Title of Invention	A process for production of iron ore super concentrate of ferrite grade from blue dust.
Abstract	The invention relates to a process for the production of iron ore super concentrate of ferrite grade from blue dust by grinding the blue dust having a combined silica and alumina of maximum 4-5% and iron more than 64% to the size below 75 micron, discarding light aluminium impurities by known methods to obtain the concentrate, conditioning the concentrate at pH 10 to 1C.5 with glucopyra-nose polymer and alkylamine, removing the undesirable silica/silicates and alumina minerals by floatation methods to obtain superconcentrate iron ore.

Title of Invention

A process for production of iron ore super concentrate of ferrite grade from blue dust.

Abstract

The invention relates to a process for the production of iron ore super concentrate of ferrite grade from blue dust by grinding the blue dust having a combined silica and alumina of maximum 4-5% and iron more than 64% to the size below 75 micron, discarding light aluminium impurities by known methods to obtain the concentrate, conditioning the concentrate at pH 10 to 1C.5 with glucopyra-nose polymer and alkylamine, removing the undesirable silica/silicates and alumina minerals by floatation methods to obtain superconcentrate iron ore.

Full Text	This invention relates to a process for the production of iron ore super concentrate of ferrite grade from blue dust. The present invention is for a process leading to produce high purity iron oxide (iron ore superconcentrate) from naturally occurring iron oxide ore (blue dust). The superconcentrates can be used as raw materials in the manufacture of hard ferrites to be used in electrical and electronic industries. The product in the form of fine powder is properly sized, classified and with selected additives further processed and finally made into desired components for end use. The existing process for production of high purity iron oxide powder is through chemically treating iron salts\iron powder or other iron bearing compounds. It is routed through extraction\leaching and purification process before making the final iron oxide powder. The prior art process is the chem.cal treatment of already synthetically manufactured produts/by-products like mill scale, metallic iron powder, iron compounds/salts etc. The existing proces based on chemical extraction is complex and likely to contain other oxides. Over and above, the chemical route involving handling of corrosive material needed for dissolution of impurities and discharge of chemical effluents, an elaborate set up with high capital outlay is necessary. The problem of environmental pollution is to be tackled in chemical route. No attempts have been made so far to produce ferrite grade iron oxide by superconcentration of naturally occurring iron ore (blue dust) either through physical or chemical routes. The main object of the present invention is to provide a process lor the production oJ iron ore superconcentrate of fer-file qrade from naturally occurring iron oxide one of blue dust type which obviates the above mentioned drawbacks. In the process of the present invention, the naturally occurring iron ore viz.. blue dust has been cor centrated to a iron ore superconcentrate suitable for ferrite grade through a physical route only. The present art is a new process for production of iron ore superconcentrate of ferrite jrade from the naturally occurring blue dust (iron ore) by physical means as against existing chemical means . In the process of the present invention by selecting a natural oxide, the purity is assured as than of. existing ones and processing of other oxides are alto-gen her eliminated. The present invention is bath simple in opera-is ion and less expensive compared to the existing toes. the present invention eliminates the problems encountered in the chemical route and for the range of a hard ferrite require-ments adequate product meeting the specificatior could be produced from naturally raw material, abundantly available by essen-tially physical process steps. Since no chemical treatment is involved, the process is environment friendly as well. The present invention consists of a process Eor making iron oxide powder lor meeting the specification of fecrites by proc-usingnaturally occurring iron oxide (blue dust having a combined silica and alumina of maximum 4-5% and iron more than 64% by eliminating the need of chemically processed synthetic material II as a source through a suit,able combination of source identification, characterization for the presence of constituent minerats their abundance, assemblage, and liberation size, selective sizing to discard the size fraction enriched with higher gang content and comminution followed by gravity separation and flotation in order to remove deleterious silica/silicate and aluminium minerals and to get a product having combined silica and alumina below 0.37% as against norm limit of 0.37 to C.8%. Accordingly the present invention provides a process for the production of iron ore super concentrate of ferrite grade from blue dust which comprises grinding the blue dust having a combined silica arid alumina of maximum 4-5% and iron more rhan 64% to the size below 75 micron, discarding light aluminium impurities by known methods to obtain the concentrate, conditioning the concentrate at pH 10 to 10.5 with glucopyranose polymer and alkylamine, removing the undesirable silica/silicates and alumina minerals by floatation methods to obtain superconcentrate iron ore. According to a feature of this invention Blue dust may oe selected having combined silica and alumina of maximum 4-5% and iron more than 64%. according to another leature of the invention the known methods used to obtain the concentrate in step (vi) may be such as gravity separation using hydrocyclone & Wilfley Table or hydrocyclone only. Although the physical process steps mentioned above are known and are not individually unique but a judicious combination of unit operations based on characterisation i;s the vital and novel part of the invention. Any arbitrary combination of above process steps may lead to reduction of impurities to a certain degree but may not be successful in bringing the Ii02+Al203 level 0.3%. However, the suggested combination of the process steps will be able to prodoce a concentrate having silica and alumina of - 0.3%. By the process ol. the present invention the combined amount of silica and alumina could be lowered to a level: of 0.37% from a !: , I oil about 1.0% by physical processing. n quantitative terms, one kg. of the naturally occurring iron 'ore (blue dust) sample on such processing could give 610 gni of final product which meets the specification of required grade' No. I and II as given in Table 1. Tabie 1. Chemical Specs, of different Superconcentrates (Table Removed) The ...following examples are given by way of illustration and should not be construed to limit the scope of the invention. The sample of blue dust under study contained 68.5% Fe and combined SiO2 and A1203 of 0.96%. Microscopic examination revealed the intergrowth of limonite with kaolinit e and this occurred as intercalations with hematite grains in varying degree. The qranulonetric analysis showed fraction coarser than +140 micron was richer in Si02 and A1203 and thus -149 micron fraction vmt subjected to different tests of physical beneficiation. Removal of Iimonite-kaoiinite was effected in tbi form of slime by .subjecting the -149 micron fraction to grind below 75 micron and hydrocycloning. Tabling of cyclone underflow in a Slime Deck Table followed by removal of silica/silicates by flotation could produce a concentrate with S102+A1203 of 0.28%. Example 1 {Condition:pH = 10.5,Qty. of alkylamine = 0."5 Kg/t and glucopyranose polymer B.O Kg/t, size -75 micron. Uydrocyclone Spigot dia during cleaning ■■ 65 mm Using Hydrocyclone & Using Hydrocyclone Wilfley Table (Table Removed) {Condition :pJH = 10.5,Qty. of alkylamine = 0. /5 Kg/t and g.lucopyranose polymer 8.0 Kg/t, size -7 5 micron. Hydrocyclone Spigot dia during cleaning - 8 5 mm (Table Removed) Example 3 (Condition :pH - 10.0,Qty. of alkylamine = 0.85 Kg/t and glucopyranose polymer 8.0 Kg/t, size -15 micron. Hydrocyclone Spigot dia during cleaning - 6.5 mm (Table Removed) The table above gives the result from repeat tests performed HI The laboratory in Kg scale. This also gives quantitative yield and purity/grade (S102 -i- A1203 %) following the process in two different equipment at stage II level. The main advantages of the present invention are : a) Ose of naturally occurring iron ore (Blue Dust J instead of a cost added processed product viz., iron powder, iron sails etc. to produce superconcentrate from naturally occurring iron ore by physical method which leads to reduction in cost of production. b) Simpler physical processing steps without any chemical processing involved leading to no harmful effluent treatment. c) The present invention does not require any costly capital intensive set up as required by known processes to pre pare synthetic equivalent. d) Ulilising blue dust type iron ore available abundantly at cheaper rate. e) The present invention produces purer product, absence of other oxide in comparison to existing pre cresses. f) The present invention is environment friendly. g) The present invention utilises waste and thereby protects ecology since blue dust type powdery ore generally reports to the tailing during wet processing of iron ores causing both disposal and ecology problem in the mines a rea. We claim : 1. A process for the production of iron ore super concentrate of ferrite grade from blue dust which comprises grinding the blue dust having a combined silica and alumina of maximum 4-5% and iron more than 64% to the size below 75 micron, discarding light aluminium impurities by known methods to obtain the concentrate, conditioning the concentrate at pH 10 to 10.5 with glucopyranose polymer and alkylamine, removing the undesirable silica/silicates and alumina minerals by floatation methods to obtain superconcentrate iron ore. 2. A process as claimed in claim 1 wherein the known methods used to obtain the concentrate in step (vi) is such as gravity separation using hydrocyclones and wilfley Table or hydrocyclone only. 3. A process for the production of iron ore super concentrate of ferrite grade from blue dust substantially as herein described with reference to the examples.

Full Text

This invention relates to a process for the production of iron ore super concentrate of ferrite grade from blue dust.
The present invention is for a process leading to produce high purity iron oxide (iron ore superconcentrate) from naturally occurring iron oxide ore (blue dust). The superconcentrates can be used as raw materials in the manufacture of hard ferrites to be used in electrical and electronic industries. The product in the form of fine powder is properly sized, classified and with selected additives further processed and finally made into desired components for end use.
The existing process for production of high purity iron oxide powder is through chemically treating iron salts\iron powder or other iron bearing compounds. It is routed through extraction\leaching and purification process before making the final iron oxide powder. The prior art process is the chem.cal treatment of already synthetically manufactured produts/by-products like mill scale, metallic iron powder, iron compounds/salts etc. The existing proces based on chemical extraction is complex and likely to contain other oxides. Over and above, the chemical route involving handling of corrosive material needed for dissolution of impurities and discharge of chemical effluents, an elaborate set up with high capital outlay is necessary. The problem of environmental pollution is to be tackled in chemical route.
No attempts have been made so far to produce ferrite grade iron oxide by superconcentration of naturally occurring iron ore (blue dust) either through physical or chemical routes.

The main object of the present invention is to provide a process lor the production oJ iron ore superconcentrate of fer-file qrade from naturally occurring iron oxide one of blue dust type which obviates the above mentioned drawbacks.
In the process of the present invention, the naturally occurring iron ore viz.. blue dust has been cor centrated to a iron ore superconcentrate suitable for ferrite grade through a physical route only. The present art is a new process for production of iron ore superconcentrate of ferrite jrade from the naturally occurring blue dust (iron ore) by physical means as against existing chemical means . In the process of the present invention by selecting a natural oxide, the purity is assured as than of. existing ones and processing of other oxides are alto-gen her eliminated. The present invention is bath simple in opera-is ion and less expensive compared to the existing toes.
the present invention eliminates the problems encountered in the chemical route and for the range of a hard ferrite require-ments adequate product meeting the specificatior could be produced from naturally raw material, abundantly available by essen-tially physical process steps. Since no chemical treatment is involved, the process is environment friendly as well.
The present invention consists of a process Eor making iron oxide powder lor meeting the specification of fecrites by proc-usingnaturally occurring iron oxide (blue dust having a combined silica and alumina of maximum 4-5% and iron more than 64% by eliminating the need of chemically processed synthetic material II as a source through a suit,able combination of source identification, characterization for the presence of constituent minerats their abundance, assemblage, and liberation size, selective

sizing to discard the size fraction enriched with higher gang content and comminution followed by gravity separation and flotation in order to remove deleterious silica/silicate and aluminium minerals and to get a product having combined silica and alumina below 0.37% as against norm limit of 0.37 to C.8%.
Accordingly the present invention provides a process for the production of iron ore super concentrate of ferrite grade from blue dust which comprises grinding the blue dust having a combined silica arid alumina of maximum 4-5% and iron more rhan 64% to the size below 75 micron, discarding light aluminium impurities by known methods to obtain the concentrate, conditioning the concentrate at pH 10 to 10.5 with glucopyranose polymer and alkylamine, removing the undesirable silica/silicates and alumina minerals by floatation methods to obtain superconcentrate iron ore.
According to a feature of this invention Blue dust may oe selected having combined silica and alumina of maximum 4-5% and iron more than 64%.

according to another leature of the invention the known methods used to obtain the concentrate in step (vi) may be such as gravity separation using hydrocyclone & Wilfley Table or
hydrocyclone only.
Although the physical process steps mentioned above are
known and are not individually unique but a judicious combination of unit operations based on characterisation i;s the vital and novel part of the invention. Any arbitrary combination of above process steps may lead to reduction of impurities to a certain degree but may not be successful in bringing the Ii02+Al203 level 0.3%. However, the suggested combination of the process steps will be able to prodoce a concentrate having silica and alumina of - 0.3%.
By the process ol. the present invention the combined amount of silica and alumina could be lowered to a level: of 0.37% from a !: , I oil about 1.0% by physical processing. n quantitative terms, one kg. of the naturally occurring iron 'ore (blue dust) sample on such processing could give 610 gni of final product which meets the specification of required grade' No. I and II as given in Table 1.
Tabie 1. Chemical Specs, of different Superconcentrates

(Table Removed)
The ...following examples are given by way of illustration and should not be construed to limit the scope of the invention.
The sample of blue dust under study contained 68.5% Fe and combined SiO2 and A1203 of 0.96%. Microscopic examination revealed the intergrowth of limonite with kaolinit e and this occurred as intercalations with hematite grains in varying degree. The qranulonetric analysis showed fraction coarser than +140 micron was richer in Si02 and A1203 and thus -149 micron fraction vmt subjected to different tests of physical beneficiation. Removal of Iimonite-kaoiinite was effected in tbi form of slime by .subjecting the -149 micron fraction to grind below 75 micron and hydrocycloning. Tabling of cyclone underflow in a Slime Deck Table followed by removal of silica/silicates by flotation could produce a concentrate with S102+A1203 of 0.28%.

Example 1
{Condition:pH = 10.5,Qty. of alkylamine = 0."5 Kg/t
and glucopyranose polymer B.O Kg/t, size -75 micron.
Uydrocyclone Spigot dia during cleaning ■■ 65 mm
Using Hydrocyclone & Using Hydrocyclone Wilfley Table
(Table Removed)
{Condition :pJH = 10.5,Qty. of alkylamine = 0. /5 Kg/t and g.lucopyranose polymer 8.0 Kg/t, size -7 5 micron. Hydrocyclone Spigot dia during cleaning - 8 5 mm
(Table Removed)
Example 3 (Condition :pH - 10.0,Qty. of alkylamine = 0.85 Kg/t and glucopyranose polymer 8.0 Kg/t, size -15 micron. Hydrocyclone Spigot dia during cleaning - 6.5 mm
(Table Removed)
The table above gives the result from repeat tests performed HI The laboratory in Kg scale. This also gives quantitative yield and purity/grade (S102 -i- A1203 %) following the process in two different equipment at stage II level.

The main advantages of the present invention are : a) Ose of naturally occurring iron ore (Blue Dust J instead of a cost added processed product viz., iron powder, iron sails etc. to produce superconcentrate from naturally occurring iron ore by physical method which leads to reduction in cost of production.
b) Simpler physical processing steps without any chemical
processing involved leading to no harmful effluent
treatment.
c) The present invention does not require any costly capital
intensive set up as required by known processes to pre
pare synthetic equivalent.
d) Ulilising blue dust type iron ore available abundantly at cheaper rate.
e) The present invention produces purer product, absence of other oxide in comparison to existing pre cresses.
f) The present invention is environment friendly.
g) The present invention utilises waste and thereby protects ecology since blue dust type powdery ore generally reports to the tailing during wet processing of iron ores causing both disposal and ecology problem in the mines a rea.

We claim :
1. A process for the production of iron ore super concentrate of ferrite grade from blue dust which comprises grinding the blue dust having a combined silica and alumina of maximum 4-5% and iron more than 64% to the size below 75 micron, discarding light aluminium impurities by known methods to obtain the concentrate, conditioning the concentrate at pH 10 to 10.5 with glucopyranose polymer and alkylamine, removing the undesirable silica/silicates and alumina minerals by floatation methods to obtain superconcentrate iron ore.
2. A process as claimed in claim 1 wherein the known methods used to obtain the concentrate in step (vi) is such as gravity separation using hydrocyclones and wilfley Table or hydrocyclone only.
3. A process for the production of iron ore super concentrate of ferrite grade from blue dust substantially as herein described with reference to the examples.

Documents:

2448-del-1997-abstract.pdf

2448-del-1997-claims.pdf

2448-del-1997-correspondence-others.pdf

2448-del-1997-correspondence-po.pdf

2448-del-1997-description (complete).pdf

2448-del-1997-form-1.pdf

2448-del-1997-form-19.pdf

2448-del-1997-form-2.pdf

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Patent Number

228262

Indian Patent Application Number

2448/DEL/1997

PG Journal Number

29/2008

Publication Date

26-Sep-2008

Grant Date

08-Dec-2006

Date of Filing

28-Aug-1997

Name of Patentee

Council of Scientific & Industrial Research

Applicant Address

Rafi Marg, New Delhi - 110 001.

Inventors:

#	Inventor's Name	Inventor's Address
1	DR.Swapan Kumar Mukherjee	Research and Development Centre for Iron and Steel, Steel Authority of India Ltd., Ranchi 834002,BIHAR.
2	S/SHRI Nidhir Chakravorty	National Metallurgical Laboratory, PO Burmamines, Jamshedpur 831 007.BIHAR.
3	Suprakas Chandra Maulik	National Metallurgical Laboratory, PO Burmamines, Jamshedpur 831 007, BIHAR.
4	Jitendra Prasad Srivastava	National Metallurgical Laboratory, PO Burmamines, Jamshedpur 831 007, BIHAR.
5	Bhaskar Banerjee	National Metallurgical Laboratory, PO Burmamines, Jamshedpur 831 007, BIHAR.
6	Rama Kant Kunwar	National Metallurgical Laboratory, PO Burmamines, Jamshedpur 831 007, BIHAR.
7	Samir Kumar Sil	National Metallurgical Laboratory, PO Burmamines, Jamshedpur 831 007, BIHAR.
8	DR.Thannirkulam Mudabi Srinivasan	Research and Development Centre for Iron and Steel, Steel Authority of India Ltd., Ranchi 834002,

PCT International Classification Number

C21B 15/00,

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA