Slag

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Molten slag is carried outside and poured into a dump Caletones.jpg
Molten slag is carried outside and poured into a dump

Slag is a by-product of smelting (pyrometallurgical) ores and recycled metals. [1] Slag is mainly a mixture of metal oxides and silicon dioxide. Broadly, it can be classified as ferrous (by-products of processing iron and steel), ferroalloy (by-product of ferroalloy production) or non-ferrous/base metals (by-products of recovering non-ferrous materials like copper, nickel, zinc and phosphorus). [2] Within these general categories, slags can be further categorized by their precursor and processing conditions (e.g., blast furnace slags, air-cooled blast furnace slag, basic oxygen furnace slag, and electric arc furnace slag).

Contents

Global production of iron and steel, 1942-2018, according to USGS. IronAndSteelProduction.jpg
Global production of iron and steel, 1942–2018, according to USGS.

Due to the large demand for these materials, slag production has also significantly increased throughout the years despite recycling (most notably in the iron and steelmaking industries) and upcycling efforts. The World Steel Association (WSA) estimates that 600 kg of by-products (about 90 wt% is slags) are generated per tonne of steel produced. [4]

Composition

Slag is usually a mixture of metal oxides and silicon dioxide. However, slags can contain metal sulfides and elemental metals.

The major components of these slags include the oxides of calcium, magnesium, silicon, iron, and aluminium, with lesser amounts of manganese, phosphorus, and others depending on the specifics of the raw materials used. Furthermore, slag can be classified based on the abundance of iron among other major components. [1]

Ore smelting

The Manufacture of Iron - Carting Away the Scoriae (slag), an 1873 wood engraving The Manufacture of Iron -- Carting Away the Scoriae.jpg
The Manufacture of Iron – Carting Away the Scoriæ (slag), an 1873 wood engraving

In nature, iron, copper, lead, nickel, and other metals are found in impure states called ores, often oxidized and mixed in with silicates of other metals. During smelting, when the ore is exposed to high temperatures, these impurities are separated from the molten metal and can be removed. Slag is the collection of compounds that are removed. In many smelting processes, oxides are introduced to control the slag chemistry, assisting in the removal of impurities and protecting the furnace refractory lining from excessive wear. In this case, the slag is termed synthetic. A good example is steelmaking slag: quicklime (CaO) and magnesite (MgCO3) are introduced for refractory protection, neutralizing the alumina and silica separated from the metal, and assisting in the removal of sulfur and phosphorus from the steel.[ citation needed ]

As a co-product of steelmaking, slag is typically produced either through the blast furnace - oxygen converter route or the electric arc furnace - ladle furnace route. [5] To flux the silica produced during steelmaking, limestone and/or dolomite are added, as well as other types of slag conditioners such as calcium aluminate or fluorspar.

Classifications

Slag run-off from one of the open hearth furnaces of a steel mill, Republic Steel, Youngstown, Ohio, November 1941. Slag is drawn off the furnace just before the molten steel is poured into ladles for ingotting. Slag runoff Republic Steel.jpg
Slag run-off from one of the open hearth furnaces of a steel mill, Republic Steel, Youngstown, Ohio, November 1941. Slag is drawn off the furnace just before the molten steel is poured into ladles for ingotting.

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

Ferrous slag

Ferrous slags are produced in different stages of the iron and steelmaking processes resulting in varying physiochemical properties. Additionally, the rate of cooling of the slag material affects its degree of crystallinity further diversifying its range of properties. For example, slow cooled blast furnace slags (or air-cooled slags) tend have more crystalline phases than quenched blast furnace slags (ground granulated blast furnace slags) making it denser and better suited as an aggregate. It may also have higher free calcium oxide and magnesium oxide content, which are often converted to its hydrated forms if excessive volume expansions are not desired. On the other hand, water quenched blast furnace slags have greater amorphous phases giving it latent hydraulic properties (as discovered by Emil Langen in 1862) similar to Portland cement. [6]

During the process of smelting iron, ferrous slag is created, but dominated by calcium and silicon compositions. Through this process, ferrous slag can be broken down into blast furnace slag (produced from iron oxides of molten iron), then steel slag (forms when steel scrap and molten iron combined). The major phases of ferrous slag contain calcium-rich olivine-group silicates and melilite-group silicates.

Slag from steel mills in ferrous smelting is designed to minimize iron loss, which gives out the significant amount of iron, following by oxides of calcium, silicon, magnesium, and aluminium. As the slag is cooled down by water, several chemical reactions from a temperature of around 2,600 °F (1,430 °C) (such as oxidization) take place within the slag. [1]

A path through a slag heap in Clarkdale, Arizona, showing the striations from the rusting corrugated sheets retaining it. Slag2.jpg
A path through a slag heap in Clarkdale, Arizona, showing the striations from the rusting corrugated sheets retaining it.

Based on a case study at the Hopewell National Historical Site in Berks and Chester counties, Pennsylvania, USA, ferrous slag usually contains lower concentration of various types of trace elements than non-ferrous slag. However, some of them, such as arsenic (As), iron, and manganese, can accumulate in groundwater and surface water to levels that can exceed environmental guidelines. [1]

Non-ferrous slag

Non-ferrous slag is produced from non-ferrous metals of natural ores. Non-ferrous slag can be characterized into copper, lead, and zinc slags due to the ores' compositions, and they have more potential to impact the environment negatively than ferrous slag. The smelting of copper, lead and bauxite in non-ferrous smelting, for instance, is designed to remove the iron and silica that often occurs with those ores, and separates them as iron-silicate-based slags. [1]

Copper slag, the waste product of smelting copper ores, was studied in an abandoned Penn Mine in California, USA. For six to eight months per year, this region is flooded and becomes a reservoir for drinking water and irrigation. Samples collected from the reservoir showed the higher concentration of cadmium (Cd) and lead (Pb) that exceeded regulatory guidelines. [1]

Applications

Slags can 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. In some smelting processes, such as ilmenite smelting to produce titanium dioxide, the slag can be the valuable product. [7]

Early slag from Denmark, c. 200-500 CE Slag from iron ore melting.jpg
Early slag from Denmark, c. 200-500  CE

Ancient uses

During the Bronze Age of the Mediterranean area there were a vast number of differential metallurgical processes in use. A slag by-product of such workings was a colorful, glassy 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. [8]

Historically, the re-smelting of iron ore slag was common practice, as improved smelting techniques permitted greater iron yields—in some cases exceeding that which was originally achieved. 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.

Modern uses

Construction

Utilization of slags in the construction industry dates back to the 1800s, where blast furnace slags were used to build roads and railroad ballast. During this time, it was also used as an aggregate and had begun being integrated into the cement industry as a geopolymer. [9]

Today, ground granulated blast furnace slags are used in combination with Portland cement to create "slag cement." Granulated blast furnace slags react with portlandite (Ca(OH)2), which is formed during cement hydration, via the pozzolanic reaction to produce cementitious properties that primarily contribute to the later strength gain of concrete. This leads to concrete with reduced permeability and better durability. Careful consideration of the slag type used is required, as the high calcium oxide and magnesium oxide content can lead to excessive volume expansion and cracking in concrete. [10]

These hydraulic properties have also been used for soil stabilization in roads and railroad constructions. [11]

Granulated blast furnace slag is used in the manufacture of high-performance concretes, especially those used in the construction of bridges and coastal features, where its low permeability and greater resistance to chlorides and sulfates can help to reduce corrosive action and deterioration of the structure. [12]

Slag can also be used to create fibers used as an insulation material called slag wool .

Slag is also used as aggregate in asphalt concrete for paving roads. A 2022 study in Finland found that road surfaces containing ferrochrome slag release a highly abrasive dust that has caused car parts to wear at significantly greater than normal rates. [13]

Wastewater treatment and agriculture

Dissolution of slags generate alkalinity that can be used to precipitate out metals, sulfates, and excess nutrients (nitrogen and phosphorus) in wastewater treatment. Similarly, ferrous slags have been used as soil conditioners to rebalance soil pH and fertilizers as sources of calcium and magnesium. [14]  

Because of the slowly released phosphate content in phosphorus-containing slag, and because of its liming effect, it is valued as fertilizer in gardens and farms in steel making areas. However, the most important application is construction. [15]

Emerging applications

Slags have one of the highest carbonation potential among the industrial alkaline waste due their high calcium oxide and magnesium oxide content, inspiring further studies to test its feasibility in CO2 capture and storage (CCS) methods (e.g., direct aqueous sequestration, dry gas-solid carbonation among others). [16] [17] Across these CCS methods, slags can be transformed into precipitated calcium carbonates to be used in the plastic, and concrete industries and leached for metals to be used in the electronic industries. [18]

However, high physical and chemical variability across different types of slags results in performance and yield inconsistencies. [19] Moreover, stoichiometric-based calculation of the carbonation potential can lead to overestimation that can further obfuscate the material's true potential. [20] To this end, some have proposed performing a series of experiments testing the reactivity of a specific slag material (i.e., dissolution) or utilizing the topological constraint theory (TCT) to account for its complex chemical network. [21]

Health and Environmental impact

Pile of steelmaking slag at the Cleveland-Cliffs Indiana Harbor steelmaking facility. Indiana-Harbor-scrap.jpg
Pile of steelmaking slag at the Cleveland-Cliffs Indiana Harbor steelmaking facility.

Slags are transported along with slag tailings to "slag dumps," where they are exposed to weathering, with the possibility of leaching of toxic elements and hyperalkaline runoffs into the soil and water, endangering the local ecological communities. Leaching concerns are typically around non-ferrous or base metal slags, which tend to have higher concentrations of toxic elements. However, ferrous and ferroalloy slags may also have them, which raises concerns about highly weathered slag dumps and upcycled materials. [22] [23]

Dissolution of slags can produce highly alkaline groundwater with pH values above 12. [24] The calcium silicates (CaSiO4) in slags react with water to produce calcium hydroxide ions that leads to a higher concentration of hydroxide (OH-) in ground water. This alkalinity promotes the mineralization of dissolved CO2 (from the atmosphere) to produce calcite (CaCO3), which can accumulate to as thick as 20 cm. This can also lead to the dissolution of other metals in slag, such as iron (Fe), manganese (Mn), nickel (Ni), and molybdenum (Mo), which become insoluble in water and mobile as particulate matter. The most effective method to detoxify alkaline ground water discharge is air sparging. [24]

Particulate (concrete dust) emission when using modern electrical power tool during home broadband installation

Fine slags and slag dusts generated from milling slags to be recycled into the smelting process or upcycled in a different industry (e.g. construction) can be carried by the wind, affecting a larger ecosystem. It can be ingested and inhaled, posing a direct health risk to the communities near the plants, mines, disposal sites, etc. [22] [23]

See also

Related Research Articles

<span class="mw-page-title-main">Cement</span> Hydraulic binder used in the composition of mortar and concrete

A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource.

<span class="mw-page-title-main">Smelting</span> Use of heat and a reducing agent to extract metal from ore

Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron, copper, silver, tin, lead and zinc. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gases or slag and leaving the metal behind. The reducing agent is commonly a fossil fuel source of carbon, such as carbon monoxide from incomplete combustion of coke—or, in earlier times, of charcoal. The oxygen in the ore binds to carbon at high temperatures as the chemical potential energy of the bonds in carbon dioxide is lower than that of the bonds in the ore.

<span class="mw-page-title-main">Wrought iron</span> Iron alloy with a very low carbon content

Wrought iron is an iron alloy with a very low carbon content in contrast to that of cast iron. It is a semi-fused mass of iron with fibrous slag inclusions, which give it a wood-like "grain" that is visible when it is etched, rusted, or bent to failure. Wrought iron is tough, malleable, ductile, corrosion resistant, and easily forge welded, but is more difficult to weld electrically.

<span class="mw-page-title-main">Steelmaking</span> Process for producing steel from iron ore and scrap

Steelmaking is the process of producing steel from iron ore and/or scrap. In steelmaking, impurities such as nitrogen, silicon, phosphorus, sulfur and excess carbon are removed from the sourced iron, and alloying elements such as manganese, nickel, chromium, carbon and vanadium are added to produce different grades of steel.

<span class="mw-page-title-main">Blast furnace</span> Type of furnace used for smelting to produce industrial metals

A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally pig iron, but also others such as lead or copper. Blast refers to the combustion air being supplied above atmospheric pressure.

<span class="mw-page-title-main">Industrial processes</span> Process of producing goods

Industrial processes are procedures involving chemical, physical, electrical, or mechanical steps to aid in the manufacturing of an item or items, usually carried out on a very large scale. Industrial processes are the key components of heavy industry.

<span class="mw-page-title-main">Copper extraction</span> Process of extracting copper from the ground

Copper extraction refers to the methods used to obtain copper from its ores. The conversion of copper ores consists of a series of physical, chemical and electrochemical processes. Methods have evolved and vary with country depending on the ore source, local environmental regulations, and other factors.

<span class="mw-page-title-main">Basic oxygen steelmaking</span> Steelmaking method

Basic oxygen steelmaking, also known as Linz-Donawitz steelmaking or the oxygen converter process, is a method of primary steelmaking in which carbon-rich molten pig iron is made into steel. Blowing oxygen through molten pig iron lowers the carbon content of the alloy and changes it into low-carbon steel. The process is known as basic because fluxes of burnt lime or dolomite, which are chemical bases, are added to promote the removal of impurities and protect the lining of the converter.

<span class="mw-page-title-main">Electric arc furnace</span> Type of furnace

An electric arc furnace (EAF) is a furnace that heats material by means of an electric arc.

<span class="mw-page-title-main">Bloomery</span> Type of furnace once used widely for smelting iron from its oxides

A bloomery is a type of metallurgical furnace once used widely for smelting iron from its oxides. The bloomery was the earliest form of smelter capable of smelting iron. Bloomeries produce a porous mass of iron and slag called a bloom. The mix of slag and iron in the bloom, termed sponge iron, is usually consolidated and further forged into wrought iron. Blast furnaces, which produce pig iron, have largely superseded bloomeries.

Pyrometallurgy is a branch of extractive metallurgy. It consists of the thermal treatment of minerals and metallurgical ores and concentrates to bring about physical and chemical transformations in the materials to enable recovery of valuable metals. Pyrometallurgical treatment may produce products able to be sold such as pure metals, or intermediate compounds or alloys, suitable as feed for further processing. Examples of elements extracted by pyrometallurgical processes include the oxides of less reactive elements like iron, copper, zinc, chromium, tin, and manganese.

Ferroalloy refers to various alloys of iron with a high proportion of one or more other elements such as manganese (Mn), aluminium (Al), or silicon (Si). They are used in the production of steels and alloys. The alloys impart distinctive qualities to steel and cast iron or serve important functions during production and are, therefore, closely associated with the iron and steel industry, the leading consumer of ferroalloys. The leading producers of ferroalloys in 2014 were China, South Africa, India, Russia and Kazakhstan, which accounted for 84% of the world production. World production of ferroalloys was estimated as 52.8 million tonnes in 2015.

<span class="mw-page-title-main">Direct reduced iron</span> Newly mined and refined type of metal

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<span class="mw-page-title-main">Ferrosilicon</span>

Ferrosilicon is an alloy of iron and silicon with a typical silicon content by weight of 15–90%. It contains a high proportion of iron silicides.

<span class="mw-page-title-main">Electrometallurgy</span>

Electrometallurgy is a method in metallurgy that uses electrical energy to produce metals by electrolysis. It is usually the last stage in metal production and is therefore preceded by pyrometallurgical or hydrometallurgical operations. The electrolysis can be done on a molten metal oxide which is used for example to produce aluminium from aluminium oxide via the Hall-Hérault process. Electrolysis can be used as a final refining stage in pyrometallurgical metal production (electrorefining) and it is also used for reduction of a metal from an aqueous metal salt solution produced by hydrometallurgy (electrowinning).

<span class="mw-page-title-main">Ground granulated blast-furnace slag</span> Granular slag by-product of iron and steel-making used as supplementary cementitious material

Ground granulated blast-furnace slag is obtained by quenching molten iron slag from a blast furnace in water or steam, to produce a glassy, granular product that is then dried and ground into a fine powder. Ground granulated blast furnace slag is a latent hydraulic binder forming calcium silicate hydrates (C-S-H) after contact with water. It is a strength-enhancing compound improving the durability of concrete. It is a component of metallurgic cement. Its main advantage is its slow release of hydration heat, allowing limitation of the temperature increase in massive concrete components and structures during cement setting and concrete curing, or to cast concrete during hot summer.

Deoxidization is a method used in metallurgy to remove the oxygen content during steel manufacturing. In contrast, antioxidants are used for stabilization, such as in the storage of food. Deoxidation is important in the steelmaking process as oxygen is often detrimental to the quality of steel produced. Deoxidization is mainly achieved by adding a separate chemical species to neutralize the effects of oxygen or by directly removing the oxygen.

Copper slag is a by-product of copper extraction by smelting. During smelting, impurities become slag which floats on the molten metal. Slag that is quenched in water produces angular granules which are disposed of as waste or utilized as discussed below.

<span class="mw-page-title-main">Archaeometallurgical slag</span> Artefact of ancient iron production

Archaeometallurgical slag is slag discovered and studied in the context of archaeology. Slag, the byproduct of iron-working processes such as smelting or smithing, is left at the iron-working site rather than being moved away with the product. As it weathers well, it is readily available for study. The size, shape, chemical composition and microstructure of slag are determined by features of the iron-working processes used at the time of its formation.

In 2022, the United States was the world’s third-largest producer of raw steel, and the sixth-largest producer of pig iron. The industry produced 29 million metric tons of pig iron and 88 million tons of steel. Most iron and steel in the United States is now made from iron and steel scrap, rather than iron ore. The United States is also a major importer of iron and steel, as well as iron and steel products.

References

  1. 1 2 3 4 5 6 Piatak, Nadine M.; Parsons, Michael B.; Seal, Robert R. (2015). "Characteristics and environmental aspects of slag: A review". Applied Geochemistry. 57: 236–266. Bibcode:2015ApGC...57..236P. doi:10.1016/j.apgeochem.2014.04.009. ISSN   0883-2927.
  2. Stroup-Gardiner, Mary; Wattenberg-Komas, Tanya (2013-06-24). Recycled Materials and Byproducts in Highway Applications—Summary Report, Volume 1. doi:10.17226/22552. ISBN   978-0-309-22368-3.
  3. "Iron and Steel Statistics and Information". www.usgs.gov. Retrieved 2021-11-27.
  4. "worldsteel | Steel industry co-products position paper". www.worldsteel.org. Retrieved 2021-11-27.
  5. Fruehan, Richard (1998). The Making, Shaping, and Treating of Steel, Steelmaking and Refining Volume, 11th Edition. Pittsburgh, PA, USA: The AISE Steel Foundation. p. 10. ISBN   0-930767-02-0.
  6. Cwirzen, Andrzej (2020-01-01), Siddique, Rafat (ed.), "10 - Properties of SCC with industrial by-products as aggregates", Self-Compacting Concrete: Materials, Properties and Applications, Woodhead Publishing Series in Civil and Structural Engineering, Woodhead Publishing, pp. 249–281, ISBN   978-0-12-817369-5 , retrieved 2021-11-26
  7. Pistorius, P.C. (2007). "Ilmenite smelting: the basics" (PDF). The 6th International Heavy Minerals Conference 'Back to Basics': 75–84.
  8. "The chemical composition of glass in Ancient Egypt by Mikey Brass (1999)" . Retrieved 2009-06-18.
  9. Netinger Grubeša, Ivanka; Barišić, Ivana; Fucic, Aleksandra; Bansode, Samitinjay S. (2016-01-01), Netinger Grubeša, Ivanka; Barišić, Ivana; Fucic, Aleksandra; Bansode, Samitinjay S. (eds.), "4 - Application of blast furnace slag in civil engineering: Worldwide studies", Characteristics and Uses of Steel Slag in Building Construction, Woodhead Publishing, pp. 51–66, ISBN   978-0-08-100368-8 , retrieved 2021-11-27
  10. Ortega-López, Vanesa; Manso, Juan M.; Cuesta, Isidoro I.; González, Javier J. (2014-10-15). "The long-term accelerated expansion of various ladle-furnace basic slags and their soil-stabilization applications". Construction and Building Materials. 68: 455–464. doi:10.1016/j.conbuildmat.2014.07.023. ISSN   0950-0618.
  11. Grubeša, Ivanka Netinger; Barišić, Ivana (2021-08-04), "Chapter 7: Diverse Applications of Slags in the Construction Industry", Metallurgical Slags, Chemistry in the Environment, pp. 194–233, doi:10.1039/9781839164576-00194, ISBN   978-1-78801-887-6, S2CID   238965391 , retrieved 2021-11-27
  12. "High Performance Cement for High Strength and Extreme Durability by Konstantin Sobolev". Archived from the original on 2009-08-03. Retrieved 2009-06-18.
  13. "Autojen jakohihnojen rikkoutumisen taustalla ferrokromikuonan eli OKTO-murskeen aiheuttama kuluminen". Geological Survey of Finland. 20 September 2022. Retrieved 20 September 2022.
  14. Gomes, Helena I.; Mayes, William M.; Ferrari, Rebecca (2021-08-04), "Chapter 8: Environmental Applications of Slag", Metallurgical Slags, Chemistry in the Environment, pp. 234–267, doi:10.1039/9781839164576-00234, ISBN   978-1-78801-887-6, S2CID   238967817 , retrieved 2021-11-27
  15. O'Connor, James; Nguyen, Thi Bang Tuyen; Honeyands, Tom; Monaghan, Brian; O'Dea, Damien; Rinklebe, Jörg; Vinu, Ajayan; Hoang, Son A.; Singh, Gurwinder; Kirkham, M.B.; Bolan, Nanthi (2021). "Production, characterisation, utilisation, and beneficial soil application of steel slag: A review". Journal of Hazardous Materials . 419: 126478. doi:10.1016/j.jhazmat.2021.126478. ISSN   0304-3894. PMID   34323725.
  16. Doucet, Frédéric J. (2010-02-01). "Effective CO2-specific sequestration capacity of steel slags and variability in their leaching behaviour in view of industrial mineral carbonation". Minerals Engineering . Special issue: Sustainability, Resource Conservation & Recycling. 23 (3): 262–269. doi:10.1016/j.mineng.2009.09.006. ISSN   0892-6875.
  17. Romanov, Vyacheslav; Soong, Yee; Carney, Casey; Rush, Gilbert E.; Nielsen, Benjamin; O'Connor, William (2015). "Mineralization of Carbon Dioxide: A Literature Review". ChemBioEng Reviews. 2 (4): 231–256. doi:10.1002/cben.201500002. ISSN   2196-9744. OSTI   1187926.
  18. Ragipani, Raghavendra; Bhattacharya, Sankar; Suresh, Akkihebbal K. (2021). "A review on steel slag valorisation via mineral carbonation". Reaction Chemistry & Engineering. 6 (7): 1152–1178. doi:10.1039/D1RE00035G. ISSN   2058-9883. S2CID   236390725.
  19. Brand, Alexander S.; Fanijo, Ebenezer O. (2020-11-19). "A Review of the Influence of Steel Furnace Slag Type on the Properties of Cementitious Composites". Applied Sciences . 10 (22): 8210. doi: 10.3390/app10228210 . hdl: 10919/100961 . ISSN   2076-3417.
  20. "Some Effects of Carbon Dioxide on Mortars and Concrete". ACI Journal Proceedings. 53 (9). 1956. doi:10.14359/11515. ISSN   0002-8061.
  21. La Plante, Erika Callagon; Mehdipour, Iman; Shortt, Ian; Yang, Kai; Simonetti, Dante; Bauchy, Mathieu; Sant, Gaurav N. (2021-08-16). "Controls on CO2 Mineralization Using Natural and Industrial Alkaline Solids under Ambient Conditions". ACS Sustainable Chemistry & Engineering. 9 (32): 10727–10739. doi:10.1021/acssuschemeng.1c00838. S2CID   238670674.
  22. 1 2 Ettler, Vojtěch; Kierczak, Jakub (2021-08-04), "Chapter 6: Environmental Impact of Slag Particulates", Metallurgical Slags, Chemistry in the Environment, pp. 174–193, doi:10.1039/9781839164576-00174, ISBN   978-1-78801-887-6, S2CID   238952198 , retrieved 2021-11-27
  23. 1 2 Ettler, Vojtěch; Vítková, Martina (2021-08-04), "Chapter 5: Slag Leaching Properties and Release of Contaminants", Metallurgical Slags, Chemistry in the Environment, pp. 151–173, doi:10.1039/9781839164576-00151, ISBN   978-1-78801-887-6, S2CID   238945892 , retrieved 2021-11-27
  24. 1 2 Roadcap, George S.; Kelly, Walton R.; Bethke, Craig M. (2005). "Geochemistry of Extremely Alkaline (pH > 12) Ground Water in Slag-Fill Aquifers". Ground Water . 43 (6): 806–816. doi:10.1111/j.1745-6584.2005.00060.x. ISSN   0017-467X. PMID   16324002. S2CID   12325820.

Further reading