Ash in the context of Incinerator bottom ash

In 79 AD, Mount Vesuvius, a stratovolcano located in the modern-day region of Campania, erupted, causing one of the deadliest eruptions in history. Vesuvius violently ejected a cloud of super-heated tephra and gases to a height of 33 km (21 mi), ejecting molten rock, pulverized pumice and hot ash at 1.5 million tons per second, ultimately releasing 100,000 times the thermal energy of the atomic bombings of Hiroshima and Nagasaki. The event gives its name to the Vesuvian type of volcanic eruption, characterised by columns of hot gases and ash reaching the stratosphere, although the event also included pyroclastic flows associated with Peléan eruptions.

The event destroyed several Roman towns and settlements in the area. Pompeii and Herculaneum, obliterated and buried underneath massive pyroclastic surges and ashfall deposits, are the most famous examples. Archaeological excavations have revealed much of the towns and the lives of the inhabitants, leading to the area becoming Vesuvius National Park and a UNESCO World Heritage Site.

Baking is a method of preparing food that uses dry heat, typically in an oven, but it can also be done in hot ashes, or on hot stones. Bread is the most commonly baked item, but many other types of food can also be baked. Heat is gradually transferred from the surface of cakes, cookies, and pieces of bread to their center, typically conducted at elevated temperatures surpassing 300 °F (148 °C). ( Dry heat cooking imparts a distinctive richness to foods through the processes of caramelization and surface browning. As heat travels through, it transforms batters and doughs into baked goods and more with a firm dry crust and a softer center. Baking can be combined with grilling to produce a hybrid barbecue variant by using both methods simultaneously, or one after the other. Baking is related to barbecuing because the concept of the masonry oven is similar to that of a smoke pit.

Baking has traditionally been performed at home for day-to-day meals and in bakeries and restaurants for local consumption. When production was industrialized, baking was automated by machines in large factories. The art of baking remains a fundamental skill and is important for nutrition, as baked goods, especially bread, are a common and important food, both from an economic and cultural point of view. A person who prepares baked goods as a profession is called a baker.

A fire whirl, fire devil or fire tornado is a whirlwind induced by a fire and often (at least partially) composed of flame or ash. These start with a whirl of wind, often made visible by smoke, and may occur when intense rising heat and turbulent wind conditions combine to form whirling eddies of air. These eddies can contract to a tornado-like vortex that sucks in debris and combustible gases.

The phenomenon is sometimes labeled a fire tornado, firenado, fire swirl, or fire twister, but these terms usually refer to a separate phenomenon where a fire has such intensity that it generates an actual tornado. Fire whirls are not usually classifiable as tornadoes as the vortex in most cases does not extend from the surface to cloud base. Also, even in such cases, those fire whirls very rarely are classic tornadoes, as their vorticity derives from surface winds and heat-induced lifting, rather than from a tornadic mesocyclone aloft.

The phoenix (sometimes spelled phenix in American English; see spelling differences) is a legendary immortal bird that cyclically regenerates or is otherwise born again. Originating in Greek mythology, it has analogs in many cultures, such as Egyptian and Persian mythology. Associated with the sun, a phoenix obtains new life by rising from the ashes of its predecessor. Some legends say it dies in a show of flames and combustion, while others say that it simply burns to death and decomposes before being born again. In the Motif-Index of Folk-Literature, a tool used by folklorists, the phoenix is classified as motif B32.

The origin of the phoenix has been attributed to Ancient Egypt by Herodotus and later 19th-century scholars, but other scholars think the Egyptian texts may have been influenced by classical folklore. Over time, the phoenix motif spread and gained a variety of new associations; Herodotus, Lucan, Pliny the Elder, Pope Clement I, Lactantius, Ovid, and Isidore of Seville are among those who have contributed to the retelling and transmission of the phoenix motif. Over time, extending beyond its origins, the phoenix could variously "symbolize renewal in general as well as the sun, time, the Roman Empire, metempsychosis, consecration, resurrection, life in the heavenly Paradise, Christ, Mary, virginity, the exceptional man, and certain aspects of Christian life". Some scholars have claimed that the poem De ave phoenice may present the mythological phoenix motif as a symbol of Christ's resurrection.

Slash-and-burn agriculture is a form of shifting cultivation in agriculture that involves the cutting and burning of plants in a forest or woodland to create a field called a swidden. The process begins with cutting down the trees and woody plants in a given area. The downed vegetation, or "slash", is left out to dry, usually right before the rainiest part of the year. The biomass is then burned, resulting in a nutrient-rich layer of ash which increases soil fertility and temporarily eliminates weeds and pests. After about three to five years, the plot's productivity decreases due to depletion of nutrients along with weed and pest invasion, causing farmers to abandon the plot and move to a new area. The time it takes for a swidden to recover depends on the location and can be as little as five years to more than twenty years, after which the plot can be slashed and burned again, repeating the cycle. In Bangladesh and India, the practice is known as jhum or jhoom.

A rough estimate says that about 200–300 million people worldwide use slash-and-burn agricultural techniques. Slash-and-burn causes deforestation and habitat loss. Ashes from the burnt trees help farmers by providing nutrients for the soil. While slash-and-burn agriculture has historically been sustainable in areas with low population density, increasing populations have accelerated the rate of deforestation, depleting the Earth's carbon reservoirs.

Bulk material handling is an engineering field that is centered on the design of equipment used for the handling of dry materials. Bulk materials are those dry materials which are powdery, granular or lumpy in nature, and are stored in heaps. Examples of bulk materials are minerals, ores, coal, cereals, woodchips, sand, gravel, clay, cement, ash, salt, chemicals, grain, sugar, flour and stone in loose bulk form. It can also relate to the handling of mixed wastes. Bulk material handling is an essential part of all industries that process bulk ingredients, including: food, beverage, confectionery, pet food, animal feed, tobacco, chemical, agricultural, polymer, plastic, rubber, ceramic, electronics, metals, minerals, paint, paper, textiles and more.

Major characteristics of bulk materials, so far as their handling is concerned, are: lump size, bulk weight (density), moisture content, flowability (particle mobility), angle of repose, abrasiveness and corrosivity, among others.

A brickfield is a field or other open site where bricks are made. Land may be leased by an owner to a brickmaster, by whom the manufacture of bricks may be conducted.Historically, the topsoil was typically removed and the clay beneath was stripped and mixed with chalk and ash to make bricks.

Subsequently, the field (if not too damaged ecologically) could be used for horticulture. In Kent such fields were often planted with fruit trees. Brickfields were mainly created from 1770 to 1881, when a new shaly clay was discovered at Fletton. This period coincided with the housing and railway boom in London and cheap river-transport in Thames sailing barges. Brickfields existed elsewhere, but often the clay layer was deeper or there was no chalk nearby. In modern times bricks are made at a brickworks.

A fire pan is a pan for holding or conveying fire. The use of a fire pan reduces the impact to the ground, vegetation and rocks, and its compact size results in the burning of less wood. Fire pans also allow users to easily burn their accumulated garbage, although the best practice is to only burn paper. Combustible items will be reduced to ash. A fire pan user can leave no trace of the fire, as the ashes can be collected and buried.

A hexamine fuel tablet (or heat tablet, Esbit) is a form of solid fuel in tablet form. The tablets burn smokelessly, have a high energy density, do not liquefy while burning and leave no ashes. Invented in 1936 in Murrhardt, Germany, the main component is hexamine, which was discovered by Aleksandr Butlerov in 1859. Some fuel tablets use 1,3,5-trioxane as another ingredient.

Esbit is a genericized trademark that people often use to refer to similar products made by other companies. In most countries from the former Soviet bloc, fuel tablets are called dry fuel.

In a volcanic eruption, lava, volcanic bombs, ash, and various gases are expelled from a volcanic vent and fissure. While many eruptions only pose dangers to the immediately surrounding area, Earth's largest eruptions can have a major regional or even global impact, with some affecting the climate and contributing to mass extinctions. Volcanic eruptions can generally be characterized as either explosive eruptions, sudden ejections of rock and ash, or effusive eruptions, relatively gentle outpourings of lava. A separate list is given below for each type.

There have probably been many such eruptions during Earth's history beyond those shown in these lists. However erosion and plate tectonics have taken their toll, and many eruptions have not left enough evidence for geologists to establish their size. Even for the eruptions listed here, estimates of the volume erupted can be subject to considerable uncertainty.

Crucible steel is steel made by melting pig iron, cast iron, iron, and sometimes steel, often along with sand, glass, ashes, and other fluxes, in a crucible. Crucible steel was first developed in the middle of the 1st millennium BCE in Southern India and Sri Lanka using the wootz process.

In ancient times, it was not possible to produce very high temperatures with charcoal or coal fires, which were required to melt iron or steel. However, pig iron, having a higher carbon content and thus a lower melting point, could be melted, and by soaking wrought iron or steel in the liquid pig-iron for a long time, the carbon content of the pig iron could be reduced as it slowly diffused into the iron, turning both into steel. Crucible steel of this type was produced in South and Central Asia during the medieval era.