FAQs

Is Benefication necessary?

Benefication is necessary. By going through Benefication you can improve the quality of the material and subsequently you will get better quality of Pellet / Sponge Iron.

At present Iron Ore Fe 66.5% getting is not possible in the Bellary sector,please clarify?

Iron ore of 66.5% is normally not available but you can use available Iron Ore, beneficate and use for Pelletization.

What should be Fe content?

Pellets are generally considered having uniform quality which can be achieved after benefication otherwise you will have pellets of wearing quality in chemistry depending upon your iron ore. Hence benefication process will ensure good and consistent quality of pellets having Fe always approx. 65%.

What is the water required per Tonne during Benefication and how we have to dispose the waste?

For Beneficiating every 3 Tonne Iron ore we require 1 tone (1m3) of water. The disposable of the waste has to be dumped in to dumping grounds or use it for filler in mines.

What is the loss during the Benefication?

The loss of material during Benefication depends upon the quality of iron ore. Normally, as a thumb rule, in beneficiation process initial loss is 8% and thereafter for every 1% increase in Fe the loss is 2%. For. eg- To have Iron ore Fe 64% to Fe 65%, total loss will be 10% and to upgrade Fe 63% to Fe 65%, the total loss will be 12%.

What type of filter is used?

We can use any filter which can reduce the moisture to 8-10%. The types of filter are : i) Open Belt Type Filters.
ii) Belt Filter (Pressure Filter)
iii) Vacuum disk filter, etc.

Type of Reymond's roller mill, capacity to be furnished.

Reymond Roller Mill ( 3 Rollers) -1 no. is required of capacity 4 Tonne/hr. This is standard mill used for grinding Limestone & Bentonite.

What is the Fuel consumption in Indurating System?

The fuel consumption of Indurating system offered by us will be 180000 K Cal/ Tonne for Magnetite & 260000 K Cal/ Tonne for Hematite. This will be further reduced if we use the coke breeze.

Whether B.F gas can be used instead of furnace oil or combination can be used in furnace heating?

Blast Furnace gas can be used as secondary fuel. It is advisable to use gas as fuel.

Can we avoid use of coal as additive as import is difficult? We propose to use gas as fuel.

You can use Gas as fuel then coal will not be required at all. We can make the pellets without addition of coal in Green Balls if imports are difficult.

The total time required for the project will be roughly 24 to 28 months.

What will be land requirement?

Land requirement will be approx 25 Acres for 1.2 MTPA plant.

By using the pellets in DRI the production of Kiln can be increased by about 25%. At the same time pellets having high tumbling index the shutdown due to accretion in Kiln is avoided considerably, which also affects the production.

What about decrepitating tendency of raw materials?

The input raw materials used in Pelletization do not have decrepitating tendency.

Can low carbon high VM coal (Steam Coal/ Power coal) be used for heating the pellet?

It can be easily used for heating the pellets. The important part is that the ash content should be barely minimum.

For Pelletizing of hematite ore the use of coke breeze in the pellet feed mixture has become a common practice to provide additional indurating energy.

Can coke be mixed in fines so as to increase carbon in Sponge Iron so as to reduce the usage of Pig Iron in Induction Furnace?

There is a limitation in adding the Coke in the fines. Maximum we can add 1% Coke in the fines. Otherwise it will effect the strength of the pellets.

Ash content is near 4% so please confirm the quality of coal.

We add 1% coal while making the Green Balls. These coals should have as low as Ash content as possible. Hence, we recommend using imported coal.

Any unit working in India with similar technology?

All the pellet Plants in India are operating with Straight Grate Technology. We are also offering the same technology but in a smaller size, this technology we have adopted considering the suitability for hematite ore.

Is pellet form Magnetite ore suitable for Sponge Iron Production?

Magnetite ore when used for Pelletization and in process Magnetite Ore gets converted to Hematite Ore at 800 deg. C. & output pellet will be of Hematite only. Hence, can be easily used for Sponge Iron Production.

What experience VT CORP have in Pelletizing Plant?

V T CORP has entered into technical tie up with M/s. , USA, world renowned company for Iron Ore Pelletization. V T CORP also has team of experts in the field of Iron Ore Pelletization who has several years of experience in Pellet Plants of India.

Hematite ore is more difficult to ball than magnetite ore hence grinding cost in hematite ore shall be higher than in case of magnetite ore.  Any material considered for Pelletizing should contain at least 70% - 325 mesh and have specific surface area of  1200 cm² / gram.

It is not that Hematite is more difficult to ball than Magnetite or vice versa. It is the hardness index of the ore which determines the hardness of the material and it is responsible for increase or decrease in grinding cost. In grinding our target should be 100% -100 mesh i.e blain number 1600- 1700 sqcm/gm.

Can we feed 100% Pellets to DRI Kiln?

Yes, you can feed 100% pellets to DRI Kiln.

Iron ore should be of 1mm size (below 3mm size), which will constitute only about 10%, what about the balance?

We have considered Iron Ore of 1 mm size to arrive at the size of the mill for costing purpose. We can use any size of iron ore but the cost of grinding i.e capital cost and running cost will go up accordingly.

Any ball mill/ grinding mill is required?

We can use any Ball Mill for grinding wet or dry depending upon the process selected.

Brazil, India, Canada, Mexico & Australia are the countries who are exporters of Pellets.

Details of squeezer.

Squeezer is used for regrinding oversize or undersize green balls. This is a standard product available in India.

Process flow scheme of Indurating furnace showing arrangement of controls of temperature, gas line, burner line, zone wise temperature, etc. What sort of instrumentation arrangement level required for operating furnace DCS, PLC, Local / instrument control panel, etc.

Temperature Zone of Indurating Furnace - Chart is included in the offer. Indurating Furnace needs to be controlled by PLC control system.

Manpower required for operation and maintenance of the plant of 0.6 MTPA Pelletizing Plant?

60 Personnel are required for operation and maintenance of the plant.

What is the local electrical system requirement 6.6 kv/ 3.3 kv, Total installed load, maximum demand, etc. motor rating of what capacity will be maximum and what is the feed voltage?

Local electrical system requirement is 6.6 KV in HT and 440 volts in LT will be required. Maximum installed load required is approx. 7 MW for 0.6 MTPA and 11 MW for 1.2 MTPA Pelletizing Plant (including grinding).

Finished outlet of pellets will not be in open, it will be stored in silo of certain size so that moisture will not be added, no breakage during handling, etc. If the pellets can be directly fed to DRI, what sort of additional transportation equipment will be required? Additional cost required for same.

Finished product can be easily stored in general shade as they do not absorb moisture. The Tumbling Index is more then 90% thus they will not break during transportation.

Please explain both technology and its cost difference?

Technology

The Grate-Kiln-Technology was earlier developed by a American company Allis Chalmer. Similar technology is now offered by Chinese Companies.

Basically, this technology is suitable for Magnetite Ore (Fe₃O₄). In their Technology, material moves on Straight Grate bar till it attains the temperature of 800 deg.. Thereafter it is transferred to rotary kiln where the temperature is further raised upto 1250/1300°C.

At 800⁰C , the Magnetite Ore gets converted into Hematite Ore (Fe₂O₃) in an exothermic reaction. The liberated heat hardens the green balls which is helpful in withstand the tumbling impact in the Rotary kiln. Thus the green balls in the kiln do not break.

In the case of Hematite Ore, which is abundantly available in India, the exothermic reaction is not possible and hence the hardening of the balls simply does not take place. Thus, at 800⁰C , green balls still remain soft. Thus they are not suitable for sustaining the tumbling impact in the Rotary kiln.

We know that a leading company of India had put up Pelletizing Plant with Grate Kiln Technology similar to Chinese design. But, they could not successfully operate it even with best of the talents available with them. Finally the plant was scrapped. Some of the design personnel working in my organization were earlier in the design team who had supplied Pelletizing Plant. After detail study with those designers and some of the prominent process experts in the country having more than 30 years of experience in this field, who are now associated with us, we have recommended Straight Grate technology which is suitable for all type of Iron Ore available in India.

We understand that a couple of Indian companies who had ordered the Pelletizing Plants on Chinese Manufacturers recently, have not got the guarantee for using 100% Hematite Ore in their plant. Their guarantee is for a specific mix of Magnetite and Hematite, which is tested by them. Also note that these plants were finalized 2 years ago, but have not even reached half way due to various difficulties such as language problem, misunderstanding in scope of supply, their ignorance of handling Hematite ore, inability in modifying their own design to suit Indian requirement, etc.

The Straight Grate technology, offered by us, is ideal for Magnetite Ore (Fe₃O₄) and Hematite Ore (Fe₂O₃)both. The Green Balls remain always in Stationary position and travel in the pellet carts at 1250⁰C / 1350⁰C  . without getting disturbed till they are transformed into the pellets.

Traveling Grate – The VT CORP Indurating Machine is a Straight Grate Indurating Furnace which is basically an endless chain of pellets. The lifting wheel guides the pellets up onto the rails of the upper strand, and the lowering wheel guides them down again at the discharge end onto the rails of the lower strand. Each Pellet cart consists of two end sections & a center part. The end sections incorporate the running and pressure rolls.

The Indurating machine has nos.of wind boxes, connected to the process gas/air lines and fitted with dust removal equipments. Out of all wind boxes, some of the wind boxes are equipped With Motorised throttle dampers, so as to be able to adapt the flow of gases in these sections to the process requirements. All wind box pipes are fitted with compensators to allow for thermal expansion between the wind boxes and gas mains. Vaned sealing plates between the wind boxes are positioned in certain area, where the gas flow reverses. These sealing plates restrict the extent to which the gases take shortcuts at these points.

Above the Indurating machine, hoods with refractory material are installed. Burner chambers are arranged along both sides of the hood in alternative sections. These Burner chambers are connected to the direct recuperation line via connecting pipes.

Dividing walls with refractory cladding are situated between various zones in the hoods. To restrict the movement of infiltrating air or process air between hood and moving pellets to a minimum, sealing air is blown in special sealing elements. Cooling water system is installed to cool the traveling grates. Burners with flame detectors are installed for firing of fuel from burner hoods.

Cost

It is not possible to compare the cost of two plants made by two different technologies.

Straight Grate equipment is always expensive as against the Grate-Kiln-Technology. It is because the Straight Grate equipment is made of high alloy Stainless Steel material for its pellet carts.

Straight Grate Technology, offered by us, has its inherent advantage that it can be used with any available iron ore as against any specific iron ore by Chinese Grate Kiln Technology.

What is Taconite?

Taconite is a Precambrian Sedimentary Rock referred to as banded iron formation or Band Magnetite Quartzite (BMQ). It is basically a low grade ore, containing: 25 - 30% Magnetite, banded in tough variety of quartz called Chert. Due to a very low Fe content they are not economical to use. Minnesota Mines - one of the biggest mines in North America started their mining operation in 1880s and due to high demand all the good hematite was exhausted between the periods of 1930-50. During that period Taconite was untouched due to its very low content of Fe.

As there was no option left hence they decided to mine the Taconite for iron ore. The process adopted was blasting of hard rocks of Taconite, crushing, beneficiation and Pelletizing. The main process of Benefication was magnetic separation as Magnetite is magnetic in nature and hence easily separate out by magnetic separator.

LKB Sweden gets their ore almost 800 mtrs. below the ground level having Fe content of 35% they beneficiated this ore to 66% +.

Even Kudramukh Iron Ore has a low grade Magnetite having Fe content nearly 35% they beneficiated to 65 to 66% Fe. Beneficiation depends purely on type of ore and impurities it contains. Numbers of procedures / methods are available for benefication of ore.

We would like to inform you that some of the companies like 1. Empire Iron Making - USA, 2. United State Steel - Minnesota -2 Units. 3. Sydvarangar - Norway - 1.5 Million Unit, are using Taconite (BMQ) which is a type of Magnetite Ore Only.

"Why is Magnetite Magnetic and Hematite Nonmagnetic?"

Magnetic fields and magnetic material properties arise from electrons in motion. Electrons are always spinning and usually orbit atomic nuclei or travel linearly through space. Electrons spinning and revolving in tiny orbits around atomic nuclei generate magnetic dipoles-fields with both north and south poles like those that would emanate from atomic-sized bar magnets. In most materials, electrons orbit around the nucleus within configurations that have particular ranges, or bands, of energy. These bands can be subdivided into orbitals, which are usually evenly filled with electrons that pair together such that the paired orbits are alike in orientation, but exactly opposite in direction. When this occurs, the two magnetic dipoles that are generated point oppositely, cancel each other, and no large-scale, or bulk, magnetic properties are exhibited. In those few materials that do exhibit bulk magnetic properties, electron orbital nearer the nucleus are not evenly filled, so those electrons are not completely paired and through an interaction between adjacent atomic dipoles, a coupling occurs that tends to align the orbits of the electrons involved. In this manner, alignment of great numbers of atomic dipoles in a material will produce bulk magnetism.

Magnetite, (Fe₃O₄), has 4/3 or 1 and 1/3 atoms of oxygen (O) for every atom of iron (Fe). Also called lodestone, magnetite is a natural ferrite. All ferrites exhibit strong magnetic properties and are hard, brittle ceramic-like materials.

Magnetite is composed of iron atoms in two different states, one atom with a valence of +2 (Fe++ or ferrous iron) and two atoms with a valence of +3 (Fe+++ or ferric iron). A valence number is usually the number of outer electrons, which are those in the outermost and highest energy band. Further, the valence indicates the number of negatively charged electrons that are available for ideal sharing (i.e. bonding) with other atoms and can be either - for a surplus or + for a deficiency. In magnetite, the magnetic dipoles of the two Fe+++ atoms are pointed oppositely and cancel each other. However, the magnetic dipole of the Fe++ atom tends to align with many adjacent dipoles of other Fe++ atoms throughout the mineral by the same interaction mentioned previously, and this parallel alignment of many atomic dipoles produces a bulk magnetism called ferrimagnetisms. Since magnetite is strongly ferromagnetic, ordinarily strong production magnets are sufficient to separate magnetite from a finely ground mixture of taconite ore, which includes magnetite and its host rock. Typical taconite ore contains about 20-25% iron by weight. After such a removal of iron-rich magnetite, the waste rock is called taconite tailings.

Hematite, (Fe₂O₃), has 3/2 or 1½ atoms of oxygen for every atom of iron. Thus, it is a more oxidized iron mineral than magnetite and may be considered iron rust, because as metallic iron oxidizes, hematite can be formed. Hematite is actually very weakly magnetic as is explained below.

Over time, randomly mobile hematite molecules will statistically self-organize to form a crystal structure, or crystal lattice, whose regular pattern of molecules in three dimensions can be regarded as produced by repeated translations in space of a unit cell of atoms. The hematite crystal is notable in that the geometry of its packing distorts its lattice such that iron atoms within the unit cell are paired with slightly altered lattice spacing and although their dipoles would be expected to point oppositely, an interaction between the paired atoms tilts the two dipoles so they do not completely cancel, making bulk hematite very weakly magnetic. Thus, exotically powerful and expensive magnets would be required to separate hematite from a finely ground mixture of hematite and host rock.