Claims:We Claim:
1. A method of producing briquettes suitable for pelletization involving Cold rolling mill (CRM) oily sludge comprising :
thoroughly mixing the Cold rolling mill (CRM) oily sludge with Calcium rich source as hardner and binder ;
subjecting the thus mixed Cold rolling mill (CRM) oily sludge with Calcium rich source as hardner and binder to natural curing for a period of 24 to 72hrs preferably about 48 Hrs such as to reduce the moisture content in the level of 1 to 3% preferably about 2% ;and
obtaining from the agglomerate mix with controlled moisture content the briquettes of said Cold rolling mill (CRM) oily sludge.

2.The method as claimed in claim 1 wherein said binder and hardeners are added to CRM oily sludge and thoroughly mixed in a paddle mixer and thereafter said agglomerated mix is subjected to step of pelletizing comprises adding said cured agglomerated mix as raw material into micropellet drum pelletizing machine to generate spherical shaped briquettes of size 1-5 mm including iron, carbon and flux material suitable for sintering processes.
3.The method as claimed in anyone of claims 1 or 2 wherein said calcium rich sources include calcium rich process wastes including Calcined lime, Limestone dolomite fines, KR Slag, BOF slag and Bentonite.
4.The method as claimed in anyone of claims 1 to 3 wherein the material used and ranges are as hereunder:
Materials used % Range Preferable %
CRM oily sludge 40-60 50
Calcined lime 10-30 20
Limedolo fines 10-20 10
KR slag 5-15 10
BOF slag 5-15 10
Bentonite 1-5 3

5. The method as claimed in anyone of claims 1 to 4 wherein the oil sludge used comprises 8-10% moisture, 35-40% of oil content, 20-25% Iron content and 25-30% of carbon contentand said binder comprises organic polymer binder of poly acrylic emulsion and inorganic bentonite.

6. The method as claimed in anyone of claims 1 to 5 comprising providing micropellets involving agglomerate produced from cold rolling mill oily sludge from 0.5-2.0 % preferably 1% maintaining the micropellt size of 1-5 mm.

7.Cold rolling mill (CRM) oily sludge including briquettes and pellets therefrom including micropellets suitable for use in iron ore sintering processes comprising by wt%:

CRM oily sludge 40-60
Calcined lime 10-30
Limedolo fines 10-20
KR slag 5-15
BOF slag 5-15
Bentonite 1-5

8.Cold rolling mill (CRM) oily sludge including briquettes and pellets therefrom as claimed in claim 7 wherein pellets comprise micropellets involving agglomerate produced from cold rolling mill oily sludge from 0.5-2.0 % preferably 1%.

9. The Cold rolling mill (CRM) oily sludge including briquettes and pellets therefrom as claimed in anyone of claims 7 or 8 wherein said pellets include micropellets having :
(I) Physical properties of micro pellets

Moisture,% 11.9
+8mm,% 13.6
+6.3mm,% 5.4
+5mm,% 5.8
+3.15mm,% 14.2
+1mm,% 32.7
-1mm,% 28.3
+100# 82.3
-100# 17.7
MPS,mm 4.2

(II) Chemical properties of micro pellets

Fe(T) ,% 39.7
SiO2,% 7.7
Al2O3,% 3.0
CaO,% 22.1
MgO,% 3.6
MnO,% 0.7
TiO2,% 0.2
P,% 0.4
Na2O,% 0.5
K2O,% 0.2
LOI,% 12.6
C,% 10.3

Dated this the 11th day of March, 2022
Anjan Sen
Of Anjan Sen & Associates
(Applicant’s Agent)
IN/PA-199
, Description:FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

1 TITLE OF THE INVENTION :
A METHOD OF PRODUCING BRIQUETTES INVOLVING CRM OILY SLUDGE BY AGGLOMERATING WITH CALCIUM RICH PROCESS WASTES TO OBTAIN MICROPELLETS.



2 APPLICANT (S)

Name : JSW STEEL LIMITED.

Nationality : An Indian Company incorporated under the Companies Act, 1956.

Address : JSW CENTRE,
BANDRA KURLA COMPLEX,
BANDRA(EAST),
MUMBAI-400051,
MAHARASHTRA,INDIA.




3 PREAMBLE TO THE DESCRIPTION

COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION

The present invention relates to a method of producing agglomerates of cold rolling mill(CRM) oily sludge by adding calcium rich process waste generated in BOF process of steel plant, alongwith a binder, wherein said agglomerates are obtained in the form of briquettes suitable for use in micropellet plant raw material mix and then to use in iron ore sintering process. Calcium rich process wastes i.e. Calcined lime, Limestone dolomite fines, KR Slag, BOF slag are used as hardener in this agglomeration process. These calcium rich process waste materials act as hardener and bentonite is used as binder. The lime present in these materials reacts with moisture present in oily sludge and promotes pozzolonic reaction which will creates bonding between iron, carbon and flux elements.The produced micropellets are feeded to iron ore sintering plant upto 5% as iron, carbon and calcium replacement material. This process solves the handling and disposal problem of CRM oily sludge by in-house utilization of same in iron ore sintering in the form of micropellets.

BACKGROUND OF THE INVENTION

Applicant’s(JSW Steel Limted) Steel manufacturing plant at Vijayanagar works is having several facilities for process waste recycling such as tailing beneficiation plant, mill scale briquetting, micro pellet plant and iron recovery plant which recycle various types of sludge and dust. Integrated steel plant generates substantial amount of iron and carbon rich process wastes right from ore beneficiation to steel rolling operations.

Vegetable oil is used in Pickling Line Tandem Cold Mill (PLTCM) of CRM unit as a coolant. When this oil after rolling mixes with iron dust and forms oily sludge which is a waste. This oily sludge is basically ester based triglyceride contains 10% moisture content, 40% iron oxide and rest 50% is oil content.JSW CRM unit generates around 8 tons of oily sludge per day from its CRM 1&2 units.

This oily sludge contains 8-10% moisture, 35-40% of oil content, 20-25% Iron content and 25-30% of carbon content. The oily sludge is basically triglyceride ester based and is typical in nature with pungent smell and. It is also difficult to store and transport this sludge due to generation of methane and hydrogen through anaerobic fermentation. Presently no method is available to recycle the CRM oily sludge.

This sludge cannot be used in as received condition in any of the process of steel industry because of its oil content, pungent smell and high viscosity.Disposal of this sludge is a concern because of the anaerobic fermentation occurs which releases methane and hydrogen sulphide gases and at the same time incineration of this sludge causes air pollution.

US patent no.4091545 describes the process of moisture reduction from rolling mill sludge at a temperature of around 150oC and then feeding the same into sintering process to evaporate the oil content with the use of heat produced during sintering.

Whereas present invention undertakes to add hardening agent to CRM oily sludge to heat naturally through reaction between lime and water present in the oily sludge.

US patent no 5885328 describes the method of mixing oil containing steel mill waste with another steel mill waste which is dry in nature and then agglomerate the both to form pellets and then reduction these pellets to form reduced iron to use in Electric Arc furnace to produce steel.

Whereas present invention directs to a process ted to mixing of CRM oily sludge with calcium rich process waste and then agglomerating in the form of briquettes suitable to use in micropellet plant raw material mix and then to use in iron ore sintering process.

US patent no.7531046 directed to a process for treating an oily mixture consisting of hydrocarbons, Solid particles, and water with steam in a reactor chamber, purging the reactor chamber with an inert gas, and creating a steam bath within the inert gas filled reactor chamber. The steam makes separate hydrocarbon matter from the solid particles at higher temperatures of >500o C.

The cited invention is about mixing of CRM oily sludge with steam and then induration of the mix above 500 o C. Whereas present invention deals with cold mixing of CRM oily sludge with calcium rich process waste and then in the form of briquettes suitable to use in micropellet plant raw material mix and then to use in iron ore sintering process.

OBJECTS OF THE INVENTION

The basic objectof the present invention is to develop a method of inhouse recycling of CRM oily sludge to be utilized in making agglomerate suitable for use in iron ore sintering process in the form of micropellets.

Another object of the present invention is to solve the disposal and handling problem of CRM oily sludge which poses an environmental concern.

A further object of the present invention is directed to a method of agglomerating CRM oily sludge by mixing withcalcium rich process waste generated in BOF process of steel plant as hardener, alongwith bentonite as binder, so as to obtainin the form of briquettes suitable for use in micropellet plant raw material mix and then to use in iron ore sintering process.

SUMMARY OF THE INVENTION

The basic aspect of the present invention is directed to a method of producing briquettes suitable for pelletization involving Cold rolling mill (CRM) oily sludge comprising :
thoroughly mixing the Cold rolling mill (CRM) oily sludge with Calcium rich source as hardner and binder ;
subjecting the thus mixed Cold rolling mill (CRM) oily sludge with Calcium rich source as hardner and binder to natural curing for a period of 24 to 72hrs preferably about 48 Hrs such as to reduce the moisture content in the level of 1 to 3% preferably about 2% ;and
obtaining from the agglomerate mix with controlled moisture content the briquettes of said Cold rolling mill (CRM) oily sludge.

A further aspect of the present invention is directed to said method wherein said binder and hardeners are added to CRM oily sludge and thoroughly mixed in a paddle mixer and thereafter said agglomerated mix is subjected to step of pelletizing comprises adding said cured agglomerated mix as raw material into micropellet drum pelletizing machine to generate spherical shaped briquettes of size 1-5 mm including iron,carbon and flux material suitable for sintering processes.
A still further aspect of the present invention is directed to said method wherein said calcium rich sources include calcium rich process wastes including Calcined lime, Limestonedolomite fines, KR Slag, BOF slag and Bentonite.
A still further aspect of the present invention is directed to said method wherein the material used and ranges are as hereunder:
Materials used % Range Preferable %
CRM oily sludge 40-60 50
Calcined lime 10-30 20
Limedolo fines 10-20 10
KR slag 5-15 10
BOF slag 5-15 10
Bentonite 1-5 3

A further aspect of the present invention is directed to said method wherein the oil sludge used comprises 8-10% moisture, 35-40% of oil content, 20-25% Iron content and 25-30% of carbon contentand said binder comprises organic polymer binder of poly acrylic emulsion and inorganic bentonite

Another aspect of the present invention is directed to said method comprising providing micropellets involving agglomerate produced from cold rolling mill oily sludge from 0.5-2.0 % preferably 1% maintaining the micropellet size of 1-5 mm

Yet another aspect of the present invention is directed to Cold rolling mill (CRM) oily sludge including briquettes and pellets therefrom including micropellets suitable for use in iron ore sintering processes comprising by wt%:

CRM oily sludge 40-60
Calcined lime 10-30
Limedolo fines 10-20
KR slag 5-15
BOF slag 5-15
Bentonite 1-5

A further aspect of the present invention is directed to said Cold rolling mill (CRM) oily sludge including briquettes and pellets therefrom wherein pellets comprise micropellets involving agglomerate produced from cold rolling mill oily sludge from 0.5-2.0 % preferably 1%.

A still further aspect of the present invention is directed to said Cold rolling mill (CRM) oily sludge including briquettes and pellets therefrom wherein said pellets include micropellets having :
(I) Physical properties of micro pellets

Moisture,% 11.9
+8mm,% 13.6
+6.3mm,% 5.4
+5mm,% 5.8
+3.15mm,% 14.2
+1mm,% 32.7
-1mm,% 28.3
+100# 82.3
-100# 17.7
MPS,mm 4.2

(II) Chemical properties of micro pellets

Fe(T) ,% 39.7
SiO2,% 7.7
Al2O3,% 3.0
CaO,% 22.1
MgO,% 3.6
MnO,% 0.7
TiO2,% 0.2
P,% 0.4
Na2O,% 0.5
K2O,% 0.2
LOI,% 12.6
C,% 10.3

The above and other aspects and advantages of the present invention are described hereunder in greater details with reference to following accompanying non limiting illustrative drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1:Schematic flow diagram of the present cold rolling mill oily sludge generation process.
Fig. 2: Schematic flow diagram of the novel process of agglomerating the cold rolling mill oily sludge and its in-house utilization.
Fig 3: shows Agglomerate of CRM oil sludge with calcium rich waste .
Fig 4: shows the Micropellets made with 1% CRM oil sludge agglomerates.
Fig. 5: illustrates Microscopic and elemental analysis of Agglomerate of CRM oil sludge with calcium rich waste.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

The present invention describes the method of making agglomerates of CRM oil sludge by adding calcium rich process waste generated from steel plant such as calcined lime, KR slag, BOF slag and BOF sludge by using inorganic binder bentonite. Both the CRM oily sludge and calcium rich process wastes are mixed thoroughly and then subjected to natural curing for 72hrs to reduce the moisture content from 10% to 2%. The produced lumpy mass is blended with micro pellet plant raw materials upto 1% to produce micropellets of size 2-5mm. These calcium rich process waste materials are acts as hardener. The lime content (CaO) present in these materials reacts with moisture present in oily sludge andoccurs pozzolonic reaction which will creates bonding between iron, carbon and flux elements. The produced micropellets are feeded to iron ore sintering plant upto 5% as iron, carbon and calcium replacement material. This process solves the handling and disposal problem of CRM oily sludge by in-house utilization of same in iron ore sintering in the form of micropellets.

Accompanying Fig. 1 shows the schematic flow diagram of the present cold rolling mill oily sludge generation process wherein following items are shown:

# Particulars
1 Cold rolling mill
2 Vegetable oil used as coolant
3 Iron oxide scaling
4 CRM oily sludge

In the process as shown in Fig 1 of cold rolling mills [1] Vegetable oil [2] is used in Pickling Line Tandem Cold Mill (PLTCM) of CRM unit as a coolant. When this oil after rolling mixes with iron dust [3] and forms oily sludge [4] which is a process waste.

Accompanying Fig. 2 shows schematic flow diagram of the novel process of agglomerating the cold rolling mill oily sludge and its in-house utilization.

CRM oil sludge is generated from the process of cold rolling [5] due to the mixing of vegetable oil used as coolant mixes with iron oxide deposit. The produced CRM oil sludge [8] is mixed with bentonite binder [6], lime rich process wastes[7] as a hardener. Both these binder and hardeners are added to CRM oily sludge and thoroughly mixed in a paddle mixer [9]. The mixed material [10] is cured in a normal atmosphere for 72 hrs to reduce the moisture and then added into the micropellet drum pelletizing machine [11] as a raw material for micro pellets. The produced micropellets [12] which are spherical in shape with size of 1-5mm is used in iron ore sintering process as a iron, carbon and flux material feed.

Characteristics of oily sludge is given in following table 1:

Table 1: Characterization of as received oil sludge
Colour Dark brown
Appearance Sludge cake
Specific gravity, gm/cc 1.2
Moisture, % 10.0
Oil content, % 60.0
Solid content, % 30.0
Residue analysis
Carbon, % 35.0
Fe, Total % 43.0
Sulphur, % 1.70
Loss on ignition, % 1.81

Calcium rich process wastes i.e.Calcined lime, Limestone dolomite fines, KR Slag, BOF slag are used as binders in this agglomeration process. The present work describes a method of developing agglomerates of CRM oily sludge by adding calcium rich process waste generated in BOF process of steel plant. These calcium rich process waste materials are acts as hardener and bentonite is used as binder. The lime present in these materials reacts with moisture present in oily sludge and occurs pozzolonic reaction which will creates bonding between iron, carbon and flux elements. Chemical analysis of various calcium rich process wastes are given in following table 2.Swelling and water absorption test of the ingredients of CRM oily sludge is conducted and the results are shown in following table 3.

Table 2: Chemical analysis of various calcium rich process wastes

CaO,
% Fe2O3,
% Sio2,
% Al2O3,
% MgO,
% Na2O,
% K2O,
% S,
% P2O5,
% LOI,
%
Calcined lime 90.0 0 0.10 0.20 1.5 0 0 0.01 0 8.20
Limestone
dolomite fines 51.0 5.0 7.00 3.30 21.0 1.50 2.70 0.05 0.25 8.20
KR slag 69.65 13.98 6.11 0.74 0.65 0.22 0.01 1.83 0.10 16.36
RO sludge 40.50 1.50 8.62 0.81 15.10 0.667 0.023 1.0 0.45 32.0
BOF slag 43.47 25.0 12.24 1.71 8.31 0.05 0.04 0.05 1.0 8.13
Bentonite 1.78 3.22 49.17 18.99 2.92 3.870 0.175 0.283 0.094 7.70

Table 3: Swelling and water absorption test
S.NO Sample Name Plate Water Absorption
(PWA)% Swelling number
1 Calcined lime fines 165 5
2 Limestone dolomite fines 53 3
3 KR Slag 46 2
4 RO sludge 38 3
5 BOF slag 42 4
6 Bentonite 610 22

Accompanying Fig 3 shows Agglomerate of CRM oil sludge with calcium rich waste .

Chemical analysis of the agglomerate produced from CRM oily sludge produced according to present invention is given in following table 4.

Table 4: Chemical analysis of the agglomerate produced from CRM oily sludge

Carbon, % 28.0
CaO, % 36.0
Fe2O3, % 15.0
SiO2, % 7.2
Al2O3,% 4.8
MgO, % 5.0
LOI, % 32.0

Proportion of blend used in agglomeration process of the invention is mentioned in table 5 below:

Table 5: Material proportion mix

Materials used % Range Preferable %
CRM oily sludge 40-60 50
Calcined lime 10-30 20
Limedolo fines 10-20 10
KR slag 5-15 10
BOF slag 5-15 10
Bentonite 1-5 3

Accompanying Fig 4 shows the Micropellets made with 1% CRM oil sludge agglomerates.

Accompanying Figure 5 shows (a) Microscopic and (b) elemental analysis of Agglomerate of CRM oil sludge with calcium rich waste as given below:

Physical properties of micro pellets produced according to present invention are given in following table 6 and Chemical properties of micro pellets are given in following table 7.

Table 6: Physical properties of micro pellets

Moisture,% 11.9
+8mm,% 13.6
+6.3mm,% 5.4
+5mm,% 5.8
+3.15mm,% 14.2
+1mm,% 32.7
-1mm,% 28.3
+100# 82.3
-100# 17.7
MPS,mm 4.2

Table 7: Chemical properties of micro pellets

Fe(T) ,% 39.7
SiO2,% 7.7
Al2O3,% 3.0
CaO,% 22.1
MgO,% 3.6
MnO,% 0.7
TiO2,% 0.2
P,% 0.4
Na2O,% 0.5
K2O,% 0.2
LOI,% 12.6
C,% 10.3

It is thus possible by way of the present invention to provide a method of developing agglomerates of CRM oily sludge by adding calcium rich process waste generated in BOF process of steel plant. These calcium rich process waste materials are acts as hardener and bentonite is used as binder. The lime present in these materials reacts with moisture present in oily sludge and promotes pozzolonic reaction which will creates bonding between iron, carbon and flux elements. The produced agglomerates in the form of briquettes are cured in atmosphere for 72hrs to reduce the moisture from 10% to 2%. The produced agglomerate is blended with micro pellet plant raw materials upto 1% to produce micropellets of size 1-5mm. The produced micropellets are used in iron ore sintering plant upto 5% as iron, carbon and calcium replacement material. This process solves the handling and disposal problem of CRM oily sludge by in-house utilization of same in iron ore sintering in the form of micropellets.