Research for Industrial Application of Bentonite-Polymer Material in Ferrous Metallurgy

Abstract

Ferrous metallurgy, in particular the process of pelletizing iron ore concentrates, is one of the main consumers of bentonite clays. The problem with the bentonite binder is well known, and is the increase in silica content (the main harmful impurity) in the roasted pellets as a result of its use. This predetermines long-term interest in the development of new binders that have lower consumption, or do not contain silicon dioxide at all. Increasing the quality characteristics of the binder makes it possible to reduce its consumption, thereby optimizing the chemical composition of the roasted pellets. The results of experimental studies on the palletization of magnetite concentrate from several iron ore plants, different enrichment depths (Fe content = 65–71%), and basicity (CaO)/(SiO₂) = 0.3–1.0 are presented. It has been shown that using the effect of mixing bentonite and a polymer additive on the binding properties of their compound makes it possible to increase the strength characteristics of pellets relative to those in current production (without polymer) and more significantly than when excluding bentonite in the case of its complete replacement with an organic binder. Much attention is paid to studying the influence of the use BPC (Bentonite Polymer Composition) on the metallurgical properties of finished pellets.

1. Introduction

The purpose of agglomeration of iron ore concentrates (pelletizing, agglomeration, and briquetting) is to create a product of the same size and shape, intensifying the recovery process. Most iron ore raw materials are processed into cast iron using a blast furnace, which requires raw materials with high reduceability and strength to increase the economic efficiency of operation. Achieving these conditions is ensured by loading the pellets inside the blast furnace without compromising the permeability of the material layer with an upward flow of reducing gas (corresponding porosity) and appropriate porosity of the pellets for the complete access of the reducing gas to the entire volume of the pellet.

A minority of pellets are created for the direct reduction process, which requires easily reducible feedstock with minimal silica content. The strength of such pellets is also important for their transportation and handling and is included in the list of requirements for the production of strong pellets. The strength of roasted pellets affects the amount of material lost due to destruction. In addition, the material is lost in the form of dust due to the abrasion of the pellets (Figure 1).

Figure 1.

Parameters depend on the binder used in the production of iron ore pellets.

The use of bentonite provides guaranteed strength characteristics of pellets that meet the requirements of transportation, blast furnace process, or metallization [1]. The significant advantage of bentonite is confirmed by the extensive accumulated experience of its use, as well as an extensive array of literary sources and reference data. At pelletizing plants in the Russian Federation, the dosage of bentonite is 0.5–0.8% by weight [2]. Bentonite is a traditional binder for the production of iron ore pellets and consists of fine clays, represented by at least 70% minerals of the smectite group (mainly montmorillonite), which belongs to the subclass of layered silicates and consists, %: 48–56 SiO₂; 11–22 Al₂O₃; 0–5 or more Fe₂O₃; 4–9 MgO; 0.8–3.5 or more CaO; 12–24 H₂O [3]. Among the properties of montmorillonite that determine the industrial value of bentonite: submicron crystal size, layered structure, large surface area (up to 800 M²/g), significant negative charge of the layer (≈120 mEq/100 g), and associated balancing exchangeable cations located on the surface [4]. These structural features of montmorillonite determine its specific properties, such as binding and sorption capacity and heat resistance.

In terms of volume of consumption, the most important areas of use of bentonite clay in the world are metallurgy, foundry, and drilling. Also, bentonite clays and materials based on them are used in other industries, including waterproofing materials, agriculture, rubber, polymer, paper industries, pharmacology, etc. [5, 6].

The main disadvantage of bentonite is the addition of silica to the pellets [7, 8]. In addition to optimizing the chemical contents (increasing the Fe_total% content in the finished pellets), reducing the silica content leads to a decrease in the amount of flux that must be added to achieve certain levels of pellet basicity, which ultimately leads to a decrease in slag volumes in blast furnaces and other units in the production of cast iron. The situation is aggravated, including for calcium bentonites, which are more accessible but less effective and require a higher dosage to achieve equivalent pellet strength [9]. Bentonite clays are divided according to the nature of the exchangeable cations in the interlayer complex of montmorillonite into alkaline (sodium) and alkaline earth (calcium and magnesium) types. Alkaline bentonites have higher technological properties compared to alkaline earth ones due to the fact that alkali metal ions, primarily sodium, have a higher hydration potential [10]. Considering that the swelling of Na-montmorillonites is significantly higher than that of Ca-montmorillonites, to improve the quality indicators, Ca-montmorillonites are converted into sodium form by activation with soda ash [11].

Despite the extensive volume of literature [12, 13, 14], the analytical study of the question of how the mechanism of operation of the pelletizing binder is implemented seems insufficient. This is especially true for composite binders consisting of two or more different materials. Research into minimizing binder consumption is clearly necessary to insure a better product and lower operating costs. A rational approach to the choice of binder to obtain strong pellets is also necessary. Even in the worst case, in which the test binder does not have any effect on the heat-strengthening process, having a thorough understanding of the process will allow you to avoid research on initially unpromising binders [15].

A material that is not dispersed throughout the pellet will not be effective as a binder. There are many examples of materials that have been tested as binders but have been ineffective in improving dry pellet strength, which is especially true for non-swelling clays (e.g., attapulgite and kaolinite). For the same reason, insoluble organic substances (e.g., oils) are, in most cases, unpromising as a binder. A material that cannot form bonds with the concentrate particles is also clearly unsuitable for use as a binder. Most industrially used binder bonds through hydroxyl of carboxyl groups, sometimes based on an inorganic base such as Si▬OH in bentonites or metasilicates.

It is generally accepted that the successful replacement of bentonite with another inorganic, organic, or composite material will ultimately solve the binder problem [16]. At the same time, it is necessary to distinguish between the binding and strengthening properties of the material used. The uniqueness of bentonite for the production of pellets is largely due to the combination of its binding properties at the stage of raw palletization and its strengthening properties at the sintering stage. Studies conducted with various mono-materials have shown that, most often, materials with excellent binding ability (organic) do not participate in thermal strengthening in any way. And vice versa—inorganic materials (e.g., colemanite, which, due to its property of reducing the sintering temperature, has found popularity among researchers [17]) practically do not contribute to the clumping of raw pellets but significantly intensify the sintering process. This reasoning in itself suggests that the most rational approach to solving the binder problem can be the study of combinations of binders and strengthening materials and, in the best case, achieving a synergistic effect from the interaction of the inorganic and organic parts of the composite material.

The typical mechanism of action of an organic binder is similar to that of bentonite clay, which is water-dispersible and forms bridges between concentrated particles. Inorganic binders exhibit a variety of mechanisms of interaction with concentrated particles and with each other. In addition to regulating the strength of the pellets (crushing strength), the choice of binder affects their dust formation (abrasion strength).

During the roasting of pellets, pyrolytic volatilization of organic binders occurs, while inorganic binders remain dispersed in the pellet volume and affect the sintering stage. Sintering is the main method of strengthening pellets for the blast furnace process [18]. The energy costs for roasting are the highest at a mining and processing plant, and in this respect, they exceed the grinding process. The approximate energy intensity of roasting magnetite pellets is 320–475 MJ/t [19], subject to the use of the best available technologies in the field of process energy efficiency, heat recovery [20], and intensification of thermal strengthening using various additives.

The traditional scheme for producing iron ore pellets by pelletizing the concentrate and further roasting the pellets has fundamental disadvantages. The desire to increase the unit power of units with the principle of palletization of charge materials underlying the production of cast iron has led to the bulkiness and energy inefficiency of the multi-link technological scheme. The idea of pelletizing a charge conflicts with the principle of global energy saving (entropy) since the huge reaction surface of ore materials crushed at the enrichment stage is subsequently reduced by at least a thousand times (Figure 2), at the cost of large material and energy costs of sintering and coke production. Heating and melting of agglomerated materials requires a long residence time and, consequently, a large volume of aggregates. In this case, the processes occur close to the state of thermodynamic equilibrium [21].

Figure 2.

The path of iron from the bowels of the earth to the blast furnace.

Large resources are invested in the search and development of a method for the cost-effective production of pellets strengthened without the use of high-temperature firing because, in theory, pellets produced using non-roasting technology will have a lower production cost and a higher final price, given their suitability for carbon-neutral steelmaking technologies. Of the binder options known today, the following are used: Portland cement, glue, sodium metasilicate, and organic compounds. Among the chemical-catalytic methods of hardening are known: carbonization of lime at 100–105°C, hardening of magnesium chloride, and hydrothermal treatment under pressure. Since bentonite is the carrier of the strength of dry pellets in current production, it can be assumed that in non-roasting technology, bentonite will be represented by a larger or smaller part of the strengthening mixture.

The paper presents the results of experimental studies of the pelletizing process using bentopolymer compositions (BPCs). Since the strength of fired pellets necessary and sufficient for the blast furnace process is successfully achieved in most industries, the key task of the research was, in addition to finding ways to reduce bentonite consumption, to improve the metallurgical properties of the pellets. It is taken into account that the strength of roasted pellets characterizes the completeness of the oxidation process—solid-phase sintering. In cases where the strength of pellets from the use of BPC at the same consumption decreased significantly, no further studies of such a binder were carried out. The nature of the relationship between metallurgical properties (provided mainly by total porosity, pore morphology, and, accordingly, reducibility) and the strength of pellets is still of interest, since practically obtained data often differ from theoretical assumptions. This is largely due to the fact that the size of recrystallized hematite grains and the temperature limits for the formation of the ore binder at the stage of solid-phase hardening are not the same for iron ore concentrates from different deposits.

2. Research methods and objects

This paper presents the summary results of several studies conducted in 2021–2023 on charge material from various iron ore enterprises in the Russian Federation and Kazakhstan.

The main component of bentopolymer composition was alkali-activated bentonite clay from the 10th Khutor deposit (Republic of Khakassia) [22], a key supplier of bentonite for the production of iron ore pellets in the Russian Federation. For the use of bentonite clay in the production of pellets at iron ore mining and processing plants, there are a number of regulated indicators that characterize the quality of the clay. For example, regulated indicators may include, in addition to the swelling index and effective viscosity, the content of montmorillonite (Table 1). The rheological properties and swelling of bentonite raw materials, in addition to the mineral composition, are influenced by the crystal-chemical (octahedral lamellar composition, type of counterion, and layer charge) and morphological (size and shape) parameters of montmorillonite.

The name of indicators	Measure	Value, no less	“10th Khutor” 5th layer center
Effective viscosity	mPa s	28	41.44
Swelling index	ml/2 g	30	33
Content montmorillonite	%	53	62.4

Table 1.

Regulated quality indicators of bentonite clay for iron ore pelletizing.

The content of montmorillonite was determined using the method of determining the cation exchange capacity by adsorption of the methylene blue dye (MB), described both in Russian standards [23] and in foreign literature [24].

The content of montmorillonite directly correlates with the degree of swelling and effective viscosity. Analysis of clay mineral content is a non-trivial task and requires specialized equipment and the work of experienced analysts. The micron and submicron sizes of aggregates of clay particles, the complex structure of crystallites, the presence of mixed-layer formations, and numerous impurities make clay diagnostics difficult. The main methods for determining the content of montmorillonite are related to the calculation of the adsorption value of organic dyes [25].

For use as the polymer part of the composite binder, a variety of substances were tested and selected from the following considerations: priority was given to organic compounds that demonstrate the effect of increasing rheological properties and regulating filtration when interacting with bentonite. We are talking about polymers that are successfully used to improve bentonite drilling fluids. Among them are polyacrylamides, carboxymethylcellulose, and xanthan gum.

Possible schemes for producing composite binders involve dry mixing of the polymer and bentonite parts in one or a combination of several different ways, ranging from joint extrusion under pressure and joint grinding, to simple mixing. Considering the opinion that mechanical activation of charge components during the production of pellets in terms of resource-saving is unacceptable [26], pilot batches of composite binders were obtained by mixing. Mixing is an important production stage in preparing the charge for palletization. Many works are devoted to improving the strength of pellets by increasing the efficiency of charge mixers [27].

The dosage of the polymer part in the BPC for each of the experiments did not exceed 0.5% of the bentonite mass. In each BPC, the polymer part is a single organic substance and not a mixture of them. This approach somewhat simplifies the description of the processes occurring during the interaction of BPC particles with water of iron ore concentrate and the surface of its particles and makes it possible to identify direct dependencies and the most promising polymer substances.

The green pellet technique used in all experimental laboratory studies is included in detail in [28] and is methodologically consistent with the method proposed by Eisel and Kawatra [29] and is still used at Michigan Technological University [30].

Before roasting, green pellets with a particle size of −12.5 + 10 mm were placed in trays and dried in an oven at a temperature of 105°C. Then, the dried pellets (sample weighing mp = 300 g) were placed in a basket made of nichrome wire. The pellets were fired in a laboratory high-temperature furnace VSP-220-1350 designed by NPVP “TOREX”.

The furnace is a vertical cylinder, the interior of which is lined with refractory and heat-insulating material. The heating elements are silicon carbide rods (15 pcs.), installed vertically around the circumference of the furnace. An alundum glass is inserted into the furnace to protect the split heaters from destruction and average the temperature field in the working space. An oxidizing atmosphere is provided in the furnace (it is possible to supply both an inert gas to maintain a neutral atmosphere and oxygen or air through an opening in the bottom cover). A compressor is provided to pump air. The maximum temperature achieved in the furnace is 1300°C.

The hardware design of the furnace makes it possible to successfully carry out laboratory roasting under conditions of the process of thermal strengthening of pellets in existing roasting machines.

3. Research results and discussion

The following results from two experimental studies share the following characteristics:

• The produced pellets are non-fluxed.

• The polymer part of the bentopolymer composition is represented by high-viscosity polyanionic cellulose (PAC HV), a universal drilling additive with a high degree of polymerization and high molecular weight, which serves as a viscosity regulator to control fluid loss and inhibit clays in drilling fluids.

Results of experimental studies of the influence of BPC on the strength of roasted non-fluxed pellets of Stoilensky GOK:

During experimental studies of the effectiveness of the process of laboratory heat-strengthening roasting of iron ore pellets of the Stoilensky GOK using a bentopolymer composition, two samples of roasted pellets were obtained, produced in a laboratory with a bentonite binder of current production and with a bentopolymer composition (BPC) [28].

First of all, the strength characteristics of the resulting pellets were assessed, namely, the compressive strength of the roasted pellets, which was 392 and 350 kg/pellet for basic and bentopolymer pellets (with a 30% reduction in consumption), respectively. In the process of thermal strengthening of pellets, their necessary metallurgical characteristics are achieved both due to solid-phase sintering or ore phases and due to the formation of a melt during roasting at maximum temperature, which solidifies during cooling in the form of iron silicate glass and forms the structure of pellets of the required strength in the initial state and during the reduction process in blast furnace smelting. Moreover, if in the production of fluxed pellets, obtaining such an amount of melt (2–6%) does not cause difficulties, then in the case of non-fluxed pellets, obtaining such an amount of melt can be problematic [31].

The results of the study showed that a reduction in the consumption of the binder (represented by low-melting silicates) by 30% had a critical impact on the strength of the roasted pellets.

Thus, it has been established that the optimal dosage of BPC, which ensures an improvement in all qualitative and technological indicators of raw pelletization, does not provide an increase in the efficiency of heat-strengthening roasting for non-fluxed pellets from regrinded concentrate. However, the use of BPC had a positive effect on the chemical composition of the finished pellets, the mass fraction of Fe_total increased by 0.2%, and in turn, SiO₂ decreased by 0.19% (Table 2).

Name of binder	Mass component, %
	Fetotal	FeO	SiO2	CaO
Basic bentonite binder	65.9	0.29	4.94	0.22
BPC-1	66.1	0.22	4.75	0.20

Table 2.

Chemical composition of pellets produced with different binders.

Reducing bentonite consumption seems necessary to optimize the chemical composition of finished pellets, which is especially important for high-quality pellets produced from re-enriched concentrates.

The results of chemical analysis showed that a significant reduction in bentonite consumption (by 30%) led to a decrease in silicon dioxide content by 0.2%, while the permissible error of chemical analysis (GOST 23581.15), depending on the technique, can range from 0.1 to 0.2%, i.e., the silica reduction values are within the acceptable error range. This suggests that a reduction in bentonite dosage by 1–2 kg/t can be practically undetected in the results of chemical analysis. Taking this into account, reducing the consumption of bentonite in the pelletizing process without losing the quality characteristics of the pellets remains an important task both from the point of view of reducing the cost of finished pellets by reducing the volume of purchased binder and from the point of view of the rational development of scarce and exhaustible high-quality bentonite.

Results of experimental studies of roasting non-fluxed pellets from high-quality iron ore concentrate from Sokolovsko-Sarbaiskiy mining and processing production association (GPO) in a laboratory furnace:

In this study, the qualitative characteristics of pellets produced using BPC were compared with the characteristics of pellets produced not with the binder additive used at the Sokolovsko-Sarbaiskiy mining and processing production association (SSGPO) pelletizing plant (variegated clay contained in overburdened rocks) but with the best and most promising bentonite clay of the commonwealth of independent states (CIS) known today—Taganskoe field, Kazakhstan. The unique rheological properties of bentonite clays from this deposit are due to the high content of the main mineral. According to X-ray diffraction and thermal analyses, the content of montmorillonite in the bentonite horizons of this deposit reaches 90–98% [32].

Thus, the effect of using BPC in the process of pelletizing and roasting was compared with the effect of using a bentonite binder, which was close to the reference one in its rheological parameters.

For both the bentopolymer composition and the bentonite binder, based on the results of green pelletization tests, the optimal consumption was determined to be 0.4% for each binder (Table 3). A further increase in binder consumption is impractical since, at the established consumption, the strength properties of the green and dried pellets met the technical requirements.

Binder	Compressive strength of green pellets, kg/pellet	Compressive strength of dry pellets, kg/pellet	Drop strength, n times; H = 500 mm
BPC consumption 0.4%	1.29	5.71	2.5
Bentonite (Taganskoe) consumption 0.4%	1.27	6.31	2.6

Table 3.

Strength of green and dry pellets.

Thanks to the use of high-quality binders, iron ore pellets with high compressive strength and low abrasion resistance (B-0.5) were obtained (Table 4).

Binder	Binder consumption, %	Strength characteristics of roasted pellets			Porosity, %	Chemical composition on roasted pellets, %
		On hit (B + 5), %	Abrasion resistance (B-0.5) %	Compression, kg/pellet
						Fetotal	FeO	SiO2	CaO	MgO	Al2O3	S	Other
Bentonite	0.4	98.0	21.7	314.0	21.7	66.44	0.66	2.7	0.51	0.71	0.99	0.0018	0.19
BPC	0.4	98.1	22.8	318.0	22.8	66.34	0.94	2.68	0.52	0.70	0.99	0.0022	0.2

Table 4.

Characteristics of finished pellets.

When using BPC, the porosity of the pellets increased by 1.1%, which led to an increase in the recoverability index according to ISO 4695 dR/dT, %/min, amounting to 0.70 for pellets produced with BPC and 0.66 for pellets produced with bentonite Taganskoye deposits. High rheological properties of binders make it possible to obtain high-quality green, dry, and roasted pellets. Thanks to the use of a bentopolymer composition, it is possible to optimize the chemical composition of the pellets with optimal binder consumption. The results of this study demonstrated that when using a bentopolymer composition and high-quality bentonite while reducing binder consumption, it is possible to obtain comparable quality characteristics of pellets. Thus, replacing a bentonite binder with a higher quality one or one with a bentopolymer composition should be considered as an equal option for implementing the idea of reducing binder consumption.

Results of pilot tests on the use of three different BPC compositions during pelletizing and roasting of DR pellets from re-enriched concentrate.

The level of negative impact is an important resource aspect of the functioning of metallurgy. Emissions from metallurgical production constitute a significant share of gross national emissions from stationary sources and manufacturing in the Russian Federation.

Parameters such as the quality of iron ore raw materials, the level of environmental pollution by emissions of carbon-containing gases, and the energy efficiency of the pyrometallurgical process are interrelated. Improving the quality of the agglomerated product (primarily its strength) ensures a reduction in the recirculation load during processing. It is accompanied by a reduction in energy costs for production and a decrease in dust emissions [26].

According to some estimates [33], the market demand for steel produced using an alternative reducing agent (carbon-free method) in DR pellets by 2030 will be 15 times higher than the current production volume (2.25 million tons versus 147 thousand tons in 2019). For example, there is evidence in the literature that the use of hydrogen gas as a reducing agent for the direct reduction of iron ore materials will make it possible to obtain a carbon-free iron product with the prospect of reducing emissions of harmful gases, regardless of the type of reduction or smelting reactor used [34]. In addition to minimizing the negative impact on the environment, including risks associated with the global greenhouse effect problem, the interest of metallurgists in the processes of direct reduction of iron is caused by the limited and rapid depletion of coking coal reserves [35].

This study was conducted on high-quality concentrate intended for the production of DR pellets. Compared to ordinary pellets, DR pellets have a higher iron content and a low level of harmful impurities – silicon and sulfur. The idea of using BPC when working with super-concentrates is especially relevant because it is primarily aimed at reducing bentonite consumption. Since the purpose of iron ore processing is to remove silicate minerals, adding silicate as a binder is counterproductive.

The formulation of the studied binders differed both in the type of polymer additive used and slightly in the dosage of soda ash Na₂CO₃ into the original clay until a sufficient level of rheological properties of activated bentonite was achieved (Table 5.). The dosage of the polymer additive is the same in each of the three binders. The basis of each of the studied binders is bentonite clay from the central part of the fifth layer of the 10th Khutor deposit (Republic of Khakassia).

Name of binder	Swelling index, ml/2 g	Effective viscosity, mPa s	Swelling, times	Polymer additive type
Bentonite binder	30.7	40	15.2	None
BPC-4	30.04	73.5	14.4	Xanthan gum
BPC-6	34.4	99.0	14.9	High-viscosity polyanionic cellulose А
BPC-7	31.6	74.0	14.2	High-viscosity polyanionic cellulose В

Table 5.

Qualitative and rheological parameters of the studied binders.

For experimental samples of pellets, the metallurgical properties of direct reduction furnaces were determined (ISO 11257 and ISO 11258).

As can be seen from Table 6, with the use of BPC-7, it was possible to achieve an increase in all parameters recorded according to ISO 11257 and ISO 11258. It is interesting to compare the two extreme compositions because the polymer additive in BPC-6 and BPC-6 is represented by highly viscous polyanionic cellulose but from different manufacturers.

Binder used	ISO 11257	ISO 11258
	Determination of reduction-grinding index at low temperature and metallization index	Determination of the reducibility index, final degree of reduction and degree of metallization, %
Defined parameter	RDIDR (<3.15мм)	М	dR/dt(40)	MR	R(90)
With base bentonite binder	1.03	92.55	1.25	83.1	8.2
With BPC-4	0.84	92.86	1.15	80.8	86.6
With BPC-6	1.76	91.43	1.39	88.7	92.1
With BPC-7	0.71	93.2	1.24	84.4	89.1

Table 6.

Results of the analysis of metallurgical characteristics of pellets for direct reduction.

Of the negative consequences of using BPC-6:

• The reduction-grinding index at low temperature increases significantly from 1.03 to 1.76.

• The metallization rate also decreased from 92.55 to 91.43%.

At the same time, the reducibility index, the final degree of reduction, and the degree of metallization significantly increased relative to the basic values. However, during reduction, the strength of iron ore pellets decreases significantly. A sharp softening on the pellets during reduction can lead to their destruction in the furnace. The main factor influencing the behavior of pellets during reduction is the structure, which determines the rate of reduction of the pellets. The higher the specific surface area and the average pore size, the more likely the reduction process is to occur throughout the entire volume of the pellet, and the higher the reduction rate, the lower the strength and the higher the destructibility of the pellets.

Thus, it has been established that by using BPC as part of the charge for pelletizing, it is possible to influence the metallurgical properties of pellets for direct reduction iron (DRI), but even such parameters as the recovery rate have their optimal limits, since, on the one hand, increasing the rate of recovery of raw materials will increase the productivity of the DRI unit, but on the other hand, an excessive reduction rate leads to destruction of the pellets during reduction and subsequent problems in the operation of the furnace.

4. Conclusions and outlook

The mechanical and metallurgical properties of pellets are determined by many factors: the mineral composition of the feedstock, the amount and composition of fluxes, the structure of the pellets, the heat treatment regime, the size of the pellets, uneven firing across the layer and the nature of porosity. Controlling these factors at a pelletizing factory is possible if technical solutions are used aimed at modifying the macrostructure and preventing its defects.

The use of bentopolymer compositions as part of the charge is a promising direction for the production of iron ore pellets in order to improve the technical and economic performance of roasting machines.

An increase in the rheological parameters of the binders at all stages of the research made it possible to obtain high-quality green, dry, and roasted pellets. Thanks to the use of a bentopolymer composition, it is possible to optimize the chemical composition of the pellets with optimal binder consumption.

As a result of laboratory and semi-industrial research, it was revealed that it is possible to influence and quality characteristics of pellets using a bentopolymer binder. It should be especially noted that the dosage of the polymer substance to bentonite, which significantly increased the quality indicators of the pellets, was negligibly small.

The main scientific and technical achievements in the palletization of iron ore raw materials in recent years are somehow related to the optimization of the composition of the charge. The results of the studies also demonstrated that there is indeed a reserve for increasing the technological parameters of the pelletizing process. With this in mind, we expect continued academic and industrial research around the world to overcome the bentonite binder problem in a variety of ways.

The combination of properties of bentonite has ensured its practical irreplaceability in the pelletizing process over the past 60 years. The development of the science of clays and nanocomposites, which has been rapidly developing in recent decades, will inevitably lead to new discoveries, which will most likely ultimately lead to a revision of traditional approaches to the use of such a unique material as bentonite.