Leonardite
Encyclopedia
Leonardite is a soft waxy, black or brown, shiny, vitreous mineraloid
that is easily soluble in alkaline solutions. It is an oxidation product of lignite
, associated with near-surface mining
. It is a rich source of humic acid
(up to 90%) and is used as a soil conditioner
, as a stabilizer for ion-exchange resins in water treatment, in the remediation of polluted
environments and as a drilling
additive. It was named for Dr. A.G. Leonard, first director of the North Dakota
Geological Survey
, in recognition of his work on these deposits.
, Canada
, in Achlada
and Zeli, Greece
, in Turkey
and in Bacchus Marsh, Australia
.
on the organic fertilising aspect of brown coal.
.
when quebracho became difficult to obtain. It has very good temperature stability and prevents solidification of lime muds near 150°C.
Mineraloid
A mineraloid is a mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amorphous glass and not a crystal. Jet is derived from decaying wood under...
that is easily soluble in alkaline solutions. It is an oxidation product of lignite
Lignite
Lignite, often referred to as brown coal, or Rosebud coal by Northern Pacific Railroad,is a soft brown fuel with characteristics that put it somewhere between coal and peat...
, associated with near-surface mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
. It is a rich source of humic acid
Humic acid
Humic acid is a principal component of humic substances, which are the major organic constituents of soil , peat, coal, many upland streams, dystrophic lakes, and ocean water. It is produced by biodegradation of dead organic matter...
(up to 90%) and is used as a soil conditioner
Soil conditioner
A soil conditioner, also called a soil amendment, is a material added to soil to improve plant growth and health. A conditioner or a combination of conditioners corrects the soil's deficiencies in structure and-or nutrients.-Purpose:...
, as a stabilizer for ion-exchange resins in water treatment, in the remediation of polluted
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
environments and as a drilling
Well drilling
Well drilling is the process of drilling a hole in the ground for the extraction of a natural resource such as ground water, natural gas, or petroleum...
additive. It was named for Dr. A.G. Leonard, first director of the North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
Geological Survey
Geological survey
The term geological survey can be used to describe both the conduct of a survey for geological purposes and an institution holding geological information....
, in recognition of his work on these deposits.
Formation
Leonardite is found associated with near surface lignite deposits. They are thought to have been formed by the oxidation of the lignite, an interpretation supported by chemical analysis of leonardite compared to lignite.Occurrence
Leonardite was first described from North Dakota and is found associated with virtually all the lignite deposits in the state. Leonardite has also been described world-wide from deposits of lignite or sub-bituminous coals e.g. in AlbertaAlberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, in Achlada
Achlada
Achlada is a village in the Florina peripheral unit, Greece. It was previously known as Κρουσοράτη or Κρουσουράτη until it was renamed by Greek authorities in 1926....
and Zeli, Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
, in Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
and in Bacchus Marsh, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
Soil conditioner
It is used to condition soils either by applying it directly to the land, or by providing a source of humic acid for application. The carbon geosequestration potential of Leonardite, particularly to rapidly accelerate microbial action to lock up and retain carbon in soils, provides the basis for extensive research in VictoriaVictoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
on the organic fertilising aspect of brown coal.
Remediation of polluted soils
Leonardite can be added directly to soils to reduce the take-up of metals by plants in contaminated ground, particularly when combined with compostCompost
Compost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming. At its most essential, the process of composting requires simply piling up waste outdoors and waiting for the materials to break down from anywhere...
.
Drilling additive
Leonardite is used to stabilise and thin fluids used in the drilling of wells for hydrocarbon exploration/extraction and geothermal drilling. It was first employed extensively during World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
when quebracho became difficult to obtain. It has very good temperature stability and prevents solidification of lime muds near 150°C.