Pelleting Process Research Articles

Influence of various parameters on the vegetable raw material pelleting process and pellets quality (review)

Determining the regularities of the process of pelleting vegetable raw materials is relevant for the improvement of technologies and technical equipment in order to reduce energy intensity and improve the quality of pellets. The generalization of the results of the research aimed at studying the influence of various parameters on the process of pelleting vegetable raw materials and the quality of feed and biofuel pellets is the purpose of the research. A selection and systematic review of the scientific literature on the subject of the study for the period of 2007-2022 has been carried out. The analysis has proved that heat pre-treatment and moistening of vegetable raw materials, as well as their composition and particle size are the factors that have the greatest impact on the quality of feed and biofuel pellets. Increasing the pressure in the range of 20...200 MPa results in increasing the pellets durability. A die temperature of around 100°C is optimum for obtaining dense pellets of highquality from vegetable raw materials. The design parameters of the pelletizer play an important role in obtaining high-quality pellets when processing vegetable raw materials. The design of the inlet in the form of a tapering cone helps to reduce energy consumption and pelleting pressure. An increase in the ratio of the die channel length to its diameter exponentially increases the pelleting pressure and its energy intensity. The interplay between the physical processes occurring in the pelletizer makes it difficult to interpret the impact of each parameter on the pelleting process, so different authors have different assessments of the contribution of individual factors in producing high-quality pellets. Therefore, the interaction between the individual pelleting parameters and their influence on the results of the process should be examined more precisely.

The Pyrolysis Behaviors of Blended Pellets of Pine Wood and Urea-Formaldehyde Resin

TG-FTIR and PY-GC/MS were used to analyze the pyrolysis behaviors of pine wood, urea-formaldehyde resin (UF resin) and their blended pellets. The pyrolysis process was divided into three stages: water evaporation, devolatilization and pyrolysis residue decomposition. During the pyrolysis process of the blended pellets, with the increase of the addition ratio of UF resin, the peak value of the weight loss decreased in the decomposition stage of the pyrolysis residue, while the temperature shifted to the low-temperature region. This was mainly due to the structural stability of pyrolytic carbon produced by UF resin, which hindered the thermal decomposition of lignin-produced residues in pine. FTIR showed that CO2 was the main product of pyrolysis. For UF resin, nitrogen compounds accounted for a large proportion. With the addition of UF resin, the nitrogen in the blended pellets increased significantly. Since the synergistic effect promoted the further decomposition of the organic oxygen-containing structure, the NO release was still increased. PY-GC/MS showed that co-pyrolysis produced more nitrogen-containing compounds and promoted the decomposition of macromolecular phenol derivatives, lipids and ketones, resulting in more small-molecule acids and alcohols.

A Review on the Humic Substances in Pelletizing Binders: Preparation, Interaction Mechanism, and Process Characteristics

Humic acid is inexpensive, and has a wide range of sources and a strong adsorption force with the surface of iron ore, and the size of its adsorption force is affected by some factors such as humic acid concentration, pH of the solution, and metal cations. The modified humic acid pellet binder (MHA) with strong adhesion and high viscosity was obtained through the separation and purification of solid wastes such as lignite and weathered coal and chemical modification treatment and successfully applied in the production process of iron ore pellets. After industrial tests, MHA can significantly improve the strength of green and dry pellets, less residue after high-temperature roasting, less metallurgical pollution, high strength of fired pellets, and can partially or completely replace bentonite.

Economic and environmental feasibility of recycling flexible plastic packaging from single stream collection

As demand for plastic increases, there is an urgent need to ramp up its collection and recycling rate. This study reports results of a pilot study in the United States to recycle flexible plastic packaging (FPP) from single stream curbside collection focusing on both the economic feasibility and carbon footprint. To explore the marketability of recycled FPP, four downstream market pathways were studied, including roof coverboard, plastic pellets, pallets, and film. Results indicated that (1) the cleaning and pelletizing process at reclaimers contributed the most to the total greenhouse gas (GHG) emissions of recycled FPP products, and (2) the GHG emissions of recycled FPP products in all four pathways are lower than the comparator products. Therefore, using a higher percentage of recycled FPP substituted in a product can result in greater GHG emission reductions. All the recycled FPP products also showed favorable economics compared to their direct competitors.

Granulation of Mn-based perovskite adsorbent for cyclic Hg0 capture from coal combustion flue gas

Circulating adsorbents in a fluidized bed integrating elemental mercury (Hg0) adsorption and oxidized mercury decomposition/desorption processes could simultaneously achieve adsorbents recycling and mercury recovery during the flue gas mercury removal. The granulation of adsorbent powder is essential to reduce elutriation the looping system. Herein, powdery La0.8Ce0.2MnO3 perovskite adsorbent, which has been demonstrated to be highly efficient for Hg0 removal, was moulded into 0.8–1 mm pellets by an extrusion-spheronization method. Meanwhile, microcrystalline cellulose (MC) was used as pore-creating template to constructing porous pellets. The results show that the La0.8Ce0.2MnO3 pellets with 20 % MC added during the pelleting process (LCMO-MC) exhibited 90 % Hg0 removal efficiency under a gaseous hourly space velocity (GHSV) of 380,000 h−1, which was comparable to that over the corresponding powdery adsorbent. The LCMO-MC performed well in Hg0 removal at a wide temperature window from 50 to 200 °C. SO2 and H2O displayed slight interference in Hg0 removal, while O2 and NO enhanced Hg0 removal over LCMO-MC. During six adsorption-decomposition/desorption cycles, the LCMO-MC presented outstanding cyclic durability and about 97 % Hg0 removal efficiency was achieved with a GHSV of 50,000 h−1. The excellent Hg0 removal capacity of LCMO-MC was ascribed to the existence of abundant pore channels for Hg0 diffusion, which in-situ retained during the burning of pore-creating templates at high temperature and newly formed accompanying with the burning gas release. These results demonstrate that the template (i.e., MC) assisted extrusion-spheronization approach is promising to mould adsorbent pellets for Hg0 removal in a fluidized-bed system, which could simultaneously realize adsorbent recycling and mercury recovery.

The Nutrient Dynamics of Major and Minor Nutrients on Pelleted and Unpelleted Dry Fodders

Background: Farmers are facing the challenges to providing adequate availability of feed and fodders to livestock during dry period (lean period) which poses a major threat in livestock productivity. This study delineates, pelleting of feed and fodder helps to meet out the fodder requirement during lean period consequently improving the livestock productivity. Methods: The experiment was conducted at Forage Pelleting Unit, Department of Forage Crops in Agricultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu from March 2020 to June 2022 to identify the best suitable dry fodder crops for quality pellets production. The laboratory experiment was conducted and laid out in completely randomized block design with 11 treatments and three replications. The treatment consists of D1: Rice straw, D2: Maize stover, D3: Maize husk, D4: Sorghum straw, D5: Ragi straw, D6: Pearl millet stover, D7: Wheat straw, D8: Groundnut haulms, D9: Groundnut shells, D10: Sugarcane tops, D11: Blackgram husk were selected and produced into individual dry fodders pellets. Then, the selected dry fodders were harvested with the help of fodder harvester cum chaffer. The chaffed material was then dried using a solar drier at 70°C for one day to attaining the ideal moisture of 12%. Then, dried materials were grinded by fodder pulverizer and then grinding material was conveyed through conditioning with passing the steam at 60 to 70°C. Then, the conditioning material was passes through a pelletizer with 6 mm die diameter. Result: The observation on macro minerals (calcium, magnesium, potassium) and micro minerals (cobalt, zinc, manganese) were analyzed by using an Inductive Coupled Plasma Mass Emission Spectroscopy. The unpelleted and pelleted dry fodders showed a significant variation in the major and minor nutrients. In this regards, the calcium content recorded higher in groundnut haulms (D8) with 1.027 per cent and whereas ragi straw (D5) were recorded higher magnesium and potassium contents with 0.433 per cent and 2.178 per cent respectively. The minor nutrients like cobalt, manganese and zinc contents varied significantly due to pelleting process. From this study, rice straw (D1) recorded higher cobalt content with 0.378 per cent and whereas, ragi straw (D5) recorded higher zinc content (16.45 per cent) and while, manganese contents were registered higher in pearl millet straw (D6) with 54.88 per cent.

Shelf-Life Performance of Fish Feed Supplemented with Bioactive Extracts from Fermented Olive Mill and Winery By-Products.

Fortifying fish feeds with bioactive compounds, such as enzymes and antioxidants, has been an adopted strategy to improve feed nutritional quality and sustainability. However, feed additives can lose activity/effectiveness during pelleting and storage processes. This work aimed to monitor functional activity stability in feeds supplemented with a bioactive extract, including cellulases, xylanases, and antioxidants. This bioactive extract (FBE) was produced by Aspergillus ibericus under solid-state fermentation of olive mill and winery by-products. Two isoproteic and isolipidic diets were formulated and unsupplemented or supplemented with lyophilized FBE (0.26% w/w). Both diets were stored at room temperature (RT) or 4 °C for 4 months. Results showed that feed storage at 4 °C enhanced the stability of the enzymes and cellulase was more stable than xylanase. Compared to RT, storage at 4 °C increased cellulase and xylanase half-life by circa 60 and 14%. Dietary FBE supplementation increased antioxidant activity and storage at 4 °C reduced antioxidant activity loss, while in the unsupplemented diet, antioxidant activity decreased to the same level in both storage temperatures. Dietary supplementation with FBE reduced lipid peroxidation by 17 and 19.5% when stored at 4 °C or RT, respectively. The present study is a step toward improving the storage conditions of diets formulated with bioactive compounds.

Оптимизация процесса работы пресс-гранулятора соевой половы

To determine the optimal design parameters and modes of operation of the screw-type pelleting press, the authors studied the granulation of soybean chaff fractions pre-crushed to 5 mm with the addition of soybean grains as a binder. The pelleting process was stable at a temperature of the pelleting press barrel of 70…80°С and the temperature of pellets at the exit of 65 to 70°С. Humidity control was carried out in accordance with GOST 13496.3-92, the crumbling of pellets - in accordance with GOST 23513-79, GOST 22834-87. Fifteen experiments were carried out in three repetitions according to the matrix of the orthogonal central composition plan of the second order. The factors of the experiment included the matrix thickness, the moisture content of the raw material and the mass fraction of soybean grains in the raw material. The crumbling of the obtained pellets served as the optimization criterion. Based on the experiment results, an adequate regression equation was obtained. It was established that the smallest percentage of pellet crumbling is observed in the moisture content ranges of raw materials of 50 to 60% and the mass fraction of soybean grinding in raw materials of 15 to 16.5%. With a fi xed value of raw material moisture content, the optimal thickness of the pressing matrix corresponds to the range of 27.5 to 39.0 mm, while the mass fraction of soybean grain in the raw material is 15 to 25%. With a fi xed mass fraction of soybean grain, the optimal values of the pressing matrix thickness range between 30 and 40 mm, the values of the initial moisture content are 40 to 60%. To obtain pellets consisting of pre-crushed and moistened soybean chaff and soybean grains with the crumbling rate of less than 12%, the thickness of the matrix with holes with a diameter of 10 mm should be 30 to 40 mm, the mass fraction of soy in the raw material should correspond to 15 to 16.5%, and the moisture content of raw materials should equal 51 to 60%.

Time-of-flight measurements of MINERVE samples containing fission products and neutron absorbing isotopes

The zero-power reactor MINERVE (CEA Cadarache) was designed to perform reactivity worth measurements by the oscillation technique. The various experimental programs, undertaken for the last thirty years, involved cylindrical samples with a diameter of about 1 cm and a height ranging from a few cm to 10 cm. Most of the samples are composed of UO2 pellets mixed with a high neutron absorbing nuclide, i.e. fission product, actinide, in a double-sealed Zry-4 container. An experimental program started in 2015 in collaboration with the Joint Research Centre of Geel to study the MINERVE samples at the time-of-flight facility GELINA by the neutron transmission technique. The two main objectives consist of checking both the composition of the MINERVE samples provided by the manufacturer and the quality of the resonance parameters recommended in the evaluated neutron data library JEFF-3.3. The pioneer experiments on MINERVE samples containing 107Ag and 109Ag revealed a substantial Tungsten contamination that was not reported by the manufacturer. Such a Tungsten contamination is related to the manufacturing process of the sample pellets. The observed Tungsten contaminations lead to non-negligible increases of the C/E ratios up to a few percent. second experimental campaign on MINERVE samples containing 99Tc provided useful insight on the quality of the 99Tc resonance parameters measured at the GELINA facility at the end of the 90s. The ongoing program continuing through 2022 will deliver data for samarium (natural, 147, 149, 152), neodymium (natural,143,145), gadolinium (natural, 155), europium (151, 153), rhodium (103), cesium (133), hafnium (180), dysprosium (160, 161, 162, 163, 164) and erbium (168, 170). The present work focuses on the data analysis technique developed for long cylindrical samples with a diameter smaller than the neutron beam, and on the grain size distribution model implemented in the resonance shape analysis REFIT.

Production of powder targets for neutron-induced cross section measurements

Nuclear powder targets for neutron-induced cross section measurements were prepared by pressing. The choice of the production technique was related to the type of nuclear experiment and the quality of the powder. This paper describes the production process of unsintered compacts of 94Mo, 95Mo, 96Mo metal powders and 239PuO2 powder with a thickness as low as possible by uniaxial pressing of powders. Special attention goes to the difficulties encountered during the preparation process of 239PuO2 pellets. Investigation on the presence of impurities and so the quality of the PuO2 material was performed by scanning electron microscopy with energy dispersive X-ray spectroscopy, by inductively coupled plasma mass spectrometry, X-ray diffraction and by thermal analysis.

Manufacture of Geopolymer Artificial Aggregates by Pelletization and Crushing Processes

Aggregates are an important ingredient of concrete. They are of two types: coarse aggregates and fine aggregates. The supply of natural aggregates on Earth is declining with technological advancement, hence, alternatives to natural aggregates are needed. Artificial aggregates have been manufactured using a coal burning waste, i.e. fly ash. On mixing fly ash with an alkaline activator, the mixture reacts and hardens. Aggregates are manufactured either by mixing materials using a granulator pan or by crushing materials using a stone crusher. The optimal manufacturing method was determined by comparing physical properties, such as bulk specific gravity, water absorption, and aggregate hardness, of the aggregates manufactured using these two methods with those of natural coarse aggregates. The average bulk specific gravity was 1.776 and 1.857 for the aggregates produced by the pelletization and crushing processes, respectively, and 2.957 for the natural aggregates. The average water absorption values were 11.62% and 8.37% for the aggregates produced by the pelletization and crushing processes, respectively, and 4.17% for the natural aggregates. The average aggregate hardness values, determined using the Los Angeles abrasion test, were 27.33% and 25.98% for aggregates produced by the pelletization and crushing processes, respectively, and 24.05% for the natural aggregates.

Synthesis of Na3SbS4 solid electrolyte from aqueous solution and its application in solid state rechargeable batteries

The tetragonal Na3SbS4 solid electrolyte was synthesized from aqueous solution in this study. The XRD results showed that the peak separation at 2θ = 30.1 and 35.1 º might from a defect in the crystal structure of t-Na3SbS4. The results of Rietveld analysis showed that the crystal structure of the Na3SbS4 sample after heat treatment belongs to the space group P-421c with the reliability coefficients Rwp=14.959%, Rp=11.690%. The lattice parameters are a = b = 7.1554(13) Å and c = 7.2829(13) Å. The pressure dependence in the pelletizing process of the ionic conductivity of the solid electrolyte t-Na3SbS4 was investigated and the pellets made at a pressure of 550 MPa had the highest ionic conductivity among the prepared samples, reaching a value of 6.0x10-4 Scm-1 at 25 ºC. The activation energies for the transport of Na⁺ ions in the prepared samples were 23, 24, 26 and 24 kJ mol-1 for pellets formed at pressures of 330, 403, 477 and 550 Mpa, respectively. These results demonstrate that the ion conduction mechanism is independent of the pellet forming pressure but the ionic conductivity at 25 ºC is directly proportional to those values. In addition, the electrochemical stability of Na3SbS4 was also evaluated through the discharge-charge characteristics of the battery cell TiS2−Na3SbS4|Na3SbS4| Na15Sn4. In the first discharge - charge cycle, the Coulomb efficiency was about 92.7% and higher than 99% from the second cycle onwards.

Effect of Anoxic Atmosphere on the Physicochemical and Pelletization Properties of Pinus massoniana Sawdust during Storage.

The 34-day anoxic storage of Pinus massoniana sawdust (PS) in a sealed constant temperature and humidity chambers was carried out to simulate the limited-oxygen storage process inside piles at industrial scale. The effects of anoxic storage on feedstock's properties and pelletization process were investigated with respect to elemental composition, dry matter loss, thermogravimetric characteristics, energy consumption, pellets' density, and microbial communities, etc. After anoxic storage, the microbial community of PS samples was altered, such as the fungi content (Clonostachys, Strelitziana, and Orbilia, etc.), resulting the elemental composition of PS was altered. Thus, the cellulose and ash content of the stored PS were increased, while the hemicellulose, volatile, and fixed carbon were decreased. The energy consumption was increased 7.85-21.98% with the increase in anoxic storage temperature and with the additive of fresh soil collected from PS field in storage process. The single pellet density was altered slightly. Meanwhile, the moisture uptake of PS pellets was decreased. After anoxic storage, the combustion behavior of the stored PS became more stable. The results can be applied directly to guide the development of commercial PS storage and pelletization process currently under development in Asia, Europe and North America.

Thermogravimetric Evaluation for the Pyrolysis Process of Pellets Produced from Quinoa and Amaranth Harvest Residues

In this study, the combustion properties of pellets produced from quinoa (C3 plant) and amaranth (C4 plant) harvest residues were evaluated by Thermogravimetric Analysis (TGA) and Differential Thermogravimetry (DTG) methods. Pelletizing was carried out at 25% moisture content and at a material temperature of 70 °C. 7.5% molasses was used as the adhesive. The pellets were heated from 25 °C to 1000 °C in a thermal analyzer at a tracking rate of 10 °C min-1 and in N2 gas environment. The mass loss and mass loss rate occurring in this temperature range were recorded simultaneously and expressed in thermograms. Combustion stages are observed as a peak in the DTG curve and these peaks represent the mass losses in the combustion stages. According to the analysis results, the highest mass loss rate in the evaporation zone of water in the quinoa plant was 2.12% at 96.65 °C, and in the amaranth plant at 2.34% at 101.7 °C. However, in the next step, the mass loss rate decreased in both pellets. At this stage of the analysis, the water in the pellets completely evaporated and the mass loss was 12.43% in quinoa and 13.38% in amaranth, according to the initial mass. With the increase of volatile matter output, the mass loss rate increased again, and the highest mass loss rates were realized as 6.42% and 4.96%, respectively, at 320 °C for quinoa and 315 °C for amaranth. The rate-determining stage in the combustion kinetics of coal and biomass is the semi-coke combustion stage. At this stage, the lowest mass loss (0.89%) occurred in both pellet samples. TGA and DTG results showed that there were no significant differences between the combustion stages of quinoa and amaranth pellets, and their combustion behaviors were generally close to each other.

Optimizing a Biowaste Treatment Design for Energy and Environmental Efficiency of an Integrated Farming System in Tien Giang Province

Agricultural wastes can be converted into biofuels. To meet the requirements of biofuels, the conditions of their manufacturing process for these products must be considered. The purpose of this research is to optimize experimental designs for converting biomass into energy products like pyrolysis and pelleting process. The products were optimized in terms of their energy performance while lowering CO2 emissions. In Tien Giang province, we experimented with pyrolysis and pelleting biowastes derived from an integrated farming system in acid sulfate soil. The experimental factors influencing the energy content of products were determined using statistical analysis and optimization methods, and the potential CO2 emissions from the products were calculated. The optimization results revealed that the ideal pyrolysis parameters were 120 minutes of combustion time at 400oC and 30% moisture content of orchard pruning residues. The best pellets were obtained by combining biogas sludge and biochar from mango pruning residues. These products will store approximately 900 kilograms of CO2 emissions a year. The optimized processes would benefit the environment and bring profits to the system.

Preparation and in vitro evaluation of hot-melt extruded pectin-based pellets containing ketoprofen for colon targeting

This work developed high drug-load pellets for colon targeting in minimal steps by coupling hot-melt extrusion (HME) with a die-surface cutting pelletizer, offering a potential continuous pellet manufacturing process. Ketoprofen (KTP) was selected as a model drug for this study due to its thermal stability and severe upper gastrointestinal side effects. Low and high methoxyl grade pectins were the enzyme-triggered release matrix, and hydroxypropyl methylcellulose (HME 4 M/HME 100LV) was used as a premature release-retarding agent. The powder X-ray diffraction technique and the differential scanning calorimetry results revealed that KTP exists in the solid-solution state within the polymeric matrix after the HME step. The scanning electron micrographs of the fabricated pellets showed a smooth surface without any cracks. The lead formulation showed the lowest premature drug release (∼13%) with an extended KTP release profile over a 24 h period in the presence and absence of the release-triggering enzyme. The lead formulation was stable for 3 months at accelerated stability conditions (40 °C/75 ± 5% RH) concerning drug content, in vitro release, and thermal characteristics. In summary, coupling HME and pelletization processes could be a promising technology for developing colon-targeted drug delivery systems.

The use of sludge-peat composition for the processing of alumina production waste

This paper covers the problem of alumina production waste recycling with the use of peat-based compounds as a carbon-containing reducing agent. The purpose of this study is to find a suitable technical solution to use red mud for the direct reduction of iron, as well as to develop and test a red mud-containing composite material to be used as a charge. The paper presents a method for carbothermic reduction of iron from a charge containing red mud. Certain test charge compounds and respective applicable heat treatment conditions were selected. In order to establish the iron oxide reduction mechanism and dynamics, the materials obtained were then tested and analyzed using X-ray diffraction, phase and chemical analysis methods. A spectral analysis of individual powder phases has demonstrated an iron content of up to 93 wt%, which indicates a high potential for subsequent direct metallurgical processing of the red mud-peat pellets. Since carbothermic reduction of iron generates magnetic materials even at low temperatures, this method may be regarded as one of the stages in magnetic separation of iron-containing raw materials. This paper successfully establishes and confirms the actual direct low-temperature carbothermic reduction of iron from a charge based on red mud and peat. According to the results of respective experimental studies, it has been preliminarily concluded that it is both technologically feasible and expedient to use red mud as a component in a respective red mud-peat charge for application as a raw material in the iron and steel industry.

Assessment of the Physical and Energetic Properties of Fuel Pellets Made from Sage Waste Biomass with the Addition of Rye Bran.

The aim of the present study was to evaluate the effect of rye bran addition on the pelleting process of sage waste biomass, and the quality and energetic properties of fuel pellets. The pelleting process was conducted on an SS-4 test stand equipped with a P-300 pelletizer with flat die roller compactors. The addition of 20% rye bran reduced the pelletizer's power/energy consumption from 3.75 kW/107 kWh t-1 (0% rye bran content) to 3.19 kW/91 kWh t-1, decreased physical and bulk density, and increased the pellet durability index (PDI). The higher heating value-HHV (19.39 MJ kg-1 at 10% humidity) and the lower heating value-LHV (18.17 MJ kg-1) of sage waste biomass indicate that this plant material is highly suitable for heat generation. The addition of 20% rye bran decreased HHV by 2.07% and LHV by 2.67%.

Application of Post-Flotation Dairy Sludge in the Production of Wood Pellets: Pelletization and Combustion Analysis

The amount and variety of waste increases every year. One of the places where biodegradable waste is generated is the agri-food industry, where it is possible to utilize it for the purpose of energy production. The aim of this research was to determine the possibility of using post-floatation dairy sludge as a raw material for co-pelletization with sawdust. The scope of this work included physical and chemical characterizations of the feedstock, the co-pelletization process, and the combustion of the produced pellets, combined with an exhaust analysis. The obtained values of the pellets’ density at each level of sludge addition allowed us to conclude that the obtained pellets had a good market quality and constituted a full-fledged, innovative solid fuel, in accordance with the guidelines of the latest, currently applicable ISO 17225 standard. Furthermore, adding ca. 20%wt of sludge to sawdust resulted in a 30% decrease in the pelletization power demand, and still, the combustion characteristics of the pellets met the European Ecodesign emission limitations in terms of the CO and NOx content in the exhaust. The addition of post-flotation dairy sludge to sawdust has a beneficial influence on the production of fuel pellets by decreasing the energy consumption of the pelletization process and improving the pellets’ kinetic durability. Due to legal requirements and the pursuit of the circular economy principle, one should expect an increased interest in the use of agri-food waste for the production of biofuels.

Study on the Roasting Process of Guisha Limonite Pellets.

In this paper, a pelletizing method has been researched to enhance the subsequent iron-making process applying Guisha limonite, with advantages including large reserves and low price. The purpose is to provide an alternative for the sinter, thus reducing the greenhouse gas emission during the iron-making process. The response surface method is used to optimize the experimental design of the pelleting process. A multivariate regression model for estimating the compressive strength of pellets was developed using Box-Behnken experimental methodology, where the relevant factors were the roasting temperature, pellet diameter, and bentonite content. The maximum influencing factors of each experimental design response are determined using analysis of variance (ANOVA). Under optimum conditions, the compressive strength of pure limonite pellets is 2705 N, similar to the response goal value of 2570.3 N, with a relative error of 5.20%. Since the high-grade iron ore resources are depleted, the comprehensive utilization of ore resources is becoming increasingly important. The aim of this paper was to provide a valuable technical foundation for lignite pellet-roasting processes in the iron and steel industries, since steel companies is increasing its imports of Guisha limonite.