What is the composition of blast furnace slag?

Blast furnace slag is a nonmetallic coproduct produced in the process. It consists primarily of silicates, aluminosilicates, and calcium-alumina-silicates. The molten slag, which absorbs much of the sulfur from the charge, comprises about 20 percent by mass of iron production.

In this manner, where does blast furnace slag come from?

Ground-granulated blast-furnace slag (GGBS or GGBFS) is obtained by quenching molten iron slag (a by-product of iron and steel-making) from a blast furnace in water or steam, to produce a glassy, granular product that is then dried and ground into a fine powder.

Similarly, what is the chemical composition of slag? The primary components of iron and steel slag are limestone (CaO) and silica (SiO₂). Other components of blast furnace slag include alumina (Alsub>2O₃) and magnesium oxide (MgO), as well as a small amount of sulfur (S), while steelmaking slag contains iron oxide (FeO) and magnesium oxide (MgO).

Also know, what is meant by blast furnace slag?

Blast furnace slag (BFS) which is defined “as the non-metallic product consisting essentially of silicates and alumina silicates of calcium and other bases, that is developed in a molten condition simultaneously with iron in a blast furnace” by ASTM C 125-16 (2016) has been widely used in construction industry for more

Is blast furnace slag toxic?

Currently, almost all blast furnace slag is utilized for various purposes, such as cement making, road construction, fertilizer, etc. In some countries, including Indonesia, steelmaking slag is categorized as hazardous and toxic waste. However, slag can be used as raw material for the other purposes.

How is slag created?

Blast Furnace Slag is formed when iron ore or iron pellets, coke and a flux (either limestone or dolomite) are melted together in a blast furnace. This forces the chemical reaction to take place throughout the ore, not only at the surface.

Can slag be used for anything?

Principal uses include: Blending with many other products such as granulated slag, fly ash and lime to form pavement material. Other uses Include, skid resistant asphalt aggregate, rail ballast asphaltic concrete aggregate, soil conditioner, hard stand areas and unconfined construction fill.

How is slag removed from a blast furnace?

The impurities are removed react with calcium oxide to make a liquid slag that floats on top of the molten iron. The slag is collected after the denser iron has been run out of a tap hole near the bottom of the furnace. The production of iron in a Blast Furnace is a continuous process.

How is blast furnace slag produced?

Blast Furnace Slag is formed when iron ore or iron pellets, coke and a flux (either limestone or dolomite) are melted together in a blast furnace. During the period of cooling and hardening from its molten state, BF slag can be cooled in several ways to form any of several types of BF slag products.

Why is slag used in cement?

Slag cement is most widely used in concrete, either as a separate cementitious component or as part of a blended cement. It works synergistically with portland cement to increase strength, reduce permeability, improve resistance to chemical attack and inhibit rebar corrosion.

How many types of slag are there?

A total of 60 slag samples for three types of slag (open-hearth furnace slag (OHFS), converter slag (CS) and high titanium slag (HTS)) were provided by Pangang Group Chengdu Ore & Steel Co., Ltd (China) in the form of slag powder.

What are the uses of slag?

Is steel slag toxic?

When SSRS compares with ground granulated blast furnace slag (GGBFS) from iron making, steel slag contains toxic ingredients such as nickel, cadmium, chromium and strontium. These compounds could be harmful not only for environment but also for human health [9,10].

What is blast furnace slag cement?

Slag cement is a hydraulic cement formed when granulated blast furnace slag (GGBFS) is ground to suitable fineness and is used to replace a portion of portland cement. It is a recovered industrial by-product of an iron blast furnace.

Why is limestone added to the blast furnace?

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 limestone decomposes in the hot furnace, forming calcium oxide. This reacts with the sandy impurities (silicon dioxide) to form a slag.

How is slag removed from the blast furnace?

The impurities are removed react with calcium oxide to make a liquid slag that floats on top of the molten iron. The slag is collected after the denser iron has been run out of a tap hole near the bottom of the furnace. The metal that leaves the Blast Furnace contains between 4% and 5% of carbon.

What is iron ore slag?

Iron and steel slag, also known as ferrous slag, is produced by adding limestone (or dolomite), lime and silica sand to blast furnaces and steel furnaces to strip impurities from iron ore, scrap and other ferrous feed materials and to lower the heat requirements of the iron- and steelmaking processes.

What are ores slag and ash used for?

2. - Slag, ash and residues containing arsenic, mercury, thallium or their mixtures, of a kind used for the extraction of arsenic or those metals or for the manufacture of their chemical compounds, are to be classified in subheading 2620.60. 26.01 Iron ores and concentrates, including roasted iron pyrites.

What is steel slag aggregate?

Steel slag aggregate (SSA) is a byproduct of the production of steel in an electric arc furnace. The high iron oxide content of the aggregate results in an aggregate that is very hard and very dense (SSA is 20-30% heavier than naturally occurring aggregates such as basalt and granite).

How does a blast furnace work?

The purpose of a blast furnace is to chemically reduce and physically convert iron oxides into liquid iron called "hot metal". The blast furnace is a huge, steel stack lined with refractory brick, where iron ore, coke and limestone are dumped into the top, and preheated air is blown into the bottom.

Who invented the blast furnace?

The successful substitution of coke for charcoal is widely attributed to English inventor Abraham Darby in 1709. The efficiency of the process was further enhanced by the practice of preheating the combustion air (hot blast), patented by Scottish inventor James Beaumont Neilson in 1828.

What is slag basicity?

The basicity of slag is. B = weight % CaO. weight % SiO 2. (6) In presence of different basic oxides, the different strength of the basic oxides should be considered.

What is slag made up of?

Slag is usually a mixture of metal oxides and silicon dioxide. However, slags can contain metal sulfides and elemental metals. In some smelting processes, such as ilmenite smelting to produce titanium dioxide, the slag is the valuable product instead of the metal.

What is slag example?

Slag is waste matter separated from metal during smelting. An example of slag is the iron and silica that is removed during copper and lead smelting.