recovery of sale-able slag from jigging tailings in femn production

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RECOVERY OF SALEABLE SLAG FROM JIGGING TAILINGS

ENVIR

ON

MEN

T

CONSERVE

NATURAL

RESOURCES

CONSE

RVE

MIN

ERAL

S

WEA

LTH

GENER

ATION

WEALTH OUT OF WASTE…

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Leader : B.D.NANDA (HEAD, FAP JODA)

Unit : FAP JODA

Division : FAMD, TATA STEEL Ltd.

Members :

D.D.Parida

B.Srinivas

Kaushik Shubhank

B.N.Rout

INNOVATORS

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PROCESS FLOW OF FERRO ALLOYS PLANT, JODA

ARC FURNACE TAPPING METAL & SLAG CAKES

H C FERRO MANGANESE

HIGH MnO SLAG

STEEL MELTING SHOP

SILICO MANGANESE INDUSTRY

CUSTOMER

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PROCESS FLOW OF METAL & SLAG RECOVERY

WASTE

MIXED METAL WITH SLAG INCLUSIONS MIXED METAL CRUSHING [0-20mm]METAL & SLAG BREAKING

JIGGED METAL

JIGGING MACHINE

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BACKGROUND [THE TRIGGERS…]

FAP, Joda produces 50400 MT of High Carbon FeMn /annum and generates about 36000 MT of High MnO slag as a byproduct.

High MnO slag is one of the input raw materials for SiMn industry [FY 11 requirement ~ 55000 MT ].

As per the TS expansion plans for FY15, 78000 MT of High MnO FeMn slag will be required.

Current demand-supply gap [19000 MT] will shoot up.

200 Kg of waste is generated per ton of FeMn produced at FAP,Joda [ ~ 800MT/month].

Storage of waste creates space constraint and dumping is not an environment friendly methodology.

Idea generation Trial implementationTriggers Results Benefits

Waste dump

GENERATION OF IDEAS

IDEA # 1: Entire waste can be sent for re-jigging with an attempt for slag separation.

6Idea generation Trial implementationTriggers Results Benefits

IDEAS

IDEA # 2: Entire waste can be sent for dressing of slag pans used for tapping.


IDEAS

IDEA # 3: Entire waste can be sent for filling of low lying areas (inside plant)


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NEED FOR AN INNOVATIVE APPROACH:

It was observed that the waste material had 60% of slag pieces in it.

Customer requirement of High MnO slag was for MnO ~30%, Silica ~22%.

Composition of tailings: MnO ~ 22%, Silica ~ 38%.

A challenge came up to convert the waste into usable material.

The major challenge was to enhance the quality from 22 – 30 % MnO.

An innovative thought of recovering slag from the waste and reducing the waste dumping simultaneously.


IDEAS

IDEA # 4: Entire waste can be sent for manual screening to recover saleable slag.


PROCESS IMPROVEMENT

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FUSED SAND

FINAL PRODUCT


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ACHIEVEMENTS: THE ASPECT OF DEMAND–SUPPLY GAP

+10 mm screen recovered slag having MnO ~ 34 % and Silica ~ 25%.

The recovery of slag is 500 MT/month.

Supply-demand gap of slag was reduced by 6000 MT/annum.

Recovered slag was used @ 400Kg/MT of SiMn as input material.

QUALITY TRAILS & RESULTS

6/8/10 mm MANUAL SCREEN [Jig feed: -20mm]

10 mm MANUAL SCREEN [Jig Feed: -15mm]

Chemical Analysis

MnO – 22% MnO – 34%

SiO2 – 38% SiO2 – 25%


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Dumping of waste was reduced by 100%.

Environment friendly approach adopted.

Elimination of diesel consumption by vehicles used for dumping from 160 L/month to 0L.

ACHIEVEMENTS: ENVIRONMENTAL ASPECT

Total captive reserve of Mn Ore in Joda contains only 20% of High grade Ore, rest being medium and low grade ore.

Recovered slag substitutes High Grade Mn ore by 400Kg/MT of SiMn produced, thus saving the precious natural reserves.

High Mn:Fe ratio helps in consuming more of low/medium grade Mn ore for SiMn.


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The undersize waste from screening is being used for dressing of slag pans.

Recovered slag substitutes fresh river sand consumption by 30%.

ACHIEVEMENTS: ENVIRONMENTAL ASPECT

Using High MnO slag instead of high grade ore reduces the need for carbothermic reduction of the substituted amount.

Coke consumption required for reduction reduces by 320 MT/annum.Power consumption accordingly drops by 50 KWH/MT of SiMn when slag is used.


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DIRECT TANGIBLE BENEFIT:

Total recovery of slag from waste till Feb’11 = 6200 MT.

Realization of slag = Rs. 6000/MT

Processing cost for screening = Rs. 90/MT

Net benefit = Rs 322 Lakhs/annum.

ACHIEVEMENTS: FINANCIAL ASPECT


RIVERSAND :

Reduction in fresh river sand consumption = 1235 Cu.m/annum.

Cost of sand = Rs 435/Cu.m

Net benefit = Rs 5.3 Lakhs/annum.

DISPOSAL:

Reduction in waste = 9600 MT/annum.Cost of handling = Rs 90/MTNet saving = Rs. 8.64 Lakhs/annum.

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BENEFITS to SiMn INDUSTRY:

[A] High Grade Mn Ore:

Substitution of high grade ore = 400 Kg/ MT of SiMnTotal substitution = 4000 MT/annum Differential cost = Rs 9000 / MTNet benefit = Rs 360 Lakhs/annum

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Total saving for FAP Joda = Rs. 336 Lakhs/annumTotal saving for SiMn industry = Rs. 412 Lakhs/annum


[B] COKE:

Reduction in coke consumption = 320 MT/annum.Cost of coke = Rs 10000/MTNet benefit to SiMn industry = Rs 32 Lakhs/yr.


[C] POWER: Reduction in power = 50 KWH/MT of SiMn Cost of power = Rs 4 /KWH Cost saving = Rs 20 Lakhs/yr

[D] QUALITY: Slag substitution helps to reduce detrimental Phosphorus contribution to Steel.

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ACHIEVEMENTS: CUSTOMER APPRECIATION

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FLOW DIAGRAM OF SALEABLE SLAG RECOVERY PROCESS

recovery of sale-able slag from jigging tailings in femn production

Engineering