FIELD OF THE INVENTION
The invention relates to a method of producing highly reactive coke through briquette
making route.
BACKGROUND OF THE INVENTION
In India, iron and steel industry is growing rapidly. The major raw materials for iron and
steel industry are coal and iron ore. Coal is converted into coke in coke ovens and
charged along with iron bearing materials such as iron ore lumps, sinter and pellets into
blast furnace. The main function of the coke in the blast furnace is to provide the heat,
reducing gases, permeability to ascending gases and support the burden. So, the coke
is an important raw material for the blast furnace. Different types of coals are blended
and cake is made in stamping machine, which is then charged into coke ovens. The
blending ratio is selected in such a way that coal cake remains stable when charged
into coke oven. Different types of coking coals such as prime, medium and weak are
used to make the coke. But coking coals reserves are very limited all over the world.
Also, price of the coking coals fluctuates so much that it becomes very costly for those
who imports the coking coals from other countries. It is very difficult to use non-coking
coals along with coking coals in conventional coke making set up as it will decrease the
cake strength. So, the first target of this application is to use non-coking coals in the
coke making process effectively.
Today, steel industry faces major challenges in terms of energy intensive processes,
CO2 emissions and cost of raw materials. A long-term research work on a wide
spectrum of innovative low-carbon technologies is still required before they can be
employed at an industrial scale. Hence, there is a need to develop a new coke making
process and produce coke which can react fast and emit less CO2 from the blast
furnace. The reactive coke will reduce starting temperature of gasification. This will
reduce thermal reserve zone temperature and hence, will decrease reducing agent ratio
in the blast furnace. Reactive coke can be produced by using non-coking coals and iron
bearing materials such as iron ore and slime. Use of non-coking coals along with iron
ore and slime in coal blending will make the cake unstable. So, there is a need to

produce reactive coke through different route to accommodate non-coking coals, iron
ore and slime. Therefore, second objective of this application is to produce reactive
coke through briquette making process (for example, see non-patent literature 1).
Use of non-coking coals and iron ore will increase the reactivity of the coke and
decrease the strength. Briquettes also need a sufficient strength to sustain in the blast
furnace. Both these challenges are solved by using binding materials in briquette
making. The binding materials will give the sufficient strength to briquette. Hence, third
objective is to use different types of binding materials (called “binder”) in briquette
making process.
In order to prevent the dust problem, form coke coated with glanz carbon was produced
by US scientist (for example, see patent literature 1). The impact of produced ferro coke
in the blast furnace in terms of reducing thermal reserve zone and increasing coke
reactivity was investigated at different heating rate (for example, see patent literature 2).
The effect of CO2 reactivity of coke in ferrocoke inside a blast furnace was studied (for
example, see patent literature 3).
Applicants’ Admitted Prior Art
A. Patent literature
1) Publish US patent application no.US3725018
2) Published European patent application no. EP 2233548 A1
3) Published European patent application no. EP 2543716 A
B. Non-Patent literature
Non-Patent literature 1: "JFE Annual Report" 22, 2008, p. 20
OBJECT OF THE INVENTION
It is therefore an object of the invention to propose a method of producing highly
reactive coke through briquette making route, which reduces the reducing agent ratio.
Another object of the invention is to propose a method of producing highly reactive coke
through briquette making route, which is enabled to use different binders.

SUMMARY OF THE INVENTION
In order to solve the above problems and achieve the objective, the present invention
provides a highly reactive coke manufacturing method for producing briquettes by
mixing coking coal, non-coking coal, iron ore, slime, moisture and binders such as coal
tar, coal tar pitch, organo-refined extract (called “OR-extract”), petroleum pitch and
phenolic resin. The raw materials are mixed and required amount of moisture is added
in the mix. This mix is filled in a hollow cylindrical mould and pressed using a hydraulic
press machine to make the briquettes. These briquettes are either cured and then
carbonized or carbonized directly to get the maximum strength. The cold compressive
strength (CCS) is measured for each briquettes (green, cured, and carbonized). The
non-coking coal is varied from 50% to 90%, iron ore is varied from 5% to 30%, binder is
varied from 0.5% to 10%, moisture varied from 5% to 15%, applied load varied from 1 to
15 ton, curing temperature varied from 25oC to 200oC, and carbonization temperature
varied from 700 to 1000oC.The product is called highly reactive coke (“HR Coke”).
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows the process flow diagram of HR coke through briquette method
Figure 2 shows the horizontal reactor furnace
Figure 3 shows the briquettes
DETAILED DESCRIPTION OF THE INVENTION
The inventors of the present invention studied the method of producing HR coke
briquettes using coking coal, non-coking coal, iron ore/slime, and binder, arrangements
to cure and carbonize the briquettes, including testing of the produced briquettes for its
strength (called “CCS”). Here, in present invention, coal includes coking coal which
shows caking property, and non-coking coals which do not show any caking property.
To increase the reactivity, iron ore or slime is used. To enhance the strength, petroleum
pitch, phenolic resin, coal tar, coal tar pitch and OR extract (solvent extracted coal) is
used as a binder.

The process flow is mentioned in the Figure 1. As per Figure 1, coal, iron ore, slime and
binder are grinded in a grinding machine (1) separately for desired size. The raw
materials size is very important in briquetting process. The grinded samples are stored
in their respective bins/storage area separately to avoid any mixing. These samples are
then mixed in a desired ratio in a mixer (2). The mixer ensures proper mixing of different
raw materials, binders and catalyst (iron ore/slime) to homogenize the samples before
briquette making. Here, water also added in the mixture in order to maintain the desired
moisture level of the sample to be briquetting. Hence, this is an important step before
briquetting step. The homogenized mix sample is put into briquette making machine.
There are different types of briquetting machine is used such as hydraulic press
machine, roller press machine (having oval or pillow groves) and extruder machine. The
sample is pressed in the machine to make the briquettes. The pressure is varied in the
machine. The briquettes thus produced are called green briquettes. These briquettes
have less strength; hence they are subjected to drying (or curing) and carbonization.
These briquettes are cured in the dryer. The curing temperature is also varied. The
curing of briquettes increases its strength. The cured briquettes are then carbonized in a
horizontal furnace. The carbonization temperature is varied. Since carbonization is done
at high temperature some amount of metallization (conversion of Fe2O3 to FeO and Fe)
also take place in the briquette. The carbonization is done in the presence of inert gas
N2. The inert gas is flown continuously in the reactor. The heating of reactor takes place
at constant heating rate. The furnace temperature is maintained at constant
temperature for few hours once it reaches the maximum desired temperature. The
cooling of the briquette starts once the carbonization is completed. The briquettes are
taken out once the temperature reaches at room temperature. The briquette’s strength
is measured as cold compressive strength (CCS). The strength of green, cured and
carbonized briquettes are measured and compared with each other. The green
briquettes are also subjected to reactivity test. In the reactivity test CO2 gas is passed in
the horizontal reactor at 1000 oC temperature for one hour. This makes the similar
condition as of blast furnace. The CO2 gas reacts with carbon present in the briquettes
and makes carbon mono oxide. The initial and final weight of the briquettes is measured

and weight loss is calculated. The reaction between carbon and CO2 gas decreases the
weight of the briquette. The calculation of weight loss shows the reactivity.
Figure 1 shows the process flow diagram of HR coke. Figure 2 shows horizontal reactor
furnace. Figure 3 shows the image of briquettes. The present invention is described
below with reference to Fig. 1. Coking coals, non-coking coals and PCI (pulverized coal
injection) coals are taken for the study. Iron ore or slime is used as a catalyst to
increase the reactivity. Petroleum pitch, coal tar, coal tar pitch, phenolic resin and OR-
extract are taken as binder materials. Coking coals and non-coking coals are grinded
separately. They are mixed in different ratio ranging from 50% to 90% non-coking coal,
more preferably below 60%. The iron ore or slime is varied from 0% to 40%, more
preferably more than 10% and less than 30%. The binder material is varied from 0.1%
to 15%, more preferably above 0.5% and below 10%. The moisture is varied from 0% to
20%, more preferably between 5 to 15%. All these materials are mixed in the desired
ratio and briquette is formed at different load in the briquetting press. The briquette load
is varied from 1 ton to 20 ton, preferably more than 5 ton but less than 10 ton. These
are called green briquettes. The CCS of these green briquettes is measured. These
briquettes are cured in dryer and temperature is varied from 25 oCto 200 oC, more
preferably between 50 to 150 oC. The CCS of cured briquettes isalso measured. The
cured briquettes are then carbonized using horizontal reactor furnace in presence of N2
gas. In the horizontal reactor, either inert atmosphere or absence of air is maintained.
This makes the situation similar to coke making where carbon is not burnt because of
air. The carbonization of briquettes removes the volatile matters of the coal and also
converts some amount of iron oxide to Iron (Fe). The carbonized briquettes are tested
of CCS. The CCS of carbonized briquettes increases as coal passes through plastic
stage and re-solidification and also binder binds the entire materials.
EXAMPLE
Table 1 shows the proximate and ultimate analysis of different coals. Coal A is medium
coking coal. Coal B and coal C are PCI coals. Coal D is non-coking coal. Table 2 shows

the chemical analysis of two iron bearing materials. The iron bearing materials contain
total iron in the range of 60-61%.

Briquettes were produced using coal, iron ore/slime and binder through hydraulic press
machine and carbonized in horizontal reactor furnace. The raw materials analysis is
presented in Table 1 and 2. Different types of binder were used and tested to increase
the strength and enhancement of binding of materials. Different parameters such as
binder percentage, applied load, moisture percentage and curing temperature were
varied for each coal. The optimum value was found out on the basis of obtaining
maximum CCS. Coal A and coal B were showing increasing trend with increasing
applied load, binder content and curing temperature. While coal C and coal D were
showing revers trend with increasing curing temperature. Therefore, two coals with
increasing and decreasing trend were mixed to see the combined effect. Two coals

(coking and non-coking) were mixed (for example coal A and D) in different ratio. Non-
coking coal was varied from 50 % to 90% of coal mass. Here 90% non-coking coal
means, coking coal is 10% and non-coking coal is 90% in the coal mass, more
preferably between 50 to 60% of non-coking coal. Binders and catalyst were added to
the coal mass. The briquettes were prepared with mixed coals (coal A and D) and coal
tar as binder and iron ore as catalyst. Binder percentage, applied load and curing
temperature were varied for the mixed coal samples. Same increasing trend of CCS
was obtained. The CCS value increased with increasing applied load and reached
maximum value and then dropped. The CCS was increased with increasing binder
percentage, reached at maximum value and then decreased with further increasing of
binder percentage. The CCS was increased with increasing curing temperature.
Different binders such petroleum pitch, coal tar pitch, phenolic resin, and OR-extract
were used in different ratio and optimized different parameters such as iron ore
percentage, applied load, curing temperature and carbonization temperature to get the
maximum value of CCS. Few results with three different binders are presented in Table
3. Maximum strength was obtained in case of coal tar pitch. The strength of the
carbonized briquettes were as follows coal tar pitch > petroleum pitch > coal tar. The
strength of these briquettes is much higher than the pellets. The usual strength of the
pellets is in the range 180 to 200 kgf per pellets. The high strength of these briquettes
makes them suitable for blast furnace operation.


WE CLAIM
1. A method of producing highly reactive coke through briquette making route, the
method comprising;
grinding of coals to less than 3 mm size, grinding iron ore and slime to
less than 500 micron, adding binding materials and moisture and making
briquettes through briquetting machine and curing briquette through dryer
and carbonizing briquette through horizontal reactor furnace.
2. The method for producing highly reactive coke as claimed in claim 1, wherein
hydraulic press is used for briquette making.
3. The method for producing highly reactive coke as claimed in claim 1, wherein
dryer is used for curing of briquettes.
4. The method for producing highly reactive coke as claimed in claim 1, wherein
horizontal reactor furnace is used for carbonization of briquettes.
5. The method for producing highly reactive coke as claimed in claim 1, wherein
coking and non-coking are taken in 40:60 ratio.
6. The method for producing highly reactive coke as claimed in claim 1, wherein
petroleum pitch, coal tar, coal tar pitch, OR-extract and phenolic resin are used
as binder materials.
7. The method for producing highly reactive coke as claimed in claim 1, wherein
binder percentage is taken as 0.5 to 10 % (weight basis) of total mass.
8. The method for producing highly reactive coke as claimed in claim 1, wherein the
coal size is less than 500 micron.

9. The method for producing highly reactive coke as claimed in claim 1, wherein
iron ore size is less than 100 micron.
10. The method for producing highly reactive coke as claimed in claim 1, wherein
iron and lime is taken 5 to 10% (weight basis) of total mass.
11. The method for producing highly reactive coke as claimed in claim 1, wherein
applied load is 5 to 15 ton.
12. The method for producing highly reactive coke as claimed in claim 1, wherein
curing temperature is 50 to 150oC.
13. The method for producing highly reactive coke as claimed in claim 1, wherein
carbonization temperature is 700 to 1000oC.
14. The method for producing highly reactive coke as claimed in claim 1, wherein
moisture content is 7-12%
15. The method for producing highly reactive coke as claimed in claim 1, wherein
maximum CCS obtained was 855, 700 and 510 kgf for coal tar pitch, petroleum
pitch and coal tar respectively.