Beneficiation is a variety of processes whereby extracted ore from mining is reduced to particles that can be separated into mineral and waste, the former suitable for further processing or direct use.
The beneficiation process improves the chemical or physical properties of the ore so that metal may be recovered profitably.
Based on this metaphor, the term has come to be used within an economic development and CSR (corporate social responsibility) context - to describe the proportion of the value derived from asset exploitation which stays 'in country' and benefits local communities.
For example, in the diamond industry, the beneficiation imperative argues that cutting and polishing processes within the diamond value-chain should be conducted in-country to maximize the local economic contribution
Iron Ore Trace Elements: Effects and Remedies (Silicon, Phosphorus, Aluminum and Sulfur)
The inclusion of even small amounts of some elements can have profound effects on the behavioral characteristics of a batch of iron or the operation of a smelter.
These effects can be both good and bad. Some catastrophically bad.
Some chemicals were deliberately added. The addition of a flux made a blast furnace more efficient.
Others were added because they made the iron more fluid, harder, or some other desirable quality.
The choice of ore, fuel, and flux determined how the slag behaved and the operational characteristics of the iron produced.
Ideally iron ore contains only iron and oxygen. In nature this is rarely the case. Typically, iron ore contains a host of elements which are often unwanted in modern steel.
Silicon
The major effect of silicon is to promote the formation of gray iron. Gray iron is less brittle and easier to finish than white iron. It was preferred for casting purposes for this reason. Turner (1900:192-7) reported
that silicon also reduced shrinkage and the formation of blowholes, lowering the number of bad castings.
Silica (SiO2) is almost always present in iron ore. Most of it is slagged off during the smelting process.
But, at temperatures above 1300/C some will be reduced and form an alloy with the iron.
The hotter the furnace, the more silicon will be present in the iron.
It is not uncommon to find up to 1.5% Si in European cast iron from the 16th to 18th centuries.
Phosphorus
Turner felt the ideal iron had 0.2-0.55% phosphorus
Phosphorus is a deleterious contaminant because it makes steel brittle, even at concentrations of as little as 0.5%. cannot be easily removed by fluxing or smelting, and so iron ores must generally be low in phosphorus to begin with.
The iron pillar of India which does not rust is protected by a phosphoric composition.
Phosphoric acid is used at a rust converter because phosphoric iron is less susceptible to oxidation.
Aluminum
Aluminum Is very hard to reduce. As a result aluminum contamination of the iron is not a problem.
However, it does increase the viscosity of the slag (Kato and Minowa 1969:37 and
Rosenqvist 1983:311). This will have a number of adverse effects on furnace operation. The thicker slag
will slow the descent of the charge, prolonging the process.
High aluminum will also make it more difficult to tap off the liquid slag. At the extreme this could lead to a frozen furnace.
There are a number of solutions to a high aluminum slag. the first is avoidance, don't
use ore or a lime source with a high aluminum content. Increasing the ratio of lime flux will decrease the viscosity (Rosenqvist 1983:311).
Sulfur
Sulfur dissolves readily in both liquid and solid iron at the temperatures present in iron smelting. The effects of even small amounts of sulfur are immediate and serious. Today iron with over 0.03% sulfur is avoided Sulfur causes iron to be red or hot short (Gordon1996:7)
Hot short iron is brittle when hot.
This was a serious problem as most iron used during the 17th and 18th century was bar or wrought iron.
Wrought iron is shaped by repeated blows with a hammer while hot. A piece of hot short iron will crack if worked with a hammer. When a piece of hot iron or steel cracks the exposed surface immediately oxidizes. This layer of oxide prevents the mending of the crack by welding.
Large cracks cause the iron or steel to break up. Smaller cracks can cause the object to fail during use.
The degree of hot shortness is in direct proportion to the amount of sulfur present.
Today iron with over 0.03% sulfur is avoided. In modern operations, sulfur is unwanted because it produces undesirable sulfur dioxide gases in the flue emissions from a smelter and interferes with the smelting process. Sulfur (S) is a frequent contaminant in coal and coke.
Iron sulfide (pyrite, FeS2), is a common iron ore. It is also present in small quantities in many ores.
It was the presence of sulfur that prevented the use of coal in blast furnaces until
1709.
They were one of the first worked out by iron makers.
To convert an oxide of iron to metallic iron it must be smelted or sent through a direct reduction
process Chemical reduction, or smelting, is a form of extractive metallurgy.
The main use of smelting is to produce a metal from its ore.
This includes iron extraction (for the production of steel) from iron ore, and copper extraction and other base metals from their ores.
It makes use of a chemical reducing agent, commonly a fuel that is a source of carbon such as coke, or in earlier times charcoal, to change the oxidation state of the metal ore; however, plants for the electrolytic reduction of aluminum are also generally referred to as smelters.
The carbon or carbon monoxide derived from it removes oxygen from the ore to leave the metal.
The carbon is oxidized, producing carbon dioxide and carbon monoxide.
As most ores are impure, it is often necessary to use flux, such as limestone to remove the accompanying rock gangue as slag (also called scoria or cinder).
Pre Test Review: Iron Ore Beneficiation & Trace Elements
1.
Beneficiation Is a variety of processes whereby extracted ore from mining is reduced to particles that can be separated into mineral and waste,the former suitable for further processing or direct use.
2.
Chemical reduction, or smelting, is a form of extractive metallurgy.
3.
To convert an oxide of iron to metallic iron it must be smelted or sent through a direct reduction process. The main use of smelting is to produce a metal from its ore.This includes iron extraction (for the production of steel) from iron ore.
4.
Most ores are impure, it is often necessary to use flux, such as limestone to remove the accompanying rock gangue as slag (also called scoria or cinder)
5.
The inclusion of even small amounts of some elements can have profound effects on the behavioral characteristics of a batch of iron or the operation of a smelter.
6.
Some chemicals are deliberately added; Others are added because they make the iron more fluid, harder, or some other desirable quality.
7.
Ideally iron ore contains only iron and oxygen but in nature this is rarely the case. Typically, iron ore contains a host of elements which are often unwanted in modern steel.
8.
The major effect of silicon is to promote the formation of gray iron.which is preferred for casting purposes.
9.
Silicon also reduced shrinkage and the formation of blowholes, lowering the number of bad castings.
10.
Gray Iron is less brittle and easier to finish than white iron.
11.
The hotter the furnace, the more silicon will be present in the iron. It is not uncommon to find up to 1.5% Si in European cast iron from the 16th to 18th centuries.
12.
Silica (SiO2) is almost always present in iron ore. Most of it is slagged off during the smelting process. But, at temperatures above 1300/C some will be reduced and form an alloy with the iron.
13.
Phosphorus is a deleterious contaminant because it makes steel brittle, even at concentrations of as little as 0.5%. cannot be easily removed by fluxing or smelting.
14.
the ideal iron should contain no more than 0.2-0.55% phosphorus
15.
Phosphoric acid is used at a rust converter because phosphoric iron is less susceptible to oxidation. The iron pillar of India which does not rust is protected by a phosphoric composition.
16.
Aluminum is very hard to reduce. As a result aluminum contamination of the iron is not a problem.
17.
Aluminum increases the viscosity of the slag resulting in a number of adverse effects on furnace operation.
18.
High aluminium makes it more difficult to tap off the liquid slag which can lead to a frozen furnace.
19.
There are a number of solutions to a high aluminum slag. the first is avoidance, don't use ore or a lime source with a high aluminum content. Increasing the ratio of lime flux will decrease the viscosity.
20.
The effects of even small amounts of sulfur are immediate and serious.
21.
Today iron with over 0.03% sulfur is avoided
22.
Sulfur causes iron to be red or hot short. The degree of hot shortness is in direct proportion to the amount of sulfur present.
23.
A piece of hot short iron will crack if worked with a hammer. When a piece of hot iron or steel cracks the exposed surface immediately oxidizes. This layer of oxide prevents the mending of the crack by welding.
24.
Large cracks cause the iron or steel to break up. Smaller cracks can cause the object to fail during use.
25.
Iron sulfide (pyrite, FeS2), is a common iron ore. It is also present in small quantities in many ores.
Sample Offer for Sale of Iron Ore
Iron Ore 63% Fe of Loei province, Thailand North Eastern origin for serious inquiries only. Detailed Product Description Iron ores are minerals from which metallic iron is extracted.
Most important use of iron is in the blast furnace for the production of pig iron. It is used in the furnace in the form of sinters and pellets as also lumpy ore. It is also consumed in the open health furnaces.
IRON ORE HANDLING
The design of the processing circuit is designed to feature a jaw crusher equipped with a rock-breaker followed by a two stage crushing and screening operation with horizontal washing screen to produce both lump and fines 0-50 mm size or as client's request. Capacity at 1,000 Mt per day and plan for 4,000 mt
Sufficient stockpiles of ore will be maintained at the processing facilities to allow for uninterrupted trucking/barging to Ayutthaya/Sriracha port.
Specifications;
Iron as Fe: 63 % min : Volumatic test method
Sulfur as S: 0.02%-0.08% max :
Phosphorus as P: 0.02%-0.05% max : Based on ASTM E278-01
Silica as SiO2: 2% to 3.5% max : Gravimatric test method
Aluminum as Al2O3: 0.98%-3.5% max : ICP test method
Specific gravity from 4.0 to 4.5.
Moisture content: Humidity at 105 deg.c on received basis 8%, Rainy season Max.10%.
More information: Iron Ores Chemical Analysis Sizes: Fine and Lump Fines are defined as iron ore with the majority of Individual particles measuring less
than 10 millimeters diameter. Conversely, lump is iron ore Majority of individual particles measuring more than 10 Millimeters diameter. Iron ore lumps varies from + 10 mm to + 75 mm.
More information: Iron ores size control
Fe Content: Iron of as high-grade as possible is required because an increased of 1% Fe in the burden increased the productivity by 2% and decreased the coke rate by 3%. In the THB Mining, the range of the Fe content in iron ore lumps is 60.52% to 66.5%.
Silica: 1.5% decreased of silica causes reduction in the slag volume of 65kg per ton of pig iron. Increase of 100-kg slag per tonne of pig iron raised fuel consumption by 40 kg of coke per tonne of pig iron. In the Thailand Plants, the range of silica in iron ore lumps varies from 1.6% (max.) to 3.5% (max.).
Alumina: If the ore is high in alumina, the fluidity of slag is affected. It should not also be too low. In the Indian Plants, alumina content in the ore varies from 3% to 3.5% Generally.
Phosphorus should not exceed 0.05%
DISTANCE ADVANTAGE:
The closest distance to China, Korea and Japan than other iron ore deposits, the transportation of the iron ore to China and Japan requires shorter time than other exporters. (Approximately 2,600 Nautical miles, India approximately 4,000 Nautical miles, Australia approximately 3,600 nautical miles, and Brazil approximately 10,000 nautical miles to China)
LOCATION OF anywhere PROVINCE, IRON ORES DEPOSITS
==============================================================
Chemical Analysis / per our standards
Iron as Fe - Iron Oxide Fe2O3
As a commercial mineral Iron Ore often also contains small amounts of the following:
Silica as Si - Silicon Dioxide SiO2 :
Silica occurs commonly in nature as sandstone, silica sand or quartzite and ores.
Method of analysis: -Spectrophotometer*
Aluminum as Ag - Aluminum Oxide Al2O3 :
Aluminum oxide is an amphoteric oxide of aluminum with the chemical formula
Al2O3. It is also commonly referred to as alumina in the mining, ceramic and materials science communities. Method of analysis: -Titrimetry (fluorine method)
Titanium as Ti - Titanium Dioxide TiO2 :
Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturally
occurring oxide of titanium, chemical formula TiO2. Method of analysis:
-Spectrophotometer*
Magnesium Mg - Magnesium Oxide MgO
Magnesium is a white solid mineral that occurs naturally as periclase and is a source
of magnesium. Method of analysis: -Spectrophotometer*
Manganese Mn - Manganese Oxide MnO Manganese is a chemical element that has the symbol Mn and atomic number 25. It is found as the free element in nature, often in combination with iron, and in many minerals. Method of analysis: Spectrophotometer*
Sulfur S - Sulfur dioxide SO2 (also sulphur dioxide)
Sulphur is the chemical compound with the formula SO2. This important gas is the main product from the combustion of sulfur. Method of analysis: Gravimetry*
Calcium as Ca - Calcium oxide CaO
Calcium commonly known as lime. Method of analysis: Spectrophotometer*
Loss On Ignition - LOI
Whilst it is desirable to have low contaminant levels of the elements mentioned above, it is considered the opposite for an LOI measure. Essentially, the LOI is a measure of the water content of the ore, which evaporates when the ore is fed into a blast furnace. A typical iron ore analysis should include an LOI determination at 1000 deg. C, normally undertaken by Thermo gravimetric Analyzer (TGA).
*Method accredited: international level for accreditation web site see http://www.cengeolab.com/argaCh_e.htm
Showing posts with label Iron Ore. Show all posts
Showing posts with label Iron Ore. Show all posts
2009/05/10
Iron Ore Processing for the Blast Furnace
The following describes operations at the National Steel Pellet Company, an iron ore mining and processing facility located on the Mesabi Iron Range of Minnesota.
Creating steel from low-grade iron ore requires a long process of mining, crushing, separating, concentrating, mixing, pelletizing, and shipping. The process of mining low-grade iron ore, or taconite, requires massive resources. Heavy industrial mining equipment, expansive mines, and a skilled labor pool are all required. The equipment used includes diamond-bit rotary drills, hydraulic shovels and loaders, water wagons, production trucks and heavy-duty conveyors.
National Steel Pellet Company’s plant is capable of producing 5.35 million tons of pellets each year. It employs approximately 500 workers.
Mining Iron Ore
Mining iron ore begins at ground level. Taconite is identified by diamond drilling core samples on a grid hundreds of feet into the earth. Taconite rock comprises about 28 percent iron; the rest is sand or silica. These samples are analyzed and categorized so that mining engineers can accurately develop a mine plan.
To uncover taconite reserves, the mine area is first "stripped" of the overburden or glacial drift, comprised primarily of rock, clay and gravel. The overburden is loaded by large hydraulic shovels into production trucks, which haul it to contour dumps. These dumps are environmentally designed to match the surrounding area.
Once the taconite rock is exposed, large drilling rigs drill blast holes 16" in diameter by 40' deep, in some cases. Nearly 400 of these holes are drilled in a blast pattern. Before the blast, the holes are filled with a special mixture of blasting agents. Once prepared, the mine site is cleared of workers and equipment, and the blast is detonated. Each of the holes is detonated just a millisecond apart, resulting in a pile of crude taconite that is broken apart to a minus 6' x 6' size.
After blasting, hydraulic face shovels and larger loaders load the taconite into 205-ton or 240-ton production trucks, which haul it to crushers. The taconite is ground to a fine powder and mixed with water. A series of magnets is run over the mixture. The magnets grab the iron particles and the rest is discarded. For every ton of iron retained, two tons of waste, or tailings, are discarded.
Crushing the Ore
The crude taconite is delivered to large gyrator crushers, where chunks as large as five feet are reduced to six inches or less. More than 6,000 tons of taconite can be crushed in one hour.
The crushed material is transferred by belt to an ore storage building, which holds up to 220,000 tons of taconite. An apron feeder sends the ore to the concentrator building for grinding, separating, and concentrating.
Concentrating
The crude taconite is now roughly the size of a football or smaller. A series of conveyor belts continuously feed the ore into ten large 27-foot-diameter, semi-autogenous primary grinding mills. Water is added at this point to transport it (94 percent of the water is recycled, while the rest is lost through evaporation).
Each primary mill contains several 4" steel balls that grind the ore as the mills turn. When the ore is reduced to 3/4" or less, it moves out of the mill in a slurry solution. The mill discharge is screened at 1/4" on trommel screens attached to the mill. Ore smaller than 1/4" is pumped in slurry solution to the wet cobber magnetic separator, which begins the process of separating the iron from the non-iron material. The magnetic iron ore is then laundered in two slurry surge tanks while the non-magnetics (silica/sand) go to the tailings disposal area.
Most of the material continues to be finely ground in one of five secondary ball mills, which are powered by electric motors ranging from 2,500 hp to 4,000 hp and are charged with 1-1/2" chrome grinding balls. Fine grinding is achieved using these smaller mills, bringing the ore to a similar grind as that found in face powder. The screen undersize is then moved to hydroseparators, where silica is floated off the top.
The hydroseparator underflow is pumped to the finisher magnetic separators. Once again, the magnetic separators grab the iron and discard the silica and sand. Thus, the ore is "concentrated" by removing the waste materials. The concentrate from the separators is pumped to fine screening.
The oversize material is returned to the balls mills, while the undersize (with the most impurities removed) becomes the final concentrate. Waste from the circuit goes to the tailings basin and the final concentrate travels to thickeners located in the pellet plant. The underflow from the thickeners is pumped to a storage tank and then to disc filters for dewatering.
The product is called “filter cake”, and is now ready for mixing with the binding agent.
Mixing with the Binding Agents
Once the filter cake is complete, it is deposited into a surge bin. It then travels onto a feeder belt and from there to a conveyor where bentonite, a bonding agent, is added. Bentonite is a clay from Wyoming used to help iron ore concentrate stick together when rolled into pellets. About 16 pounds of Bentonite are added to every ton of iron ore concentrate.
Small amounts of limestone (1%) are also added and mixed with the concentrate at this point. Limestone is added to meet the requirements of steel customers in the blast furnace process.
The iron ore concentrate is now mixed and ready for the pelletizing process.
Pelletizing
A pellet plant contains a series of balling drums where the iron ore concentrate is formed into soft pellets, in much the same manner that one rolls a snowball, to make a pellet about the size of a marble (between 1/4" and 1/2"). Pellets are screened to meet the size specification, with undersized or oversized pellets crushed and returned to the balling drums.
The soft pellets are then delivered to the roller feeder for final removal of the fines, which are also returned to the balling circuits. Now the soft pellets, correctly sized, are delivered to the traveling grate furnace for further drying and preheating. The grate is fired by natural gas.
From this point, the pellets are charged into the large rotary kiln where they are heat-hardened at 2,400 degrees Fahrenheit. The pellets are discharged into the revolving cooler and then moved to the pellet screening plant, onto the pellet loadout system. The whole process consumes energy in the form of electricity and natural gas. Over the past several years, millions of dollars have been spent to improve energy efficiency and to recoup waste heat and re-use it in the process. These efforts have significantly reduced expenditures on energy.
The pelletizing process has now been completed. The pellets are run through a final screening to remove those not meeting size specifications or those that are chipped or broken into fines. Pellets that meet the necessary standards are conveyed to the pellet stockpile, which holds about 30,000 tons.
Pellet Loadout and Shipping
The pellets are now ready for shipping by train to customers or to ore docks. They are sent to blast furnaces and steel mills, where they will be turned into finished steel.
A trainload of iron ore pellets bound for the blast furnace
National Steel Pellet Company’s iron ore pellets have the following characteristics (FOB Mine):
Total Iron: 65.85% Silica (SiO2): 4.5% Lime (CaO): 0.68% Phosphorous: 0.010
Size: %+1/4” 96.5% (after tumble) Compression Strength: 560 pounds
from: http://www.steel.org
Creating steel from low-grade iron ore requires a long process of mining, crushing, separating, concentrating, mixing, pelletizing, and shipping. The process of mining low-grade iron ore, or taconite, requires massive resources. Heavy industrial mining equipment, expansive mines, and a skilled labor pool are all required. The equipment used includes diamond-bit rotary drills, hydraulic shovels and loaders, water wagons, production trucks and heavy-duty conveyors.
National Steel Pellet Company’s plant is capable of producing 5.35 million tons of pellets each year. It employs approximately 500 workers.
Mining Iron Ore
Mining iron ore begins at ground level. Taconite is identified by diamond drilling core samples on a grid hundreds of feet into the earth. Taconite rock comprises about 28 percent iron; the rest is sand or silica. These samples are analyzed and categorized so that mining engineers can accurately develop a mine plan.
To uncover taconite reserves, the mine area is first "stripped" of the overburden or glacial drift, comprised primarily of rock, clay and gravel. The overburden is loaded by large hydraulic shovels into production trucks, which haul it to contour dumps. These dumps are environmentally designed to match the surrounding area.
Once the taconite rock is exposed, large drilling rigs drill blast holes 16" in diameter by 40' deep, in some cases. Nearly 400 of these holes are drilled in a blast pattern. Before the blast, the holes are filled with a special mixture of blasting agents. Once prepared, the mine site is cleared of workers and equipment, and the blast is detonated. Each of the holes is detonated just a millisecond apart, resulting in a pile of crude taconite that is broken apart to a minus 6' x 6' size.
After blasting, hydraulic face shovels and larger loaders load the taconite into 205-ton or 240-ton production trucks, which haul it to crushers. The taconite is ground to a fine powder and mixed with water. A series of magnets is run over the mixture. The magnets grab the iron particles and the rest is discarded. For every ton of iron retained, two tons of waste, or tailings, are discarded.
Crushing the Ore
The crude taconite is delivered to large gyrator crushers, where chunks as large as five feet are reduced to six inches or less. More than 6,000 tons of taconite can be crushed in one hour.
The crushed material is transferred by belt to an ore storage building, which holds up to 220,000 tons of taconite. An apron feeder sends the ore to the concentrator building for grinding, separating, and concentrating.
Concentrating
The crude taconite is now roughly the size of a football or smaller. A series of conveyor belts continuously feed the ore into ten large 27-foot-diameter, semi-autogenous primary grinding mills. Water is added at this point to transport it (94 percent of the water is recycled, while the rest is lost through evaporation).
Each primary mill contains several 4" steel balls that grind the ore as the mills turn. When the ore is reduced to 3/4" or less, it moves out of the mill in a slurry solution. The mill discharge is screened at 1/4" on trommel screens attached to the mill. Ore smaller than 1/4" is pumped in slurry solution to the wet cobber magnetic separator, which begins the process of separating the iron from the non-iron material. The magnetic iron ore is then laundered in two slurry surge tanks while the non-magnetics (silica/sand) go to the tailings disposal area.
Most of the material continues to be finely ground in one of five secondary ball mills, which are powered by electric motors ranging from 2,500 hp to 4,000 hp and are charged with 1-1/2" chrome grinding balls. Fine grinding is achieved using these smaller mills, bringing the ore to a similar grind as that found in face powder. The screen undersize is then moved to hydroseparators, where silica is floated off the top.
The hydroseparator underflow is pumped to the finisher magnetic separators. Once again, the magnetic separators grab the iron and discard the silica and sand. Thus, the ore is "concentrated" by removing the waste materials. The concentrate from the separators is pumped to fine screening.
The oversize material is returned to the balls mills, while the undersize (with the most impurities removed) becomes the final concentrate. Waste from the circuit goes to the tailings basin and the final concentrate travels to thickeners located in the pellet plant. The underflow from the thickeners is pumped to a storage tank and then to disc filters for dewatering.
The product is called “filter cake”, and is now ready for mixing with the binding agent.
Mixing with the Binding Agents
Once the filter cake is complete, it is deposited into a surge bin. It then travels onto a feeder belt and from there to a conveyor where bentonite, a bonding agent, is added. Bentonite is a clay from Wyoming used to help iron ore concentrate stick together when rolled into pellets. About 16 pounds of Bentonite are added to every ton of iron ore concentrate.
Small amounts of limestone (1%) are also added and mixed with the concentrate at this point. Limestone is added to meet the requirements of steel customers in the blast furnace process.
The iron ore concentrate is now mixed and ready for the pelletizing process.
Pelletizing
A pellet plant contains a series of balling drums where the iron ore concentrate is formed into soft pellets, in much the same manner that one rolls a snowball, to make a pellet about the size of a marble (between 1/4" and 1/2"). Pellets are screened to meet the size specification, with undersized or oversized pellets crushed and returned to the balling drums.
The soft pellets are then delivered to the roller feeder for final removal of the fines, which are also returned to the balling circuits. Now the soft pellets, correctly sized, are delivered to the traveling grate furnace for further drying and preheating. The grate is fired by natural gas.
From this point, the pellets are charged into the large rotary kiln where they are heat-hardened at 2,400 degrees Fahrenheit. The pellets are discharged into the revolving cooler and then moved to the pellet screening plant, onto the pellet loadout system. The whole process consumes energy in the form of electricity and natural gas. Over the past several years, millions of dollars have been spent to improve energy efficiency and to recoup waste heat and re-use it in the process. These efforts have significantly reduced expenditures on energy.
The pelletizing process has now been completed. The pellets are run through a final screening to remove those not meeting size specifications or those that are chipped or broken into fines. Pellets that meet the necessary standards are conveyed to the pellet stockpile, which holds about 30,000 tons.
Pellet Loadout and Shipping
The pellets are now ready for shipping by train to customers or to ore docks. They are sent to blast furnaces and steel mills, where they will be turned into finished steel.
A trainload of iron ore pellets bound for the blast furnace
National Steel Pellet Company’s iron ore pellets have the following characteristics (FOB Mine):
Total Iron: 65.85% Silica (SiO2): 4.5% Lime (CaO): 0.68% Phosphorous: 0.010
Size: %+1/4” 96.5% (after tumble) Compression Strength: 560 pounds
from: http://www.steel.org
2009/05/06
New gasification method to produce Direct Reduced Iron (DRI)
A small Dutch company developed a new gasification concept to produce syngas in order to reduce iron ore in a direct reduction process using pulsed combustion burner technology. Utilising a gasifier to generate reducing gases is a technically and commercially viable method for innovative steelmakers to produce DRI in areas where low cost natural gas is not available. The company is looking for a commercial agreement with a company that can use the technology in its product.
Commercial gasifiers have been in operation for over 50 years. In general, gasification can be defined as a partial oxidation process in which carbonaceous fuel (gas, liquid, or solid) reacts at high temperature and usually at high pressure with oxygen and possible steam to produce a synthesis gas. This gas can then be used to fuel a Direct Reduction Process. Utilising a gasifier to generate reducing gases is a technically and commercially viable method for innovative steelmakers to produce DRI in areas where low cost natural gas is not available. Even better economics can be derived when the project includes a melt shop and an integrated gasification combined cycle-based power plant.
Pulsed combustion burners can be used wherever you use conventional burners. In the last decade the development has made progress, resulting in a number of projects around the world utilising the above principle with great advantages, like e.g. high production increase in case of drying applications. The company is capable of building stable industrial high-frequency pulsed high-power burners. Pulsed combustion has been known for a long time. In the last decade the development has made further progress, resulting in a number of projects around the world utilising the above principle. At this moment the company has built a gasification unit of several MW using the same principle of pulsed combustion.
During the development a number of obstacles have been encountered and overcome, namely the ability to up scale, and to increase frequency proved to be a stumbling block for the growth of this technology and its application. However this did not prevent a number of diverse applications. A few examples are:
- gasification units,
- product drying such as vegetables,
- chemical powder drying with small particles,
- the ability to utilise various waste materials for burning,
- typical sludge incineration from sewage plants and industrial water waste,
- boiler, heaters of all kind,
- desalination plants (for evaporators) to produce fresh water installations,
- air heaters,
- incinerators,
- production of steam for turbines and electricity generation,
- kilns. Innovative Aspects: The company also claims to have perfected gasification and burner technology where it would be possible to design and build a 10 MW burner, where further up scaling would not present any problem.
This technology is unique in so far that with this technology the company is capable of designing and manufacturing this type of pulsating burner without any moving parts, resulting in an industrial stable high-frequency high-power burner and/or gasification unit. Main Advantages: - High efficient gasification.
- To have an efficient burning rate resulting in a lower energy cost.
- By having a higher energy transfer rate will mean smaller and cost-effective equipment (fast return of investment).
- Creating lower pollution (low NOx in accordance with the recent Kyoto environmental requirements).
- In the application of sludge, a significant reduction of possible precipitor agent such as polyelectrolyte commonly used in the de-watering processes.
- It has a built in self-cleaning advantage, due to the pulsating mechanism of the combustion technology.
- The final product after drying tends to have a light structure which a high porosity.
from:http://www.invenia.es/tech:06_nl_nlse_0f8l
Commercial gasifiers have been in operation for over 50 years. In general, gasification can be defined as a partial oxidation process in which carbonaceous fuel (gas, liquid, or solid) reacts at high temperature and usually at high pressure with oxygen and possible steam to produce a synthesis gas. This gas can then be used to fuel a Direct Reduction Process. Utilising a gasifier to generate reducing gases is a technically and commercially viable method for innovative steelmakers to produce DRI in areas where low cost natural gas is not available. Even better economics can be derived when the project includes a melt shop and an integrated gasification combined cycle-based power plant.
Pulsed combustion burners can be used wherever you use conventional burners. In the last decade the development has made progress, resulting in a number of projects around the world utilising the above principle with great advantages, like e.g. high production increase in case of drying applications. The company is capable of building stable industrial high-frequency pulsed high-power burners. Pulsed combustion has been known for a long time. In the last decade the development has made further progress, resulting in a number of projects around the world utilising the above principle. At this moment the company has built a gasification unit of several MW using the same principle of pulsed combustion.
During the development a number of obstacles have been encountered and overcome, namely the ability to up scale, and to increase frequency proved to be a stumbling block for the growth of this technology and its application. However this did not prevent a number of diverse applications. A few examples are:
- gasification units,
- product drying such as vegetables,
- chemical powder drying with small particles,
- the ability to utilise various waste materials for burning,
- typical sludge incineration from sewage plants and industrial water waste,
- boiler, heaters of all kind,
- desalination plants (for evaporators) to produce fresh water installations,
- air heaters,
- incinerators,
- production of steam for turbines and electricity generation,
- kilns. Innovative Aspects: The company also claims to have perfected gasification and burner technology where it would be possible to design and build a 10 MW burner, where further up scaling would not present any problem.
This technology is unique in so far that with this technology the company is capable of designing and manufacturing this type of pulsating burner without any moving parts, resulting in an industrial stable high-frequency high-power burner and/or gasification unit. Main Advantages: - High efficient gasification.
- To have an efficient burning rate resulting in a lower energy cost.
- By having a higher energy transfer rate will mean smaller and cost-effective equipment (fast return of investment).
- Creating lower pollution (low NOx in accordance with the recent Kyoto environmental requirements).
- In the application of sludge, a significant reduction of possible precipitor agent such as polyelectrolyte commonly used in the de-watering processes.
- It has a built in self-cleaning advantage, due to the pulsating mechanism of the combustion technology.
- The final product after drying tends to have a light structure which a high porosity.
from:http://www.invenia.es/tech:06_nl_nlse_0f8l
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