1 DESIGN & FABRICATION OF IRON ORE SINTERING MACHINE A Project Report Submitted by ALBIN KURIACHAN CHERIAN (090250121028) SIDDHARTH RATHOD (100253121009) In fulfillment for the award of the degree of BACHELOR OF ENGINEERING In Department of B.E. in Metallurgy Engineering Indus Institute of Technology & Engineering, Ahmedabad Gujarat Technological University, Ahmedabad May 2013
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Design And Fabrication Of Iron Ore Sintering Machine
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DESIGN & FABRICATION OF IRON ORE
SINTERING MACHINE
A Project Report
Submitted by
ALBIN KURIACHAN CHERIAN (090250121028)
SIDDHARTH RATHOD (100253121009)
In fulfillment for the award of the degree
of
BACHELOR OF ENGINEERING
In
Department of B.E. in Metallurgy Engineering
Indus Institute of Technology & Engineering, Ahmedabad
Gujarat Technological University, Ahmedabad
May 2013
2
Indus Institute of Technology and Engineering, Ahmedabad
Department of B.E. in Metallurgy Engineering
2013
CERTIFICATE
Date: 23/05/2013
This is to certify that the dissertation entitled “ Design and Fabrication
Of Iron Ore Sintering Machine ” has been carried out by Albin K.
Cherian & Siddharth Rathod under my guidance in fulfillment of the
degree of Bachelor of Engineering in Department of B.E. in Metallurgy
Engineering (7th
Semester/8th
Semester) of Gujarat Technological
University, Ahmedabad during the academic year 2012-13.
Guides:
INTERNAL
Mr. D.K. Chauhan
Mr. Shashi Tandon
Head of The Department
Prof. D. K. Basa
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ACKNOWLEDGEMENT
We feel profound pleasure in bringing out this project report for which
we have to go from pillar to post to make it a reality. This project work
reflects contributions of many people with whom we had long discussions
and without which it would not have been possible. We must first of all,
express our heartiest gratitude to respected Mr. D.K. Chauhan, Mr. Shashi
Tandon for providing us all guidance to get an insight about the project,
“Design And Fabrication Of Iron Ore Sintering Machine”. We are sure
that their experience and the valuable guidelines will help us completing this
project successfully. Also, we wish to receive their guidance for the
upcoming part of the project as well.
We feel greatly honored to mention the invaluable Contribution and timely
co-operation extended to us by the staff members of our department and
especially we are grateful to the most worthy advices given by Mr. D. K.
Basa (H.O.D.) that would help us in the future also.
Albin K. Cherian(090250121028)
Siddharth Rathod (100253121009)
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Abstract
The sintering process converts fine-sized raw materials, including iron, coke breeze,
limestone, mill scale and flue dust, into an agglomerated product, sinter of suitable size
for charging into the blast furnace. The raw materials are something mixed with water to
provide a cohesive matrix, and then placed on a continuous, travelling grate called the
after which the combustion is self supporting and it provides sufficient heat 1200 –
1300oC, to cause surface melting and agglomeration of the mix. On the underside of the
sinter strand is a series of windboxes that draw combusted air down through the material
bed into a common duct, leading to a gas cleaning device.
The fused sinter is discharged at the end of the sinter strand, where it is crushed and
screened. Undersize sinter is recycled to the mixing mill and back to the strand. The
remaining sinter product is cooled in open air or in a circular cooler with water sprays or
mechanical fans. The cooled sinter is crushed and sreened for a final time, then the fines
are recycled, and the product is sent to be charged to the blast furnaces. Generally, 1 Mg
of raw materials, including water and fuel, are required to produce 0.9 Mg of product
sinter.
PROBLEM SUMMARY
To make working model of sintering machine in metallurgical engineering
department laboratory for experimental studies.
Materials used in fabrication of sintering machine are :-
Cylindrical container with conical end for charging sintering raw materials.
Grit for supporting the charge.
Gas burner for igniting the sinter charge.
Arrangement for regulating flow of combustion air.
Blower for suction of products of combustion.
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LIST OF TABLES
NO. Table Description Page No.
Table 3.5.1 Details of Sinter Strands
provided in early years in
Indian Steel Plants
16
Table 3.8 Indian Sintering Plants
And their Performance
29
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LIST OF FIGURES
No. Figures Description Page No.
1. Dwight – Llyod
Sintering Machine
17
2. Spark Plasma Sintering
Machine
20
3. Selective Laser Sintering
Machine
23
4. Gas Fired Sintering
Machine
26
5. Design of Iron Sintering
Machine
36 to 40
6. Dimensions of sintering
machine
41 to 46
7. Cylindrical Container 48
8. Manometer 49
9. Grid with Gasket 50
10. Dust collector 51
11. Blower 52
12. Seamless pipe 53
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TABLE OF CONTENTS
Acknowledgment …………………………………………………. ….. ..3
Abstract ………………………………………………………………….4
List of Tables……………………………………………………………..5
List of Figures ……………………………………………………………6
Table of Contents…………………………………………………………7
Chapter :1 Introduction to Project
1.1 Sintering Process……………………………………………..9
1.2 Advantages……………………………………………………10
Chapter: 2 Detail Description of Sintering process…………………..11
Chapter: 3 Literature Survey
3.1 Principle of Sintering process……………………………….13
3.2 Process Variables…………………………………………….14
3.3 Function of sintering process………………………………..14
3.4 Advantages …………………………………………………...14
3.5 Types Of Sintering machine…………………………………15
3.6 Sinter Quality…………………………………………………27
3.7 Mechanism of sintering………………………………………28
3.8 Efficiency of sintering Machine……………………………..29
3.9 Control of sintering process…………………………………30
3.10 Principle of sinter making machine……………………….31
3.11 Economics of sintering……………………………………...32
3.12 Recent trends in sintering practice………………………..33
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3.13 Sintering of iron ore fines in india…………………………34
3.14 Steps in making Iron ore sinter……………………………35
Chapter: 4 Implementation of the project work
4.1 Design Of The Iron Ore Sintering Machine………………37
4.2 Dimesions of Iron Ore Sintering Machine………………...41
4.3 Raw Materials & Equipments……………………………...47
4.4 Process Parameters…………………………………………47
4.5 Fabrication…………………………………………………..47
4.6 Plan Of Work……………………………………………….54
4.7 Scope of future work………………………………………..55
4.8 Conclusion…………………………………………………...56
References………………………………………………………………57
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Chapter : 1
Introduction To Project
1.1 Sintering Process:
Sintering of iron ore was developed as a means to utilize the iron ore fines which
otherwise cannot be directly charged into the Blast Furnace. The function of the Sinter
Plant is to supply the blast furnaces with sinter, combination of blended ores, fluxes and
coke, which is partially ‘cooked’ or sintered. In this form, the materials combine
efficiently in the blast furnace and allow for more consistent and controllable iron
manufacture.
Common methods of burden preparation related to the performance improvements of iron
making (blast furnaces & direct reduction process)
The merits of sintering process are listed below in comparsion to iron ore pellets:
i. The sintering process uses cheap coke breeze as fuel while pellets need
expensive oil for firing.
ii. It is possible to agglomerate finer ore particles by sintering process
without any ore grinding step as needed by pelletising technique. It may be
recalled that grinding iron ore grinding step as needed by pelletising
technique. It may be recalled that grinding iron ore is very expensive
process.
The iron ore particles from 10mm to 3mm are accepted directly for
sintering. The particles smaller than 0.5mm are nodulised to 3 – 4 mm size
and then sintered.
iii. The limestone and dolomite can be added during sinter making to increase
the basicity (CaO/SiO2) up to 3 whereas addition of lime during pellet
making is not possible due to formation of low melting calcium ferrite
which renders pellet firing difficult.
iv. Calcination of limestone occurs during sintering process with coke breeze
as cheap energy source. This offers saving of expensive metallurgical coke
in the blast furnace.
v. The good reducibility of iron ore sinter promotes its use.
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vi. The large voidage in sinter offers good bed permeability in the furnace.
vii. The chemistry of iron ore sinter can be adjusted as per need.
viii. Sintering process can accept a variety of solid waste for recycling which is
the need of the day in the light of environmental considerations.
The major advantages of using sinter in BFs are
Use of iron ore fines, coke breeze, metallurgical wastes, lime, dolomite for hot
metal production.
Better reducibility and other high temperature properties.
Increased BF productivity due to higher softening temperature and lower
softening melting temperature range.
Improved quality of hot metal.
Reduction in coke rate in blast furnaces.
1.2 ADVANTAGES OF SINTERING PROCESS
Allows making complex geometries.
Ultilization of iron ore fines, mill scale and coke breeze.
High Precision.
Stability in large scale production process.
Good strength and stability.
Cost economy in comparsion with aaglomeration process.
Improvements and efficiency can be gained from higher softening
temperature and narrower softening in the melting zone, which increases the
volume of the granular zone and shrinks the width of the cohesive zone. A
lower silica content and higher hot metal temperature contributes to more
sulphur removal.
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Chapter : 2
DETAIL DESCRIPTION OF SINTERING PROCESS
The principal feed materials for sintering are fine untreated ores (8–10 mm) and ore
concentrates, as well as fuel (coke breeze and anthracite breeze up to 3 mm), flux
(limestone and dolomite up to 3 mm), and in some cases fine wastes (flue dust, scale, and
others). The end product is sinter cake. Over 95 percent of the sinter is used in ferrous
metallurgy; sinter is used in aluminum production, nickel production, and lead production
in nonferrous metallurgy.
The sintering process includes preparation of the charge, including proportioning or
batching the individual components, mixing, moistening, and pelletizing; sintering a
prepared charge on sintering machines; and processing the hot sintered cake by
fragmentation, screening to remove lumps up to 5–10 mm, cooling up to 100°C and
sorting. Sintering is closely coordinated with the operation of process machinery
preparing raw materials for sintering. This relationship places a premium on stabilization
of the principal input parameters of the process (blending and proportioning of materials,
chemical composition, moisture content, and so on), which opens up avenues for
comprehensive automation of the sintering process.
Sintering is carried out at sintering plants, which include stockpiles for blending and
storing reserves of charge materials, receiving hoppers, departments for comminution of
coke and limestone (also for calcining limestone), a charge preparation department, a
sintering department, and a department for processing the finished sinter cake.
Sintering machines are the basic process equipment in the sintering process. Conveyor-
type sintering machines featuring an endless train of grate-bottomed sinter buggies
(pallets) in motion are widely used. The buggy passes under the feeder, which lays down
a bed of charge of 250–400 mm on the pallet and then passes under the ignition furnace,
where the solid fuel contained in the surface zone of the sinter bed is ignited. The exhaust
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fan draws air downward through the bed (80–100 m3/min per square meter of sintering
area); the combustion zone (15–20 mm) progresses downward through the bed at a speed
of 20–40 mm/min. Much of the charge melts at temperatures of 1200–1500°C, in the
combustion zone of the solid fuel. As the combustion zone progresses downward, the
semi-molten mass in the upper portion of the bed cools to form sinter cake. Gases
emanating from the combustion zone dry out and heat the lower portions of the sinter bed,
from which hygroscopic and hydrate water, carbon dioxide gas, and other volatiles are
driven off, as well as sulfur, arsenic, and other harmful impurities.
Many countries, including Russia, France and Germany, have underground deposits of
iron ore in dust from (blue dust). Such iron ore cannot be directly charged in a blast
furnace . In the early 20th
century, sinter technology was developed for converting ore
fines into lumpy material chargeable in blast furnace. Sinter technology took 30 years to
gain acceptance in the iron- making domain, but now plays an important role. Initially
developed to generate steel, it is now a means of using metallurgical waste generated in
steel plants to enhance blast furnace operation and reducing waste.
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CHAPTER: 3
LITERATURE SURVEY
3.1 Principle Of Sintering Process
In iron – ore sintering, essence is carried out by putting mixture of iron bearing
fines mixed with solid fuel on a permable grate.
Since coke breeze is available as a otherwise wasted product in an intergrated iron
and steel plant.
Its universally incorporated as a solid fuel in the sinter mix.
The top layer of this sinter bed is heated to the sintering temperature 12000
–
13000C by a gas or oil burners and air is drawn downwards, through the grate,
with the help of blowers connected from underwater to the grade.
The narrow combustion zone developed initially at the top layer travels through
the bed, raising temperature of the bed, layer by layer to the sintering level.
The cold blast drawn through the bed cools the already sintered layer and thereby
get itself heated. The heat of the blast is utilized in drying and preheating the
lower layer in bed.
Therefore combustion advances, each layer gets dried and preheated by the heat
transferred from the upper combustion zone. Much of the heat in the gases is
absorb by the lower portion of the bed.
Sinter coke is then tipped from the grate in the hot condition or after particle
cooling.
Its broken, screened and cooled to produced desired fraction. The undersize is
recycled.
This process is known as down – draught since the air blast is draw through the
sinter-bed downwards.
In the first decade of the present century dwight and llyod in mexio developed the
continuous sintering for ferrous and Non- metal.
So it was adopted for iron ore sintering
Today Dwight – Lloyed - for only large scale machine for both ferrous and non-
metal.
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3.2 Process variables:
The variables of the sintering process are broadly as follow:
1. Bed permability as decided by the particle by the particle size and shape.
2. Thickness of the bed.
3. Volume of air blast drawn through sintering.
4. Rate of blast drawn through the sinter bed.
5. Amount and type of carbonates present in the charge.
6. Amount of moisture in the charge.
7. Amount and quaility of solid fuel in the charge.
8. Nature of ore fines. E.g. chemical composition.
9. Non-uniformity in the bed composition.
3.3 Role of Sinter Plant
The function of the Sinter Plant is to supply the blast furnaces with sinter, combination of
blended ores, fluxes and coke, which is partially ‘cooked’ or sintered. In this form, the
materials combine efficiently in the blast furnace and allow for more consistent and
controllable iron manufacture.
3.4 Advantages of using Sinters in the blast furnace
There are certain advantages of using sinters as opposed to using other materials
which include recycling the fines and other waste products, to include flue dust,
mill scale, lime dust and sludge. Processing sinter helps eliminate raw flux, which
is a binding material used to agglomerate materials, which saves the heating
material, coke, and improves furnace productivity.
Improvements and efficiency can be gained from higher softening temperature
and narrower softening in the melting zone, which increases the volume of the
granular zone and shrinks.
15
3.5 TYPES OF SINTERING MACHINES:
1. Dwight – Lloyed Sintering Machine
2. Spark Plasma Sintering Machine
3. Selective Laser Sintering Machine
4. Gas Fired Sintering Machine
3.5.1 Dwight – Lloyed Sintering Machine:
of iron ore fines is now universally carried out on travelling machine
running on a continuous basis.
In 1958 large machine in operation was 3.7m in width, 223 m2 area,
production 800t/day.
Rigt now, the largest machine are use in japan and is nearly 8m width ,
500m2, 24000t/day.
The Dwight-Llyod sintering machine is essentially an endless bend of pellets
moving over rails.
Stretched across and over two huge pulleys, oe which is driven by a motor
through a reduction gear system.
The rotating machine are loaded at one end of the machine and top layer is
ignited as it immediately comes under a fixed ignition hood.
As pellets moves the ignited portion comes over series of stationary wind-
boxes connected an exhaust blower.
Sintering of charge is completed by the time the pellets travels over nearly
the whole useful length of machine.
The sintered cake does out at the other end when the pellets turn upside
down.
The coke is broken, screened and the oversize is cooled.
The undersize is usually 9mm, is returned to machine for re-sintering whereas
the oversize after rescreening goes to the blast furnace as charge.
The exhaust gases from the windboxes are let off into the atmosphere through
a chimney after dust extraction.
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Table 3.5.1.Details of Sinter Strands provided in early years in Indian Steel Plants
Bhilai Durgapur Rourkela TISCO Bokaro
No. Of Strands 4 2 2 2 2(1.7Mt)
2(in
second
stage)
Width 2 2.5 2.5 2 4
Working length, m 25 57 50 30 63
Working area, m2
50 142.5 125 60 252
Annual prod. Capacity
, Mt
2 2.1 1.2 1.26 4.2
Depth of bed mm 300 300 300 300 350
Area of cooling
section m2
- - - - 60
The important parts of the machine and its accessories that make the complete
sinter plant are as follows:
1. Storage bins, mixers, feeder, etc.
2. Charge leveler.
3. Ignition hood
4. Band of pallets and rails for its movement.
5. Drive mechanism.
6. Sinter breaker, screen, cooler, etc.
7. Spillage collector.
8. Windboxes, dust extractor , exhaust fan , chemistry, etc.
17
Figure.1 Dwight – Llyod Sintering Machine.
18
3.5.2 Spark Plasma Sintering Machine:
Spark plasma sintering (SPS), also known as field assisted sintering
technique (FAST) or pulsed electric current sintering (PECS), is
a sintering technique.
Spark plasma sintering (SPS) is a form of sintering where both external pressure
and an electric field are applied simultaneously to enhance the densification of the
metallic/ceramic powder compacts. This densification uses lower temperatures
and shorter amount of time than typical sintering. The theory behind it is that there
is a high-temperature or high-energy plasma that is generated between the gaps of
the powder materials; materials can be metals, inter-metallic, ceramics,
composites and polymers. Using a DC pulse as the electrical current, spark
plasma, spark impact pressure, joule heating, and an electrical field diffusion
effect would be created.
Certain ceramic materials have low density, chemical inertness, high strength,
hardness and temperature capability; nanocrystalline ceramics have even greater
strength and higher superplasticity.
Many microcrystalline ceramics that were treated and had gained facture
toughness lost their strength and hardness, with this many have created ceramic
composites to offset the deterioration while increasing strength and hardness to
that of nanocrystalline materials. Through various experiments it has been found
that in order to design the mechanical properties of new material, controlling the
grain size and its distribution, amount of distribution and other is pinnacle.
The main characteristic of Spark Plasma Sintering is that the pulsed DC
current directly passes through the graphite die, as well as the powder compact, in
case of conductive samples. Therefore, the heat is generated internally, in contrast
to the conventional hot pressing, where the heat is provided by external heating
elements. This facilitates a very high heating or cooling rate (up to 1000 K/min),
hence the sintering process generally is very fast (within a few minutes). The
general speed of the process ensures it has the potential of densifying powders
with nanosize or nanostructure while avoiding coarsening which accompanies
standard densification routes. Whether plasma is generated has not been
confirmed yet, especially when non-conductive ceramic powders are compacted.
19
It has, however, been experimentally verified that densification is enhanced by the
use of a current or field.
Spark Plasma Sintering as a Useful Technique to the Nanostructuration of Piezo-
Ferroelectric Materials
Benefits of Spark Plasma Sintering Machine:
Reduced sintering time.
Good grain to grain bounding.
Clean grain boundaries.
Initial activation of powders by pulsed voltage.
Resistance under sintering pressure.
Principle of Spark Plasma Sintering Machine:
The SPS process features a very high thermal efficiency because of the direct
heating of the sintering graphite in old and stacked powder materials by the large
spark pulse current. It can easily consolidate a homogeneous, high-quality sintered
compact because of the uniform heating, surface purification and activation made
possible by dispersing the spark points.
Examples of Spark Plasma Sintering applications:
High-temperature short-period SPS sintering is expected to provide almost all
ceramic materials with new characteristics and sintered effects which are different
from those obtained by the HP and HIP processes. The ceramic materials which
can be sintered at high density include oxides such as A1203, mullite, Zr02, MgO,
Hf02 and SO2, carbides such as Sic, B4C, TaC and Tic, borides such as TiB2 and
HfB2 and nitrides such as Si3N4, TaN, TiN and AIN.
20
Fig 2 Spark Plasma Sintering Machine
21
3.5.3 Selective Laser Sintering Machine:
Selective Laser Sintering was developed and patented by Dr. Carl Deckard at the
University of Texas at Austin in the mid-1980s, under sponsorship of DARPA. A
similar process was patented without being commercialized by R.F. Housholder in
1979.
Selective laser sintering (SLS) is an additive manufacturing technique that uses a
high power laser (for example, a carbon dioxide laser) to fuse small particles of
plastic, metal (direct metal laser sintering), ceramic, or glass powders into a mass
that has a desired 3-dimensional shape. The laser selectively fuses powdered
material by scanning cross-sections generated from a 3-D digital description of the
part (for example from a CAD file or scan data) on the surface of a powder bed.
After each cross-section is scanned, the powder bed is lowered by one layer
thickness, a new layer of material is applied on top, and the process is repeated
until the part is completed.
Because finished part density depends on peak laser power, rather than laser
duration, a SLS machine typically uses a pulsed laser. The SLS machine preheats
the bulk powder material in the powder bed somewhat below its melting point, to
make it easier for the laser to raise the temperature of the selected regions the rest
of the way to the melting point.
Some Selective Laser Sintering machines use single-component powder, such as
direct metal laser sintering. However, most Selective Laser Sintering machines
use two-component powders, typically either coated powder or a powder mixture.
In single-component powders, the laser melts only the outer surface of the
particles (surface melting), fusing the solid non-melted cores to each other and to
the previous layer.
22
Compared with other methods of additive manufacturing, Selective Laser
Sintering can produce parts from a relatively wide range of commercially
available powder materials. These include polymers such as nylon, (neat, glass-
filled, or with other fillers) or polystyrene, metals including steel, titanium, alloy
mixtures, and composites and green sand. The physical process can be full
melting, partial melting, or liquid-phase sintering. Depending on the material, up
to 100% density can be achieved with material properties comparable to those
from conventional manufacturing methods. In many cases large numbers of parts
can be packed within the powder bed, allowing very high productivity.
Selective Laser Sintering is performed by machines called Selective Laser
Sintering systems. Selective Laser Sintering technology is in wide use around the
world due to its ability to easily make very complex geometries directly from
digital CAD data. While it began as a way to build prototype parts early in the
design cycle, it is increasingly being used in limited-run manufacturing to produce
end-use parts. One less expected and rapidly growing application of Selective
Laser Sintering is its use in art.
Unlike some other additive manufacturing processes, such as stereolithography
(SLA) and fused deposition modeling (FDM), SLS does not require support
structures due to the fact that the part being constructed is surrounded by
unsintered powder at all times.
23
(a)
Figure 3(b) Selective Laser Sintering Machine
24
The STL file of your 3D CAD data is entered into the Sinter station system. A thin
layer of powdered SLS material is then spread across the build platform by a roller
mechanism. Using data from the STL file, a CO2 laser selectively draws a cross
section of the object on the layer of powder. As the laser draws the cross section,
it selectively 'sinters' (heats and fuses) the powder creating a solid mass that
represents one cross section of the part. Once a cross section is completed the
build platform lowers by 0.1mm layer thickness and a new layer of powder is
spread. The system continually spreads and sinters layer after layer until the object
is complete. Once the build is completed, the part is removed from the machine
and the unsintered, loose powder is simply brushed away leaving a fully
functional nylon model, ready to send to the customer.
Selective laser sintering Applications:
1. Rapid Manufacturing:
Aerospace Hardware
UAS, UAV, UVG, UGV Hardware
Medical and Healthcare
Electronics; packing , connectors
Homeland Security
Military Hardware
2. Rapid Prototypes:
Functional proof of concept prototypes
Design Evaluation Models (Form, Fit & Function)
Product Performance & Technique
Engineering Design Verification
Wind – Tunnel Test Models
3. Tooling and Patterns:
Rapid tooling ( concept development & bridge tools)
Injection Mold Inserts
Tooling and manufacturing estimating visual aid
25
3.5.4 Gas Fired Sintering Machine:
Gas Fired furnaces T max. 900 – 1400c
For the temperature range between 900 to 1400 c
Thermoconcept supplies different furnaces individually designed to meet the