Iron Ore Magnetite The key economic parameters for magnetite ore being economic are the crystallinity of the magnetite, the grade of the iron within the banded iron formation host rock, and the contaminant elements which exist within the magnetite concentrate. The size and strip ratio of most magnetite resources is irrelevant as a banded iron formation can be hundreds of meters thick, extend hundreds of kilometres along strike, and can easily come to more than three billion or more tonnes of contained ore. The typical grade of iron at which a magnetite-bearing banded iron formation becomes economic is roughly 25% iron, which can generally yield a 33% to 40% recovery of magnetite by weight, to produce a concentrate grading in excess of 64% iron by weight. The typical magnetite iron-ore concentrate has less than 0.1% phosphorus, 3â??7% silica and less than 3% aluminium. Currently magnetite iron ore is mined in Middle East,Australia& Canada Magnetite bearing banded iron formation is currently mined extensively in Brazil, which exports significant quantities to Asia, and there is a nascent and large magnetite iron-ore industry in Australia. We can supply Iron ore from lower grade of 40% Fe to 65% Fe. Magnetite is magnetic, and hence easily separated from the gangue minerals and capable of producing a high-grade concentrate with very low levels of impurities The grain size of the magnetite and its degree of commingling with the silica groundmass determine the grind size to which the rock must be comminuted to enable efficient magnetic separation to provide a high purity magnetite concentrate. This determines the energy inputs required to run a milling operation. Mining of banded iron formations involves coarse crushing and screening, followed by rough crushing and fine grinding to comminute the ore to the point where the crystallized magnetite and quartz are fine enough that the quartz is left behind when the resultant powder is passed under a magnetic separator. Generally most magnetite banded iron formation deposits must be ground to between 32 and 45 micrometers in order to produce a low-silica magnetite concentrate. Magnetite concentrate grades are generally in excess of 70% iron by weight and usually are low phosphorus, low aluminium, low titanium and low silica and demand a premium price.
Iron ore is any rock or mineral from which iron can economically be extracted. It comes in a variety of colors, including dark gray, bright yellow, deep purple, and rusty red. The iron comes in the form of iron oxides such as magnetite, hematite, limonite, goethite, or siderite. Economically viable forms of ore contain between 25% and 60% iron. In the old days of mining, some ores, known as "natural ores," had 66% iron and could be fed into iron-making blast furnaces directly. The three primary sources of iron ore are banded iron formations, magmatic magnetite ore deposits, and hematite ore. The most metal is extracted from banded iron formations, geological structures laid down mostly between 3 and 1.2 billion years ago. Blue-green algae released oxygen in the days when the atmosphere and oceans were very oxygen-poor, binding together with dissolved iron in the world's oceans. These iron fixation events went through cycles as the algae had alternating blooms and busts, leaving the characteristic bands seen in banded iron formations. This ore is in either the form of magnetite or hematite. Banded iron formations are found on all continents, but especially rich deposits are found in Australia, Brazil, and the United States. Another prominent source of iron is found as magmatic magnetite iron ore deposits, formed during ancient volcanic eruptions that released large amounts of magnetite which later crystallized. Granite-associated deposits have been found in places like Malaysia and Indonesia and require very little post-processing to extract the iron. Titanomagnetite, a special class of magmatic magnetite ore, also serves as a source of titanium and vanadium, which is extracted via specialized smelters. A third source is in hematite ore deposits, which are found on all continents, but especially in Australia, Brazil, and Asia. Most hematite originates from banded iron formations that have undergone chemical alteration over billions of years due to hydrothermal fluids. The world's largest producer of iron ore, Vale, located in Brazil, produces it from hematite ore. Vale produces 15% of the entire world's iron supply. In total, worldwide ore production is about one billion metric tons.
