Pig iron and HBI are two separate kinds of products that manufacturing process is closely connected and many steel products are directly related to them. Iron is the second most abundant metal in the earth's crust. As you know, iron is one of the metals that react quickly with oxygen and moisture in the air, so pure iron ore is not found in nature. Iron ore extracted from nature has many impurities and is called by different names. Iron extracted from different mines in different geographical areas has many differences from iron extracted from other regions, such as iron oxide, carbonate and sulfide minerals found in nature, each of which is an ore from a geographical region. To produce pig iron from iron ore, its impurities must be separated from other minerals found in the iron. The ores from which pig iron is extracted are called iron oxides, such as magnetite and hematite, which contain other impurities such as silicates and aluminates. 
There are two methods of producing pig iron from iron ore. With both methods, all impurities such as silicates and aluminates are separated from the iron ore and finally, pig iron is produced. Regarding the steps involved in the production of pig iron from iron ore, the steps in the two methods can be explained separately. To produce pig iron, iron ore must be processed. In fact, iron ore cannot be used directly intact to produce pig iron. Therefore, processed iron ore (known by various names such as granular ore, iron ore concentrate, and iron pellets) is used to produce pig iron. The first method used to produce pig iron is the blast furnace method. In fact, this method was the first method invented by man, and the pig iron was produced and supplied by this method. 
A large part of the world's steel is also produced in the same way. First, a mixture of iron ore, processed under the name granulated iron and iron ore concentrate, mixed with lime and coke is poured into the furnace in layers from above. The temperature required to produce pig iron in this mountain is about 300 degrees Celsius, at which temperature the coke can combine with oxygen in the air, using the incomplete combustion of the coke to provide the heat needed for smelting the iron ore. The next method used to produce pig iron is the arc method. This method is newer and less old than the blast furnace method. In this method, sponge iron and steel scrap is used to produce pig iron. The end product of this method has all impurities removed, is used as raw material for steel production, and sent to the casting unit to make ingots. 
Pig iron manufacturing process
In many countries, they are using High blast furnaces in the manufacturing process of iron. Pig iron is the first product that is directly produced from Iron ore. China is the largest steel producer and largest consumer, with a consumption of 500 million tons per year. The top 20 countries in the world's steel consumption consume more than 83% of the world's steel. The chart below shows the value of steel and other commonly used materials. Although the exact value of the material produced varies with production time and price increases, the relative magnitude of the product's value in the world compared to other materials is obvious. 
In general, crude steel is produced by the following two methods: 1- Production of pig iron or molten iron in a blast furnace and steel production in an oxygen converter, carried out in Isfahan Iron Works. 2- Direct recovery of iron ore and smelting of sponge iron and scrap in electric furnaces such as arc furnaces such as Khuzestan Steel's arc furnaces or Southern Steel Complex's induction furnaces. It should be noted that there are other methods of steel production, such as the open furnace method, which is due to its very limited production in the world, accounting for about 2.5% of the total amount, according to the World Steel Association. World steel production in 2007. As well as the continued production cuts of this method, are not taken into account here. The first method is the traditional production method, where indirect iron recovery is used, and the iron ore treated with lime and coke enters the blast furnace to obtain pig iron or molten iron. In the next step, pig iron is converted into molten steel in a converter, where carbon and other impurities are removed using oxygen, and pig steel is produced. The other method of steel production is the use of electric furnaces and the heavy melting of scrap steel. Due to the scarcity of scrap sources in the world and the constant increase in prices over the past years, sponge iron can be fused with scrap in a furnace by this method. In India, about 70% of sponge iron production is produced using coal (thermal or non-coking), and about 30% is produced using natural gas (at 7 plants). There are various ways of using coal in the direct regeneration process in India, some of them are:
- SL/RN method
- Jindal method
- The Democratic Republic of the Congo law
- CODIR method
HBI steel products
There are a wide variety of products coming out of the HBI process of steel making. The most used process in making them is high blast furnace. How a blast furnace works The main processes that take place in blast furnaces are the regeneration of iron oxides and the smelting of pig iron and its separation from impurities. The blast furnace is a huge facility. Iron ore, coal and limestone are brought in from above, and preheated air is blown in from below. The raw materials take 6 to 8 hours to reach the bottom of the furnace, where the final product, molten iron and slag, is formed. These liquid products are removed from the oven at regular intervals. The hot air blown to the bottom of the furnace rises to the top of the furnace within 6-8 seconds after many chemical reactions. From the time the work on the blast furnace begins, its work continues for 4 to 10 years, with occasional stops for maintenance operations. Iron oxide enters the blast furnace in the form of raw ore, pellets or sinter. The rough is removed from the ground and shaped into small pieces from 1.25 to 3.75 cm. 
This stone is hematite or magnetite and contains 50-70% iron. This iron obtained from the ore can be discharged directly into the blast furnace without further processing. Iron ore contains a small amount of iron and must be prepared for smelting. Tablets are made of stone with low iron content. The mineral is pulverized and pulverized into a powder, which can then be separated into waste called impurities. The remaining iron-rich powder is rolled into balls and fired in a kiln to produce strong, marble-sized pellets containing 60 to 65 percent iron. The products are made from diluted ore, small coal, sand-sized iron ore, and large amounts of ferrous scrap. These diluted materials are proportioned and mixed together to obtain the desired product. This raw material mixture is placed on sintered filaments, ignited by combustible gases in a furnace, which are converted into 1.25 to 5-centimeter chunks by the heat of coal water. 
Iron ore, pellets, and sinter are converted into molten iron produced by the blast furnace without impurities. Coal is a combination of several coking coals. The coal is placed in the powder, which is then discharged into the furnace. It is then boiled to remove most of the light substances, including oil and pulp. After a reaction time of 18 to 24 hours, the liquefied coal called coke is removed from the furnace. The coking coal is cooled and divided into 2.5 to 10 cm pieces. Coke is 90 to 93 percent carbon, some slag, and sulfur. But it is very strong compared to green coke. Strong coke flakes with high energy values generate the heat and gases required for the reduction and smelting of iron ore, pellets, and sinter. 
iron manufacturing process
There are some necessities in having high blast furnaces in the manufacturing process of iron. The blast furnace is considered the first step in the production of steel from iron oxide. The first blast furnaces appeared in the 14th century and produced a ton of steel per day. The blast furnace equipment continues to develop, with modern large blast furnaces producing 13,000 tonnes of steel per day. Despite advances in equipment and increased productivity, blast furnace operations have remained the same. Blast furnaces will survive into the next millennium because large blast furnaces can produce cast iron that is competitive in price with other pig iron technologies. 
blast furnace effective height It is the distance between the axis of the iron pipe and the load level at its opening. Since the load level is always variable, the falling edge of the large clock is considered the load level when it is low. The effective height of the blast furnace depends on the strength of the composition of solid fuel. If the furnace is too high, fuel residues and the resulting filling can interfere with its operation. On the other hand, if the blast furnace is too short, it will not be able to heat and prepare the required number of loads. The full height of the blast furnace It is the distance between the axis of the iron pipe and the upper edge of the large cone. The total height of the blast furnace is equal to the height of the cone, the height of the bell jar and the downward distance of the bell jar, which is greater than the effective height. The diameter of the bushing depends on the amount of fuel consumed per unit of time. Experience has shown that the larger the diameter of the bushing, the better, but there must be a certain ratio between the diameter of the bushing and other dimensions. 
Crucible pot height It is the distance between the axis of the railway and the bottom surface of the coke bed. If the diameter of the furnace is known, its height depends on the amount of melt. The diameter of the arch is effective for the distribution of the airflow at all levels of the blast furnace section. The ratio between stomach diameter and diameter at chest height must be 1.11-1.14. Blast furnace opening height If the diameter of the hearth and the opening of the blast furnace are known, the size and slope of the hearth will depend on the height of the hearth. The slope of the furnace wall affects the distribution of the airflow in each section of the blast furnace and the sedimentation of the raw material column. Opening diameter It is very effective in distributing material in the upper part of the blast furnace. The ratio of caliber to abdominal diameter should be about 0.75-0.67. The height of the opening significantly affects the material distribution. 
HBI manufacturing process and steel products
Steel products are made from HBI. Cast iron is produced at the factory with the manufacturing process in blast furnaces No. 1, 2, and 3. Blast furnace No. 1 has a volume of 1,033 cubic meters and an annual production capacity of 760,000 tons. Blast furnace No. 2 has a volume of 2,000 cubic meters and an annual production capacity of 1.4 million tons. Blast furnace No. 3 has a volume of 2,000 cubic meters and an annual production capacity of 1.4 million tons. During the production of cast iron in a blast furnace, raw materials enter through the furnace mouth, and oxygen-enriched air and other auxiliary fuels are blown into the furnace from the furnace top. The blown air causes the coke to burn and generate enough heat and regeneration gas to restore the melting of the iron ore and agglomerates. 
The molten material is collected in furnace crucibles and discharged periodically. After the cast iron and slag are separated, the discharged melt is discharged into the cast iron and slag carrier trays, respectively, through a special atmosphere prepared with suitable refractory materials. The slag pellets are then sent by locomotive to the slag granulation workshop and the cast iron pellets are transported to the steel mill.
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