Drum Granulation Research Articles

Nghiên cứu tạo hạt hấp phụ trên cơ sở Fe2O3/TiO2 ứng dụng loại bỏ As(V) trong môi trường nước

Granular adsorbent-based Fe2O3/TiO2 was fabricated via the drum granulation method with bentonite as the binder. The granulation process consists of three steps: mixing Fe2O3/TiO2 composite powder; fine coal dust into a homogeneous mixture; granulating by spraying water mist; drying granules and calcining at 500 oC for 1 hour to create pores. The granules used to remove As(V) from aqueous media were investigated using a fixed-bed adsorption column. The effects of inlet As(V) concentration, flow rate, and bed height on the breakthrough characteristics of the adsorption system were determined. The adsorption data were fitted to three well-established fix-bed adsorption models, namely, the Adam-Bohart, Thomas, and Yoon-Nelson models, with a correlation coefficient, R2 > 0.96.

Effect of nuclei particle shape and baffle setting on the drum granulation in iron ore sintering process

Discrete element method is used in this work to investigate the sintering granulation process of different-shaped nuclei iron ore particles and different drum baffle settings in rotating drums. The results show that the nuclei particle shape does not affect the flow pattern much, and the baffle setting can affect the time needed for particle flow to stabilize and the fluctuation intensity of particle collisions. The shape of iron ore nuclei significantly affects the number of attached small particles (per unit area), with the order of sphere > schistose > sphero-polyhedron > ellipsoid > polyhedron. Drums with the inclined baffles and ring baffles have faster water exchange rate. The 4-baffle drum has the highest number of adhered particles on the nuclei particle surface, showing a better granulation performance. The drum baffle setting does not affect the proportion of adhered iron ore, coke, and flux particles much.

An investigation of drum granulation of post‐pyrolysis washed biochar

AbstractBiochar, unwashed and washed with a solution of Triton and hydrogen peroxide, was wet drum granulated using molasses binder solutions. Unwashed biochar was very hydrophobic and granulation proceeded through forming liquid marbles and layering. Washing reduced the hydrophobicity of the biochar. The effectiveness of the wash depended on the biochar source; it significantly reduced the hydrophobicity of biochar from woodchips and moderately reduced the hydrophobicity of biochar from flower digestate. Therefore, washed biochar from woodchips was granulated using a hydrophilic mechanism, while washed biochar from digestate was granulated according to a combination mechanism of liquid marbles collapsing and then coalescing. The change in granulation mechanism produced stronger and denser granules with higher yields of granules in the 1–4 mm optimal size range. Washing and then granulating biochar created a product that could be further tailored for optimal soil amendment.

Distribusi Ukuran Granul dari Tepung Singkong dengan Tepung Tapioka sebagai Pengikat pada Rotary Drum Granulator

Granulation is a process of monoparticle attachment with a particular mechanism to form a bigger and compact particle which is called granule. Granulation application has been used on many industries like pharmacy and agriculture industries. Research about granulation has been done continuously to get predictive models for various cases. The model which is only applicable to the specific material used in this research is expected to be useful to optimize the perfomances of the granulator in the industries. This research aims to develop the kinetics model of granule size distribution of cassava flour and its connection to granulation time by varying the mass of tapioca starch as the binder in rotary drum granulator. 2 grams of Cassava flour and tapioca starch were mixed in the rotary drum granulator and then water was sprayed during the granulation process. The duration of granulation were 5, 10, 15, 20, and 25 minutes. The variations of mass of the binder used in this research were 1, 1,5, and 2 gram. The granules were dried in the oven at 80°C until 30 minutes, and afterwards the granules were screened through various screen layers with different mesh size. The results of this research show that binder mass variations do not influence the layering rate of granule, and the increase of binder mass will decrease the birth rate.

Investigating the role of dry compaction and layer-wise agglomeration to control the dissolution of granular urea fertilizer

Pore size distributions and degree of anisotropy (pore channel orientation) affect the mechanical properties, fragmentation, and dissolution kinetics of granular composites. Especially in porous solids such as granular urea fertilizers, uncontrolled dissolution leads to soil and water contamination from nutrient leaching. In this work, a dry compaction method and a bilayer granulation process were compared to investigate their ability to control the nutrient release from granular urea fertilizers. Urea and binary mixtures of urea and a xanthan and konjac gum binder were dry compacted. The compacts were then milled to specific particle sizes producing core granules. The core granules were drum granulated along with a known percent of fines and water to produce bilayer granules. The drum granulation parameters were optimized based on the granules' particle size distributions and color analysis. Dissolution and porosity distributions of core and bilayer granules were investigated and compared to market urea granules. Core granules with or without a binder compacted at 100 MPa had smaller pore size distributions compared with core granules compacted at 50 MPa, bilayer granules, and market urea granules. Core granules compacted at 100 MPa showed a significant decrease in the dissolution rate compared to less dense systems, such as core granules at 50 MPa, bilayer, and market urea granules. The addition of gums as binder caused an additional delay in the dissolution rate, indicating that formulation design is essential in controlling nutrient release. Less porous structures, i.e., higher compaction pressure to produce core granules, along with binder addition resulted in delayed dissolution rates due to binder migration and gelation at the solid-liquid interface. These results show that densification and formulation design can help control the release of urea from granular fertilizers with the potential of reducing leaching losses and pollution.

Research on the Quality Improvement and Consumption Reduction of Iron Ore Agglomeration Based on Optimization

In order to increase agglomeration production and improve its quality while reducing energy consumption, a new intelligent blending method has been established at Ansteel to optimize its sinter blends. The statistical model of the ore blending results shows that (1) a blending ratio of 47.2% Ore A and 52.8% Ore C corresponded to the best sinter yield of 72.44%. (2) From the viewpoint of sinter reducibility, sinter basicity should not be less than 1.98 when the proportion of Ore A in the blend is more than 35%. Due to the low mixing efficiency of disc pelletizers, Ansteel has therefore gone through a massive technical transformation at Sinter Plant 3 to replace its 16 existing disc pelletizers with one drum granulator. Since the installation of the drum granulator, the standard deviation has decreased from 1.517 to 0.7332 for total Fe (T.Fe) and from 0.146 to 0.0956 for basicity. In the case of the drum granulator, the standard deviation for sinter T.Fe and basicity were 0.6926 and 0.05449, respectively, as compared to 0.8902 and 0.2033 for the disc pelletizers. In addition, a single lattice method is proposed to optimize the particle-size distribution of the coke breeze to further improve sinter quality and reduce fuel consumption. The lattice method indicated that the optimum coke breeze to achieve maximum sinter tumble strength should consist of approximately 57.20%: −1 mm, 25.63%: 1–3 mm, 11.17%: 3–5 mm, and 6.00%: >5 mm particles. Given the international trend of increasing bed depth, Ansteel has successfully achieved a bed height of 1050 mm or more under its blend conditions, which typically contain 75% concentrates. Finally, some new iron ore agglomerations research is discussed.

Low-cost drum granulator for mechanized seedball production

Seed granulation is a coating technique, which turns a raw material mixture of sand, loam, water, seeds, and fertilizers into seedballs. It enhances the seedling establishment and early growth of crops, like pearl millet, in nutrient-poor soil. Mechanization is highly required, as large-scale production poses challenges to local farmers due to time constraints and labor demand. The prototype of a drum granulator for seeds, also known as a seedball machine, essentially consists of a metal frame and a drum. The seedballs are formed by a rotational motion of the drum. The construction and operation of the machine were designed to be simple. In this study, the combined effect of different factors, such as substrate composition, rotational speed and residence time was taken into account. This study revealed that the amount of loam and the rotational speed of the drum appeared to be the most influencing factors on seedball production and quality. The machine had a production capacity of seedballs ten times higher than manual production. The machine-made seedballs were also of high quality, exceeding 98% germination rate under greenhouse conditions. Besides pearl millet, the machine can be potentially used for other small-sized seeds, such as cotton or sesame.

Effect of Various Binders on the Properties of Microalgae-Enriched Urea Granules.

As the human population grows and the demand for food grows with it, the recycling, or containment of materials is important for resource consumption. Nitrogen is one of the main plant nutrients, most commonly used as the chemical substance urea. Because urea is very soluble and at a relatively low temperature (50-60 °C) it hydrolyses easily (releases N2 and CO2) in soil solutions; this is why very large amounts of nitrogen are lost and greenhouse gases are released and this causes serious environmental problems. Therefore, the aim of this study was to create microalgae-enriched nitrogen fertilizers with different binders that inhibit nitrogen leaching from the soil. Binders such as water (W), polyvinyl acetate dispersion (PVAD), molasses (M), potato starch (S), and carboxymethyl cellulose (CMC) were used in this study and their influence on leaching was analysed. Granular fertilizers were produced in a drum granulator and dryer under equal conditions: granulation time was 7 min, granulation took place at a temperature of 50-60 °C, at a drum rotation speed of 26 rpm, with a 5° inclination angle of the drum. The results show that the highest quantity of the marketable fraction was 43.01 (±3.068%) and it was obtained using urea, with 10% (w/w) microalgae additive, and 11.4% (w/w) of 5% concentration molasses solution. The granules of the fertilizer marketable fraction are similar in size because the size guide number (SGN) of the granules vary in a narrow range and fall within the interval of 287 to 304; this means that the average particle size is ~3 mm. When different binders were used, the average static crushing strength of the granulated fertilizers was lower (approximately 6-12 MPa) than using water alone (approximately 12-16 MPa), but the lower values still fell into the required range. Additives of PVAD solutions and molasses solutions have been found to retain nitrogen in sand. The method of one-way analysis of variance (ANOVA) was used to evaluate the results.

In Silico CFD Investigation of the Granulation Hydrodynamics in Rotating Drum: Process Sensitivity to the Operating Parameters and Drag Models

Computational fluid dynamics (CFD) have been extensively used to simulate the hydrodynamics of multiphase flows (MPFs) in rotating machinery. In the presence of a granular dense phase, the Kinetic Theory of Granular Flow (KTGF) is usually coupled to Eulerian multi-fluid models to obtain tractable computational fluid models. In the present work, the hydrodynamic behavior of a three dimensional, industrial scale, and rotating drum granulator with gas–solid flows is assessed using the Eulerian–Eulerian approach coupled with the k-ε standard turbulence model. A Eulerian–Eulerian Two-Fluid Model (TFM) is used with the KTGF model for the granular phase. The sensitivities to different operating parameters, including the rotational speed (8, 16, and 24 rpm), inclination degree (3.57∘, 5.57∘, and 7.57∘), and degree of filling (20%, 30%, and 40%) are studied. Moreover, the impact of the drag model on the simulation accuracy is investigated. The flow behavior, regime transitions, and particle distribution are numerically evaluated, while varying the operating conditions and the drag models. The rotational speed and filling degree appear to have greater influences on the granulation effectiveness than on the inclination degree. Three drag models are retained in our analysis. Both the Gidaspow and Wen and Yu models successfully predict the two-phase flow in comparison to the Syamlal and O’Brien model, which seems to underestimate the hydrodynamics of the flow in both its axial and radial distributions (a fill level less than 35%). The methodology followed in the current work lays the first stone for the optimization of the phosphates fertilizer wet-granulation process within an industrial installation.

Comparisons of iron ore granulation and sintering performance between horizontal high-shear granulators and drum granulators

Granulation is a key operation unit in preparation of iron ore raw materials. This work presented an experimental study on the iron ore granulation and sintering using a novel horizontal high-shear granulator and a traditional drum granulator. The mixing and granulation performance and the effect of granulation on sintering indicators were analyzed. The results showed that the optimal filling level of the shear granulator was about 9%, which was slightly lower than that of the drum granulator (12%). However, the uniformity, bed permeability and the fracture strength of the granules from the shear granulator were significantly better than those from the drum granulator. Compared with the drum granulator, the shear granulator had better mixing ability in the axial direction, more even distributions of water and calcium and less segregation. For the thick-bed sintering with a height of 900 mm, the sintering indicators in terms of sintering speed, sinter yield, strength and flue composition showed the shear granulator was significantly better than that of the drum granulator.

Studies on the Possibilities of Processing Buckwheat Husks and Ash in the Production of Environmentally Friendly Fertilizers

The sustainable utilization of different food waste and other products is one of the challenges of the European Green Course. Buckwheat has major potential as a food ingredient; however, processing buckwheat into food products generates a large amount of solid waste that needs to be sustainably disposed of. The by-products that come from the processing of the buckwheat contain high contents of carbon and hydrogen and can be used as raw materials for the production of granular biofuels. This work proposes and explores the potential of a different route of buckwheat husk ash utilization. Chemical analysis of the buckwheat husk ash (BHA) and uncleaned buckwheat husks (UBH) showed significant amounts of primary and secondary nutrients (0.28 ± 0.06%–5.84 ± 0.43% P2O5; 4.56 ± 0.46%–38.63 ± 1.82% K2O; 0.09 ± 0.01%–12.18 ± 0.38% CaO and 0.47 ± 0.08%–3.56 ± 0.18% MgO) as well as micronutrients (Zn, Mn, Cu, and Fe) and carbon (29.53 ± 0.50%–54.35 ± 0.58% C). It has been determined that granular biofertilizers can be produced by using drum granulators from the mixture of raw materials in an 80–20% BHA, 20–80% UBH, and 10% polyvinyl acetate (PVA) solution. However, when more than 20% of the UBH is present in the raw material mixture, the humidity of granules is high (more than 6%), and bulk density is low (less than 450 kg/m3). The pH values of 10% solution of the produced granules range from 12.0 to 9.7; thus, the fertilizers can act as a liming agent, which can be recommended for acid soils. This suggests a potential for a cradle-to-cradle type of regenerative engineering process design, where the end product of buckwheat processing—buckwheat husk ash and untreated buckwheat husks—can be returned back to the soil to replenish the nutrients, resulting in an overall sustainable process.

Technology for production of granular calcium-ammonium nitrate

The article presents the technology for production of granular calcium-ammonium nitrate, which is suitable for implementation into the existing production of complex mineral fertilizers. The paper considers the physicochemical foundations of manufacturing calcium-ammonium nitrate and provides the calculations of the equilibrium constants of the reactions occurring at the temperatures of 25–1700С. A new process flow diagram was proposed. It was shown that the production of calcium ammonium nitrate as a valuable agrochemical fertilizer is possible by mixing of 82–84% ammonium nitrate solution with solid carbonate raw materials with further granulation and drying in a drum granulator and dryer. The work determines the conditions for the interaction of reagents making it possible to reduce the losses of nitrogen. The density of aqueous suspensions of chalk and the rate of its precipitation are established. The obtained results allow improving an industrial plant based on the existing equipment for the production of complex mineral fertilizers. The technological parameters for the preparation of the product are optimized to meet the requirements of technical conditions. During commissioning and stabilization of the technological regime, a product was obtained containing 25.9–27.8% of total nitrogen, 15.6–16.8% of CaCO3, 0.01–0.64% of Ca(NO3)2, and 0.32–0.75% of H2O with the following particle size distribution: 95.3–96.3% of 1–5 mm particle size, and 3.7–4.8% of particle size of less than 1 mm with a granule hardness of 30 N per granule.

Valorization of apatite mining flotation residues by the manufacture of artificial aggregates

Mining residues are usually stockpiled because of their understudied physico-chemical properties and of their abundance, which make their valorization challenging. In this work, a cold-bonding granulation apparatus was built in order to transform a mining residue sludge from an apatite ore, into artificial aggregates suitable for use in civil engineering. A 25 rpm rotation speed, 15° angle relative to horizontal, and an ideal feeding amount of the granulation drum, as such as the liquid (supernatant) distribution method, were preliminary determined. Effects of rotation speed, liquid content, and granulation time were then studied to evaluate the best combination for appropriate aggregate size distribution. Box-Behnken experimental designs were used to investigate the evolution of compressive strength of the individual aggregates when Portland cement is added to the mix, and when granulation time varies, around the critical liquid content of 14% of total weight. Thus, the possible parameters combinations which allow a maximization of compressive strength without exclusively increasing cement content, were determined and used to confirm the Box-Behnken predictions. Spherical aggregates were thus manufactured, with diameters mainly comprised between 5 and 40 mm, and compressive strength comparable to those of commercialized aggregates, up to 7 MPa and to 3 MPa for aggregates with diameters respectively below and above 10 mm. Paths for greater consolidation as prior homogenization, use of humid cure conditions, and use of other additives emerge from literature and from the results presented.

Double-Loop Control Structure for Rotary Drum Granulation Loop

The operation of granulation plants on an industrial scale is challenging. Periodic instability associated with the operation of the granulation loop causes the particle size distribution of the particles flowing out from the granulator to oscillate, thus making it difficult to maintain the desired product quality. To address this problem, two control strategies are proposed in this paper, including a novel approach, where product-sized particles are recycled back to maintain a stable granulation loop process. A dynamic model of the process that is based on a population balance equation is used to represent the process dynamics. Both of the control strategies utilize a double-loop control structure that is suitable for highly oscillatory systems. The simulation results show that both control strategies, including the novel approach, are able to remove the oscillating behaviour and stabilize the granulation plant loop.

Evaluation of spent coffee grounds application in organic fertilizers industry

The main purpose of this thesis was to determine chemical and physical properties of spent coffee grounds (SCG) and evaluate their application in organic fertilizers industry. During the experiment, some physical properties, like particle size distribution and pH level of spent coffee grounds solutions of different concentration, were determined. Two different methods have been chosen to determine carbon content in coffee grounds. Also, several instrumental analysis methods have been used to analyse coffee grounds. The results show that spent grounds are not very acidic, values of 10% solution vary between 5.2–5.8. The concentration of organic carbon is quite high and varies between 4.75–5.74%. The TGA and DSC curves show three-stage decomposition. Above 400℃ spent coffee grounds fully decompose. The total mass loss of SCG varies between 97–98%. Functional groups (such as O–H, C=O) were determined by using FTIR spectroscopy. It is clear from XRD that spent coffee grounds are amorphous material. The SEM results show that particles of coffee grounds have high porosity. A drum granulator was used to make granular fertilizers by using water and phosphoric acid solution, but no pellet was obtained without an additional binder.

Production of bio-waste granules and their evaluation as adsorbent for removal of hexavalent chromium and methylene blue dye

In this research, compost was used as raw materials in the production of biomass adsorbent granules using drum granulation technique. Different concentrations of aqueous sodium silicate solution were used as the binding agents. Chromium and Methylene Blue solutions were selected as model adsorbates for heavy metals and dyes, respectively. The results obtained showed that the concentration of sodium silicate used had a positive influence on the mechanical strength of the granules, increasing the concentration would increase the compressive strength of the granules. The adsorbent granules had sufficient strength to survive wet conditions they were subjected during the adsorption study. However, increasing the concentration has a negative influence on the adsorption properties of the compost granules for both Chromium and Methylene Blue.

A review of regime maps for granulation.

Granulation, a size enlargement technique to form agglomerates of primary particles, has proven to be effective in the production of solid dosage forms. Numerous granulation techniques can be applied, such as roll compaction, drum granulation, high shear granulation, twin-screw granulation or fluid-bed granulation. If the fundamental knowledge about the granule growth mechanism, its impacts as well as their extent and proportions on the mechanism is known, a correlation of the input variables with the granule attributes paves the way regarding a granulation process design and prediction of a systems growth behaviour if one or more affecting parameters change. The dimensionless correlation of the main controlling parameters of the process physics is able to confine an operation window within which different regime areas are defined and where the influencing parameters have different implications on the final product. A regime map is created. The usage of dimensionless numbers ensures a reduction of both the experimental workload and the number of parameters that have to be considered. Thus, a scale-independent operation window can be defined. The aim of the review is a critical discussion of proposed regime maps for different granulation processes.

A comparison of liquid binders for drum granulation of biochar powder

Wet drum granulation of biochar using binder solutions of hydroxypropyl methylcellulose, molasses and ammonium nitrate was investigated to compare granule characteristics to better understand how liquid binder solution affects the granulation of biochar into a soil amendment. The biochar granules were free flowing and approximately spherical with a significant yield between a size range of 1 to 4 mm. The binder concentration, total binder solution volume and drum rotational speed of the drum all affected the yield of granules within this size range. The binder concentration and volume of binder solution affected attrition resistance with molasses binder solution providing the most resistance. The results demonstrated that biochar can be granulated using wet drum granulation with all three binder solutions.

Dynamic model for simulating transient behaviour of rotary drum granulation loop

Dynamic model for simulating transient behaviour of rotary drum granulation loop

STUDY OF GRANULATION PROCESS OF ILMENITE CONCENTRATE BY PELLETING METHOD

The use of highly dispersed ilmenite ore in the titanium concentrate enrichment technology is accompanied by high dustiness at the stage of titanium charge preparation, which inevitably leads to technological losses and adversely affects the working conditions of the staff. In connection with this, the aim of the present work was to study the process of granulating ilmenite concentrate from the Malyshevsky deposit by pelletization. The size and morphology of ilmenite concentrate particles were determined using a high-resolution electron scanning microscope and a laser diffraction particle size analyzer. The granulation process was carried out in a drum granulator thermostated by assessing the effect of temperature, rotation speed granulator, process duration and a binder flow rate on particle size distribution and static strength formed granules of the title product. During the investigations it was established that the maximum yield of granules fraction of 1.0 - 5.0 mm was obtained using an aqueous solution of molasses molasses volume ratio: water = 5:1. The use as undiluted molasses binder leads to a strong increase in ductility formed mass and negatively affects the possibility of producing a granular product. It was shown that with increasing concentration of binder in the composition of the starting mixture the average yield and static strength of granules fraction of 1.0 - 5.0 mm increases, due to the uniform distribution of the solution between the ilmenite concentrate particles. At the same time when the amount of binder in the composition of the starting raw materials over 9.5% the formation of relatively large lumps is observed, which size is more than 5.0 mm. It has been experimentally proved that with increasing duration pelletization yield pellets of ilmenite concentrate fraction of 1.0 - 5.0 mm increases, passing through a maximum at 300 s.