What are the factors affect blast furnace productivity?
Blast furnace productivity greatly depends on the quality of sinter. Sinter is to have optimum grain distribution, high strength, high reducibility, high porosity, softening temperatures greater than 1250 deg C, constant FeO content in the range of 7 % to 8 % and constant basicity.
What are the major limitations of blast furnace ironmaking?
Blast Furnace Disadvantages: 1. Blast furnace ironmaking is inseparable from the coke source, but the coke resources are getting less and less, but the price is getting higher and higher, the cost of iron making will be higher and higher, and it is likely that one day will meet the depletion of coke resources.
What is Deadman in blast furnace?
The dead man is situated beneath the active coke zone and (mostly) below the raceways. The upper part of the dead man is cone-shaped with a rounded top in the region between the raceways. The inclination from the dead-man apex to the raceways is about the same as the repose angle of the charged coke.
How can we reduce slag rate in blast furnace?
Higher iron (Fe) content in these materials means lower gangue material is going inside the furnace which needs to be fluxed for slag formation. Hence higher Fe content helps in the reduction of slag volume and coke rate. As per thumb rule 1 % increase in the Fe content reduces coke rate by 0.8 %n to 1.2 %.
What is the impact of CSR in blast furnace operations?
Evidence showing a strong correlation between increased CSR and reduced degradation has been reported by a number of furnace operators. Some operators also reported the need for increased cold strength as well, particularly as furnace size increased.
What problem does blast furnace solve?
Blast furnaces produce pig iron from iron ore by the reducing action of carbon (supplied as coke) at a high temperature in the presence of a fluxing agent such as limestone.
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 the role of limestone 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).
Why is coke added to the 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 raceway in blast furnace?
In the lower part of an ironmaking blast furnace, a hot air jet is injected horizontally into a bed of coke particles, forming a void zone, called a “raceway”. In this paper, two-fluid gas–solid modeling is used to study the influence of various operational parameters on the size and shape of the raceway (void zone).
What is cohesive zone in blast furnace?
In an iron making blast furnace, the iron bearing particles descend through the furnace, undergoing processes of reduction, softening, melting and dripping on to the hearth, and at temperatures between the start of softening and complete melting they form the cohesive zone.
What are the most common problems with a blast furnace?
One of the most expensive and pollution-prone aspects of blast furnace operation is the production of coke. To reduce coke usage, blast furnaces may inject natural gas or pulverized coal directly into the blast furnace.
Are there any furnace irregularities in the furnace?
However, the furnace irregularities are not as frequent as they were in former years, but still the upsets in the BF operations are there which cause considerable concern and frequently need quick thinking and the use of good judgement and skill as well as timely corrective actions on the part of the operator to prevent serious trouble.
What are the facilities for the experimental work of blast furnace?
The facilities for the experimental work consisted of an experimental blast furnace and auxiliary equipment for supplying, heating, and humidifying the air blast; drying, screening, and charging raw materials; and disposing of iron and slag products.
How to light a blast furnace?
Lighting: Any one of several methods may be used to light a blast furnace; however, hot blast lighting consists of blowing hot blast into the furnace; low blast volume is applied, and within a matter of minutes, all tuyeres are become bright. BF coke is easily ignited and blast temperature at around 370 °C.