*3.1.1 Materials*

Raw materials are important in geopolymer formation and materials rich in Si and Al are the primary requirement. These two materials react with alkaline solution (comprising of sodium silicate and sodium hydroxide) for dissolution of Si and Al to form reactive precursor necessary for mechanical strength. Combination

**65**

**Table 5.**

*Utilization of Iron Ore Mines Waste as Civil Construction Material through Geopolymer Reactions*

of these two materials has traditionally been used for geopolymer formation. The role of calcium either in formation of C▬S▬H gel giving cementitious bond or as a substitute in Al and Si as partial replacement towards geopolymerisation reaction is yet a controversy. In the current study as a calcium source; GGBS, fly ash and slag

Fly ash is a waste by-product from coal burning power plants for generation of electricity. It has pozzolanic properties and is widely used in cement making industries as an admixture in portland cement. GGBS is a byproduct from iron making industries namely blast furnace. GGBS can be used as a replacement for, or be blended with portland cement. When blended with portland cement it is called portland slag cement. Addition of GGBS has shown improvement in properties of cement, like resistance to chemical attack. However, the quality of slag depends on certain conditions. For instance, slow cooling of the slag results in more crystallized product, while rapid cooling results in desired non-crystallized product which exhibits enhanced reactivity. Slag sand is an admixture of blast furnace slag and other calcia based alumina-silicate compounds produced by Jindal Steel Ltd., Karnataka, India. The materials are generally used in civil engineering construction for early development of strength in concrete. IOT is a low grade iron ore generated

in iron ore mines after sorting out of good quality ore (>65% hematite).

Water glass, also known as sodium silicate, contains compounds of sodium oxide (Na2O) and silica (SiO2) and forms a glassy material that is soluble in water. Water glass can be produced as both an aqueous solution and as solid material. It is produced when burning sodium carbonate and silica sand in a furnace at temperatures between 1000 and 1400°C. The viscosity of the solution depends on the ratio of SiO2 and Na2O; the higher the concentration of both, the more viscous is the solution. Water glass dissolves in water and produces an alkaline solution which is glassy in nature and colorless. Due to the alkali properties, water glass will react under acidic conditions and form a hard glassy gel, which is a very useful as bonding agent. Sodium hydroxide (NaOH), also known as caustic soda is a white material commonly found in the form of pellets, granules or flakes. NaOH is highly soluble in water and because of its high alkaline activator levels; it is normally used in geopolymer reactions. The NaOH concentration has a significant effect on the

In the present study 8 and 10 M NaOH solution were used. The NaOH was delivered by Merck (Germany). **Table 5** presents the chemical composition of all the raw materials used. **Figure 13** shows the XRD patterns of different raw materials. XRD analysis was performed to understand the nature of the material. Sharp and intense peaks of samples A and D, is attributed to its crystalline nature. Broad diffraction peaks of samples B and C, exhibited its amorphous nature. The full width at half maximum (FWHM) of a peak is inversely proportional to crystallite size. Lower crystallite size of samples B and C, compared to samples A and D is obvious from

Fly ash 66.87 23.34 1.17 0.31 — — 4.41 GGBS 31.79 17.07 38.78 6.23 — — 0.49 Slag sand 30.73 16.32 38.47 6.41 — — 0.56 IOT 16.05 6.34 1.52 0.28 1.20 0.38 44.82

**SiO2 Al2O3 CaO MgO MnO2 TiO2 Fe2O3**

*DOI: http://dx.doi.org/10.5772/intechopen.81709*

compressive strength of geopolymers.

the diffraction patterns.

*Chemical composition of raw materials.*

sand were used in the various batch compositions.

#### *Utilization of Iron Ore Mines Waste as Civil Construction Material through Geopolymer Reactions DOI: http://dx.doi.org/10.5772/intechopen.81709*

of these two materials has traditionally been used for geopolymer formation. The role of calcium either in formation of C▬S▬H gel giving cementitious bond or as a substitute in Al and Si as partial replacement towards geopolymerisation reaction is yet a controversy. In the current study as a calcium source; GGBS, fly ash and slag sand were used in the various batch compositions.

Fly ash is a waste by-product from coal burning power plants for generation of electricity. It has pozzolanic properties and is widely used in cement making industries as an admixture in portland cement. GGBS is a byproduct from iron making industries namely blast furnace. GGBS can be used as a replacement for, or be blended with portland cement. When blended with portland cement it is called portland slag cement. Addition of GGBS has shown improvement in properties of cement, like resistance to chemical attack. However, the quality of slag depends on certain conditions. For instance, slow cooling of the slag results in more crystallized product, while rapid cooling results in desired non-crystallized product which exhibits enhanced reactivity. Slag sand is an admixture of blast furnace slag and other calcia based alumina-silicate compounds produced by Jindal Steel Ltd., Karnataka, India. The materials are generally used in civil engineering construction for early development of strength in concrete. IOT is a low grade iron ore generated in iron ore mines after sorting out of good quality ore (>65% hematite).

Water glass, also known as sodium silicate, contains compounds of sodium oxide (Na2O) and silica (SiO2) and forms a glassy material that is soluble in water. Water glass can be produced as both an aqueous solution and as solid material. It is produced when burning sodium carbonate and silica sand in a furnace at temperatures between 1000 and 1400°C. The viscosity of the solution depends on the ratio of SiO2 and Na2O; the higher the concentration of both, the more viscous is the solution. Water glass dissolves in water and produces an alkaline solution which is glassy in nature and colorless. Due to the alkali properties, water glass will react under acidic conditions and form a hard glassy gel, which is a very useful as bonding agent. Sodium hydroxide (NaOH), also known as caustic soda is a white material commonly found in the form of pellets, granules or flakes. NaOH is highly soluble in water and because of its high alkaline activator levels; it is normally used in geopolymer reactions. The NaOH concentration has a significant effect on the compressive strength of geopolymers.

In the present study 8 and 10 M NaOH solution were used. The NaOH was delivered by Merck (Germany). **Table 5** presents the chemical composition of all the raw materials used. **Figure 13** shows the XRD patterns of different raw materials. XRD analysis was performed to understand the nature of the material. Sharp and intense peaks of samples A and D, is attributed to its crystalline nature. Broad diffraction peaks of samples B and C, exhibited its amorphous nature. The full width at half maximum (FWHM) of a peak is inversely proportional to crystallite size. Lower crystallite size of samples B and C, compared to samples A and D is obvious from the diffraction patterns.


#### **Table 5.**

*Chemical composition of raw materials.*

*Geopolymers and Other Geosynthetics*

**64**

**3.1 Experimental**

*3.1.1 Materials*

**Figure 12.**

**Figure 11.**

**3. Part B: case study with JSW Steel mines Ltd**

*SEM micrograph of brick specimen with 50% IOT (a) 7d curing, (b) 28d curing.*

*Relationship between Si/(Al + Fe) ratio and compressive strength at different curing periods.*

Raw materials are important in geopolymer formation and materials rich in Si and Al are the primary requirement. These two materials react with alkaline solution (comprising of sodium silicate and sodium hydroxide) for dissolution of Si and Al to form reactive precursor necessary for mechanical strength. Combination

**Figure 13.** *XRD patterns of (A) fly ash, (B) GGBS, (C) slag sand, and (D) IOT.*
