what is course slag

What is steel slag?

Jun 29, 2017 · Slag. Depending on where you’re from, it may be an insult, a term meaning trash, or, in our case, the waste left over from metal smelting or refining. Outside of the construction industry, it might seem that uses for slag are considered limited. But some recent research here at USGS might change slag’s poor public image.

What are the uses of slag aggregates?

Coarse aggregates are used in every Construction projects which includes the construction of roads, Buildings, Railway Tracks etc. Coarse Aggregate in concrete was considered as chemically inactive and acts as a filler material only. The coarse aggregates are used for the manufacturing of mortar and concrete.

What is slag run off?

Nov 09, 2017 · The iron and steel slag used as aggregates for asphalt roads are iron and steel by-products. Steel slag is residue from the steelmaking process, made of minerals like silica, alumina and titanium from iron sand, and combinations of calcium and magnesium oxides. During the steelmaking process, slags float on top of the molten iron, forming a barrier against oxygen …

Why is slag production so high?

In agriculture, slag aggregates (Ag-Slag) have been used as an agricultural liming material since the 1920's in all types of crop production and landscaping. The materials are used to maximise yields of cultivated crops and pasture, improve soil texture and neutralize high soil acidity.

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 are the different types of slag?

There are three types of slag: ferrous, ferroalloy, non-ferrous slags, which are produced through different smelting processes.Ferrous slag.Non-ferrous slag.Ancient uses.Modern uses.

What is slag process?

Slag is a by-product of the metallurgical smelting process. Slag has a double role: it permits removal of impurities, known as gangue, from the melt by forming oxides.Jul 29, 2014

Does slag have value?

Actual prices per ton ranged in 2019 from a few cents for some steel slags at a few locations to about $120 or more for some GGBFS. Owing to low unit values, most slag types can be shipped only short distances by truck, but rail and waterborne transportation allow for greater travel distances.

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.

Is slag a mineral?

Slags are nonmetallic byproducts of many metallurgical operations and consist primarily of calcium, magnesium, and aluminum silicates in various combinations. Iron and steel slags are coproducts of iron and steel manufacturing.

What is reducing slag?

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.

What are the sources of slag?

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.

What are the main content of the 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).

Is slag a waste?

Slag is a waste product of metallurgical processes. Molten material contains ore impurities, deoxidizers, metal oxides or carbonaceous residues. It is a mass of glassy ash. Depending on how the slag is formed, it has different uses and properties.May 26, 2017

Is iron 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].Jul 30, 2015

Can slag be reused?

The work established that the copper slag, a waste material, can be successfully processed to generate reusable products through pyrometallurgical processing.

What Is Coarse Aggregate

There are many building materials which are used in the construction industry. Coarse Aggregate is one of the most important and massively used bui...

Coarse Aggregate

Coarse aggregates are a construction component made of rock quarried from ground deposits.

Coarse Aggregate Definition

The Aggregates which will get retained on the 4.75 mm sieve or the aggregates which have size more than 4.75 mm are known as Coarse aggregate.

Origin of Aggregates

Aggregates are commonly obtained by crushing the naturally occurring rocks. The properties of the rocks are mainly depended upon the type of rock w...

Requirements of Good Coarse Aggregates

It should be angular or cubical in shape., It must be sound & durable., A Good Coarse Aggregate should be absolutely clean and free from any organi...

What is the crushing value of coarse aggregate?

The crushing value of the coarse aggregate is defined as the relative measure of the resistance which is offered by the aggregate to the crushing under the gradually applied load .

What are the requirements for coarse aggregate?

Requirements of Good Coarse Aggregates: The Aggregates which are used in the construction must have the following properties. The coarse aggregate should be durable. The coarse aggregate should be hard and strong. It should be clean and free from the dust and organic materials otherwise it will reduce the bonding of the aggregate with concrete.

Why are angular and irregular shapes used in aggregates?

Generally, the angular and Irregular shape of aggregates is used because they have more Interlocking effect. The total surface area of the angular aggregate is more in the angular aggregates as compared to the rounded Aggregates.

Why are grade limits and maximum aggregate size specified?

Grading limits and maximum aggregate size are specified because these properties affect the amount of aggregate used as well as cement and water requirements, workability, pumpability, and durability of concrete.

What are the advantages of coarse aggregates?

It will help to increase the volume of the concret e and also reduces the cost of the project.

What is flaky aggregate?

an aggregate is termed flaky when its least dimension (thickness) is less than three-fifths of its mean dimension. The mean dimension of aggregate is the average of the sieve sizes through which the particles pass and are required, respectively.

Which has a higher specific surface area, angular or smooth?

Angular aggregates have a higher specific surface area than the smooth rounded aggregate. With a greater specific surface area, the angular aggregate may show higher bond strength than rounded aggregates.

What is hot slag?

Hot slag, or steel waste, is poured into piles to cool before being used for asphalt road construction. (Source: Fractum) While POSCO works to improve its recycling capabilities, manufacturing and other industries are starting to see the benefits of steel and iron slag.

What is steel slag made of?

Steel slag is residue from the steelmaking process, made of minerals like silica, alumina and titanium from iron sand , and combinations of calcium and magnesium oxides. During the steelmaking process, slags float on top of the molten iron, forming a barrier against oxygen and maintaining the internal temperature.

How does slag affect the environment?

The use of slag minimizes environmental impact as it saves energy and conserves resources. Steelmakers need to actively find ways to reuse steel by-products to reduce their overall waste. For example, POSCO is dedicated to reusing by-products of steel making as it has a strong commitment to environmentally friendly practices.

What is asphalt made of?

Asphalt roads are made of a mixture of aggregates, binders and fillers. The aggregates are typically iron and/or steel slag, sand, gravel or crushed rock, and they are bound together with asphalt itself, which is a bitumen. Asphalt comes from natural deposits, or more commonly, as a by-product of the petroleum industry.

What is the substance in asphalt?

One of the ingredients of asphalt is steel slag, a by-product of the steel and iron production processes. Steelmakers like POSCO are putting the sustainable, recycled material to use to make roads stronger and safer.

Is steel slag a procurement item?

Base course material containing iron and steel slag as well as asphalt mixture containing iron and steel slag were designated as a procurement item under the Green Procurement Law. These materials are recognized as items with environmental benefits. The use of slag minimizes environmental impact as it saves energy and conserves resources.

Is steel slag good for asphalt?

Slag is also very hardy, resistant to both weather and wear. Steel slag is a sustainable aggregate for asphalt road production.

What is granulated slag?

Granulated slag is produced by rapidly cooling molten blast furnace slag with water as the slag is tapped from the furnace. Also known as granulate. Used in cement manufacture and cementitious applications

What is Ag slag used for?

Agriculture. In agriculture, slag aggregates (Ag-Slag) have been used as an agricultural liming material since the 1920's in all types of crop production and landscaping. The materials are used to maximise yields of cultivated crops and pasture, improve soil texture and neutralize high soil acidity.

What are the physical and chemical properties of blast furnace and steel slag aggregates?

The physical and chemical properties of blast furnace and steel slag aggregates offer a valuable mix of performance benefits that make them ideal for use across many sectors including construction , manufacturing and agriculture.

What is blast furnace slag used for?

Blast furnace slag can also be used to make Ground Granulated Blast-furnace Slag (GGBS) which is used as a cement replacement in concrete.

What is steelmac asphalt?

A proprietary asphalt product range produced by Tarmac using steel slag. SteelMac takes advantage of the high durability of steel slag compared to standard aggregate products. The products combined with advanced asphalt design and bitumen technology, offer application solutions for all industrial locations.

What are the components of slag?

The major components of these slags therefore include the oxides of calcium, magnesium, silicon, iron, and aluminum, with lesser amounts of manganese, phosphorus, and others depending on the specifics of the raw materials used.

What is slag made of?

Slag from steel mills in ferrous smelting, on the other hand, is designed to minimize iron loss and so mainly contains oxides of calcium, silicon, magnesium, and aluminium. Any sandy component or quartz component of the original ore automatically carries through the smelting process as silicon dioxide.

What is ground granulated slag used for?

Ground granulated slag is often used in concrete in combination with Portland cement as part of a blended cement. Ground granulated slag reacts with a calcium byproduct created during the reaction of Portland cement to produce cementitious properties. Concrete containing ground granulated slag develops strength over a longer period, leading to reduced permeability and better durability. Since the unit volume of Portland cement is reduced, this concrete is less vulnerable to alkali-silica and sulfate attack.

What is iron ore slag used for?

During the early 20th century, iron ore slag was also ground to a powder and used to make agate glass, also known as slag glass.

What temperature does slag cool?

As the slag is channeled out of the furnace, water is poured over it. This rapid cooling, often from a temperature of around 2,600 °F (1,430 °C), is the start of the granulating process. This process causes several chemical reactions to take place within the slag, and gives the material its cementitious properties.

Why do we use slag in smelting?

While slags are generally used to remove waste in metal smelting, they can also serve other purposes, such as assisting in the temperature control of the smelting, and minimizing any re-oxidation of the final liquid metal product before the molten metal is removed from the furnace and used to make solid metal.

What was slag used for in the Bronze Age?

During the Bronze Age of the Mediterranean there were a vast number of differential metallurgical processes in use. A slag by-product of such workings was a colorful, glassy, vitreous material found on the surfaces of slag from ancient copper foundries. It was primarily blue or green and was formerly chipped away and melted down to make glassware products and jewelry. It was also ground into powder to add to glazes for use in ceramics. Some of the earliest such uses for the by-products of slag have been found in ancient Egypt.

What is slag made of?

Slag, generally classed as a synthetic aggregate (also called artificial aggregate ), is produced by altering both physical and chemical properties of a parent material, which may be produced and processed specifically for use as synthetic aggregate.

How is slag aggregate obtained?

Slag aggregates are obtained by crushing of smelter slag or by special treatment of fire-liquid slag melt (molten slag aggregates). Currently there are many types of concrete that are developed and used in construction that include metallurgical slags both as a binding component and as fillers.

What is synthetic aggregate?

A synthetic aggregate may also be the byproduct of manufacturing and a final burning process —blast furnace slag is an example of a synthetic aggregate. Briefly, blast furnace slag is formed when iron ore or iron pellets, coke, and a flux (such as limestone, CaCO 3, or dolomite, CaCO 3 ·MgCO 3) are melted together in a blast furnace.

What is the most logical route for destruction of digested sewage sludge?

Incineration is often the most logical route for destruction of digested sewage sludge, and can recover useful energy in the process. In Japan, extensive research to use the ash produced by this process has led to the development of sewage bricks, tiles, slag, aggregate, cement, and pumice.

Is air cooled slag good?

Research and construction practice have proved that air-cooled slag can provide a high level of performance in unbound uses. The good performance and slag aggregate products emanate from well-controlled production processes with good quality control procedures.

Can slag be cooled in a blast furnace?

During the period of cooling and hardening from its molten state, blast furnace slag can be cooled in several ways to form any of several types of ballast furnace products, including aggregate for the manufacture of road asphalt. In addition, bottom ash is also used.

Is steel slag better than limestone?

The steel slag aggregate concrete showed better behavior than the limestone concrete. The limestone concrete lost strength, but the strength of the concrete with EAF slag (CEAF) slightly increased from the outset. This improvement could be attributed to the fact that there was no loss of adhesion between the aggregate and the matrix, a loss that was observed in the reference concrete around its aggregates. Following exposure to high temperature and relative humidity, the CEAF has proven itself to be a more stable concrete than the ordinary concrete with regard to linear expansion and contraction, with no appreciable external signs of physical deterioration or loss of mechanical compressive strength (which even increased). There was less expansion in the slag mortars than in the reference mortar as a result of the sulfate attack, which after one year of exposure did not exceed the standard threshold (ASTM C452). Over time, these slag mortars showed a greater increase of strength than the reference concrete, thereby confirming the absence of internal damage and the null reactivity of the fine fraction of the slag aggregate. As regards the aggregate–alkali reaction, the expansion of the slag aggregate mortars did not exceed the limit and may, therefore, be considered nonreactive when used in cement mixes. With regard to the exposure of the concretes to sea tides, chloride penetration was greater (or similar) in the CEAF than in the reference concrete (CR). Finally, the corrosion of the steel rebars in the reinforced EAF slag concrete, after a year in the tidal seawater environment, showed greater susceptibility to corrosion than in the limestone reference concrete. The study confirms the viability of producing steel-reinforced concrete with slag aggregate (Arribas, Vegas, San-Jose, & Manso, 2014 ).

How is slag cooled?

The molten slag can also be quickly cooled by a column of pressurized water to form a glassy granular slag. Little or no crystallization occurs when the slag is cooled and rapidly quenched to a glassy state. This process produces sand-sized (or fleet-like) fragments, often with some fragile clinker. At this point, the particle size of slag is mostly <5mm. With the use of the ball mill, the granular slag can be processed into ultrafine slag powder. The focus is to enhance the grinding function of the ball mill.

What is blast furnace slag used for?

Blast furnace slag can be used as paving material after mechanically stabilizing. It takes longer to harden, which can be used to create a thinner pavement than using natural gravel (i.e., mechanically stable gravel). It is easy to process which enables the road can be opened to traffic immediately after the end of the work, and road compaction base can continue to be carried out even on rainy days, which is widely praised. In addition to being used as the base material, it is also used as aggregate for asphalt mixture due to its excellent hardness and wear resistance.

What is the demand for blast furnace slag?

The largest demand for blast furnace slag is cement. Ground granulated blast furnace slag has potential hydraulic performance that can be shown under the action of cement clinker, lime, gypsum and other activators, so it is a high-quality cement raw material. About 60% of the blast furnace slag is made into granulated slag as a cement mixing material. Using granulated blast furnace slag can save energy by 20-40%, reduce costs by 10-30%, and reduce CO 2 emissions by 44%.

What is BFS aggregate?

The processed BFS aggregate does not contain organic impurities, clay, shells or similar materials, and has many valuable properties, which is one of the reasons for chemical reactions with alkaline aggregates. It reduces the impact on the environment, preserves the precious natural resources needed to sustain the ecosystem, and can reduce the energy consumed in mining, crushed rock and other activities. It is called almighty engineering aggregate.

Is BFS aggregate better than natural aggregate?

In general, concrete containing BFS aggregates has similar plastic properties to natural aggregate. Concrete made of BFS aggregates can be pumped, placed and refined successfully. BFS aggregate results in a better cement paste-aggregate interaction due to its vesicle nature. In many cases, the performance of hardened concrete is improved when BFS aggregates are added to properly designed blends.

What is slag glass?

Though it is known by several names, slag glass is a variety of pressed glass that is universally celebrated by collectors for its characteristically subtle variations in color and opacity. Adding to the beauty of slag glass – also known as malachite glass, marble glass, and mosaic glass – is its rich history ...

How did slag glass get its name?

Slag glass gets its name from slag, or the byproduct of steel production. When iron ore is smelted in that process, the remaining residue is a glass-like, often glossy material that takes on different colors depending on the minerals and elements present in the iron. The visual marbling of this slag is reminiscent of slag glass, however, ...

Who makes Sowerby's slag glassware?

Sowerby’s slag glasswares, along with the similar pressed glass designs of contemporaneous English makers Davidson and Greener & Company, are still some of the most coveted today, particularly those that feature their unique brown malachite glass.