Ash is the solid remnants of .
Ashes as the end product of incomplete combustion are mostly mineral, but usually still contain an amount of combustible organic compound or other Redox residues. The best-known type of ash is wood ash, as a product of wood combustion in , , 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 that make soil Soil fertility. 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).[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] The World Health Organization recommends ash or sand as alternative for handwashing when soap is not available.[WHO 2014: Water Sanitation Health. How can personal hygiene be maintained in difficult circumstances? Accessed Oct. 2014 [1]] Before industrialization, ash soaked in water was the primary means of obtaining potash.
Natural occurrence
Ash occurs naturally from any
fire that burns
vegetation, and may disperse in the soil to
Soil fertility, or clump under it for long enough to
Carbonisation 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 to .
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), the type of soil, and the time of year. The composition of these ashes also differs greatly depending on the mode of combustion.
, in addition to residual carbonaceous materials (unconsumed embers, activated carbons impregnated with carbonaceous particles, tars, various gases, etc.), contain 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.
For example, ash collected from wood boilers is composed of
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 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 and twice as much magnesium in elm 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
Cremation ashes
Cremation ashes, also called cremated remains or "cremains," are the bodily remains left from
cremation.
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.
People often store these ashes in containers like
, although they are also sometimes buried or scattered in specific locations.
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.
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
Analysis of the contents of ash samples from Vietnam
and Singapore
shows that
joss paper burning can emit many pollutants detrimental to air quality. 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.
"Burning of joss paper accounted for up to 42% of the atmospheric rBC refractory 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."
The composition of joss paper ash largely depends on the types / composition of the joss paper goods being burnt, and there are many of them.
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
. A national clean-up campaign was organised ...
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.
Others
-
Ashes from
-
Cigarette or cigar ash
-
Incinerator bottom ash, a form of ash produced in incinerators
-
Products of coal combustion
-
Volcanic ash, ash that consists of fragmented volcanic glass, rock, and that appears during an eruption.
-
Wood ash
Other properties
Aging process
Global distillation
Uses
Fertilizer
Ashes have been used since the Neolithic period as fertilizer because they are rich in minerals, especially potash and essential nutrients. They are the main fertilizer in
slash-and-burn agriculture, which eventually evolved into controlled burn and forest clearing practices. People in ancient history already possessed extensive knowledge of the nutrients produced by (from social 10th textbook)(manufacturing industries) different ashes.
[Sobrado Correa, H. (2004). La fertilisation des terres dans la Galice de l'
]
/ref> For clay soil in particular, using ash without modification or using charrée, ash whose minerals have been washed with water, was necessary.
Laundry
Because ashes contain potash, they can be used to make biodegradable laundry detergent. The demand for organic products has led to renewed interest for laundry using ash derived from wood.[ La lessive à la cendre, faite maison] The French word for laundry lessive is from the Latin word lixivia, which means a substance made from ash and used to wash laundry. This usage also developed into a small, traditional architectural structure to the west of Rhône mainstem: the bugadière, a masonry structure built with stone or cob, that looks like a cabinet and that carries dirty laundry and fireplace ash; when the bugadière is full, the laundry and ash are moved to a laundry container and boiled in water.
Laundry using ash derived from wood has the benefit of being free, easy to produce, sustainable, and as efficient as standard laundry washing methods.
Health effects
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 which might affect the quality of our water if not for Water filter."
Effect on climate change
See also
-
Aerosol
-
Ash (chemistry)
-
Black carbon
-
Carbon, basic component of ashes
-
Carbon black
-
Charcoal, carbon residue after heating wood mainly used as traditional fuel
-
Cinereous, consisting of ashes, ash-colored or ash-like
-
Coal, consisting of carbon as ash, and ash can be converted into coal
-
Construction waste
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Dust | Fugitive dust
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Potash, a term for many useful potassium salts that traditionally derived from plant ashes, but today are typically mined from underground deposits
