Research & Development

Agglomeration of Ferromanganese alloy Fines to Use in LD Steel Making Process

Authors

Veerendra Singh, Prabhash Gokarn,

Ashutosh Kumar, B D Nanda, and Amitabh Bhattcharjee

Tata Steel Ltd., Jamshedpur - 831001, Jharkhand, India.

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

Presentation outline

1. Introduction

2. Objective

3. Experimental Studies 3.1. Characterization Studies

3.2. Agglomeration Studies

3.3. Lab Trials

4. Plant Trials & Commercialization

5. Conclusion

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

Mn alloys are added as deoxidizing agents and additives to increase strength, elasticity and abrasion resistance of steel.

Mn ferroalloys are made by carbo-thermic reduction of manganese ores, cast into pans and crushed into 10mm to 60mm size lumps.

Mn is added in the form of lumps of high carbon FeMn, SiMn and Mn metal.

The fines generated during sizing can not be used directly in LD, so these are sold at lower price ( <Rs 12-15k than lumps) to foundries.

• Low Mn Recovery• Handing losses• Low grade

An efficient agglomeration process can make them

suitable for steel making process.

Lumps (10-80mm) ( Mn : >70, C : 6-8)

Fines & Chips (0-3,3-10mm) ( Mn : 65-70, C : 6-

8)

FeMn Cake

FeMn Casting

Introduction

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

To produce a suitable Agglomerate to use in steelmaking in a cost effective way.

AgglomerateLadle

Size : <3mm Size : 20-30mm

FeMn Fines

It should not add any unwanted ingredient (P,S etc in steel)

High Cold Compressive Strength to avoid fine generation during handling.

High Hot Compressive Strength to avoid disintegration at high temperature.

Agglomeration process should be economical.

Objective

Challenges

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

(a) Chemical analysis of FeMn Lumps & Fines

Element FeMn Lumps (>10mm)

FeMn Fines (0-3mm)

Mn >70 >67Si 1.5 1.4-2P 0.30 0.25C 6-8 6-8

(b) Size analysis of fines (C) SEM analysis of FeMn Lumps & Fines

Experimental Studies : Characterization of Fines

0.0 0.5 1.0 1.5 2.0 2.5 3.0

0

20

40

60

80

100

Comm.Pass

%, P

asse

d

Particle Size (mm)

FeMn Fines

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

(a) Binder Selection : Metallic fines shows significantly different behavior than the ore fines

hence binder selection is most critical task.

Molasses +Lime

Cement

Lignosulphate

Coal tar

Sodium Silicate

Resins

Phenol-formaldehyde Resin

Acrylic Resin

Experimental Studies : Agglomeration Process

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

(b) Process parameter (Compaction load, dosage & curing conditions) optimization

Experimental Studies : Agglomeration Process

Binder % Load (ton) Curing ConditionSodium Silicate 5, 7.5 & 10 1 & 5 100 C, 1 hourSodium Silicate+ Bentonite 5+2, 7.5+2 & 10+2 1 100 C, 1 hourAcrylic Resin 5, 8 & 10 1 & 3 100 C, 1 hourPhenol formaldehyde Resin 3,4, 5, 8 & 10 1 & 5 100 & 150 C, 1 hour

Sample Preparation

(0-3mm) FeMn fine)

Mixing

Pressing(1-5ton)

Curing (100° C, 60 minutes)

Compressive strength Test

Binder

Process Methodology for Binder Selection Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

• Phenol-formaldehyde resin (resole resin) properties are as follow

PH(1 % Soln.) : 7.15 Specific Gravity :1.18 Solid Content : 70.65 % Viscosity at 25deg. C: 200 cps. Min Carbon : 35 %

• Phenol-formaldehyde resins are commonly used in coating, foundry, composites, molding, refractory and adhesive for woods.

Addition Condensation Curing

Experimental Studies : Binding Mechanism

(a) Mn Ore Particle (b) FeMn Particle

• Various kinds of forces act on particles in agglomeration process. (1) Intermolecular forces :Vander Waals, Hydrogen bonding, Electrostatic and (2) Others: Capillary force, Solid bridges, Mechanical Interlocking .

• The alloy particles are smooth with low

wettability and do not have crakes for binder absorption like ore particles.

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

Experimental Studies : Agglomeration Process

© Agglomerate Quality

Properties BriquetteSize & Shape 30-20mmApparent Density 5200 kg/m3Compressive Strength 55MpaTensile Strength 15MpaTumbler Index (Wt 15kg, rpm 200@25) 95% (>6.3mm)Abrasion Index (Wt: 15kg, rpm 200@25) 3%( <0.5mm)Shatter Index (10 kg, 4 drops, Height : 2m) 98%(<5mm) (i) FeMn lump (ii) FeMn Briquette

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

Agglomeration Process Flow Sheet

Lab Trials (5Kg)

Small Scale Pant Trials (500Kg)

Large Scale Plant Trials (10ton)

Shikher trials

Recovery Operational Performance Cost benefit analysis

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

Steel Scrap (20kg)Slag

Metal

FeMn agglomerate(5 kg)

Tempt. : 1650o C (Mn: 0.15, C : 0.2,P : 0.011) (Mn: 66.33, C : 7, P : 0.25)

FeMn Lumps FeMn Fines FeMn Briquettes

 Metal (kg)

Mn (%)

Reco. (%)

Lump 24.9 12.7 90.87

Briq. 24.7 12.7 90.73

Fine 24.5 11.1 81.09

1. It is safe to add the agglomerate

2. The Mixing of fines is very difficult and very faster for briquettes

3. Mn recovery was lowest (81 %) for fines and similar for briquettes and lumps.

Lab Trials

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

Metal Analysis

Slag Analysis

(a) Briquette addition not increases level of P,S

and Nitrogen in the steel.

(b) Manganese and carbon pickup in steel was

similar for lumps and briquettes.

(c) Briquettes contain lower Mn content than

the lumps but recovery was slightly better

(~3%) for briquettes (t-test -p value:0.13).

(d) NO other operational problem was faced

during the trial.

Plant Trials

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

Commercialization

(a) Vendor Development (250tpm)

(b) Addition in vesse

l

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

(i) Tangible : Profit = Cost Difference in lumps and fine - Briquetting cost = Rs 12-15,000 - Rs 5-7000 = Rs 7000/ton ( for Tata Steel : 2-3 Crore/annum)

(ii) Non-tangible Benefits Environment friendly recycling process Effective utilization of resources There is also potential to use low price fines of other Ferro-alloys(SiMn, FeCr

etc.) by adapting the similar practice

Conclusion

(a) A suitable agglomerate for Steel making can be produced from High Carbon ferromanganese alloys fines using the Phenolic resin as a binder.

(b) The developed agglomerate shown good physical properties and did not add any unwanted ingrinednt in the steel.

(c) Benefits :

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development

Contents

LD#1Mr. Debashish Das

Mr. H BillmoriyaMr. Alok Das Gupta

Ferro Alloys & Minerals Division Mr. Rajeev SinghalMr. L S Devikera

Mr. S Tanwer

ACKNOWLEDGEMENT

R & D and SSDr. D Bhattacharjee

Dr. Vilas Tathavadkar Dr. P K BanerjeeDr. D. Srinivas

Dr. Sandip BhattacharyyaProf. A K Laheri

Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals

Research & Development Presented at the 50th National Metallurgists’ Day ATM of the Indian Institute of Metals