Ash

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This article is about the residue of burning a material. Not to be confused with Volcanic ash or Ash (plant).For other uses, see Ash (disambiguation).
Wood ash Wood ash.jpg
Wood ash

Ash or ashes are the solid remnants of fires. [1] Specifically, ash refers to all non-aqueous, non-gaseous residues that remain after something burns. In analytical chemistry, to analyse the mineral and metal content of chemical samples, ash is the non-gaseous, non-liquid residue after complete combustion.

Contents

Ashes as the end product of incomplete combustion are mostly mineral, but usually still contain an amount of combustible organic or other oxidizable residues. The best-known type of ash is wood ash, as a product of wood combustion in campfires, fireplaces, etc. The darker the wood ashes, the higher the content of remaining charcoal from incomplete combustion. The ashes are of different types. Some ashes contain natural compounds that make soil fertile. Others have chemical compounds that can be toxic but may break up in soil from chemical changes and microorganism activity.

Like soap, ash is also a disinfecting agent (alkaline). [2] The World Health Organization recommends ash or sand as alternative for handwashing when soap is not available. [3]

Natural occurrence

Ash occurs naturally from any fire that burns vegetation, and may disperse in the soil to fertilise it, or clump under it for long enough to carbonise into coal.

Composition

The composition of the ash varies depending on the product burned and its origin. The "ash content" or "mineral content" of a product is derived its incineration under temperatures ranging from 150 °C (302 °F) to 900 °C (1,650 °F). [4]

Wood and plant matter

The composition of ash derived from wood and other plant matter varies based on plant species, parts of the plants (such as bark, trunk, or young branches with foliage), type of soil, and time of year. The composition of these ashes also differ greatly depending on mode of combustion.

Wood ashes, in addition to residual carbonaceous materials (unconsumed embers, activated carbons impregnated with carbonaceous particles, tars, various gases, etc.), contain a between 20% and 50% calcium in the form of calcium oxide and are generally rich in potassium carbonate. Ashes derived from grasses, and the Gramineae family in particular, are rich in silica. [5] The color of the ash comes from small proportions of inorganic minerals such as iron oxides and manganese. The oxidized metal elements that constitute wood ash are mostly considered alkaline.

For example, ash collected from wood boilers is composed of [6]

The pH of the ash is between 10 and 13, mostly due to the fact that the oxides of calcium, potassium, and sodium are strong bases. Acidic components such as carbon dioxide, phosphoric acid, silicic acid, and sulfuric acid are rarely present and, in the presence of the previously mentioned bases, are generally found in the form of salts, respectively carbonates, phosphates, silicates and sulphates.

Strictly speaking, calcium and potassium salts produce the aforementioned calcium oxide (also known as quicklime) and potassium during the combustion of organic matter. But, in practice, quicklime is only obtained via lime-kiln, and potash (from potassium carbonate) or baking soda (from sodium carbonate) is extracted from the ashes.

Other substances such as sulfur, chlorine, iron or sodium only appear in small quantities. Still others are rarely found in wood, such as aluminum, zinc, and boron. (depending on the trace elements drawn from the soil by the incinerated plants).

Mineral content in ash depends on the species of tree burned, even in the same soil conditions. More chloride is found in conifer trees than broadleaf trees, with seven times as much found in spruces than in oak trees. There is twice as much phosphoric acid in the European aspen than in oaks and twice as much magnesium in elm trees than in the Scotch pine.

Ash composition also varies by which part of the tree was burnt. Silicon and calcium salts are more abundant in bark than in wood, while potassium salts are primarily found in wood. Compositional variation also occurred based on the season in which the tree died.

Specific types

Joss paper ash. With wind and dispersion, the size of particulates decreases, while the number of particles increases. HK Sheung Wan Wing Lok Street fire burning offering papers Chinese style December 2018 IX2 02.jpg
Joss paper ash. With wind and dispersion, the size of particulates decreases, while the number of particles increases.

Cremation ashes

Cremation ashes, also called cremated remains or "cremains," are the bodily remains left from cremation. [7] They often take the form of a grey powder resembling coarse sand. While often referred to as ashes, the remains primarily consist of powdered bone fragments due to the cremation process, which eliminates the body's organic materials. [8] [9] People often store these ashes in containers like urns, although they are also sometimes buried or scattered in specific locations. [10]

Food ashes

In food processing, mineral and ash content is used to characterize the presence of organic and inorganic components in food for monitoring quality, nutritional quantification and labeling, analyzing microbiological stability, and more. [4] This process can be used to measure minerals like calcium, sodium, potassium, and phosphorus as well as metal content such as lead, mercury, cadmium, and aluminum.

Joss paper ash

Metal contents analysis of ash samples shows that joss paper burning emits a lot of toxic components causing ... There is a significant amount of heavy metals in the dust fume and bottom ash, e.g., aluminium, iron, manganese, copper, lead, zinc and cadmium. [11] [12]

“Burning of joss paper accounted for up to 42% of the atmospheric rBC [refractory black carbon] mass, higher than traffic (14-17%), crop residue (10-17%), coal (18-20%) during the Hanyi festival in northwest China", according to a 2022 study, "the overall air quality can be worsened due to the practice of uncontrolled burning of joss paper during the festival, which is not just confined to the people who do the burning,” and “burning joss paper during worship activities is common in China and most Asian countries with similar traditions.” [13]

Slash-and-burn ash

Wildfire ash

High levels of heavy metals, including lead, arsenic, cadmium, and copper were found in the ash debris following the 2007 Californian wildfires. A national clean-up campaign was organised ... [14] In the devastating California Camp Fire (2018) that killed 85 people, lead levels increased by around 50 times in the hours following the fire at a site nearby (Chico). Zinc concentration also increased significantly in Modesto, 150 miles away. Heavy metals such as manganese and calcium were found in numerous California fires as well. [15]

Others

Other Properties

Shape

Size

Hardness

Incomplete combustion

Aging process

Global distillation

Health effects

Mechanism

Oxidative stress

Inflammation

Others

Health conditions

Effect on precipitation

“Particles of dust or smoke in the atmosphere are essential for precipitation. These particles, called ‘condensation nuclei,’ provide a surface for water vapor to condense upon. This helps water droplets gather together and become large enough to fall to the earth” [16]

Effect on climate change

See also

Related Research Articles

<span class="mw-page-title-main">Carbonate</span> Salt or ester of carbonic acid

A carbonate is a salt of carbonic acid, H2CO3, characterized by the presence of the carbonate ion, a polyatomic ion with the formula CO2−3. The word "carbonate" may also refer to a carbonate ester, an organic compound containing the carbonate groupO=C(−O−)2.

<span class="mw-page-title-main">Potash</span> Salt mixture

Potash includes various mined and manufactured salts that contain potassium in water-soluble form. The name derives from pot ash, plant ashes or wood ash soaked in water in a pot, the primary means of manufacturing potash before the Industrial Era. The word potassium is derived from potash.

<span class="mw-page-title-main">Weathering</span> Deterioration of rocks and minerals through exposure to the elements

Weathering is the deterioration of rocks, soils and minerals through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs in situ, and so is distinct from erosion, which involves the transport of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity.

<span class="mw-page-title-main">Sodium carbonate</span> Chemical compound

Sodium carbonate is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield alkaline solutions in water. Historically, it was extracted from the ashes of plants grown in sodium-rich soils, and because the ashes of these sodium-rich plants were noticeably different from ashes of wood, sodium carbonate became known as "soda ash". It is produced in large quantities from sodium chloride and limestone by the Solvay process, as well as by carbonating sodium hydroxide which is made using the chloralkali process.

<span class="mw-page-title-main">Manganese dioxide</span> Chemical compound

Manganese dioxide is the inorganic compound with the formula MnO
2. This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for MnO
2 is for dry-cell batteries, such as the alkaline battery and the zinc–carbon battery. MnO
2 is also used as a pigment and as a precursor to other manganese compounds, such as KMnO
4. It is used as a reagent in organic synthesis, for example, for the oxidation of allylic alcohols. MnO
2 has an α-polymorph that can incorporate a variety of atoms in the "tunnels" or "channels" between the manganese oxide octahedra. There is considerable interest in α-MnO
2 as a possible cathode for lithium-ion batteries.

The Leblanc process was an early industrial process for making soda ash used throughout the 19th century, named after its inventor, Nicolas Leblanc. It involved two stages: making sodium sulfate from sodium chloride, followed by reacting the sodium sulfate with coal and calcium carbonate to make sodium carbonate. The process gradually became obsolete after the development of the Solvay process.

The Solvay process or ammonia–soda process is the major industrial process for the production of sodium carbonate (soda ash, Na2CO3). The ammonia–soda process was developed into its modern form by the Belgian chemist Ernest Solvay during the 1860s. The ingredients for this are readily available and inexpensive: salt brine (from inland sources or from the sea) and limestone (from quarries). The worldwide production of soda ash in 2005 was estimated at 42 million tonnes, which is more than six kilograms (13 lb) per year for each person on Earth. Solvay-based chemical plants now produce roughly three-quarters of this supply, with the remaining being mined from natural deposits. This method superseded the Leblanc process.

<span class="mw-page-title-main">Barium carbonate</span> Chemical compound

Barium carbonate is the inorganic compound with the formula BaCO3. Like most alkaline earth metal carbonates, it is a white salt that is poorly soluble in water. It occurs as the mineral known as witherite. In a commercial sense, it is one of the most important barium compounds.

Calcination is thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O2 fraction of air), generally for the purpose of removing impurities or volatile substances and/or to incur thermal decomposition.

<span class="mw-page-title-main">Lime (material)</span> Calcium oxides and/or hydroxides

Lime is an inorganic material composed primarily of calcium oxides and hydroxides. It is also the name for calcium oxide which occurs as a product of coal-seam fires and in altered limestone xenoliths in volcanic ejecta. The International Mineralogical Association recognizes lime as a mineral with the chemical formula of CaO. The word lime originates with its earliest use as building mortar and has the sense of sticking or adhering.

<span class="mw-page-title-main">Calcium sulfide</span> Chemical compound of formula CaS

Calcium sulfide is the chemical compound with the formula CaS. This white material crystallizes in cubes like rock salt. CaS has been studied as a component in a process that would recycle gypsum, a product of flue-gas desulfurization. Like many salts containing sulfide ions, CaS typically has an odour of H2S, which results from small amount of this gas formed by hydrolysis of the salt.

In analytical chemistry, ashing or ash content determination is the process of mineralization by complete combustion for preconcentration of trace substances prior to a chemical analysis, such as chromatography, or optical analysis, such as spectroscopy.

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

Mineral ascorbates are a group of salts of ascorbic acid. They are composed of a mineral cation bonded to ascorbate.

<span class="mw-page-title-main">Hexafluorosilicic acid</span> Octahedric silicon compound

Hexafluorosilicic acid is an inorganic compound with the chemical formula H
2SiF
6. Aqueous solutions of hexafluorosilicic acid consist of salts of the cation and hexafluorosilicate anion. These salts and their aqueous solutions are colorless.

A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas/smoke or a combination of these, as a result of non-detonative self-sustaining exothermic chemical reactions. Pyrotechnic substances do not rely on oxygen from external sources to sustain the reaction.

<span class="mw-page-title-main">Manganese(II) sulfate</span> Chemical compound

Manganese(II) sulfate usually refers to the inorganic compound with the formula MnSO4·H2O. This pale pink deliquescent solid is a commercially significant manganese(II) salt. Approximately 260,000 tonnes of manganese(II) sulfate were produced worldwide in 2005. It is the precursor to manganese metal and many other chemical compounds. Manganese-deficient soil is remediated with this salt.

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

Alkaline precipitation occurs due to natural and anthropogenic causes. It happens when minerals, such as calcium, aluminum, or magnesium combine with other minerals to form alkaline residues that are emitted into the atmosphere, absorbed by water droplets in clouds, and eventually fall as rain. Aquatic environments are especially impacted by alkaline precipitation. Because alkaline precipitation can be harmful to the environment, it is important to utilize various methods such as air pollution control, solidification and stabilization, and remediation to manage it.

<span class="mw-page-title-main">Alkali soil</span> Soil type with pH > 8.5

Alkali, or alkaline, soils are clay soils with high pH, a poor soil structure and a low infiltration capacity. Often they have a hard calcareous layer at 0.5 to 1 metre depth. Alkali soils owe their unfavorable physico-chemical properties mainly to the dominating presence of sodium carbonate, which causes the soil to swell and difficult to clarify/settle. They derive their name from the alkali metal group of elements, to which sodium belongs, and which can induce basicity. Sometimes these soils are also referred to as alkaline sodic soils. Alkaline soils are basic, but not all basic soils are alkaline.

<span class="mw-page-title-main">Wood ash</span> Residue powder left after the combustion of wood

Wood ash is the powdery residue remaining after the combustion of wood, such as burning wood in a fireplace, bonfire, or an industrial power plant. It is largely composed of calcium compounds, along with other non-combustible trace elements present in the wood, and has been used for many purposes throughout history.

References

  1. ↑ "the definition of ash". www.dictionary.com. Retrieved 2018-06-18.
  2. ↑ Howard et al. 2002: Healthy Villages A guide for communities and community health workers. CHAPTER 8 Personal, domestic and community hygiene. WHO. Accessed Oct. 2014. http://www.who.int/water_sanitation_health/hygiene/settings/hvchap8.pdf
  3. ↑ WHO 2014: Water Sanitation Health. How can personal hygiene be maintained in difficult circumstances? Accessed Oct. 2014
  4. 1 2 McClements, D. Julian. "Analysis of Ash and Minerals". Analysis of Food Products Lectures. Retrieved 2024-06-15.
  5. ↑ Pépin, Denis (2013). Composts et paillis: pour un jardin sain, facile et productif. Terre vivante. p. 54. ISBN   978-2360980918.
  6. ↑ Couturier, Christian; Brasset, Thierry. "Gestion et valorisation de cendres de chaufferies bois" [Management and recovery of wood boiler ashes](PDF) (in French). Agence de l'Environnement et de la Maîtrse de l'Energie. Archived from the original (PDF) on 2015-01-15. Retrieved 2024-06-24.
  7. ↑ "What Are Cremains? (& What to Do with Them) » Urns | Online". www.usurnsonline.com. 31 May 2022.
  8. ↑ "All About Cremation Ashes | What Are Human Ashes Made of | Scattering Ashes". www.cremationsolutions.com.
  9. ↑ "Education | Cremation ashes". www.lonite.ca.
  10. ↑ "What To Do With Cremated Remains". cremation.com. Retrieved 25 June 2023.
  11. ↑ Giang, Lam Van; Thanh, Tran; Hien, Truong Thanh; Tan, Lam Van; Thi Bich Phuong, Tran; Huu Loc, Ho (2021). "Heavy metals emissions from joss paper burning rituals and the air quality around a specific incinerator". Materials Today: Proceedings. 38: 2751–2757. doi: 10.1016/j.matpr.2020.08.686 . S2CID   226353498.
  12. ↑ Khezri, B.; Chan, Y. Y.; Tiong, L. Y. D.; Webster, R. D. (2015). "Annual air pollution caused by the Hungry Ghost Festival". Environmental Science: Processes & Impacts. 17 (9): 1578–1586. doi:10.1039/C5EM00312A. hdl: 10356/82684 . PMID   26220212.
  13. ↑ Lin C, Huang RJ, Duan J, Zhong H, Xu W, Wu Y, Zhang R (April 2022). "Large contribution from worship activities to the atmospheric soot particles in northwest China". Environ Pollut. 299: 118907. Bibcode:2022EPoll.29918907L. doi:10.1016/j.envpol.2022.118907. PMID   35091017.
  14. ↑ Finlay SE, Moffat A, Gazzard R, Baker D, Murray V (November 2012). "Health impacts of wildfires". PLOS Currents. 4: e4f959951cce2c. doi: 10.1371/4f959951cce2c (inactive 1 November 2024). PMC   3492003 . PMID   23145351.{{cite journal}}: CS1 maint: DOI inactive as of November 2024 (link)
  15. ↑ "Wildfire smoke can increase hazardous toxic metals in air, study finds | Climate crisis | The Guardian". 21 July 2021.
  16. ↑ "Precipitation". National Geographic. 19 Oct 2023. Retrieved 19 Aug 2024.
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