Atomic weights of Fe at 56 and oxygen at In nature magnetite often contains impurities in the ore which makes the Fe content of mined ore lower than hematite. As stated the impurities in magnetite can be removed via processing often resulting in an Fe percentage higher than hematite.
So the statements above make little sense to me. So the opening line in the section on magnetite above is perhaps misleading since it is not the chemical composition which is the difference. The difference is the level of impurities in magnetite deposits which are removed by magnetic seperation and then pelletising is needed to agglomerate the fine magnetite material. Fe2O3 can be turned into Fe3O4 with heat to drive out contamination and convert molecular structure. Natural Magnetite is much better for iron production.
This artical has everything backwards. Back to basic chemistry…. Hi there, thanks for commenting, and apologies for the error.
You are, of course, correct — magnetite does have a higher iron content than Hematite. However, I believe the original offer failed to make the distinction between hematite and hematite ores the same goes for magnetite.
Hematite can occur in high-grade ores, referred to as direct-shipping ores, which have higher iron content than naturally occurring magnetite ores. Still, as you note and as the article states, iron produced from magnetite makes for a higher quality end-product. The author has not done her research thoroughly enough : processing magnetite ores result in a significantly higher carbon footprint than with the processing of hematite ores.
Thanks for both comments. Newell, regarding hematite vs. As a consequence, magnetite concentrate production is more CO2 emissions intensive than direct shipping ore DSO production. But when entire life cycle emissions are considered ground to steel , magnetite comes ahead of hematite, with a net savings of kg CO2e per tonne of magnetite concentrate, as per the report.
The process continued for nearly a billion years and eventually let to the accumulation of oxygen in the atmosphere. Most of the world's important iron ore resources occur in banded iron formations, which are almost exclusively of Precambrian age i. BIFs occur on all continents. Mt Tom Price; iron oxides deposited along ancient, mainly Tertiary age river channels palaeochannels ; and iron oxide deposits formed from the erosion of existing orebodies detrital iron ore deposits.
The BIF enrichment deposits comprising hematite and hematite goethite are the most important in regard to resources and production. Yarrie , and the Yilgarn Block e. Koolyanobbing and in South Australia e.
Iron Duke, Middleback Range. The palaeochannel deposits composed of pisolitic limonite are the next in importance and are prized for their low impurities such as phosphorus. They are not as rich in iron as the BIF enrichment ores.
Detrital iron ore deposits are found downhill of the BIF enrichment deposits from which they have been eroded. Further resource and production information. As with most iron ore mines throughout the world, all the major Australian iron ore mines are open cut. The iron-ore bearing rock is first blasted and dug up from open pit mines. The ores from the major mines in Western Australia's Pilbara region are hauled from working faces to crushing and screening plants using trucks that can carry over tonnes.
Hematite and magnetite ore processing includes crushing, screening and grinding to produce hematite lumps and fines. Magnetite ore is further processed through magnetic separation, an important process in producing magnetite iron concentrate. Concentration includes all the processes that will increase upgrade the iron content of an ore by removing impurities.
Beneficiation, a slightly broader term, includes these processes as well as those that make an ore more usable by improving its physical properties e. Many of the iron ore mines employ some form of beneficiation to improve the grade and properties of their products. At many operating mines, including Mount Tom Price, Paraburdoo, Mount Whaleback and Christmas Creek, ore processing facilities have been constructed to enable beneficiation of low-grade iron ores, including ores which have been contaminated with shale, to be mined and, after upgrading, sold as high-grade products.
Pelletising is a treatment process used for very fine or powdery ores. These are often in intimate association, and the ore is mined, crushed, and processed to recover both minerals. Historically, much of the hematite was not recovered and was sent to tailings piles. More efficient processing today allows more hematite to be recovered from the ore.
The tailings can also be reprocessed to recover additional iron and reduce tailings volume. Martian "Blueberries": In , NASA's Mars Exploration Rover Opportunity discovered that soil near its landing site contained millions of tiny spheres that researchers nicknamed "blueberries. The iron content of Martian rocks and soil contribute to its red appearance from Earth and helped it earn the name "The Red Planet. NASA has discovered that hematite is one of the most abundant minerals in the rocks and soils on the surface of Mars.
An abundance of hematite in Martian rocks and surface materials gives the landscape a reddish brown color and is why the planet appears red in the night sky.
It is the origin of Mars' "Red Planet" nickname. Taconite Pellets: These taconite pellets consist of finely crushed taconite rock that has been processed to improve the iron content and mixed with a small amount of clay to improve pelletization.
This is one of the standard ways of shipping iron ore from a mine to a steel mill. Image by Harvey Henkelmann. Although magnetite contains a higher percentage of iron and is easier to process, hematite is the leading ore because it is more abundant and present in deposits in many parts of the world.
Hematite is mined in some of the largest mines in the world. These mines require investments of billions of dollars, and some will remove over million tons of ore per year.
These open-pit mines can be hundreds to thousands of feet deep and several miles across by the time they have been worked to completion. Iron ore production in the United States occurs in Michigan and Minnesota. Hematite Pigment: Hematite was one of the first pigment minerals used by people. At least 40, years ago, people obtained hematite, crushed it into a fine powder, and used it to make paints.
Shown above are commercial hematite pigments that are available today. Since the Renaissance, pigments have often been named after the locations where they were produced. The color variations are a result of the type of hematite used and the impurities, such as clay and other iron oxides, that are commingled with it. Hematite gems: Hematite and taconite are often made into tumbled stones or cut into cabochons and beads. These are popular as inexpensive jewelry items.
Tumble-polished hematite is also popular as a "healing stone. This use has no scientific merit and can actually be harmful because it diverts people who need medical attention from seeing a doctor. The name hematite is from the Greek word "haimatitis" which means "blood-red. Primitive people discovered that hematite could be crushed and mixed with a liquid for use as a paint or cosmetic.
Cave paintings, known as " pictographs ," dating back to 40, years ago were created with hematite pigments. Hematite continues to be one of the most important pigment minerals. It has been mined at many locations around the world and has been traded extensively as a red pigment. During the Renaissance when many painters began using oils and canvas, hematite was one of the most important pigments. Hematite color was opaque and permanent.
It could be mixed with a white pigment to produce a variety of pink colors that were used to paint flesh. The best way to learn about minerals is to study with a collection of small specimens that you can handle, examine, and observe their properties. Inexpensive mineral collections are available in the Geology. Chemical composition - Fe 2 O 3 Hardness - Specific gravity - 5.
Introduction Properties Common rock-forming minerals Economic minerals.
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