CHEMICAL ENGINEERING TRANSACTIONS  
 

VOL. 76, 2019 

A publication of 

 

The Italian Association 
of Chemical Engineering 
Online at www.aidic.it/cet 

Guest Editors: Petar S. Varbanov, Timothy G. Walmsley, Jiří J. Klemeš, Panos Seferlis 
Copyright © 2019, AIDIC Servizi S.r.l. 

ISBN 978-88-95608-73-0; ISSN 2283-9216 

Synthesis of Block Ceramic Catalyst Carriers Based on 

Natural Raw Materials and Metallurgical Slags 

Meruyert Erkinovna Utegenovaa, Marzhan Anuarbekovna Sadenovaa,*, Jiří Jaromír 

Klemešb 

aPriority Department Centre «Veritas», D. Serikbayev East Kazakhstan State Technical University, 19, Serikbayev str. 

 070000, Ust-Kamenogorsk, Kazakhstan 
bSustainable Process Integration Laboratory – SPIL, NETME Centre, Faculty of Mechanical Engineering, Brno, University 

 of Technology - VUT Brno, Technická 2896/2, 616 00 Brno, Czech Republic 

 MSadenova@ektu.kz 

For ecological catalysis, including the purification of exhaust gases, the most promising are block catalysts. The 

synthesis of ceramic block catalyst carrier was carried out based on classical methods of powder metallurgy, in 

which moulding compounds were prepared from the starting materials in the form of powders, which were then 

extruded with thermal training at each stage. It is proposed to use ceramic block carriers synthesized from a 

mixture of natural Kazakhstan aluminosilicates and metallurgical slag of lead and copper production for 

environmental catalysis. The obtained results prove the possibility of extruding new materials for use as ceramic 

carriers for catalysts from a mixture of natural Kazakhstan's aluminosilicates and metallurgical slag of lead and 

copper production without additional preliminary chemical treatments. In works of other authors haven't found 

such combinations of components for the manufacture of catalysts 

1. Introduction 

The development of the advanced level of industrial catalytic chemistry requires fundamentally new solutions 

for the development of catalyst technology of effective geometric shapes, in particular, block type, with high-

performance characteristics. Ceramic block materials with a combination of properties such as high structural 

strength, low hydraulic resistance, developed specific surface area are predetermined for use as carriers for 

catalytic systems. 

The use of secondary sources remains a serious concern for the metallurgical industry and environmental 

agencies. Recycling of metallurgical slag will make it possible to free land intended for dumps and slag storages 

and reduce the environmental effect on the environment (Yang et al., 2013). The main components of 

metallurgical slag, as well as aluminosilicate natural raw materials,  are oxides of silicon, aluminium and iron, 

which allows them to be used in the preparation of ceramics as an additional component of the charge. 

For ecological catalysis, including the purification of exhaust gases, the most promising are block catalysts. To 

solve the problem under study, special attention should be paid to powder metallurgy methods. Powder 

metallurgy, used for the production of ceramics or composite materials, is a process consisting of mixing 

powdered materials, compacting them into the desired shape, heating and sintering the synthesized material in 

a controlled atmosphere, followed by cooling to room temperature. According to Omole et al. (2015) great 

progress in sintering technology and powder metallurgy technology allows us to constantly develop modern 

materials, such as composites - materials formed from two (or more) components (for example, metal, 

intermetallic or ceramic) with different physical and chemical properties, which together allow one to get various 

and usually improved characteristics in relation to the individual components. The authors (Nosewicz et al., 

2016) note that the use of modelling and simulation can help to better understand the influence of powder 

characteristics and process parameters on the production process and the final properties of sintered material. 

It is known that currently modelling the process of powder metallurgy of composites is a new and complex 

research task. The need to build an effective model of powder metallurgy and sintering processes is due to the 

 
 
 
 
 
 
 
 
 
 
                                                                                                                                                                 DOI: 10.3303/CET1976026 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Paper Received: 22/08/2019; Revised: 12/09/2019; Accepted: 12/09/2019 
Please cite this article as: Utegenova M.E., Sadenova M.A., Klemes J.J., 2019, Synthesis of Block Ceramic Catalyst Carriers Based on Natural 
Raw Materials and Metallurgical Slags, Chemical Engineering Transactions, 76, 151-156  DOI:10.3303/CET1976026 
  

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need to accurately analyze the production process. The properties of the sintered material, such as its density, 

porosity, as well as its mechanical properties, should be predicted. The microstructure of the material during 

sintering undergoes changes as a result of compaction and rearrangement of particles, the formation and growth 

of bonding bonds, leading to a decrease and elimination of porosity. Microscopic processes cause changes in 

macroscopic physical properties. 

The role of the carrier is to improve the structure of the catalyst. The carrier must have sufficient mechanical 

strength and a specific surface with a pore structure, together with a shape suitable for the reaction. So block 

carrier is increasingly being developed in the catalysis (Tsai et al., 2018). One of the main reasons for using the 

block form in environmental catalysis is better mass transfer, low-pressure drop, thermal stability and good 

mechanical strength compared to other catalytic structures such as granules, tablets or powders. Boger et al. 

(2004) emphasize that it is necessary to distinguish between catalysts in which the active phase is applied in 

the form of a coating (for example, a primer coating) on an inert support, and catalysts in which the entire 

monolithic structure is made of active material, for example, bulk catalysts. Coated monoliths are usually 

considered when the intrinsic reaction rates are high compared to diffusion and mass transfer in the catalyst 

structure, and the performance depends on the geometric surface area, and not on the weight of the catalyst.  

Combinations of ceramics obtained from mixtures of clay materials are generally referred to in the literature as 

refractory materials because of their ability to withstand abrasive and corrosive solids, liquids, or gases at high 

temperatures. Govender et al. (2017) suggest that one of the main factors in choosing a combination of materials 

for the production of composites should be a lower cost of production compared to other composites. They 

investigated the properties of ceramics synthesized from a clay mixture in combination with iron filings in order 

to study the usefulness of the products obtained and substantiated that the resulting composite will find 

application in areas where high wear resistance and abrasion resistance are required. They obtained block 

systems representing homogeneous blocks consisting of parallel channels, which are obtained by extrusion. 

For widespread use of catalysts in practice, it is necessary that they satisfy certain requirements. Essential 

characteristics of the catalyst: the constancy of the chemical composition, the constancy of the phase 

composition, the absence of harmful impurities, the required particle size, the required humidity. Commercial 

catalysts, according to (Keane, 2003) must have sufficient mechanical strength to withstand loss due to crushing 

(when operating in a packed bed) or attrition (in intensive mixing reactors). High surface areas can be achieved 

either by manufacturing small particles or clusters where the surface to volume ratio of each particle is high or 

by creating materials whose void surface (pore) area is high compared to the amount of bulk substrate of the 

material. The most common methods for forming catalysts and carriers are droplet coagulation, extrusion, 

tabletting, plate granulation, spray drying, and grinding of the material. The preparation method determines the 

degree of dispersion of the catalytic component, the shape, porous structure and activity of the contact mass. 

Govender et al. (2017) believe that preference when choosing the form of catalysts should be given to monolithic 

structures. They claim that monolithic structures are an attractive alternative to traditionally prepared catalytic 

granules or powders due to a number of properties. Monoliths provide better mass transfer, low-pressure drop, 

thermal stability and good mechanical strength compared to conventional catalytic tablets or powders. Monoliths 

are essentially homogeneous blocks consisting of parallel channels that can be extruded into various shapes 

and sizes and can be extruded from zeolites. The primary producers of ceramic and metal monoliths are Corning 

and Johnson Matthey. 

A review of the literature showed that researchers are actively using aluminosilicates and various metallurgical 

wastes to develop new ceramic materials. It is of interest to study the possibility of synthesizing new ceramic 

materials with desired properties from a mixture of aluminosilicates and metallurgical slags. The authors suggest 

that the most promising approach is the use of specific techniques of powder metallurgy for the synthesis of 

ceramics. The aim of the work is to create a catalytic composite system from a mixture of natural aluminosilicates 

of Kazakhstan and metallurgical slag of lead or copper production. 

2. Methodology 

Natural aluminosilicates in the form of zeolite, bentonite and metallurgical slags of lead and copper production 

were used as objects of study. The possibility of using natural aluminosilicates represented by natural zeolite of 

the clinoptilolite type and bentonite clay represented by montmorillonite as a part of complex gas purification 

catalysts was studied in (Sadenova et al. 2016). In (Tahir et al., 2016), a system based on a clay material, 

montmorillonite, was also successfully used as a basic component of a catalyst for selective reduction of CO2. 

The synthesis of ceramic block catalyst carrier was carried out on the basis of classical methods of powder 

metallurgy, in which moulding compounds were prepared from the starting materials in the form of powders, 

which were then extruded with thermal training at each stage. It is known that a characteristic feature of extrusion 

as an industrial method of manufacturing various kinds of materials is the use of raw materials in the form of 

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powders, which are then pressed through special technological equipment (matrix) and molded into products of 

specified sizes (Fan et al., 2016). 

For the manufacture of ceramic block catalyst carrier, natural aluminosilicates were used - zeolite from the 

Taizhuzgen deposit, bentonite from the Tagansky deposit and representative technological samples of slag from 

copper and lead production. The components of the mixture were previously subjected to fine grinding to a 

fraction of 0.01 mm on a vibratory grinder IV-4 to ensure a homogeneous mixture. The initial charge components 

- natural zeolite and bentonite - were mixed with metallurgical slags. An important characteristic is the moisture 

capacity of the starting components and the resulting mixture. The moisture content was varied in the range of 

15 ÷ 20 % to ensure the required moulding moisture. To obtain a mass of a given composition, the zeolite, 

bentonite and slag powders were mixed until a homogeneous mass was obtained in the mixer.  

The difficulty in complying with the requirements of quality standards for block catalysts is due to the dependence 

on many technological parameters. Therefore, the modelling method was used in work, which allowed the data 

obtained during the study of the model to be applied in real conditions for the synthesis of block ceramic carriers 

for catalysts. The visualization of the extrusion process of a block ceramic carrier was modelled in SolidWorks 

using the Flow Simulation module. For calculations, a model of the non-Newtonian fluid flow was chosen. When 

using this method, slippage conditions are applied that apply to all walls of the model, as well as the yield 

strength. Modeling was carried out with the following parameters: yield strength: 5.8 Pa; roughness: 10 µm; 

punch feed rate: 0.5 mm/s (30 mm/min); outlet pressure: 101,325 Pa. 

After mixing, the prepared mixture was sent to moulding. The moulding (extrusion) of block ceramic carriers was 

carried out on a Shimadzu Autograph AG-Xplus universal machine. The software tool TRAPEZIUM X was used, 

allowing full control of the test process. 

To obtain blocks of the honeycomb structure, the moulding material was pressed through special dies. The use 

of a catalyst based on a carrier of this form can significantly increase the surface area and reduce the gas-

dynamic resistance of the reactor. For forming blocks, steel moulds are used, including a matrix with a forming 

punch. 

The resulting materials were kept in the air and then subjected to heat treatment in a muffle electric furnace in 

the temperature range 100 – 1,000 °С. During calcination, evaporation of moisture occurs and the physical 

structure of the carrier is formed due to sintering processes. The compression strength of the catalyst carrier 

was determined using a hydraulic press. The compressive strength (Rstr, MPa) was calculated by the formula: 

Rstr = P/S, (1) 

where P is the breaking load, N (kgf); S is the cross-sectional area of the sample, mm2. The pressing was carried 

out under double-sided loading, and the pressing pressure was the same order that occurs during extrusion of 

the press mass. 

3. Results and discussion 

3.1 Technological tooling 

The complexity of managing and investigating the properties of various types of catalytic materials is determined 

by the choice of the manufacturing method and sensitivity when choosing control actions at the manufacturing 

stage. The development of computer simulation of the synthesis process has increased the information content 

and efficiency of the process of obtaining new ceramic materials. The created virtual prototype of the product 

(Figure 1), contains all the information about its geometry, manufacturing and control requirements.   

 

Figure 1: Modeling an extrusion process for the production of block ceramics (a) a matrix, (b) an extrusion 

process, (c) catalyst block carrier 

The developed model of the synthesis process made it possible to fabricate technical toolings for producing 

block ceramic materials by extrusion based on the forcing of the plastic mass through a forming head with 

channels (Figure 2). 

Technical accessories are made of structural alloyed steel with high strength, a viscous core and high surface 

hardness, designed for the manufacture of products operating at high speeds and high specific pressures under 

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the action of shock loads, including a matrix with a forming punch. Technical accessories are made from simple 

to more complex geometric shapes. 

 

Figure 2: General view of the manufactured technical tooling for extrusion (matrix) 

At the next stage of the study, using the manufactured equipment, synthesized samples of block ceramic 
materials for use as a catalyst carrier for various processes. 

3.2 Synthesis of block ceramic catalyst carriers 

For the first time, it was proposed to use ceramic block carriers synthesized from a mixture of natural Kazakhstan 

aluminosilicates and metallurgical slag from lead and copper production for ecological catalysis. To ensure the 

required thermal stability of the ceramic carrier for the catalyst, a composite system of a mixture of natural 

aluminosilicates and metallurgical slags is considered. These materials are promising because each of them 

individually is sufficiently thermally stable up to 800 - 1,000 °С. Metallurgical slags are smelting products in the 

range up to 1,500 °С, and therefore it can be assumed that they should no longer undergo significant structural 

changes upon repeated thermal exposure in the same temperature ranges. 

The use of metallurgical slag in the production of ceramic materials requires determining the composition of the 

material, structure and properties. According to the developed technology (Figure 3) before the synthesis of 

block ceramic materials, the initial components were studied using X-ray diffraction (XRD), simultaneous thermal 

analysis (thermogravimetry / differential thermal analysis) (TGA / DTA), optical microscopy (OM) and scanning 

electron microscopy. According to the data obtained, it was determined that the main components of 

metallurgical slags, as well as aluminosilicate natural raw materials, are oxides of silicon, aluminum and iron, 

which allows them to be used in the manufacture of ceramics as an additional component of the charge. 

 

Figure 3: The synthesis scheme of block ceramic catalyst carriers 

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For the synthesis of block ceramic materials, a series of compositions based on natural aluminosilicates and 

metallurgical slags have been prepared. To obtain a moulding material with the required characteristics, the 

ratio of zeolite:bentonite:slag components was varied over a wide range. In powder metallurgy, when choosing 

a composition for moulding a ceramic material, mass moisture, pressing pressure, calcination temperature, and 

other characteristics are usually selected taking into account the design of technological tooling. Optimization 

of the composition and sintering temperature leads to various microstructures and phases, giving strength 

characteristics to the product (Rawlings et al., 2006). In this investigation, compositions were prepared to contain 

50 to 80 wt.% zeolite, 20 - 40 wt.% bentonite and 10 - 30 wt.% slag. According to the results of the selection of 

the composition to ensure the maximum possible porosity and specific surface area, it was found that the highest 

content in the charge should be zeolite. To develop the specific surface of block carriers, to give the charge 

plastic properties to the zeolite, bentonite clay additives were introduced.  

By extruding the mouldable mixture through a die (Figure 3), an article was obtained in the form of a block with 

a wall thickness of 1 mm and a length of 30 - 100 mm, which has a strength sufficient for manual movement 

and transportation. Some samples of the synthesized batch of block catalyst carrier are shown in Figure 3. It 

was experimentally established that the optimal composition of the mixture is based on (wt.%) zeolite 60, 

bentonite 20, metallurgical slag 20 (copper and lead slags were used in this investigation). 

The prepared mixture for forming blocks of a honeycomb structure has structural homogeneity, which is ensured 

by efficient mixing of the dispersed medium and the completeness of spontaneous dispersion of particles in 

contact with water. During the extrusion process, the flow of the press mass is organized in such a way that the 

stress-strain state makes it possible to separate the mass into separate streams and then form them into a 

honeycomb structure with the thixotropic restoration of strength along the lines connecting the streams. 

The use of powder metallurgy methods in the technology of manufacturing catalyst carriers allows one to obtain 

ceramic materials capable of becoming less viscous and extrudable under the influence of mechanical forces. 

After stress relieving, they acquire thixotropic properties that restore plasticity and strength, as a result of which 

the moulded product becomes suitable for further transportation. 

2.1 Strength characteristics 

It is not possible to assess the prospects of using natural aluminosilicates and metallurgical slags for the 

manufacture of carriers for gas purification catalysts without a preliminary study of the structural and mechanical 

properties. Figure 4 shows the research data on the strength of ceramic catalyst carriers depending on the 

composition of the charge and the calcination temperature. To determine the mechanical strength, a batch of 

samples was prepared from a zeolite: bentonite (Z: B) mixture in a ratio of 60:40 and a zeolite: bentonite: slag 

mixture in a ratio of 60:20:20 (Z: B: S (Cu) and Z: B : S (Pb)). The results of the strength characteristics are 

presented in Figure 4. 

 

Figure 4: Strength of ceramic catalyst carriers 

Figure 4 shows that the lowest strength value at an annealing temperature of 500 °C for a zeolite-bentonite 

sample is 4 MPa. With the introduction of copper and lead slag into the zeolite-bentonite mixture, the values 

increased and amounted to 13 MPa for Z + B + S (Cu) and 16 MPa for Z + B + S (Pb). At an annealing 

temperature of 750 °C, the indicator for all three samples increased. After increasing the calcination temperature 

from 750 °C to 1,000 °C, the strength values also increased and fluctuated within 37 - 54 MPa. For all three 

samples, the strength values at 1,000 °C are more than 30 MPa, which corresponds to the requirements for 

catalyst carriers. 

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3. Conclusion 

In the present study, the synthesis of a block catalyst carrier based on natural aluminosilicates and metallurgical 

slags was carried out by powder metallurgy. Powder metallurgy technology opens up extensive opportunities 

for the development of ceramic products of new geometric shapes for various purposes, including catalysis. 

The optimal compositions based on a zeolite-bentonite-slag mixture to obtain block ceramic catalyst carriers 

(wt.%) with a component ratio of 60:20:20 were determined. It was found that in order to ensure the maximum 

possible porosity and specific surface area, the zeolite should have the highest content in the composition. The 

use of metallurgical slag as an additional component in the composition of the charge not only provides a 

reduction in the environmental impact associated with its disposal but also provides a productive role by 

increasing the strength characteristics of the catalyst carriers. At the next stage, using developed ceramic 

carriers of a honeycomb structure, catalysts will be manufactured for purification of exhaust gases from nitrogen 

and carbon oxides and an assessment of their catalytic activity will be carried out. 

In the work on the basis of classical methods of powder metallurgy, the experimental batch of ceramic block 

catalyst carriers was synthesized from a mixture of natural aluminum silicates of Kazakhstan and metallurgical 

slag of lead or copper production. The obtained results prove the possibility of extruding new materials for use 

as ceramic carriers for catalysts from a mixture of natural aluminosilicates of Kazakhstan and metallurgical slag 

of lead or copper production without additional preliminary chemical treatments. In works of other authors 

haven't found such combinations of components for the manufacture of catalysts for environmental catalysis. 

Acknowledgements 

This research has been supported by the Project IRN AP05134733 “Development of technology for obtaining 

new ceramic materials based on domestic raw materials and technogenic wastes of metallurgical companies of 

Kazakhstan”, funded by the Science Committee of The Ministry of Education and Science of the Republic of 

Kazakhstan and by EU project “Sustainable Process Integration Laboratory – SPIL”, project No. 

CZ.02.1.01/0.0/0.0/15_003/0000456 funded by EU “CZ Operational Programme Research, Development and 

Education”, Priority 1: Strengthening capacity for quality research. 

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