETs). Large-scale implementation of BECCS has been criticized of the associated increase in land use. The existing large Nordic pulp and paper production units enable BECCS deployment without additional land use, as they currently release large amounts of bio-based carbon dioxide (CO2). The application of BECCS in pulp mills has been found technically feasible in earlier studies. This study explores key factors that affect the propensity to invest in BECCS in different types of existing European pulp and paper mills. The results give fresh understanding on the effects of BECCS on the market price of pulp and paper products and the required level of incentives. Based on statistical data, the marginal carbon dioxide credit (€ per ton CO2) to make BECCS profitable was derived. The results show that the required level of credit greatly depends on the mill type and details and that the feasibility of BECCS does not clearly correlate with the economic performance or the measured efficiency of the mill. The most promising mill type, a market kraft pulp mill, would find BECCS profitable with a credit in the range of 62–70 €/tCO2 and a credit of 80 €/tCO2 would decrease pulp production costs by 15 €/tproduct on average if 50% of CO2 emissions was captured. The EU Emission Trading System (ETS) is the main policy instrument to achieve the climate targets related to fossil energy use, but does not yet contemplate bio-based emissions.

COMPARATIVE INVESTIGATION OF GLASS WASTE GRINDING IN VARIOUS MILLS

The present work deals with systematic grinding investigation and determination of grindability of container glass bottles. The systematic grinding tests were carried out in three different kinds of ball mills (a drum mill, a vibrating mill, and a planetary mill) with different energy intensities (low, medium, and high intensity) in dry conditions. In addition, the specific grinding work and specific surface area were determined in every case. The grindability test was performed by the Universal Hardgrove Mill, moreover, the Bond-Work Index was calculated from the Hardgrove Grindability Index. In this research work, the focus was on analysing the grindability of container glass bottles and the goal was energy-efficient milling of glass waste to produce glass foam powder for further utilization (for example glass foam) in a sustainable way. Based on the obtained results, it can be concluded that the optimal milling apparatus for container glass grinding is the drum mill. The reason why is that it has a low specific grinding work (151.52 kWh/t) in comparison with the other two types of mills (3488.37 kWh/t for the planetary mill and 1106.38 kWh/t for the vibrating mill) resulting in a relatively high specific surface area (11314 cm2/g). In the case of grinding industrial quantities of glass waste, the drum mill has a much higher capacity compared to the vibrating mill and the planetary mill.

Impact of sorghum grain processing on morphological characteristics of particles of wholegrain sorghum flour

This work studies the physical characteristics of sorghum whole flour particles produced with grains reduced in tannins by hydrothermal treatment. Flours ground with two types of mills: a roll mill and a blade mill were used; grains were hydrated with a moisture content of 25%. For this moisture the maximum yield was obtained. The effect of the grain moisture during the grinding was evaluated regarding the morphological characteristics, the granulometry and fractal dimension (Df) of particles. In all the analysed samples, bimodal size distribution curves were obtained. The treated samples showed medium size particles bigger than the samples without treatment. The samples without hydrothermal treatment presented particles with lower damage than the treated samples for both mills. The difference in Df between samples indicated more roughness for the samples with treatment. The proposed treatment could contribute to the development of sorghum whole flour with different properties for the development of gluten-free food.

Digestability of Dry Materials and Organic Ingredients of Rice Bran Circulated in Bima District

The research which aims to determine the dry matter digestibility (DMD) and organic matter (OMD) of rice bran from static and mobile milling in Bima Regency had been carried out from September to October 2020. The rice bran used in this study was obtained from 2 types of different mills from the 18 sub-districts in Bima Regency. Samples were taken as much as 1 kg from each milling unit per sub-district and then analyzed for dry matter and organic matter digestibility at the Laboratory of Nutrition and Animal Feed, Faculty of Animal Science, University of Mataram. The variables observed in this study included physical properties, DMD and OMD of rice bran. To determine whether there is a difference between DMD and OMD from the two types of mills, the data obtained from this study were tested by T-test using SAS statistical program package. The results show that the texture, DMD and OMD of rice bran from static milling were better than that of mobile milling.

Use of enameling wastewater in the wet milling process for ‘monoporosa’ tile composition

Water is becoming scarce for ceramic processing, even in certain regions of Brazil. In the wet milling process, the ceramic slips are formed by 30 wt% water to achieve the adequate density and viscosity for an efficient milling. Wastewater from other ceramic processes, as enameling, could be used for milling. The aim of this work was the study of the milling process of a ceramic tile composition using wastewater without treatment in place of clean water. The raw materials forming the ‘monoporosa’ composition and the wastewater were characterized (XRF, particle size) as well as the monoporosa composition (STD) (XRD, residue at #325 ASTM sieve, flow time viscosity, density). The milling parameters were mill rotation (15 or 19 rpm), mill loading capacity (70 or 100%) and type of water (wastewater or clean water) used as the factors (and levels) in a full factorial design, totaling 8 experiments (level factor = 2³). The tests were carried out in a mill of 148 L capacity, with a load of 87 kg of raw materials and addition of 34 L of wastewater (1.05 g/L) or clean water (1.0 g/L density). The density, viscosity, and residue at the 4, 6, 8 and 10th hour of milling were determined. As a result, the use of wastewater increases the density of the liquid medium and thus increases the milling residue, as evidenced in the 10th milling hour. At the end of the work, it was possible to reduce the total milling time in a 12,000 L industrial mill by 2 h (25%), without changing the characteristics of the slip, even using wastewater as liquid medium. • Wastewater from enameling was used in industrial milling process of ‘monoporosa’. • Mill rotation, loading capacity and wastewater were the main factors of the design. • The milling residue and slip viscosity were determined along milling time. • At the end of milling, the rotation was the most significant factor for milling. • A reduction of 25% of milling time (2 h) was possible even using wastewater.

PSXVI-26 Using synchrotron/globar techniques to reveal synergistic and interactive association between molecular structures and nutrient supply in enzymatic and thermal treated oat tissue and whole grain

Abstract As an advanced technique, synchrotron radiation-based microspectroscopy SR-FTIRM has been a rapid, direct, non-destructive and non-invasive bioanalytical method. Globar molecular spectroscopic technique -attenuated total reflectance-ATR-FTIR spectroscopy will be used. For this research, feed type CDC Nasser, forage type CDC haymaker, and milling types CDC Arborg and Summit with three consecutive years are studied. There are three treatments for oat samples: Treatment 1, steam pressure processing alone; Treatment 2, adding innovative fibrolytic enzyme; Treatment 3, steam pressure processing plus fibrolytic enzyme. Each treatment combination has three replications. The objectives of this research are to detect the molecular structure spectral features of processed oat endosperm tissues at a molecular and cellular level in relation to chemical profiles, protein and carbohydrate fractions, energy profiles, degradation kinetics, intestinal digestibility, microbial protein production and true nutrient supply of whole oat grains. This research reveals the interactive association between induced molecular structure changes and nutrient properties and true nutrient supply. This research is also to increase economic returns to oat producers and related dairy industries through efficient utilization of feed-type or milling type of oat grains.

Dynamics and chatter stability of crest-cut end mills

Chatter is a major problem reducing part quality and productivity in milling operations. In order to improve productivity with standard end mills, higher cutting speeds must be employed to reach deeper stability lobes. However, due to machine tool and machinability limitations in cutting hard-to-cut materials, higher cutting speeds are not feasible. For those cases, special milling tools such as variable pitch and crest-cut cutters offer an alternative method to increase productivity. Due to their special geometry crest-cut tools introduce large stable regions at low-speed ranges where variable pitch tools provide narrow stability lobes. This advantage is caused by the wavy edge shape along the cutting edges of the crest-cut tools. In this study, stability of crest-cut tools is studied using the semi-discretization method by implementing a novel geometrical modeling approach enabling accurate cutting force predictions verified experimentally for the first time in literature. Based on the proposed model, the effect of edge wave geometry on stability is analyzed and compared with standard and variable pitch tools. Results show that the crest-cut tools introduce significant advantages in terms of stability limit and stable zones compared to other types of end mills. This superiority results in higher productivity as well as higher robustness at a different cutting speed zones. Finally, a guideline is presented for selection of the best crest-cut tool geometry for desired operating conditions.

Can carbon capture be a new revenue opportunity for the pulp and paper sector?

Transition towards carbon neutrality will require application of negative carbon emission technologies (NETs). This creates a new opportunity for the industry in the near future. The pulp and paper industry already utilizes vast amounts of biomass and produces large amounts of biogenic carbon dioxide. The industry is well poised for the use of bioenergy with carbon capture and storage (BECCS), which is considered as one of the key NETs. If the captured carbon dioxide can be used to manufacture green fuels to replace fossil ones, then this will generate a huge additional market where pulp and paper mills are on the front line. The objective of this study is to evaluate future trends and policies affecting the pulp and paper industry and to describe how a carbon neutral or carbon negative pulp and paper production process can be viable. Such policies include, as examples, price of carbon dioxide allowances or support for green fuel production and BECCS implementation. It is known that profitability differs depending on mill type, performance, energy efficiency, or carbon dioxide intensity. The results give fresh understanding on the potential for investing in negative emission technologies. Carbon capture or green fuel production can be economical with an emission trade system, depending on electricity price, green fuel price, negative emission credit, and a mill’s emission profile. However, feasibility does not seem to evidently correlate with the performance, technical age, or the measured efficiency of the mill.

Comminution energy and particulate properties of cutting and hammer-milled beech, oak, and spruce wood

As a result of the development of innovative technologies for use of renewable materials, these materials are increasingly used for the production of precursors and basic chemicals for the chemical industry. The upstream process of comminution is a key element in the use of renewable raw materials, which impacts the consecutive disintegration of the materials, which means the separation of the three main components cellulose, hemicellulose and lignin as well as the handling. Energy efficiency of the comminution process is of utmost importance to make renewable resources more competitive with petrochemical products. The key parameters to increased energy efficiency are, besides the mill type and the mill operation parameters, the species of the renewable resource, in terms of moisture content and the mechanical properties. A better understanding of these interdependencies can help to improve the adjustment of particle size distribution and particle shape as well as the energy demand for the comminution process, which impacts the overall efficiency of the supply chain process, disintegration as well as the conversion. This work focuses on the comminution of lignocellulosic biomass in a cutting mill and a hammer mill and how the specific comminution energy and particulate properties are affected by the type of mill, the species of wood, the archived size reduction as well as the moisture content. Therefore two spices of hardwood, common beech (F. sylvatica L.) and oak (Q. robur L.), and one species of coniferous wood common, spruce (P. abies L.), where comminuted under variation of different process parameters. The specific comminution energies were determined and the comminution products were characterized by dynamic image analysis. This work describes the influence of the process parameters, internal classifying screen, type of stress and moisture content, on the comminution products and the specific comminution energy. From the results of the experiments, functions were determined which can describe the influence of the type of mill, the moisture content, the type of wood and the comminution ratio on the specific comminution energy.

Fault analysis and optimization technology of HP bowl type medium speed coal mill

HP type medium speed coal pulverizer produced by Shanghai heavy machinery works has been widely used in recent years, with common faults in operation, short maintenance cycle and heavy task. In order to facilitate the staff to complete the maintenance task more quickly and with higher quality, this paper introduces the common faults in HP type bowl type medium speed coal pulverizer in detail from the reality, and analyzes the causes, At the same time, part of the performance optimization scheme of this type of coal mill is introduced.

Changes in Crystallite Size of Tricalcium Silicate during the Laboratory Grinding

The paper is focused on one of the most important component of Portland clinker-on the tricalcium silicate. The study reported in this article is focuses on the changes in crystallite size of synthetic tricalcium silicate obtained using solid state reaction method. Crystallite size changes are monitored during the grinding in three types of laboratory mills in two different conditions. Changing in crystallite size at various grinding time up to 120 minutes are studied with the aid of X-ray diffraction and using the Scherrer equation. It has been found that the most efficient laboratory mill in terms of speed and fineness of the material was the planetary mill.

Effect of Grinding and the Mill Type on Magnetic Properties of Carboxylated Multiwall Carbon Nanotubes.

The influence of the grinding process on the magnetic properties of as prepared and functionalized multiwall carbon nanotubes (MWCNTs) is presented. We have observed that 3 h mechanical grinding at 400 rpm in contrast to functionalization does not remove the iron contamination from MWCNTs. However, it changes the Fe chemical states. The magnetic properties of iron nanoparticles (Fe-NPs) embedded in the carbon matrix of MWCNTs have been analyzed in detail. We have proven that single-domain non-interacting Fe(C,O)-NPs enriched in the Fe3C phase (~10 nm) enclosed inside these nanotubes are responsible for their magnetic properties. Mechanical grinding revealed a unique impact of -COOH groups (compared to -COONH4 groups) on the magnetism of functionalized MWCNTs. In MWCNT-COOH ground in a steel mill, the contribution of the Fe2O3 and α-Fe phases increased while the content of the magnetically harder Fe3C phase decreased. This resulted in a 2-fold coercivity (Hc) decrease and saturation magnetization (MS) increase. A 2-fold remanence (Mr) decrease in MWCNT-COOH ground in an agate mill is related to the modified Fe(C,O)-NP magnetization dynamics. Comparison of the magnetostatic exchange and effective anisotropy length estimated for Fe(C,O)-NPs allows concluding that the anisotropy energy barrier is higher than the magnetostatic energy barrier. The enhanced contribution of surface anisotropy to the effective anisotropy constant and the unique effect of the -COOH groups on the magnetic properties of MWCNTs are discussed. The procedure for grinding carboxylated MWCNTs with embedded iron nanoparticles using a steel mill has a potential application for producing Fe-C nanocomposites with desired magnetic properties.

Determinant factors of olive oil stability, phenolic content and antioxidant capacity

PurposeThis study aims to identify the effect of selected agro-industrial factors associated with the olive oil phenolic composition, total phenolic content (TPC), antioxidant capacity and oxidative stability index (OSI). The study also aims to assess the relationship between the quality indices and each of the individual phenol, TPC, antioxidant capacity and OSI.Design/methodology/approachOlive oil samples (n=108) were collected from Lebanese northern (Akkar and Zgharta-Koura) and southern (Hasbaya and Jezzine) regions, at three harvesting times (early, intermediate, late) and using different types of mills (traditional, sinolea, two- and three-phase decanters). The samples were analyzed using official standard methods.FindingsThe highest TPC, antioxidant capacity and OSI were obtained in early harvested olive oil, using two-phase decanters for TPC and three-phase decanters for antioxidant capacity and OSI. A prediction model, including the free acidity, K232, TPC, C18:2, C18:0, tyrosol and apigenin, was obtained; it allowed to predict very highly significantly the OSI (p < 0.001). Apigenin, tyrosol and C18:2 recorded the highest standardized coefficients (ß^+= 0.35) and thus had the highest influence on OSI. As per antioxidant capacity of olive oil, another very highly statistically significant prediction model was constructed (p < 0.001). It included only two predictors, oleacein and TPC, with the latter having the most influence (ß^+= 0.37).Originality/valueThe overall results highlighted the detrimental effects of agro-industrial factors on olive oil chemical composition, and this contributes significantly to improve olive oil’s quality and characteristics, which are important for the product economical and nutritional values.

Preliminary Investigations on the Use of a New Milling Technology for Obtaining Wholemeal Flours

Wholemeal flours from various cereals and pseudocereals are a valuable source of nutritionally important fiber components, especially beta-glucans and arabinoxylans, as well as bioactive substances accompanying dietary fiber. Most types of whole-wheat flours have unfavorable baking and sensory properties. The finest granulation of bran particles in the flour has a significant effect on reducing or eliminating these deficiencies. Special disintegration equipment is required to achieve fine granulation of the bran particles. In this study, we have tested a special type of impact mill (originally intended for grinding of plastics) to produce special finely ground wholemeal flours with lower starch damage and higher farinographic absorption. Moisture content in the studied flours was significantly lower (7.4–9.8%) than is common in standard flour (13–14%). According to the results of flour analyses obtained from several cereal sources, it seems that especially in rye and wheat, this technology is suitable for both achieving fine granulation of bran particles and in terms of not very substantial damage of starch granules.

Effect of cleaning corn on mycotoxin concentration and nursery pig growth performance.

Mycotoxins are naturally produced hazards that result from molds grown on cereal grains and other commodities. These molds may produce carcinogenic mycotoxins, which can be harmful to humans and animals. Removing broken kernels has been demonstrated to reduce mycotoxin concentration, but with high variability. Therefore, two experiments were conducted to quantify the magnitude of natural mycotoxin concentration that may be reduced by cleaning corn. Two loads of corn that were naturally contaminated with mycotoxins were procured. Corn for Experiment 1 was contaminated with aflatoxin (1,074 parts per billion; ppb), fumonisin (8.3 parts per million; ppm), and ochratoxin A (206 ppb), while corn for Experiment 2 was contaminated with only fumonisin (5.5 ppm). Corn was cleaned by mechanical sieving. For each experiment, corn was divided into twenty 150 kg runs. Runs were randomly assigned to 1 of 4 experimental treatments: 1) no screen 2) 12.7 mm screen, 3) 4.8 mm screen, and 4) 12.7 + 4.8-mm screen. The corn cleaner was sanitized between runs. Three 5 kg corn samples were collected from each run, and analyzed for mycotoxin concentration. In Experiment 1, cleaning reduced (P < 0.05) aflatoxin and fumonisin concentration by an average of 26% and 45%, respectively, compared to the original uncleaned corn level, but did not impact (P > 0.10) ochratoxin A. The resultant screenings had nearly four times the aflatoxin (4,224 ppb) and 7.5 times the fumonisin concentration (60.4 ppm) as the uncleaned corn. In Experiment 2, cleaning reduced (P < 0.05) fumonisin concentration by 32%. The resultant screenings had 19.6 times the fumonisin concentration (65.4 ppm) as the uncleaned corn. To determine the effect that cleaning corn may have on nursery pig growth performance, 360 nursery pigs were used in Experiment 3 to evaluate the impact of cleaning or pelleting on growth performance. Treatments were arranged in a 2 × 3 factorial with corn type (uncleaned vs. cleaned) and feed form (mash vs. pelleted from either mill A or B). Neither cleaning corn nor pellet mill type affected (P > 0.19) nursery pig growth performance. Pelleting improved (P < 0.0001) gain to feed ratio (G:F) by 7.6% compared to mash diets. These data suggest that cleaning is an effective method to legally reduce aflatoxin and fumonisin concentration, but does not impact animal growth performance. Screenings should be used cautiously when feeding to animals.

РАЗВИТИЕ ОБОРУДОВАНИЯ ДЛЯ ТОНКОДИСПЕРСНОГО ИЗМЕЛЬЧЕНИЯ МИНЕРАЛЬНОГО СЫРЬЯ

Introduction. The huge energy costs of fine and ultrafine grinding operations have led to numerous studies aimed at developing new devices and methods for producing powdered materials. The first way leads to an increase in specific productivity while maintaining energy consumption at approximately the same level. The second way allows not only to increase the specific productivity, but also to reduce the specific energy consumption, since with a decrease in the exposure time, the body is more easily deformed and destroyed. The grinders in which the intensification of the destruction process is carried out in the first way can include planetary and vibrating mills. The second method of intensification is used in jet and various types of centrifugal mills. It is determined that vertical centrifugal mills are the equipment of a new type that can effectively perform grinding operations at high technological indicators and low energy consumption. The purpose of the research. Development of measures for obtaining a finely dispersed product by destroying mineral raw materials in vertical centrifugal mills by mechanical means. Research methodology. The paper uses a comprehensive research method: analysis of the state of grinding equipment according to literary and patent sources; development of mathematical models of the movement of bulk material in the working space of a vertical centrifugal mill based on the Navie-Stokes equations; computer modeling of the movement of the crushed material using the OpenFOAM package for solving hydrodynamic equations; a solver program was created to perform calculations, implementing the SIMPLER algorithm and using the MRF model; laboratory experiments; granulometric method for the analysis of grinding products; fractional analysis of crushed material with a grain size of 0.08 mm using an X-ray analytical centrifuge ВrооkhаvеnBI-ХDС. The development of measures for the effective evacuation of the crushed product from the working space of a centrifugal mill was evaluated by comparative tests of mills using various design solutions. Research results and discussion 1. It is established that vertical centrifugal mills are the devices of a new type capable of effectively performing grinding operations at high technological indicators and low energy consumption. 2. A mathematical model of the movement of bulk material in the working space of a vertical centrifugal mill has been developed based on the Navier-Stokes equations, which allows determining the speed and direction of movement of material layers at any point in the working space, the energy costs for their movement, the influence of the height of the material column on the nature of its movement in the space above the rotor. 3. The directions of increasing the efficiency of grinding mineral raw materials in a vertical centrifugal mill are determined by reducing the number of radial ribs installed in the cavity of the mill rotor; making cutouts in the radial ribs of the rotor, in the area near the rotor hub; installing coaxial rings in the working space of the mill above the rotor. 4. A method of effective evacuation of the crushed product from the mill body by installing additional screening surfaces in the peripheral part of the working space of the mill has been developed. 5. For the first time, the distribution of the granulometric composition of fine and medium - dispersed crushed product obtained as a result of processing lump dolomite in a centrifugal mill was obtained. It was found that particles with a size class of -0.08 + 0.03 mm are absent in the output of the crushed product from the mill. Conclusions. A mass-produced vertical centrifugal mill will find its effective application at enterprises of the Russian Federation for the preparation of powdered materials and will allow to obtain a significant effect by reducing the price of the final product, simplicity of design and maintenance of equipment, as well as small occupied production areas.