*1.2.3 Technological and ecological aspects of the production of sinters from poor and rich iron-bearing materials*

As part of the implementation of laboratory experiments on a laboratory sintering pot, the following iron-bearing raw materials were used for sintering, **Table 10**.

In the sintering process, standard coke breeze was used as fuel. These raw materials were incorporated in the prepared sintering mixtures, which had a basicity in the range of 1.7–2.8. The next relation was used to calculate the basicity: B = (wt.%CaO + wt.%MgO)/(wt.%SiO2 + wt.%Al2O3). It was therefore the production of highly basic sinters. The produced sinters had content of iron in the range of about 46–52%.

In the experiments, the ratio of ferriferous raw materials (Krivbas and Michajlov) – 100% sinter grade ore and 100% concentrate was changed. Concentrate Nižná Slaná was used in mixtures of sinter grade ore/concentrate. In this chapter, primarily the experiments with separate ferriferous raw materials are specified due to the more significant impact of fuel consumption on sinter quality.


essence of the sintering process – i.e. producing the sinter with the required production, qualitative and quantitative parameters, was not accomplished in this case. The theoretical minimal quantity of fuel is always required for sinter production, which depends on the physical–chemical properties of input iron bearing raw materials and basicity of the produced sinter. In the presence of 5% of coke in sintering mix, standard temperatures of 1150–1320°C were achieved in the sintered layer with 100% of sinter grade ore, resulting in sinter with the required properties. On the surface of individual grains, the melt was formed, and due to the low viscosity of the liquid phase, multiple grains were bound together producing a sinter. At 7% of coke in mixture, high temperatures (up to about 1420°C) were reached in the sintered layer, resulting in sinter with the extended melting phase. Similar connections were found in the sintering of iron concentrates, with the fact that at higher fuel content (8% of coke) the sinter was disintegrated. A high FeO content was determined in this sinter (14.23%), which was a significant increase compared to FeO content in the charge (5.2%). Since the added fuel was probably not uniformly distributed into the individual grains (some were already partially sintered), there might have been microvolumes with a higher proportion of fuel. In these volumes, reducing conditions were created with high temperatures (up to about 1440°C), under which higher Fe2O3 and Fe3O4 oxides were reduced to FeO. In some samples of the sinter, break-up of sinter was observed. The disintegration of the sinter is sometimes associated with the formation of dicalcium silicate, sometimes with higher content of fuel. When using poor iron concentrate Nižná Slaná in the mixtures, higher amounts of fuel had to be used and the properties of

*Advances in Sintering of Iron Ores and Concentrates DOI: http://dx.doi.org/10.5772/intechopen.94051*

the sinter were not adequate for the blast furnace process.

burden (approx. 3–7% depending on the basicity).

parameters of the produced sinter are achieved.

optimization of the underpressure, etc.) [10].

following points:

gases.

layer.

**71**

The achieved results from laboratory experiments can be summarized in the

• Theory and balance calculations of the sintering process defined fuel (coke breeze) were the main source of gaseous emissions of CO and CO2 in the flue

• Due to the production of a highly basic sinter, a certain amount of CO2 passes into the flue gas also through the dissociation of carbonates present in the

• By reducing the underpressure, the temperature level in the sintered layer increases, the yield of the produced sinter is increased and the required quality

• It has been found that increasing the fuel in the sintering charge increases the FeO content in the sinter. This fact is also confirmed by the effect of increasing FeO in the sinter with an increase in temperatures in the sintered

• By increasing the ratio of concentrate/ore in the sintering burden (from 1.2 to

• Technological recommendations were proposed in terms of achieving the required qualitative and quantitative parameters of the sintering process with emphasis on reducing CO and CO2 emissions. Among the most important can be mentioned regular control of the permeability of the sintering charge, control and regulation of the vertical sintering rate in operating conditions,

1.8) there was a decrease in the yield of the produced sinter.

#### **Table 10.**

*Chemical analysis of iron materials for sintering.*

**Table 11** shows a thermal profile and sinter made by sintering using 100% sinter grade ore, while coke breeze was used for sintering. Due to lack of fuel (3% of coke in mixture), there were low temperatures of 600–900°C in the sintered layer. The sinter had unacceptable properties – only some microgranules were connected. The


**Table 11.**

*Production of sinters in laboratory conditions.*

## *Advances in Sintering of Iron Ores and Concentrates DOI: http://dx.doi.org/10.5772/intechopen.94051*

essence of the sintering process – i.e. producing the sinter with the required production, qualitative and quantitative parameters, was not accomplished in this case. The theoretical minimal quantity of fuel is always required for sinter production, which depends on the physical–chemical properties of input iron bearing raw materials and basicity of the produced sinter. In the presence of 5% of coke in sintering mix, standard temperatures of 1150–1320°C were achieved in the sintered layer with 100% of sinter grade ore, resulting in sinter with the required properties. On the surface of individual grains, the melt was formed, and due to the low viscosity of the liquid phase, multiple grains were bound together producing a sinter. At 7% of coke in mixture, high temperatures (up to about 1420°C) were reached in the sintered layer, resulting in sinter with the extended melting phase. Similar connections were found in the sintering of iron concentrates, with the fact that at higher fuel content (8% of coke) the sinter was disintegrated. A high FeO content was determined in this sinter (14.23%), which was a significant increase compared to FeO content in the charge (5.2%). Since the added fuel was probably not uniformly distributed into the individual grains (some were already partially sintered), there might have been microvolumes with a higher proportion of fuel. In these volumes, reducing conditions were created with high temperatures (up to about 1440°C), under which higher Fe2O3 and Fe3O4 oxides were reduced to FeO. In some samples of the sinter, break-up of sinter was observed. The disintegration of the sinter is sometimes associated with the formation of dicalcium silicate, sometimes with higher content of fuel. When using poor iron concentrate Nižná Slaná in the mixtures, higher amounts of fuel had to be used and the properties of the sinter were not adequate for the blast furnace process.

The achieved results from laboratory experiments can be summarized in the following points:


**Table 11** shows a thermal profile and sinter made by sintering using 100% sinter grade ore, while coke breeze was used for sintering. Due to lack of fuel (3% of coke in mixture), there were low temperatures of 600–900°C in the sintered layer. The sinter had unacceptable properties – only some microgranules were connected. The

Iron ore (100%) 3 600–900

Iron ore (100%) 5 1150–1320

Iron ore (100%) 7 1180–1420

4 530–1020

6 1130–1350

8 1210–1440

**Iron ore material Fe FeO Fe2O3 Mn SiO2 Al2O3 CaO MgO P S Na2O K2O**

Sinter grade ore Krivbas

Concentrate Michajlov

Concentrate Nižná Slaná

Iron concentrate (100%)

Iron concentrate (100%)

Iron concentrate (100%)

*Production of sinters in laboratory conditions.*

**Table 11.**

**70**

*Chemical analysis of iron materials for sintering.*

**Iron burden Coke breeze**

**(%)**

**Table 10.**

*Iron Ores*

**(wt.%)**

60.70 0.14 86.26 0.02 9.61 1.35 0.07 0.06 0.05 0.02 0.29 0.08

64.52 23.57 66.44 0.01 8.60 0.06 0.19 0.09 0.01 0.01 0.08 0.20

51.76 20.02 45.19 1.97 5.30 1.83 3.82 6.58 0.08 0.12 0.07 0.42

**Photo Mechanism Temperatures**

**(°C)**
