Deposition Samples Research Articles

Improved rRNA extraction from biofouling and bioreactor samples

Mixed microbial communities are major drivers of biofouling phenomena that lead to deterioration of materials or compromise process efficiency and are also extensively employed in environmental biotechnology. The metabolically active organisms in these communities are central to further development of environmental bioprocesses or of countermeasures for biofouling control. These organisms can be targeted selectively by analysis of ribosomal RNA because the number of ribosomes in a cell is proportional to the rate of protein synthesis. Comparative analysis of the deficiencies of 6 different rRNA extraction protocols using activated sludge as model system led to the formulation of a new protocol, that consistently produced cleaner extracts from fresh or frozen samples of activated sludge with better rRNA quality and better preservation of the proportions between signatures from different community members after 10 cycles PCR. PCR amplification was best with pfu buffer + 4 mM MgCl2 at a lower annealing temperature of 60 °C. Inhibition of PCR occurred in solutions with 2% formamide. rRNA of good quality was extracted with the new protocol from samples of corrosion deposits, of both the solid and liquid fraction of chalcopyrite bioleaching experiments, of biofilms on slow sand filter media, from walls of water reservoirs and of water pipes, as well as of fouling deposits on reverse osmosis membranes.

Green Electrorefining of Crude Lead with High-Quality Deposits in an Additive-Assisted Methanesulfonic Acid System

The conventional electrorefining process of crude lead (Pb)─employing a bone glue (BG)- and calcium lignosulfonate (CL)-synergistically assisted fluosilicic acid (H2SiF6) system─suffers the undesired environment burden caused by the high saturated vapor pressure and low stability of H2SiF6. Herein, we propose an additive-assisted methanesulfonic acid (MSA) system for green and efficient electrorefining of crude Pb based on the low volatility and high stability of MSA. Combinations of MSA with additives are evaluated and screened using photographic images, SEM observations, XRD, white light interference, etc. The electrochemical analysis of cyclic voltammetry and chronoamperometry elucidates the Pb deposition behavior in the Lugalvan BNO12-assisted MSA system, in which a three-dimensional nucleation model is applicable. Using MSA as the solvent and β-naphthol ethoxylate (Lugalvan BNO12) as the assisted additive, the bench-scale operation of crude Pb electrorefining experimentally achieves an electric energy requirement (W) of 87 kWhe/t Pb and a cathodic current efficiency (η) of 99.6%. This is very competitive with the W of 120 kWhe/t Pb and η of 95.0% for the BG-CL-assisted H2SiF6 system. Also, the bench-scale operation obtains a plat and dense deposit sample with a Pb purity of >99.99%. The distribution behavior of elements shows that most of the Pb element is recovered in the form of the cathodic Pb, elements Sn, Zn, and Fe mainly accumulate in the electrolyte, and elements As, Sb, Bi, Ag, and Cu remain in the anode slime. This work opens new directions for more technically and economically feasible Pb electrorefining.

Atmospheric silicon wet deposition and its influencing factors in China

Silicon (Si) is considered a “quasi-essential” nutrient element for plants and is also an essential nutrient for some phytoplankton. Except for the silicate provided by weathering, atmospheric deposition has gradually become an important supplementary method for Si nutrients to enter the ecosystem. However, national observational studies on atmospheric silicon deposition have not yet been reported. Herein, based on the China Wet Deposition Observation Network, we continuously collected monthly wet deposition samples from 43 typical ecosystems from 2013 to 2020 and measured the content of dissolved silica (dSi) in precipitation to quantify the spatiotemporal patterns of Si wet deposition in China. The results showed that the mean annual dSi wet deposition in China during 2013–2020 was approximately 2.07 ± 0.27 kg ha−1 yr−1. Atmospheric dSi deposition was higher in Southwest, North, and South China but lower in the Northwest and Northeast China, which was mainly regulated by precipitation and soil available Si content. There was no significant annual variation trend in dSi deposition during 2013–2020 in China, which showed disorderly fluctuations from year to year. This study revealed the spatiotemporal patterns of atmospheric dSi deposition in China for the first time, which can provide unique scientific data to explore the potential effect of dSi deposition on carbon sequestration in aquatic ecosystems. A comprehensive evaluation of the nutrient balance of aquatic ecosystems from the perspective of nitrogen, phosphorus, and silicon stoichiometry is required in the future.

Characterization of Atmospheric Deposition as the Only Mineral Matter Input to Ombrotrophic Bog

Ombrotrophic peatlands contain a very small percentage of mineral matter that they receive exclusively from atmospheric deposition. Mineral matter deposited on the Šijec bog was characterized using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). We collected solid atmospheric deposition from snow, rainwater, and using passive samplers. Samples were collected at average atmospheric conditions and after two dust events. Size, morphology, and chemical composition of individual particles were determined. We distinguished four main particle groups: silicates, carbonates, organic particles, and Fe-oxyhydroxides. Silicate particles are further divided into quartz and aluminosilicates. Proportions of these groups vary between samples and between sample types. In all samples, silicate particles predominate. Samples affected by dust events are richer in solid particles. This is well observed in passive deposition samples. Carbonates and organic particles represent smaller fractions and are probably of local origin. Iron-oxyhydroxides make up a smaller, but significant part of particles and are, according to their shape and chemical composition, of both geogenic and anthropogenic origin. Estimated quantity and percentage of main groups vary throughout the year and are highly dependent on weather conditions. Dust events represent periods of increased deposition and contribute significantly to mineral matter input to peatlands.

Atmospheric deposition of microplastics in the megalopolis (Shanghai) during rainy season: Characteristics, influence factors, and source

Urban areas are the hardest hit by microplastic pollution, and deposition is an important part of microplastic migration and transport in the atmosphere, therefore, the study of microplastics in an urban atmospheric deposition is of great significance. This study aims to investigate the deposition characteristics of atmospheric microplastics in megapolis, to clarify the influence of meteorological and anthropogenic factors, and to analyze the sources of atmospheric microplastics. Six sampling sites in Shanghai were selected to collect atmospheric deposition samples during the rainy season. The mean deposition flux of microplastics was 3261.22 ± 2847.99 P·m−2·d−1 (median: 2559.70 P·m−2·d−1), and the types were mainly polyamide (PA, 27.79 %), polyethylene terephthalate (PET, 27.29 %), polypropylene (PP, 16.95 %), and polyvinyl fluoride (PVF, 12.88 %). The microplastic with the particle size of <1000 μm accounted for 88.23 %, and the shape was mainly fiber (73.55 %). The results of correlation analysis and variance analysis of microplastic characteristics with meteorological and anthropogenic factors (land-use, atmospheric pollutants, and urban indicators) showed that wind and precipitation had effects on deposition flux, size and shape, and were more significant at small scales (individual cities), while at large scales, the population was the main influence of microplastics. Atmospheric microplastics in Shanghai may be dominated by exogenous sources, through a combination of microplastic characteristics, wind and backward trajectories. This study further reveals the fate of urban atmospheric microplastics, which has implications for the study of global microplastic pollution.

Seasonal Variation of the Atmospheric Bacterial Community in the Greenlandic High Arctic Is Influenced by Weather Events and Local and Distant Sources.

The Arctic is a hot spot for climate change with potentially large consequences on a global scale. Aerosols, including bioaerosols, are important players in regulating the heat balance through direct interaction with sunlight and indirectly, through inducing cloud formation. Airborne bacteria are the major bioaerosols with some species producing the most potent ice nucleating compounds known, which are implicated in the formation of ice in clouds. Little is known about the numbers and dynamics of airborne bacteria in the Arctic and even less about their seasonal variability. We collected aerosol samples and wet deposition samples in spring 2015 and summer 2016, at the Villum Research Station in Northeast Greenland. We used amplicon sequencing and qPCR targeting the 16S rRNA genes to assess the quantities and composition of the DNA and cDNA-level bacterial community. We found a clear seasonal variation in the atmospheric bacterial community, which is likely due to variable sources and meteorology. In early spring, the atmospheric bacterial community was dominated by taxa originating from temperate and Subarctic regions and arriving at the sampling site through long-range transport. We observed an efficient washout of the aerosolized bacterial cells during a snowstorm, which was followed by very low concentrations of bacteria in the atmosphere during the consecutive 4 weeks. We suggest that this is because in late spring, the long-range transport ceased, and the local sources which comprised only of ice and snow surfaces were weak resulting in low bacterial concentrations. This was supported by observed changes in the chemical composition of aerosols. In summer, the air bacterial community was confined to local sources such as soil, plant material and melting sea-ice. Aerosolized and deposited Cyanobacteria in spring had a high activity potential, implying their activity in the atmosphere or in surface snow. Overall, we show how the composition of bacterial aerosols in the high Arctic varies on a seasonal scale, identify their potential sources, demonstrate how their community sizes varies in time, investigate their diversity and determine their activity potential during and post Arctic haze.

Engineering-geological assessment of rocky soils based on the analysis of the collection of Albazinskoye deposit samples

The article deals with the engineering-geological assessment of the rocky soils of the Albazinskoye deposit located in the north of the Khabarovsk Territory, Russia conducted on the example of the analysis of the collection of samples of various petrographic types of certain geological formations. The purpose of the research is to implement a specially developed complex methodological scheme including an optical method (analysis of thin rock sections), measurement of seismic (surface and through sounding of samples to determine longitudinal seismic wave velocity), strength (vertical compression and tension) and physical (density and water absorption) properties. Using the obtained data, a comparative analysis of samples is performed based on the results of seismic, strength and physical properties taking into account petrographic information. Anisotropy in terms of seismic and strength properties is established. Using a cluster analysis program, the correlation coefficients between property indicators are determined. On example of the materials of the collection, it is shown that the differences in the velocity of longitudinal seismic waves and strength are determined by the textural-structural features and composition of rocky soils, which are studied at the micro level.

Глубоководный автономный пробоотборник газодинамического типа для опробования рыхлых отложений и залежей плотного сложения

The article reviews general challenges of exploration in the South China Sea related to prospecting and sampling of solid mineral deposits. The importance of sampling as the only scientifically sound method of identifying and defining properties of minerals is emphasized. Information is provided on the equipment and methods used in Vietnam for sampling bottom sediments in the South China Sea. An autonomous gas-dynamic boomerang sampler designed by the authors is presented. The sampler is designed to close the clamshell buckets with subsequent surfacing of the unit using the energy of expanding gases. The sampler consists of clamshell buckets, an operating cylinder with a piston and a lifting cylinder mounted on a rigid frame. The sampler can be used for sampling solid grounds with the drillability grade above III, and it significantly reduces the sampling time, while increasing the reliability of the survey.

The influence of severe plastic deformation on the thermal expansion of additively manufactured Ti6Al4V alloy

The thermal expansion properties of the Ti6Al4V alloy deposited with direct energy subjected to severe plastic deformation through ECAP were studied in the temperature region 23–700 °C. The deposit samples exhibited two orientations: with the longitudinal axis in the deposition plane and perpendicular to the deposited layers. The microstructure of the deposited alloy and the alloy after thermomechanical treatment was analysed on a scanning electron microscope using the EBSD method. The ECAP process substantially refined the structure of the grains. The temperature dependence of the thermal expansion coefficient estimated for the alloy after ECAP processing exhibited a non-monotonous course. The microstructural changes are the reason for this finding.

Intrusive sampling of dust deposition in a granular bed filter-cyclone coupled separator

A separator coupling cyclone with a built-in granular bed filter is proposed for gas purification. Due to the complicated mutual influences between the outer cyclone shell and the inner granular bed, the dust deposition is different from that in the traditional granular bed filter. By using the intrusive sampling method, the dusts deposited in the bed are sampled under varying inlet dust concentrations and inlet gas velocities. It is implied that the outer screen of the built-in granular bed is more sensitive to the operating conditions. The dust concentration percentage in the inner bed increases less with the gas velocity. On the contrary, its distribution changes greatly along with the axial height. In addition, the local filtration efficiency changes slightly in the whole built-in granular bed under high inlet dust concentration. Based on the measured data, a new equation for estimating the local filtration efficiency is obtained.

VIS-NIR-SWIR spectroscopic mapping for classification of hydrothermal-metasomatic alterations on the flanks of the Stolbovoe uranium deposit (Eastern Cis-Sayan)

Background. The Stolbovoe deposit is located in the northern part of the Eastern Sayan, in the Nizhneudinsky district of the Irkutsk region, within the N-47-IX map sheet. The surveying of the territory began in the sixties of the last century. The Stolbovoe deposit was discovered based on direct search signs (radioactivity). At the same time, the search was not aimed at revealing new deposits hidden under the Riphean cover; therefore, most of the territory remained unexplored.Aim. To map and classify the near-ore hydrothermal-metasomatic alterations manifested on the flanks of the Stolbovoe uranium deposit.Materials and methods. During the 2018–2020 period, within the framework of prospecting work, the employees of the All-Russian Scientific-Research Institute of Mineral Resources named after N.M. Fedorovsky (VIMS) carried out the mapping of ore alterations using an innovative method of Infrared (IR) spectroscopy. The diagnostics of mineralization was carried out using a portable TerraSpec 4 Hi-Res spectrometer. The instrument was used to measure diffuse reflectance spectra in the Ultraviolet-Visible-Short-Wave Infrared (UV-Vis-SWIR) ranges; the composition of various mineral phases was determined using the TSGVersion 7 database and software.Results. This study confirmed the efficiency of the method applied for the diagnostics of all varieties of clayey (kaolinite, montmorillonite) and fine micaceous (phengite, sericite, paragonite and their illite varieties) minerals, as well as carbonates (dolomite, ankerite, siderite) and chlorites in the rock in situ or in samples without preliminary sample preparation.Conclusions. The use of the described method for investigating cores and samples of the Stolbovoe uranium deposit (East Sayan region) made it possible to classify the epigenetic changes in rocks and to map hydrothermal-metasomatic halos, including those near-ore, formed by mineralization that could not be identified by conventional visual and optical methods.

Experimental research on fully burning high‐alkali coal in a 300 MW boiler with slag‐tap furnace

AbstractSafety issues such as contamination and slagging restrict the use of high‐alkali coal. To explore the possibility of fully burning high‐alkali coal in a boiler with slag‐tap furnace, Na2CO3‐blended burning tests and a fully burning high‐alkali coal test were carried out in a 300 MW boiler with slag‐tap furnace. The results showed that fully burning high‐alkali coal had little effect on the steam parameters and the boiler could operate safely. The Na content in the flue gas tended to decrease from SH5 to RH2 and increased from RH2 to ECON. The increase of Na content in the fuel would significantly raise Na content in the flue gas, slightly increase the K content, and increase the ability of liquid slag to capture Na. Before the Na content in SH coal ash was increased by 150%, the capture ability of liquid slag to Na had reached saturation. The added Na2CO3 made the Al and Ca elements migrate to the liquid slag to form a high melting point Na‐Al‐Ca compound. The microstructure analysis showed that liquid slag has a rich pore structure inside and outside and the Na content in the pore was higher than that out. Mineralogy analysis found that deposition samples mainly included Quartz, Magnesioferrite, Anhydrite, Lime, and CaSiO4 and the addition of Na2CO3 hardly affected the mineral composition.

Conventional Meso-Scale and Time-Efficient Sub-Track-Scale Thermomechanical Model for Directed Energy Deposition.

Thermally-induced distortion and residual stresses in parts fabricated by the additive manufacturing (AM) process can lead to part rejection and failure. Still, the understanding of thermo–mechanical behavior induced due to the process physics in AM process is a complex task that depends upon process and material parameters. In this work, a 3D thermo-elasto-plastic model is proposed to predict the thermo–mechanical behavior (thermal and distortion field) in the laser-directed energy deposition (LDED) process using the finite element method (FEM). The predicted thermo–mechanical responses are compared to stainless steel 316L (SS 316L) deposition, with single and double bead 42-layer wall samples subject to different inter-layer dwell times, which govern the thermal response of deposited parts in LDED. In this work, the inter-layer dwell times used in experiments vary from 0 to 10 s. Based on past research into the LDED process, it is assumed that fusion and thermal cycle-induced annealing leads to stress relaxation in the material, and is accounted for in the model by instantaneously removing stresses beyond an inversely calibrated relaxation temperature. The model predicts that, for SS 316L, an increase in dwell time leads to a decrease in in situ and post-process distortion values. Moreover, increasing the number of beads leads to an increase in in situ and post-process distortion values. The calibrated numerical model’s predictions are accurate when compared with in situ and post-process experimental measurements. Finally, an elongated ellipsoid heat source model is proposed to speed up the simulation.

Variabilities of biochemical properties of the sea surface microlayer: Insights to the atmospheric deposition impacts

Atmospheric deposition (AD) of nutrients and its impact on the sea surface requires consideration of interfacial processes within the sea surface microlayer (SML), the ocean-atmosphere boundary layer of major importance for many global biogeochemical and climate-related processes. This study comprised a comprehensive dataset, including dissolved NO3−, NH4+ and PO43− in ambient aerosol particles, wet deposition and sea surface samples collected from February to July 2019 at a central Adriatic coastal site. The aerosol mean concentration of dissolved nitrogen (DIN = NO3− + NH4+) and PO43− were 48.8 ± 82.8 μmol m−3 and 0.8 ± 0.6 μmol m−3, respectively, while their total fluxes (dry + wet) ranged from 24.2 to 212.3 μmol m−2 d−1 (mean 123.2 ± 53.2 μmol m−2 d−1) and from 1.2 to 2.1 μmol m−2 d−1 (mean 1.5 ± 0.3 μmol m−2 d−1), respectively. Intensive local episodes of open biomass burning (BB) significantly increased aerosol DIN concentrations as well as DIN deposition fluxes, particularly altering the molar DIN/PO43− ratio of atmospheric samples. The DIN temporal patterns showed high variability in the SML (range 0.2–24.6 μmol L−1, mean 5.0 ± 7.1 μmol L−1) in contrast to the underlying water samples (range 0.5–4.2 μmol L−1, mean 1.9 ± 1.2 μmol L−1), with significant increases during BB periods. Variability in abundance of heterotrophic bacteria and autotrophs in the SML along with concentrations of bulk dissolved and particulate organic carbon as well as dissolved and particulate lipids and carbohydrates, gel particles and surfactants followed DIN enhancements with a two-week delay. This study showed that AD can affect the short-term scale enrichments of organic matter in the SML, especially when accompanied by BB emissions typical of the overall Mediterranean coastal environment. This could have strong implications for global air-sea exchange processes, including those of climate relevant gases, mediated by the SML.

К вопросу об источниках россыпных алмазов Эбеляхского района (Арктическая зона России)

The work considers the identification of potentially diamond areas based on the geological and statistical analysis of data from heavy mineral concentrate sampling of alluvial deposits of the Ebelakh River and its confluents. The researchers compress the information of the diamond placer mineral field of the Ebelyakh River and identify the main components based on information entropy (K. Shannon). The spatial heterogeneity of polymineral fields, revealed using the entropy method, allow outlining areas of possible localization of intermediate hosts (or their former development) in the Ebelyakhskiy region.

Evaluation of the Terrestrial 222Rn Flux from 210Pb Deposition Measurements

The study of the 222Rn terrestrial flux (Bq/(m2·s) or Bq/(m2·h)) is a complex issue involving both radiation-protection and environmental aspects. While the radiation-protection aspects are quite obvious—it has been well known for several decades that soil is the major source of indoor radon—environmental issues such as the correlation with conventional pollutants (PM2.5, PM10, NOX, etc.) and the use of radon for the esmation of the natural component of GHG (CO2) emissions are relatively less discussed in spite of their growing relevance. In this work we present a method for the estimation of the average value of 222Rn flux from HPGe γ-spectrometry 210Pb measurements performed on wet and dry deposition samples gathered monthly in the period 2006–2020. The results obtained with this technique give an average radon flux in the period Φ = 57 ± 27 Bq/(m2·h), the value of which is comparable with those coming from other methods and direct radon flux measurements as well. The method can thus be used to obtain a worldwide map of the radon flux.

Effects of Trace Boron Addition and Different Arc Types on Microstructure and Mechanical Properties of TC11/TC17 Dual Alloy Fabricated by Wire Arc Additive Manufacturing

Wire arc additive manufacturing (WAAM) provides an efficient and low‐cost potential for manufacturing TC11/TC17 dual titanium alloy. In this work, six deposition samples were fabricated for the test of microstructure and mechanical properties by the combination of trace boron addition and different arc types (direct current (DC), high frequency pulsed current (HC), low frequency pulsed current (LC)). Results show that the epitaxial growth β columnar grains were formed except for the combination of low frequency pulsed current and trace boron addition (LCB). A special microstructure of coarser α phases surrounding thin α phases was formed by the effect of LC arc or trace boron addition. Some TiB particles exhibited a specific orientation relationship with surrounding α phases, but not all: (0001)α||(001)TiB and &lt;11‐20&gt;α||[010]TiB. About mechanical properties, the elongation decreased with trace boron addition, and comprehensive mechanical properties of LC method was better than that of DC or HC methods whether it contained trace boron or not, with tensile strength of 1057 MPa and elongation of 14.4% in the longitudinal direction. Meanwhile, the strength of LCB group is highest than that of other groups, which is caused by the refined β grains and the uniform distribution of TiB particles.

Comparison of Water Sensitive Paper and Glass Strip Sampling Approaches to Access Spray Deposit by UAV Sprayers

Target and off-target spray depositions determine the spray’s effectiveness and impact on the environment. A decisive stage in the measurement of spray deposition and drift is selecting an appropriate sampling approach under field conditions. There are various approaches available for sampling spray deposition and drift, during the evaluation of ground sprayers used for the UAV sprayer assessment, under field conditions. In this study, two sampling approaches (water-sensitive paper, and glass strip collectors) were compared to analyze spray deposition in target and off-target zones. The results showed a variation in the estimation of the spray deposits among the two applied sampling methods. The results showed that the water-sensitive paper recorded the droplet deposition in the target zone with a range from 0.049 to 4.866 µLcm−2, whereas the glass strip recorded from 0.11 to 0.793 µLcm−2. The results also showed the water sensitive paper recorded an 80.3% higher deposition than that of the glass strip at zero position during the driving flight height 2 m and flight speed 2 ms−1 (T1 treatment). It can be concluded that variation in recorded depositing is due to the sampling material. It is recommended that the confident deposition results, measurement methods and sampling approaches must be standardized for UAV sprayers according to the field conditions and controlled within artificial assessments.

Contrasting mineral dust abundances from X-ray diffraction and reflectance spectroscopy

Abstract. Mineral dust particles dominate aerosol mass in the atmosphere and directly modify Earth's radiative balance through absorption and scattering. This radiative forcing varies strongly with mineral composition, yet there is still limited knowledge on the mineralogy of atmospheric dust. In this study, we performed X-ray diffraction (XRD) and reflectance spectroscopy measurements on 37 different dust deposition samples collected as airfall in an urban setting to determine mineralogy and the relative proportions of minerals in the dust mixture. Most commonly, XRD has been used to characterize dust mineralogy; however, without prior special sample preparation, this technique is less effective for identifying poorly crystalline or amorphous phases. In addition to XRD measurements, we performed visible and short-wave infrared (VSWIR) reflectance spectroscopy for these natural dust samples as a complementary technique to determine mineralogy and mineral abundances. Reflectance spectra of dust particles are a function of a nonlinear combination of mineral abundances in the mixture. Therefore, we used a Hapke radiative transfer model along with a linear spectral mixing approach to derive relative mineral abundances from reflectance spectroscopy. We compared spectrally derived abundances with those determined semi-quantitatively from XRD. Our results demonstrate that total clay mineral abundances from XRD are correlated with those from reflectance spectroscopy and follow similar trends; however, XRD underpredicts the total amount of clay for many of the samples. On the other hand, calcite abundances are significantly underpredicted by SWIR compared to XRD. This is caused by the weakening of absorption features associated with the fine particle size of the samples, as well as the presence of dark non-mineral materials (e.g., asphalt) in these samples. Another possible explanation for abundance discrepancies between XRD and SWIR is related to the differing sensitivity of the two techniques (crystal structure vs. chemical bonds). Our results indicate that it is beneficial to use both XRD and reflectance spectroscopy to characterize airfall dust because the former technique is good at identifying and quantifying the SWIR-transparent minerals (e.g., quartz, albite, and microcline), while the latter technique is superior for determining abundances for clays and non-mineral components.

Characterization and comparison of deposits in a coal-fired rotary kiln for iron ore fluxed pellets and acidic pellets productions

Compared to iron ore acidic pellet production, the deposit problem in kiln became more severe to produce iron ore fluxed pellets. This study characterized the deposit samples in a grate-kiln process for iron ore fluxed pellet production. The deposited samples were analyzed by chemical analysis, XRD, SEM-EDS, and thermodynamic software. The deposits contained mainly hematite particles embedded in bonding phases, mainly comprising silicates with different compositions. There was a significant change in the composition of bonding phases in deposits when the CaO content increased in the iron ore pellets. The bonding phases of deposits for fluxed pellets had higher CaO and Fe2O3 contents than acidic iron ore pellets. For the deposit samples from iron ore fluxed pellet production, the area of bonding phases in the phase diagram of CaO-Al2O3-SiO2-5wt%MgO moved to the higher CaO part, which had a lower liquid temperature. The change in the bonding phase caused a high proportion of formed liquid phases in the deposits, then led to severe deposit formation in the grate-kiln production plant.