Ash or ashes are the solid remnants of

fire Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction products. At a certain point in the combustion reaction, called the ignition point, flames a ...

s. Specifically, ''ash'' refers to all non-

aqueous An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be re ...

, non-

gas Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...

eous residues that remain after something burns. In

analytical chemistry Analytical chemistry studies and uses instruments and methods to separate, identify, and quantify matter. In practice, separation, identification or quantification may constitute the entire analysis or be combined with another method. Separati ...

, to analyse the mineral and metal content of

chemical sample In general, a sample is a limited quantity of something which is intended to be similar to and represent a larger amount of that thing(s). The things could be countable objects such as individual items available as units for sale, or an uncou ...

ash Ash or ashes are the solid remnants of fires. 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-

eous, non- liquid residue after complete combustion. Ashes as the end product of

incomplete combustion Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combusti ...

are mostly

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

, but usually still contain an amount of

combustible A combustible material is something that can burn (i.e., ''combust'') in air. A combustible material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort and a flammable mat ...

organic or other oxidizable residues. The best-known type of ash is

wood ash 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 presen ...

, as a product of wood combustion in

campfire A campfire is a fire at a campsite that provides light and warmth, and heat for cooking. It can also serve as a beacon, and an insect and predator deterrent. Established campgrounds often provide a stone or steel fire ring for safety. Campfires ...

fireplace A fireplace or hearth is a structure made of brick, stone or metal designed to contain a fire. Fireplaces are used for the relaxing ambiance they create and for heating a room. Modern fireplaces vary in heat efficiency, depending on the design ...

s, 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 Soil, also commonly referred to as earth or dirt Dirt is an unclean matter, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty. Common types of dirt include: * Debri ...

Soil fertility, 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). The World Health Organization recommends ash or sand as alternative when soap is not available.WHO 2014: Water Sanitation Health. How can personal hygiene be maintained in difficult circumstances? Accessed Oct. 201

/ref>

Natural occurrence

Ash occurs naturally from any

that burns vegetation, and may disperse in the soil to Soil fertility, fertilise it, or clump under it for long enough to Carbonisation, carbonise into coal.

Specific types

* Wood ash * Products of coal combustion ** Bottom ash ** Fly ash * Cigarette or cigar ash * Incinerator bottom ash, a form of ash produced in incinerators * Ashes and dried bone fragments, or "cremains", left from cremation * Volcanic ash, ash that consists of fragmented volcanic glass, glass, rock, and mineral, minerals that appears during an Types of volcanic eruptions, eruption.

References

{{Authority control Combustion

Natural occurrence

Specific types

See also

References