Loss on Ignition

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  • Topic: Iron, Hematite, Iron ore
  • Pages : 20 (4710 words )
  • Download(s) : 103
  • Published : April 28, 2013
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Loss on Ignition is a test used in inorganic analytical chemistry, particularly in the analysis of minerals. It consists of strongly heating ("igniting") a sample of the material at a specified temperature, allowing volatile substances to escape, until its mass ceases to change. This may be done in air, or in some other reactive or inert atmosphere. The simple test typically consists of placing a few grams of the material in a tared, pre-ignited crucible and determining its mass, placing it in a temperature-controlled furnace for a set time, cooling it in a controlled (e.g. water-free, CO2-free) atmosphere, and redetermining the mass. The process may be repeated to show that mass-change is complete. A variant of the test in which mass-change is continually monitored as temperature is changed, is thermogravimetry. The loss on ignition is reported as part of an elemental or oxide analysis of a mineral. The volatile materials lost usually consist of "combined water" (hydrates and labile hydroxy-compounds) and carbon dioxide from carbonates. It may be used as a quality test, commonly carried out for minerals such as iron ore. For example, the loss on ignition of a fly ash consists of contaminant unburnt fuel.

Advantages of Straight Grate Indurating Furnace over Chinese System (Grate Kiln Technology) 1. We offer Pelletizing Plant with Straight Grate Indurating Furnace which is proven worldwide whereas Chinese plants offer Grate Kiln Technology. Its usage is shown below:               

2.    Straight Grate Technology is available with us which is widely used for Hematite as the ore .we have expertise to handle Hematite, whereas for Chinese manufacturers handling hematite ore is an experiment. We assure you guaranteed performance with Hematite ore.

3. India’s all the five Pelletization plants Installed are of this Straight traveling grate technology. In case of certain operational & consultancy on finding right person for Chinese plants which runs on Grate Kiln technology is not possible. Moreover, we are fully geared up to supply this technology furnace to you with our Design team experienced in working with the pioneer Pelletizing plants in India. 4. The mechanical properties of the pellets made by Straight grate furnace are much better than others  like: * Tumbling Index of 95% +6.5mm.

* Average cold compressive strength of fired pellets is at least 2500 Newton per pellet, applied to pellets of diameter of 12 ± 1mm. * Pellets having cold crushing strength below 800 N max 5%. Hence chances of breakage during transportation are non existent whereas Grate Kiln results in lot of transits wastages due to breakage. The Pellets produced with this technology are of DRI quality. Use of a single unit for Pellet Drying, Preheating, Firing and Cooling: * Pellets remain undisturbed throughout the entire process (including cooling). * Uniform heat treatment.

* Minimized dust and fines generation.
* No intermediate strength requirement.
Several burners in preheating and firing zones:
* Superior process flexibility.
* Adjustable temperature profile.
* Adaptation of different firing profiles to changing raw materials. Stationary refractories, grate maintenance off-line:
* Low maintenance costs and high availability
Several recuperation techniques:
* Low specific heat consumption
Heat transfer by convection instead of radiation :
Uniform heat treatment, leading to uniform product quality.
Moreover when some better technology is available within India we must get maximum utilisation of it. RAW MATERIAL REQUIREMENT
a)IRON ORE FINES (Hematite Ore): -
* 66.5% Fe is normally not available from mines. It needs to be achieved after Beneficiating available iron ore fines. b) BENTONITE (Binder): -
* It is a montmorillonite type of clay which is formed by alteration of volcanic ash deposited in water. * Addition of 0.5 to 1.5%.
* Absorbs huge amount of water,10 times of its own...
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