**4. Discussion**

No significant differences were observed in the qualitative mineral composition of the sinters. A diversity in some minor components (silicates) was determined, excluding dicalcium silicates which were present in all sinters. The chemical composition and qualitative mineralogical investigations could not provide enough information about any dependence between a mineral composition and the quality indices of sinters. The next step was to apply quantitative phase analysis to check whether – or not – a quantitative dependence existed. The application of the Rietveld method to quantitative phase analysis in sinters was the only possible solution to obtain sensible results. The one of the most important problems in the refinements was the removing of background. The shape of background in sinters is not linear, the presence of amorphous component can influence on both intensity and shape of the background. Moreover, the intensity and shapes of reflexes of minor components (as it can be seen clearly in **Figure 4**, where the positions of

**85**

**Figure 5.**

**Figure 4.**

*caused by the number of reflexes.*

*Application of X-Ray Diffraction to Study Mineralogical Dependence of Reduction…*

*A small part of a diffraction pattern of one of the sinters. The marks show the positions of reflexes of all components of the sinter, according to their standard data taken from PDF-4+ file. Complexity of the pattern is* 

*The RDI-1-3.15 (top) and RDI-1+6.3 (bottom) dependence on contents of magnetite in the examined sinters. The growing tendency of RDI-1-3.15 with growing content of magnetite and the opposite dependence of RDI-1+6.3 are shown.*

*DOI: http://dx.doi.org/10.5772/intechopen.95086*

*Application of X-Ray Diffraction to Study Mineralogical Dependence of Reduction… DOI: http://dx.doi.org/10.5772/intechopen.95086*

#### **Figure 4.**

*Iron Ores*

**Table 3.**

*Space groups of sinters' crystalline components.*

**84**

**4. Discussion**

**Figure 3.**

*plot is shown.*

No significant differences were observed in the qualitative mineral composition of the sinters. A diversity in some minor components (silicates) was determined, excluding dicalcium silicates which were present in all sinters. The chemical composition and qualitative mineralogical investigations could not provide enough information about any dependence between a mineral composition and the quality indices of sinters. The next step was to apply quantitative phase analysis to check whether – or not – a quantitative dependence existed. The application of the Rietveld method to quantitative phase analysis in sinters was the only possible solution to obtain sensible results. The one of the most important problems in the refinements was the removing of background. The shape of background in sinters is not linear, the presence of amorphous component can influence on both intensity and shape of the background. Moreover, the intensity and shapes of reflexes of minor components (as it can be seen clearly in **Figure 4**, where the positions of

*An example of the Rietveld refinement of a diffraction pattern of one of a sinter. The upper line is the experimental pattern (as measured). Below, there is the experimental pattern after removing background (points) and the calculated refined diffraction pattern (solid line). The higher intensity of the background in the range of lower angles is concerned with a presence of amorphous component. At the bottom, a difference* 

**Phase Space group Phase Space group Magnetite Fd-3 m Hedenbergite C2/c Hematite R-3c Kirschsteinite Pmnb Larnite P21/n MgSiO3 Pbcn γ**-**CaSiO4 Pnma SFCA phase P-1 Wollastonite P-1 SFCA-1 phase P-1 Wuestite Fm-3 m Quartz P3221**

*A small part of a diffraction pattern of one of the sinters. The marks show the positions of reflexes of all components of the sinter, according to their standard data taken from PDF-4+ file. Complexity of the pattern is caused by the number of reflexes.*

#### **Figure 5.**

*The RDI-1-3.15 (top) and RDI-1+6.3 (bottom) dependence on contents of magnetite in the examined sinters. The growing tendency of RDI-1-3.15 with growing content of magnetite and the opposite dependence of RDI-1+6.3 are shown.*

reflexes of all crystalline components are shown in a small range of a diffraction pattern of one of the sinters) also take part in forming the background. In this case, the careful manual removing of background before start of refinements should be used instead of the refinement of background.

The quantitative results show a noticeable dependence of RDI-1-3.15 on contents of all kinds of minerals, excluding amorphous component (**Figures 5**–**9**). The reverse dependence was observed for main components, namely magnetite and hematite.

#### **Figure 6.**

*The RDI-1-3.15 (top) and RDI-1+6.3 (bottom) dependence on contents of hematite in the examined sinters. The lowering tendency of RDI-1-3.15 with growing content of hematite (in a range of values of RDI-1-3.15 from 20 to 30) and the opposite dependence of RDI-1+6.3 are shown in Figure 7.*

**87**

**Figure 7.**

*sinters. No tendency is observed for both indices.*

*Application of X-Ray Diffraction to Study Mineralogical Dependence of Reduction…*

The lower value of RDI-1-3.15 (the lower means the better) corresponded with higher values of content of hematite (but not in a full range of values of RDI-1-3.15) and with lower values of magnetite. No clear tendency was noticed for amorphous component. Unexpectedly the quite high content of dicalcium silicates and also slag phases accompanied the lowest values of RDI-1-3.15. As an explanation of the results, one could assume that both, silicates and slags, could form a kind of binder among grains of other minerals and because of it had an effect on obtaining the low values of RDI-1-3.15.

*The RDI-1-3.15 (top) and RDI-1+6.3 (bottom) dependence on contents of amorphous component in the examined* 

*DOI: http://dx.doi.org/10.5772/intechopen.95086*

*Application of X-Ray Diffraction to Study Mineralogical Dependence of Reduction… DOI: http://dx.doi.org/10.5772/intechopen.95086*

**Figure 7.**

*Iron Ores*

reflexes of all crystalline components are shown in a small range of a diffraction pattern of one of the sinters) also take part in forming the background. In this case, the careful manual removing of background before start of refinements should be

The quantitative results show a noticeable dependence of RDI-1-3.15 on contents of all kinds of minerals, excluding amorphous component (**Figures 5**–**9**). The reverse dependence was observed for main components, namely magnetite and hematite.

*The RDI-1-3.15 (top) and RDI-1+6.3 (bottom) dependence on contents of hematite in the examined sinters. The lowering tendency of RDI-1-3.15 with growing content of hematite (in a range of values of RDI-1-3.15 from 20 to* 

*30) and the opposite dependence of RDI-1+6.3 are shown in Figure 7.*

used instead of the refinement of background.

**86**

**Figure 6.**

*The RDI-1-3.15 (top) and RDI-1+6.3 (bottom) dependence on contents of amorphous component in the examined sinters. No tendency is observed for both indices.*

The lower value of RDI-1-3.15 (the lower means the better) corresponded with higher values of content of hematite (but not in a full range of values of RDI-1-3.15) and with lower values of magnetite. No clear tendency was noticed for amorphous component. Unexpectedly the quite high content of dicalcium silicates and also slag phases accompanied the lowest values of RDI-1-3.15. As an explanation of the results, one could assume that both, silicates and slags, could form a kind of binder among grains of other minerals and because of it had an effect on obtaining the low values of RDI-1-3.15.

#### **Figure 8.**

*The RDI-1-3.15 (top) and RDI-1+6.3 (bottom) dependence on contents of a sum of dicalcium silicates in the examined sinters. The linear, lowering tendency with increasing content of dicalcium silicates is seen for RDI-1- 3.15 No tendency is seen for RDI-1+6.3.*

The dependence of RDI-1+6.3 values on fractions of mineral components of sinters was also considered (**Figures 5**–**9**). As in of RDI-1-3.15 case, magnetite and hematite contents showed a linear dependence from RDI-1+6.3 values; the increasing values of RDI-1+6.3 were related with lower values of magnetite contents and higher values of hematite fractions. The other minerals did not show so clear regularities.

The observed dependencies of RDI-1-3.15 on basicity is shown in **Figure 10** - the higher value of basicity the lower RDI-1-3.15 was obtained what can be thought as

**89**

**Figure 9.**

*Application of X-Ray Diffraction to Study Mineralogical Dependence of Reduction…*

a beneficial result. In comparison, the rise of FeO content (not as a mineral, but as Fe2+ recalculated to oxide) gives higher values of RDI-1-3.15 (**Figure 10**) what is an unfavorable tendency. This result is in accordance with the results for magne-

*The RDI-1-3.15 (top) and RDI-1+6.3 (bottom) dependence on contents of a sum of slag phases in the examined* 

tite (FeO.Fe2O3) (**Figure 5**) which is the main source of Fe2+ in sinters

*sinters. It can be seen that higher content of slag phases lowers the value of RDI-1-3.15.*

*DOI: http://dx.doi.org/10.5772/intechopen.95086*

*Application of X-Ray Diffraction to Study Mineralogical Dependence of Reduction… DOI: http://dx.doi.org/10.5772/intechopen.95086*

**Figure 9.**

*Iron Ores*

**88**

**Figure 8.**

*3.15 No tendency is seen for RDI-1+6.3.*

The dependence of RDI-1+6.3 values on fractions of mineral components of sinters was also considered (**Figures 5**–**9**). As in of RDI-1-3.15 case, magnetite and hematite contents showed a linear dependence from RDI-1+6.3 values; the increasing values of RDI-1+6.3 were related with lower values of magnetite contents and higher values of hematite fractions. The other minerals did not show so clear regularities. The observed dependencies of RDI-1-3.15 on basicity is shown in **Figure 10** - the higher value of basicity the lower RDI-1-3.15 was obtained what can be thought as

*The RDI-1-3.15 (top) and RDI-1+6.3 (bottom) dependence on contents of a sum of dicalcium silicates in the examined sinters. The linear, lowering tendency with increasing content of dicalcium silicates is seen for RDI-1-*

*The RDI-1-3.15 (top) and RDI-1+6.3 (bottom) dependence on contents of a sum of slag phases in the examined sinters. It can be seen that higher content of slag phases lowers the value of RDI-1-3.15.*

a beneficial result. In comparison, the rise of FeO content (not as a mineral, but as Fe2+ recalculated to oxide) gives higher values of RDI-1-3.15 (**Figure 10**) what is an unfavorable tendency. This result is in accordance with the results for magnetite (FeO.Fe2O3) (**Figure 5**) which is the main source of Fe2+ in sinters

#### **Figure 10.**

*The dependence of RDI-1-3.15 on basicity CaO/SiO2 (top) and on FeO content (bottom) in sinters with calculated tendency lines.*
