Why do we use coke in blast furnace?

Blast furnace ironmaking makes use of coke as the major source for both energy and reduction of iron oxides. In the blast furnace process, coke has multifunctions and plays an important role as reductant, burden support, and fuel.

Why is coke used in a blast furnace?

Metallurgical coke, along with iron ore and limestone, is layered into a blast furnace to convert the iron ore to metallic iron. Coke, which is mostly carbon, reacts with the blast air to produce carbon monoxide, which, in turn, reacts with the iron oxide to produce carbon dioxide and metallic iron.

What is the purpose of adding coke?

Coke is a grey, hard, and porous fuel with a high carbon content and few impurities, made by heating coal or oil in the absence of air—a destructive distillation process. It is an important industrial product, used mainly in iron ore smelting, but also as a fuel in stoves and forges when air pollution is a concern.

Why is coke preferred over coal for burning?

Coke is a better fuel than coal. Coke is more efficient and has a higher calorific value than coal.

Why coke is used not coal?

Solution : Coke has higher heat efficiency and has higher proportion of carbon than coal.

Purpose of coke in the blast furnace is

What is coke rate in blast furnace?

The effect of automatic process control on the blast furnace coke rate is in the range of 3 % to 5 %. Blast temperature is other parameter which influences the coke rate in a blast furnace. Blast furnace coke rate reduces by around 2 % with the blast temperature increasing by 100 deg C.

What is difference between coke and coal?

Coal and Coke are both a type of fossil fuels. The difference between these two fuels is that coal is mostly carbon but coke contains mostly water and less than half the carbon content of coal.

What is the advantage of coke over coal?

Solution : (i) Coke produces more heat than an equal mass of coal. (ii) It produces ni smoke on burning and leaves no residue and as such does not cause air pollution. (iii) It is used as a reducing agent in the extraction of metals from their ores.

Why is coke considered as a clean fuel?

Coke is used as a fuel and as a reducing agent in smelting iron ore in a blast furnace. The carbon monoxide produced by its combustion reduces iron oxide (hematite) to the iron product. Although coke is more expensive than coal, it can be used in households as a clean fuel, relatively free of smoke and impurities.

Why is coke needed to make steel?

To make steel in a blast furnace, coal must first be turned into coke. Coke has a dual role in the steelmaking process. First, it provides the heat needed to melt the ore, and second, when it is burnt, it has the effect of 'stealing' the oxygen from the iron ore, leaving only the pure iron behind.

Is coke an oxidizing agent?

Coke is a good reducing agent, especially at higher temperatures, because it is a non-metal and it combines with oxygen and forms its gaseous non-metallic oxides. It helps in oxidation.

What is coke in the steel process?

In the steel-making process, coke is used in the blast furnace as a (1) fuel to produce added heat; (2) chemical-reducing agent for the reduction of iron oxides; and (3) as a permeable support in the molten material in the furnace.

Why limestone is used in blast furnace?

Limestone is also used to remove impurities from the blast furnace when making iron. The impurities are mostly silicon dioxide (also known as sand). The calcium carbonate in the limestone reacts with the silicon dioxide to form calcium silicate (also known as slag).

How is coke superior than coal as a?

Coke is a better fuel because coke produces more heat on burning as compared to coal. Coke has higher calorific value than coal. When equal masses of coke and coal are bunt, coke produces more heat. Also when coke is burnt, smoke is not obtained whereas coal produces smoke on coal.

What is the difference between coal and coking coal?

The key difference between coking coal and thermal coal is that coking coal is mainly used to produce high-quality coke, whereas thermal coke is important in producing electricity. Coal is a type of sedimentary rock that is combustible. It appears in black or brownish-black colour.

What is difference between coke and carbon?

Coke is a fuel that is obtained from the calcination or dry distillation of mineral coal. It is composed of carbon and has a high calorific value, but it is highly polluting. It is used as fuel in the blast furnaces of steel foundries.

What is coke made of?

Here's the list of ingredients in Coca‑Cola: Carbonated water – Approximately 90% of Coca-Cola is water. The carbonated part is purified carbon dioxide, which gives the drink its “bubbles” or “fizz”. Sugar – Coca-Cola Classic's sweet taste (and also some of its mouthfeel) comes from sugar.

What kind of coal is coke?

By distilling bituminous coal in retorts to obtain gas for illumination, or by burning it in kilns or pits, the residue left behind is called coke, which is simply coal charcoal, and is nearly pure carbon.

Is coke used in an EAF?

Solid carbon sources, like coal, petrol, coke, etc., are used in the EAF in two ways. The charge carbon is charged together with the scrap or other iron sources and additives at the beginning of the heat.

Why coal is not used in blast furnace?

Coal cannot be directly charged via the furnace top, it must first be transformed to coke. Raw materials are charged to the furnace in alternating layers of coke and ore. This alternating layer structure inside the furnace has a profound impact on the operation of the furnace and on the required quality of coke.

What is metal slag?

ORIGIN. Steel slag, a by-product of steel making, is produced during the separation of the molten steel from impurities in steel-making furnaces. The slag occurs as a molten liquid melt and is a complex solution of silicates and oxides that solidifies upon cooling.

Why calcium carbonate is used in blast furnace?

Limestone is calcium carbonate (CaCO₃) and it is added to the blast furnace to remove the impurities in the iron ore, as mentioned above.

What is the role of coke and limestone in the extraction of iron?

The main role of limestone in extraction of iron is to decomposes in hot furnace and form the calcium oxide. Iron is extracted from its ore, haematite, in a blast furnace. The ore is fed into the top of the furnace along with coke and limestone. ... The limestone decomposes in the hot furnace, forming calcium oxide.

What is slag used for?

Granulated blast furnace slag has been used as a raw material for cement production and as an aggregate and insulating material. and granulated slag have also been used as sand blasting shot materials.

What is the function of coke oven?

In the coke oven, the coal is heated to 1,800°F for up to 18 hours. During that time, the volatiles of the coal are driven into the offgas and a pure carbon form called “coke” remains. The coke, when exposed to oxygen, will immediately ignite and begin to burn.