- Email: [email protected]
BASIC CONTROL PRINCIPLES FOR PRODUCING A HIGH PERFOMING NEW CERAMIC GLASS BY MIXING FLY ASH, FERRONICKEL SLAG AND WASTE GLASS
16th IFAC Symposium on Automation in Mining, Mineral and Metal Processing August 25-28, 2013. San Diego, California, USA
BASIC CONTROL PRINCIPLES FOR PRODUCING A HIGH PERFOMING NEW CERAMIC GLASS BY MIXING FLY ASH, FERRONICKEL SLAG AND WASTE GLASS IZET IBRAHIMI1, MUSA RIZAJ1, JUSTINA PULA3 FLORIAN KONGOLI2, IAN MCBOW2 1
University of Prishtina, Faculty of Mining and Metallurgy, Kosovo 2 FLOGEN Technologies Inc., Montreal, Canada 3 University of Prishtina, Faculty of Economics, Kosovo [email protected], [email protected]
Abstract: The combined land filled quantity of the fly-ash produced by a power plant and the slag produced by a ferronickel plant amounts to 3 (three) million tons per year in Kosovo. Due to environmental considerations, using this waste to produce new value-added materials constitute an efficient way to achieve waste sustainable processing. Development of technological processes for producing of high performing ceramic-glasses through mixing of waste glass, fly ash and ferronickel slag has been undertaken in cooperation with Canadian company FLOGEN. FO\ DVK IURP ³.RVRYR (QHUJ\ &RUSRUDWLRQ´ (Kosovo) and ferronickel slag from "New Co Ferronikeli" (Kosovo) (containing SiO2, CaO, MgO, FeO, Fe2O3, MnO, P2O5, Cr2O3, CaS, MnS, FeS as main components) and waste glass are jointly treated in order to produce a new ceramic glass with improved E-module and flexural strength (fracture) as compared to those produced by traditional aggregates. Depending on the mixing of components (fly ash, slag, and waste of glass) the ceramic glass semi-products can be used for the production of silicate tiles, pipes, decorative brick wall, etc. The purpose of this paper is to describe the basic control principles to achieve high performance properties based on the process parameters, treatment procedure, mixing ratios, concentrations of components. Keywords: control, waste, ceramics, fly ash, ferronickel slag, waste glass, mechanical properties
cooperation with Canadian company FLOGEN Technologies Inc. From a qualitative analyses viewpoint, the glass ceramics produced by these materials have shown high quality at reasonable production cost along with attractive possibilities of application and positive impact on environmental protection.
INTRODUCTION The rising volume of industrial waste, its potential impact on the environment and the irrational use of resources and energy have given rise of the necessity to transform them into useful materials through recycling. On this ground, the usage of ash from FRPEXVWLRQ RI OLJQLWH LQ ³7& .RVRYD $ %´ slags produced by ³)HUURQLNHO´ company and waste glass to produce a new glass ceramics have been undertaken in 978-3-902823-42-7/2013 © IFAC
Metallurgical slag waste and fly ash are actually invaluable materials in the production of many construction materials 470
10.3182/20130825-4-US-2038.00057
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
through recycling technologies[4]. Chemical and mineralogical composition of Fe-Ni slag and recent research data regarding the use of ferronickel slag form Kavadarci and ash from Oslomej are examples of this recycling process. The produced new ceramics glasses have advantages in terms of strength on breakage, high chemical durability, biocompatibility and manufacturing costs. Results from the research of thermalmechanical properties at "AHN Group", prove the fact that in addition to the qualities (properties and composition) of these wastes, the prevailing factor for the quality of the product is the preparation of appropriate recipe and setting fully proportional ratio of mixing components, regulating agents of structural composition and most importantly the control of the procedure and treatment methods.
obligatory to achieve high physical and mechanical properties. The aim of this article is to describe basic control principles of the processes used to produce new glass-ceramics materials from power plant fly ash, Fe-Ni slag and glass waste as well as drafting appropriate recipes and identification of indicators that enable the control of the technical performance of products.
TECHNOLOGICAL PROCESS Basic control principles in producing new glass-ceramics from fly ash, Fe-Ni slag and waste glass as well as the preparation of appropriate recipes and identification of indicators that enable the control of technical performance of products are mainly based on the tests performed in the "AHN" Laboratory in Kosovo. The production of glass-ceramics in most cases is developed through two stages - glass production under low cooling followed by re-ripening in the second stage. Addition of different agents and other technological interventions are determinants for the crystalline composition and product quality which include: zero porosity, high durability, transparency or invisibility, pigmentation, opulent (monochromatic), uniformly low thermal expansion, high thermal stability, fluorescence, ferromagnetism, biocompatibility, insulating capacity, high resistance, etc. Production of glass-ceramics from fly ash obtained from the combustion of coal in "Kosovo A & B", slag from "Fe-Ni-Drenas" and glass remaining from windows and bottles is developed according to the scheme in Figure 1.
Glass-ceramics share many attributes of ceramics and glass, consisting of one amorphous phase and some glass phases. These are polycrystalline materials produced through the VR FDOOHG ³FRQWUROOHG FU\VWDOOLVLQJ SURFHVV´ LQ FRQWUDVW ZLWK spontaneous crystallising process applied in the production of glass. Physical and chemical attributes of glass-ceramics are primarily dependant on the composition of mixture components and their proportion in the mixture, which can vary in fairly wide limits. Therefore, determination of accurate proportion of glass based components, preliminary design of mixtures and management of phase transformation processes are considered as the determining part of the design solution and process control. The control of the process includes the chosen recipes, methods of processing, phases of hot treatment, melting of mixture, cooling, time period of nuclear cells formation and crystallisation. The above are
471
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
472
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
The results of the granulometric analysis of materials are presented in Table 2. Table 2 - Granulometric analysis of fly ash, slag and waste glass Granulation mm(v/v) 6±5 5±4 4±3 3±2 2±1 1 ± 0.589 0.589 ± 0.417 0.417 ± 0.295 0.295 ± 0.208 0.208 ± 0.147 0.147± 0.104 0.104± 0.074 0.074± 0.052 0.052± 0.037
Fly ash
Ash slag
0 2.16 3.36 5.99 10.11 24.05 24.89 31.00 31.62
0 2.8 6.5 20.1 45.1 63.7 73.7 87.5 89.66 92.38 94.78 96.72 99.68
Fe-Ni granulated slag
Bottle Glass 100 79.3 59.3 5.4 0
0 8.3 15.7 32.9 48.7 67.5 72.3 79.7 89.3 100
Results from the research of thermal characteristics are given in Table 3. Table 3 - Thermal characteristics of industrial waste Diameter [mm] Fly ash FeNi slag Window glass Bottle glass
Contraction expression 0C 1140 1260 650 650
Softening temperature 0C 1300 1370 850 850
Melting temperature 0C 1340 1390 950 960
processing methods, performance of products and environmental suitability. For the purposes of this work three different types of materials were chosen with the participation of pre-designed components, in accordance with the technical requirements as shown in Table 4, 5 and 6.
MIXTURES AND PROCEDURES
Effective management of the process is conditioned by the control of the relationship between mixing components, properties of mixing components,
473
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
Table 4- Mixture ± PP1 Preliminary Mixture ±PP1 Material Proport. in mixt. [%(m/m) ³)HUURQLNHOL´ 6ODJ 30 ³7&.RVRYD $ %´ IO\ DVK 50 Window glass 10 Bottle glass 10 3 Density after homogenisation PP [g/cm ] 2.9 - 3.2
Density [g/cm3] 2.820 2.400 2.30 2.35
Table 5 Mixture ± PP2 Preliminary Mixture -PP1 Material Proport. in mixt. [%(m/m) ³)HUURQLNHOL´ 6ODJ 50 ³7&.RVRYD $ %´ IO\ DVK 30 Window glass 10 Bottle glass 10 3 Density after homogenisation PP [g/cm ] 2.9 - 3.2
Density [g/cm3] 2.820 2.400
Table 6- Mixture ± PP3 Preliminary Mixture ±PP3 Material Proport. in mixt. [%(m/m) ³)HUURQLNHOL´ 6ODJ 30 ³7&.RVRYD $ %´ IO\ DVK 30 Window glass 20 Bottle glass 10 Material 10 Density after homogenisation PP [g/cm3] 2.9 - 3.2
Density [g/cm3] 2.820 2.400 2.378 2.30 2.35
Grinding of composition materials was carried out in a one axial compression mill ("planetar" -150 MPa) in 60 minutes, reaching granulometric composition with particle size of 38 P. Sintering for the mixture of flying ash was carried in an oven with an atmospheric air current, at heating gradient of 100C/min in the temperature interval of 900-11500C. Sintering for the slag mixture was carried in the temperature interval of 1100-13500C. Isothermal treatment is developed in two steps and timed - 30, 60, 120 and 140 min according to Figure 2.
474
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
Figure 2 - Isothermal two-stage mixture treatment A control regime in time and temperature sintering regimes and mixture recipes for gradients followed at all stages of the flying ash-compressed glass treated at process and from time to time the addition temperatures gradient of 900-1150 0C/ h, of agents was performed in order to and compressed slag-glass treated at stimulate the formation of nuclear cells. temperature gradients of 900-1350 0C/ h, are given in Table 7. The produced glassceramics indicated highly advanced values and general crystalline stability and thermal RESULTS equilibrium. The properties of the obtained glassceramics from the above mentioned Table 7 - Properties of glass-ceramics for optimal compositions depending on the synthesis regimes Mixtures
PP1 PP2 Glassceramics PP1 PP2
Temp. Gradient of sintering [0C/h]
!rel. density [g/cm3]
E module [GPa]
.-strength in breakage [MPa]
Thermal coeff. in expans. 10-6 0 C
1050/2h 1150/2h 650
2.79 2.82 2.74
87±3 96±3 85±4
80±4 102±3 88±9
7.6 6.3 6.0
650 650
2.80 2.83
5.8 6.7
If literature data [2,3,6] are used as guidance it can be easily shown that the crystalline products obtained after sintering of fly ashglass mixtures had improved mechanical properties while the products obtained by slag-fly ash-glass mixture showed excellent crystalline properties, favorable coefficient of thermal expansion and breakage.
content in the mixture affect an increase of the fracture strength by up to 80 MPa, Emodule by up to 87 GPA and thermal coefficient by up to 7.6 [10-6 0C]. (PP1 mixture) Higher relative amounts of Fe-Ni slag in the mixture compared to fly ash increases the fracture strength at 102 Mpa and E-module up to 96 GPA, and thermal coefficient up 6.3[10-6 0C]. (PP2 mixture)
It should be noted that PP1 mixtures where fly ash is the majority reaches the highest relative density of 71 ± 1% at sintering gradient temperature of 10500C in 2 hours. On the other hand PP2 mixtures where FeNi Slag is the majority reaches the highest relative density of 81 ± 1% at gradiant temperature of 11500C in 2 hours. Sintering process at temperatures higher than abovementioned ones shows side effects such as breakage and ramification [6].
All physic-mechanical parameters in all thermal regimes and composition showed better technical performance than traditionally synthesized glass-ceramics.
BASIC PRINCIPLES OF PROCESS CONTROL
It can be seen that for higher relative amounts of fly ash compared to the slag
The main control parameters for the production of glass-ceramics are the speed 475
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
and the degree of the crystallization which have significant effect on glass-ceramic properties.
and controlled are the speed of crystallisation, temperature/time relation during the process steps and nucleus formation. These parameters are controlled as given in Figure 3 [3]
This is because glass-ceramics are somewhat in-between the fully crystalline phases and amorphous phases and are produced by controlled crystallization of the glass base. These products are generally categorized as profitable if crystallization is reached above 90% (m/m) and the crystal nucleus (about 1015ml) in all volume proportions.
Normally the speed of crystallization process can vary from 35% (m/m) to 90% (m/m). The addition of appropriate agents at the proper time is an effective way to control the process. Special agents lead to the forming of nuclear cells and to the regulation of relations between the creation of nuclear cells, crystal growth and temperature (Figure 3)
To achieve the above mentioned goals the parameters that have to be strictly measured
Fig.3. Relation between expansion of crystals, temperature and cooling rate In the production of low porosity glassceramics, porosity control is set on compliance of the growing of nucleus and crystallizing cells with the rate of cooling. The production of high porosity glassceramics is possible with the use of chalk polyurethane (polymer) or SiC as agent [1]. Porosity also depends on the type of materials used in the mixture. For mixtures with high fly ash concentrations porosity reached 70 ± 5%, while for those with high Fe-Ni slag concentrations porosity reaches 65 ± 5%. Adding glass to both mixtures
increases the density while significantly decreases the values of porosity [1]. Control of hazardous components is another issue. Fly-ash from coal combustion and ferronickel slags contain considerable dangerous elements such as heavy metals, organic components, etc. For this reason, the treatment of pre mixing of ash-slag-glass waste is done in high temperature (above 13000C), a process which enables the production of relatively inert product since heavy metals can be fully incorporated into 476
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
the matrix of the product or separated from the waste through evaporation-drying or different precipitations. These temperatures allow also the entire destruction of the organic components.
REFERENCES 1. Bianka V. Mangutova, Emilija M. Fidancevska, Milosav I. Milosevski and Joerg H. Bossert, Production of highly porous glass-ceramics from metallurgical slag, fly ash and waste glass, APTEFF, 35, 1-280, Skopje, 2004 2. Barbieri L., Lancellotti I.,Manfredini T., Queralt I., Rincon J., Romero M, Desing, Obtainment and Properties of glasses and glass-ceramics from coal fly ash, Fuel 78 271-276.London, UK, 1999 3. Karamanov A., Pelino M., Salvo M., Metekovits I. , Sintered glass-ceramics from incerator fly ashes, Part II, J. Europ, Ceram. Soc. 23 1609-1615, 2003 4. Murati N., Ibrahimi I., Rizaj M. , Research on possible use of the IHUURQLFNHO HOHFWULFDO IXUQDFHV¶ VODJ Ior production of construction materials, 14th International Metallurgy & Materials Congress, ISTANBUL October 16th-18th, 2008 5. Ibrahimi I, Rizaj M, Ramadani A, Research the Possibility of Transforming the Ferronickel Slag in the Product with the Economical and Environmental Importance, JIEAS, Vo.5(2)/278-283, Konya, Turkey 2010 6. Ahmaruzzaman M A, Review on the utilization of fly as, progress in energy and combustion science 36; 327-363, Assam, India, 2010
Based on the above control principles a fully control and automation system is being developed in cooperation with Canadian Company FLOGEN Technologies Inc. These control system not only properly monitors the system but also control the cooling gradient and nucleolus formation and crystallization. This system will be subject of a subsequent article. CONCLUSION The development of technological processes for producing of high performing ceramicglasses through mixing of waste glass, fly ash and ferronickel slag has been undertaken in cooperation with Canadian company FLOGEN. By mixing and properly controlled processing of Fly ash from ³.RVRYR (QHUJ\ &RUSRUDWLRQ´ (Kosovo), ferronickel slag from "New Co Ferronikeli" (Kosovo) and waste glass new ceramic glasses have been obtained with improved E-module and flexural strength (fracture) as compared to those produced by traditional aggregates. Depending on the mixing of components (fly ash, slag, and waste of glass) the ceramic glass semi-products can be used for the production of silicate tiles, pipes, decorative brick wall, etc. The basic control principles to achieve high performance properties based on the process parameters, treatment procedure, mixing ratios, concentrations of components were described. Based on the above control principles a fully control and automation system is being developed in cooperation with Canadian Company FLOGEN Technologies Inc. These control system not only properly monitors the system but also control the cooling gradient and nucleolus formation and crystallization.
477
BASIC CONTROL PRINCIPLES FOR PRODUCING A HIGH PERFOMING NEW CERAMIC GLASS BY MIXING FLY ASH, FERRONICKEL SLAG AND WASTE GLASS IZET IBRAHIMI1, MUSA RIZAJ1, JUSTINA PULA3 FLORIAN KONGOLI2, IAN MCBOW2 1
University of Prishtina, Faculty of Mining and Metallurgy, Kosovo 2 FLOGEN Technologies Inc., Montreal, Canada 3 University of Prishtina, Faculty of Economics, Kosovo [email protected], [email protected]
Abstract: The combined land filled quantity of the fly-ash produced by a power plant and the slag produced by a ferronickel plant amounts to 3 (three) million tons per year in Kosovo. Due to environmental considerations, using this waste to produce new value-added materials constitute an efficient way to achieve waste sustainable processing. Development of technological processes for producing of high performing ceramic-glasses through mixing of waste glass, fly ash and ferronickel slag has been undertaken in cooperation with Canadian company FLOGEN. FO\ DVK IURP ³.RVRYR (QHUJ\ &RUSRUDWLRQ´ (Kosovo) and ferronickel slag from "New Co Ferronikeli" (Kosovo) (containing SiO2, CaO, MgO, FeO, Fe2O3, MnO, P2O5, Cr2O3, CaS, MnS, FeS as main components) and waste glass are jointly treated in order to produce a new ceramic glass with improved E-module and flexural strength (fracture) as compared to those produced by traditional aggregates. Depending on the mixing of components (fly ash, slag, and waste of glass) the ceramic glass semi-products can be used for the production of silicate tiles, pipes, decorative brick wall, etc. The purpose of this paper is to describe the basic control principles to achieve high performance properties based on the process parameters, treatment procedure, mixing ratios, concentrations of components. Keywords: control, waste, ceramics, fly ash, ferronickel slag, waste glass, mechanical properties
cooperation with Canadian company FLOGEN Technologies Inc. From a qualitative analyses viewpoint, the glass ceramics produced by these materials have shown high quality at reasonable production cost along with attractive possibilities of application and positive impact on environmental protection.
INTRODUCTION The rising volume of industrial waste, its potential impact on the environment and the irrational use of resources and energy have given rise of the necessity to transform them into useful materials through recycling. On this ground, the usage of ash from FRPEXVWLRQ RI OLJQLWH LQ ³7& .RVRYD $ %´ slags produced by ³)HUURQLNHO´ company and waste glass to produce a new glass ceramics have been undertaken in 978-3-902823-42-7/2013 © IFAC
Metallurgical slag waste and fly ash are actually invaluable materials in the production of many construction materials 470
10.3182/20130825-4-US-2038.00057
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
through recycling technologies[4]. Chemical and mineralogical composition of Fe-Ni slag and recent research data regarding the use of ferronickel slag form Kavadarci and ash from Oslomej are examples of this recycling process. The produced new ceramics glasses have advantages in terms of strength on breakage, high chemical durability, biocompatibility and manufacturing costs. Results from the research of thermalmechanical properties at "AHN Group", prove the fact that in addition to the qualities (properties and composition) of these wastes, the prevailing factor for the quality of the product is the preparation of appropriate recipe and setting fully proportional ratio of mixing components, regulating agents of structural composition and most importantly the control of the procedure and treatment methods.
obligatory to achieve high physical and mechanical properties. The aim of this article is to describe basic control principles of the processes used to produce new glass-ceramics materials from power plant fly ash, Fe-Ni slag and glass waste as well as drafting appropriate recipes and identification of indicators that enable the control of the technical performance of products.
TECHNOLOGICAL PROCESS Basic control principles in producing new glass-ceramics from fly ash, Fe-Ni slag and waste glass as well as the preparation of appropriate recipes and identification of indicators that enable the control of technical performance of products are mainly based on the tests performed in the "AHN" Laboratory in Kosovo. The production of glass-ceramics in most cases is developed through two stages - glass production under low cooling followed by re-ripening in the second stage. Addition of different agents and other technological interventions are determinants for the crystalline composition and product quality which include: zero porosity, high durability, transparency or invisibility, pigmentation, opulent (monochromatic), uniformly low thermal expansion, high thermal stability, fluorescence, ferromagnetism, biocompatibility, insulating capacity, high resistance, etc. Production of glass-ceramics from fly ash obtained from the combustion of coal in "Kosovo A & B", slag from "Fe-Ni-Drenas" and glass remaining from windows and bottles is developed according to the scheme in Figure 1.
Glass-ceramics share many attributes of ceramics and glass, consisting of one amorphous phase and some glass phases. These are polycrystalline materials produced through the VR FDOOHG ³FRQWUROOHG FU\VWDOOLVLQJ SURFHVV´ LQ FRQWUDVW ZLWK spontaneous crystallising process applied in the production of glass. Physical and chemical attributes of glass-ceramics are primarily dependant on the composition of mixture components and their proportion in the mixture, which can vary in fairly wide limits. Therefore, determination of accurate proportion of glass based components, preliminary design of mixtures and management of phase transformation processes are considered as the determining part of the design solution and process control. The control of the process includes the chosen recipes, methods of processing, phases of hot treatment, melting of mixture, cooling, time period of nuclear cells formation and crystallisation. The above are
471
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
472
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
The results of the granulometric analysis of materials are presented in Table 2. Table 2 - Granulometric analysis of fly ash, slag and waste glass Granulation mm(v/v) 6±5 5±4 4±3 3±2 2±1 1 ± 0.589 0.589 ± 0.417 0.417 ± 0.295 0.295 ± 0.208 0.208 ± 0.147 0.147± 0.104 0.104± 0.074 0.074± 0.052 0.052± 0.037
Fly ash
Ash slag
0 2.16 3.36 5.99 10.11 24.05 24.89 31.00 31.62
0 2.8 6.5 20.1 45.1 63.7 73.7 87.5 89.66 92.38 94.78 96.72 99.68
Fe-Ni granulated slag
Bottle Glass 100 79.3 59.3 5.4 0
0 8.3 15.7 32.9 48.7 67.5 72.3 79.7 89.3 100
Results from the research of thermal characteristics are given in Table 3. Table 3 - Thermal characteristics of industrial waste Diameter [mm] Fly ash FeNi slag Window glass Bottle glass
Contraction expression 0C 1140 1260 650 650
Softening temperature 0C 1300 1370 850 850
Melting temperature 0C 1340 1390 950 960
processing methods, performance of products and environmental suitability. For the purposes of this work three different types of materials were chosen with the participation of pre-designed components, in accordance with the technical requirements as shown in Table 4, 5 and 6.
MIXTURES AND PROCEDURES
Effective management of the process is conditioned by the control of the relationship between mixing components, properties of mixing components,
473
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
Table 4- Mixture ± PP1 Preliminary Mixture ±PP1 Material Proport. in mixt. [%(m/m) ³)HUURQLNHOL´ 6ODJ 30 ³7&.RVRYD $ %´ IO\ DVK 50 Window glass 10 Bottle glass 10 3 Density after homogenisation PP [g/cm ] 2.9 - 3.2
Density [g/cm3] 2.820 2.400 2.30 2.35
Table 5 Mixture ± PP2 Preliminary Mixture -PP1 Material Proport. in mixt. [%(m/m) ³)HUURQLNHOL´ 6ODJ 50 ³7&.RVRYD $ %´ IO\ DVK 30 Window glass 10 Bottle glass 10 3 Density after homogenisation PP [g/cm ] 2.9 - 3.2
Density [g/cm3] 2.820 2.400
Table 6- Mixture ± PP3 Preliminary Mixture ±PP3 Material Proport. in mixt. [%(m/m) ³)HUURQLNHOL´ 6ODJ 30 ³7&.RVRYD $ %´ IO\ DVK 30 Window glass 20 Bottle glass 10 Material 10 Density after homogenisation PP [g/cm3] 2.9 - 3.2
Density [g/cm3] 2.820 2.400 2.378 2.30 2.35
Grinding of composition materials was carried out in a one axial compression mill ("planetar" -150 MPa) in 60 minutes, reaching granulometric composition with particle size of 38 P. Sintering for the mixture of flying ash was carried in an oven with an atmospheric air current, at heating gradient of 100C/min in the temperature interval of 900-11500C. Sintering for the slag mixture was carried in the temperature interval of 1100-13500C. Isothermal treatment is developed in two steps and timed - 30, 60, 120 and 140 min according to Figure 2.
474
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
Figure 2 - Isothermal two-stage mixture treatment A control regime in time and temperature sintering regimes and mixture recipes for gradients followed at all stages of the flying ash-compressed glass treated at process and from time to time the addition temperatures gradient of 900-1150 0C/ h, of agents was performed in order to and compressed slag-glass treated at stimulate the formation of nuclear cells. temperature gradients of 900-1350 0C/ h, are given in Table 7. The produced glassceramics indicated highly advanced values and general crystalline stability and thermal RESULTS equilibrium. The properties of the obtained glassceramics from the above mentioned Table 7 - Properties of glass-ceramics for optimal compositions depending on the synthesis regimes Mixtures
PP1 PP2 Glassceramics PP1 PP2
Temp. Gradient of sintering [0C/h]
!rel. density [g/cm3]
E module [GPa]
.-strength in breakage [MPa]
Thermal coeff. in expans. 10-6 0 C
1050/2h 1150/2h 650
2.79 2.82 2.74
87±3 96±3 85±4
80±4 102±3 88±9
7.6 6.3 6.0
650 650
2.80 2.83
5.8 6.7
If literature data [2,3,6] are used as guidance it can be easily shown that the crystalline products obtained after sintering of fly ashglass mixtures had improved mechanical properties while the products obtained by slag-fly ash-glass mixture showed excellent crystalline properties, favorable coefficient of thermal expansion and breakage.
content in the mixture affect an increase of the fracture strength by up to 80 MPa, Emodule by up to 87 GPA and thermal coefficient by up to 7.6 [10-6 0C]. (PP1 mixture) Higher relative amounts of Fe-Ni slag in the mixture compared to fly ash increases the fracture strength at 102 Mpa and E-module up to 96 GPA, and thermal coefficient up 6.3[10-6 0C]. (PP2 mixture)
It should be noted that PP1 mixtures where fly ash is the majority reaches the highest relative density of 71 ± 1% at sintering gradient temperature of 10500C in 2 hours. On the other hand PP2 mixtures where FeNi Slag is the majority reaches the highest relative density of 81 ± 1% at gradiant temperature of 11500C in 2 hours. Sintering process at temperatures higher than abovementioned ones shows side effects such as breakage and ramification [6].
All physic-mechanical parameters in all thermal regimes and composition showed better technical performance than traditionally synthesized glass-ceramics.
BASIC PRINCIPLES OF PROCESS CONTROL
It can be seen that for higher relative amounts of fly ash compared to the slag
The main control parameters for the production of glass-ceramics are the speed 475
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
and the degree of the crystallization which have significant effect on glass-ceramic properties.
and controlled are the speed of crystallisation, temperature/time relation during the process steps and nucleus formation. These parameters are controlled as given in Figure 3 [3]
This is because glass-ceramics are somewhat in-between the fully crystalline phases and amorphous phases and are produced by controlled crystallization of the glass base. These products are generally categorized as profitable if crystallization is reached above 90% (m/m) and the crystal nucleus (about 1015ml) in all volume proportions.
Normally the speed of crystallization process can vary from 35% (m/m) to 90% (m/m). The addition of appropriate agents at the proper time is an effective way to control the process. Special agents lead to the forming of nuclear cells and to the regulation of relations between the creation of nuclear cells, crystal growth and temperature (Figure 3)
To achieve the above mentioned goals the parameters that have to be strictly measured
Fig.3. Relation between expansion of crystals, temperature and cooling rate In the production of low porosity glassceramics, porosity control is set on compliance of the growing of nucleus and crystallizing cells with the rate of cooling. The production of high porosity glassceramics is possible with the use of chalk polyurethane (polymer) or SiC as agent [1]. Porosity also depends on the type of materials used in the mixture. For mixtures with high fly ash concentrations porosity reached 70 ± 5%, while for those with high Fe-Ni slag concentrations porosity reaches 65 ± 5%. Adding glass to both mixtures
increases the density while significantly decreases the values of porosity [1]. Control of hazardous components is another issue. Fly-ash from coal combustion and ferronickel slags contain considerable dangerous elements such as heavy metals, organic components, etc. For this reason, the treatment of pre mixing of ash-slag-glass waste is done in high temperature (above 13000C), a process which enables the production of relatively inert product since heavy metals can be fully incorporated into 476
IFAC MMM 2013 August 25-28, 2013. San Diego, USA
the matrix of the product or separated from the waste through evaporation-drying or different precipitations. These temperatures allow also the entire destruction of the organic components.
REFERENCES 1. Bianka V. Mangutova, Emilija M. Fidancevska, Milosav I. Milosevski and Joerg H. Bossert, Production of highly porous glass-ceramics from metallurgical slag, fly ash and waste glass, APTEFF, 35, 1-280, Skopje, 2004 2. Barbieri L., Lancellotti I.,Manfredini T., Queralt I., Rincon J., Romero M, Desing, Obtainment and Properties of glasses and glass-ceramics from coal fly ash, Fuel 78 271-276.London, UK, 1999 3. Karamanov A., Pelino M., Salvo M., Metekovits I. , Sintered glass-ceramics from incerator fly ashes, Part II, J. Europ, Ceram. Soc. 23 1609-1615, 2003 4. Murati N., Ibrahimi I., Rizaj M. , Research on possible use of the IHUURQLFNHO HOHFWULFDO IXUQDFHV¶ VODJ Ior production of construction materials, 14th International Metallurgy & Materials Congress, ISTANBUL October 16th-18th, 2008 5. Ibrahimi I, Rizaj M, Ramadani A, Research the Possibility of Transforming the Ferronickel Slag in the Product with the Economical and Environmental Importance, JIEAS, Vo.5(2)/278-283, Konya, Turkey 2010 6. Ahmaruzzaman M A, Review on the utilization of fly as, progress in energy and combustion science 36; 327-363, Assam, India, 2010
Based on the above control principles a fully control and automation system is being developed in cooperation with Canadian Company FLOGEN Technologies Inc. These control system not only properly monitors the system but also control the cooling gradient and nucleolus formation and crystallization. This system will be subject of a subsequent article. CONCLUSION The development of technological processes for producing of high performing ceramicglasses through mixing of waste glass, fly ash and ferronickel slag has been undertaken in cooperation with Canadian company FLOGEN. By mixing and properly controlled processing of Fly ash from ³.RVRYR (QHUJ\ &RUSRUDWLRQ´ (Kosovo), ferronickel slag from "New Co Ferronikeli" (Kosovo) and waste glass new ceramic glasses have been obtained with improved E-module and flexural strength (fracture) as compared to those produced by traditional aggregates. Depending on the mixing of components (fly ash, slag, and waste of glass) the ceramic glass semi-products can be used for the production of silicate tiles, pipes, decorative brick wall, etc. The basic control principles to achieve high performance properties based on the process parameters, treatment procedure, mixing ratios, concentrations of components were described. Based on the above control principles a fully control and automation system is being developed in cooperation with Canadian Company FLOGEN Technologies Inc. These control system not only properly monitors the system but also control the cooling gradient and nucleolus formation and crystallization.
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