Leonardite is a subtype of brown coal. It is an organic product consisting of
substances useful for plants and living organisms. The basic
components here are humic and fulvic acids. They are formed from
plant and animal tissues by exposure to chemical and biological
processes resulting in humus formation. Leonardite grinding allows
obtaining highly concentrated organic fertilizers which are an
alternative to chemical products.
Compared to other humic substances, leonardite is distinguished by
a high biological activity in the molecular structure which is
associated with a large molecular weight of humic acids obtained
from this substance.
Leonardite application
Leonardite is a substance in which essential high-molecular-weight
organic components are concentrated and contribute to improvement
of soil microflora and stimulation of microorganisms’ activity in
soil. Humic substances saturate plants with useful components,
affect their growth, development, germination ability, and
immunity. They reduce the amount of pesticides and heavy metals in
soil. Humic acids have a detoxifying effect on substrates. In
addition, humic preparations increase the assimilability of useful
substances in living organisms.
Owing to such properties of leonardite products, they are used in
the following fields:
Replenishment of useful substances stock in humus, restoration of
microflora, normalization of soil acidity and ability to retain
moisture.
Owing to humic acids, plants receive substances for active growth,
development, resistance to diseases, pests, drought, and cold. They
grow faster, produce high-quality crops, and extend the shelf life
of fruit and vegetables.
Increasing the resistance to adverse weather conditions,
strengthening and activating the ability to germinate.
Neutralization of pesticides, radionuclides, heavy metals,
reduction of soil toxicity.
- Supplementary feeding of animals, poultry, and fish
It is a biologically active supplement in livestock, fish, and
poultry farming which contributes to increasing the nutritional
capacity of feedstuff, assimilation of useful elements and
substances by living organisms.
In addition, leonardite is used for production of fuel briquettes.
It is also used in the field of water treatment when drilling the
oil wells.
In order to obtain a high-quality product used in these fields, it
is important to activate the substance properly and efficiently.
Leonardite grinding, obtaining humic substances by chemical
extraction, and other processing methods shall ensure a high yield
of the product with minimum impact on its organic structure. It
shall be environmentally safe.
Conventional methods for leonardite processing
The most common methods for obtaining humic preparations from
leonardite involve chemical extraction by leaching. At the same
time, a variety of technologies make it possible to obtain ballast
and ballastless products. The former are considered to be
fertilizers, and the latter are considered to be humic
preparations. Fertilizers are distinguished by a considerable
remediating effect on soils, they activate the mobility of
phosphorus compounds, improve the substrate structure, the
hydrophysical properties, etc. The preparations are mainly used for
foliar dressing and seed processing, because they have no
significant effect on soil properties.
In general, a great number of methods for leonardite processing are
practiced in order to obtain fertilizers and preparations:
- leonardite grinding;
- oxidation using chemical agents;
- leaching technology;
- acidic precipitation;
- electrochemical processing;
- raw stuff settling;
- centrifugation and filtration;
- thickening, drying, and evaporation.
This diversity is determined by the need to obtain products with
different properties to be used for various purposes. Each of the
technologies is mainly used for production of a specific type of
fertilizers or preparations — suspension gels, fulvic acids, humic
biologically active preparations. The listed leonardite processing
technologies are combined for manufacturing certain products. For
example, a popular method for manufacturing humic products involves
initial raw stuff grinding, further oxidation, leaching, and other
processes.
Basically, the listed technologies are distinguished by their
complexity, duration of operations, and costliness due to high
energy consumption and the use of chemical agents. In addition, it
is not always possible to obtain a sufficiently high yield of the
product, or it is partially subjected to alteration because of
using the chemical agents, temperatures, and pressure.
