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The iron and steel slag that is generated as a byproduct of iron and steel manufacturing processes can be broadly categorized into blast furnace slag and steelmaking slag
Iron and steel slag refers to the type of metal manufacturing slag that is generated during the process of manufacturing iron and steel products. The term "slag" originally referred to slag produced by metal manufacturing processes, however it is now also used to describe slag that originates from molten waste material when trash and other substances are disposed of at an incinerator facility.
Blast furnace slag |
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Blast furnace slag is recovered by melting separation from blast furnaces that produce molten pig iron. It consists of non-ferrous components contained in the iron ore together with limestone as an auxiliary materials and ash from coke. Approximately 290 kg of slag is generated for each ton of pig iron. When it is ejected from a blast furnace, the slag is molten at a temperature of approximately 1,500℃. Depending on the cooling method used, it is classified either as air-cooled slag or granulated slag.
Air-cooled slag
The molten slag flows into a cooling yard, where it is cooled slowly by natural cooling and by spraying with water. This results in a crystalline, rock-like air-cooled slag.
Granulated slag
The molten slag is cooled rapidly by jets of pressurized water, resulting in a vitreous, granulated slag.
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| Air-cooled slag |
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Granulated slag |
Steelmaking slag |
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This slag is a byproduct from steelmaking processes in which the components of pig iron and steel-scrap are modified in order to produce steel that is so highly valued for excellent toughness and workability.
Steelmaking slag consists of converter slag that is generated by converter and electric arc furnace slag that is generated during the electric arc furnace steelmaking process that uses steel-scrap as the raw material.
Converter slag
In the same way as air-cooled blast furnace slag, converter slag is cooled slowly by natural cooling and water spray in a cooling yard. It is then processed and used for various iron and steel slag (converter) applications. Approximately 110 kg of slag is generated for each ton of converter steel.
Electric arc furnace slag
Electric arc furnace slag is generated when iron scrap is melted and refined. It consists of oxidizing slag that is generated during oxidation refining, and reducing slag that is generated during reduction refining. Approximately 70 kg of electric arc furnace oxidizing slag and 40 kg of reducing slag are generated for each ton of electric arc furnace steel.
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| Converter |
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Electric arc furnace |
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Steelmaking slag (converter slag) |
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