A typical schematic diagram of the straight grate system is shown in Fig 2.The grate-kiln system depicted in Fig 1 consists of a traveling grate for drying and preheating the pellets to about 1040 deg C, a rotary kiln for uniformly heating the throughput to the final induration temperature of 1315 deg C, and an annular cooler for cooling the product and heat recuperation. The iron ore is mined mostly from open pit deposits through mining operations... 3. The configuration of iron ore powder in a blast furnace is more tightly-packed and restricts the air flow. The green pellets are then charged on top of the hearth of indurated pellets. Iron ore and iron ore pellets are important sources of iron for manufacturing steel. The fines resulting from the concentration process must be agglomerated for use in iron and steelmaking. Hence, as described by Moraes and Ribeiro [Mining companies work toward obtaining pellets with customized properties for each type of ironmaking process and also to meet specific requirements of different iron- and steelmaking companies. This process generates iron ore filter cake which needs to be pelletized so that it can be used in an iron making process. After that, they move down and pass under the water sprayers so that they can find fresh feed.The balling disc works in close circuit with the screening step, where pellets smaller than 8 mm or larger than 16 mm are desegregated and the material is recirculated to the balling process.The balling drum equipment fundamentally consists of an inclined rotating cylindrical shell with water sprays in its inlet end, where the feed material is introduced to make balls. Compressive strengths of individual pellets depend upon the mineralogical composition and physical properties of the concentrate, the additives used, the balling method, pellet size, firing technique and temperature, and testing procedure. Although slag bonding may promote more rapid strengthening at slightly lower firing temperatures, pellet strength is normally decreased, especially resistance to thermal shock. It is also very difficult to produce fluxed pellets in a shaft furnace. Different ores have distinct characteristics and varying performances in the mining and in the metallurgical processes. The resulting heated air is used in the upstream steps of firing and drying.Induration processes were initially developed for ores composed of magnetite, since they are oxidized, producing hematite, and generating heat (−482.4 kJ/mol of FeThe most widely used industrial processes for pellet induration are the straight grate and the grate-kiln.The straight grate process is composed of a single furnace where an endless line of pallet cars moves. These self-reducing pellets are made from a mixture of iron ore concentrate, reductor (coal or coke), and binder. Also during the processing of high grade iron ores which do not need beneficiation, generated fines can be pelletized and used instead of being disposed of. The particle size distribution of iron ore is a very important requirement to be characterized after its mineral processing.Materials containing a very fine particle size distribution are not adequate to be used directly in the reduction reactors, requiring to be agglomerated by different processes such as sintering or pelletizing.The main used reduction reactors are the blast furnace (BF) and direct reduction reactors (DR). %PDF-1.7 As the added ore aggregates unto the surface of the pellets, they increase in size and the coefficient of friction is reduced causing the pellets to acquire a centrifugal force that carries them out of the nucleation zone. Pelletizing is an agglomeration process which converts very fine grained iron ore into balls of a certain diameter range (normally 8mm to 20 mm, also known as pellets.

These plants receive iron ore mostly by rails.

The production of self-fluxing pellets is an example of an innovation that has been accepted on a commercial scale and has led to major advances in blast furnace performance. >> These plants are independent of iron ore mines. It is been reported [Schematic diagram of the grate-kiln induration process [29].The pre-heating zone is divided into two steps: tempered pre-heating zone and pre-heating zone, where maximum temperatures may reach between 1000 and 1100°C. The system offers good temperature control in the firing zone.

Understanding Pellets and Pellet Plant Operations. Built by scientists, for scientists. In order to confer to the pellets high resistance metallurgic mechanics and appropriate characteristics, the pellets are subjected to thermal processing, which involves stages of drying, preheating, firing, after-firing and cooling. Typically limestone, dolomite and olivine is added and Bentonite is used as binder.. Pellet Plant Process Flow Chart With Straight Grate Technology. /Length 31 0 R <>/ColorSpace<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI]/Properties<>/Font<>>> Iron Ore Pelletizing Process: An Overview, Iron Ores and Iron Oxide Materials, Volodymyr Shatokha, IntechOpen, DOI: 10.5772/intechopen.73164. The iron ore production has significantly expanded in recent years, owing to increasing steel demands in developing countries, such as China and India. Plant capacities were between 10,000 and 60,000 tons/year [The world installed pelletizing capacity is currently estimated to be 480.7 million tons/year [World installed pelletizing capacity (millions of tons/year). The remaining 75 % of the furnace air enters via the cooling air inlet. stream Hot air from the cooler is used to support combustion in the kiln and is also recuperated to the traveling grate for drying and tempering preheat.The grate-kiln system offers excellent temperature control in all stages of the process and produces a consistently uniform quality pellet.