INTRODUCTION;
Humic substances arise from chemical and biological degradation of plant and animal residues and from the synthetic activities of microorganisms. They are dark colored, acidic, predominantly aromatic, hydrophilic,
chemically complex and polyelectrolyte material. The molecular weight ranging from a few hundreds to several thousands.
On the basis of solubility in acids and bases, humic substances are differentiated into the Humins, Humic and Fulvic acids. These forms are in a state of dynamic equilibrium. Humins are more condensed form of humic acid, even though there may be a few structural differences among them. Humins are highly complex forms in which they are known to help the soil particles to form aggregates. The Fulvic acids are the simplest forms, which are known to be absorbed by plants. Beneficial effects of Fulvicchelate
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complexes on crop plants have been well established. Humic acids are intermediate in complexity between humins and fulvic acids. But their molecular weights have a wide range. Humic acids with high molecular weight are not known to be assimilable, while the low molecular weight humic acids are said to be assimilable by the plant. Beneficial, physiological effects of humic acids on several crops have been observed under nutrient solution culture, which is subject to rapid fluctuations such as pH and nutrients imbalance. Hence such favorable effects of humic acids on crop appeared to be more indirect than direct. Humin, the alkali, insoluble part of organic matter represents the high molecular fraction of humic substances. Humic acids and fulvic acids are the soluble part of organic matter.

PRIOR ART AND PRESENT ART;
The history of investigation on humic matters could date back to 9th century. Initial data on humus formation firom plant and animal residues are found in the works of Wallerius and Lomonosw in 1761-63 and the effect of humus matter on yields in Komows works (1782) Achard ( 1786 ) was probably the first Scientist v/bo extracted humic matters from peat. Saussre found out for the first time that humic matters mainly consisted of carbon and to a lesser extent hydrogen and oxygen.
Systematic investigations of humic matters were carried out by Spenyel (1825-1837 ) and Beizellus (1833 ID 1839 ). Development of scientific knowledge on the role of humic matters was initiated by Liebig (1840 ).
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Grandeau (1872) developed a new thecny of organic mineral plant nourishment and determined the importance of capability of exchange and soiption of humic matters. Significant contributions to the knowledge of chemistry of humic matter in peat was made by Fischer and Schrader as well as by Fuchs by study of functional groups and humic matters decomposition products. But production and application of humic matters for agricultural purposes have not been made till the beginning of this century. Utilization of coal and beneficiated products from these has been investigated during the past sixty years. Both coal and lignite contain humic matter and lignite is richer in this respect. Earlier, crude coal or lignite was used as such as fertilizers, But in view of the slow activity of the humus matter and also the large

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quantity required per hectare of land (10 to 20 t/ha) this type of application was abandoned long ago. Subsequently enrichment of coal by mixing with ammonia solution, ammonium acetate, super phosphate, phosphoric acid, potassium salts etc. had been used and the nutrient values of the product were enriched to about 2.5% nitrogen, 1.3% phosphorus pentoxide, 2.1% potassium oxide and the total organic matter at 55%. In France ,a number of lignite based fertilizers is produced and utilized. For many years some 2,50,0001 / year of lignite based fertilizers have been produced out of lignite imported from West Germany. In Yugoslavia, a technology was developed for the production of organic fertilizers out of lignite by adding superphosphate and ammonia to coal. But obtaining of higher amount of nutrient, particularly nitrogen from Ugnite was attempted in USA by the oxidation of coal / lignite by nitric acid and neutralizing the product with ammonia. The product, ammonium nitro humate fertilizer contained 8-14% nitrogen according to the degree of purification. Oxidation and ammoniation of naturally occurring leonardite and lignite also has given a nitrogen content of 8%. Investigations on these lines have been conducted in India also.
Traditional agriculture based on organic manure, is not however target-oriented and in addition organic manure are not available in adequate quantities. It is well known that soil should have certain inherent properties that will help it adapt and assimilate the input nutrients and release the same for plant growth. Organic matter is most important tool for such an ,activity. Thus humus matter in soil serves to stimulate the plant growth. These conditions have necessitated the application of humus mater extracted from coal, peat and lignite.

Investigations on the possibilities of utilizing coal, peat lignite and younger brown coals and products derived from it as fertilizer were carryout for the past 80 years. In Yugoslavia, academicians, V.Vouck tested right back in 1928 the action of some of the countries-coals on the pot cultures he operated on. In the studies he determined a favorable action of coal. The requirement of coal per hectare was as high as 10 tonnes in order to obtain a favorable effect. It was latter abandoned because of the high handling cost. In order to reduce the quantily, coal / lignite was mixed with ammonium solution, ammoniates, super phosphates, phosphoric acids, various other phosphates, potassium salts etc.. Such coal based fertilizers were developed in Germany, USSR, France and Yugoslavia. In all the above processes there was no change in the structure of coal / lignite.
One group of Engineers attempted to bind a higher amount of nitrogen to coal / lignite by oxidation process with nitric acid and the subsequent. neutralization with liquor ammonia. Acid action primarily increases the content of humic acid by destruction of existence of humates. The excess quantity of nitric acid caused, nitro humic acid. In some cases the oxidation was carried out with air and hydrogen peroxide.
EXPERIMENTS IN CARD/NLC:
The extraction of humic acid was done by treating lignite with a base preferably NaOH and neutralization with HCl. It is then dissolved in KOH to get potassium humate, which is one of the soluble forms of humic acid. The above process proved commercially not viable because it requires NaOH and KOH besides some pollution problem due to NaCl and HCl.

The invention provides an improved and efficient method for making potassium humate from lignite as raw material. The mined out Lignite having moisture of 40-55% is taken and air dried to reduce the moisture level to 15-20 % and used as raw material. Then it is pulverized to less than 8 mm using a Pulveriser. 5 to 30 % of pulverized lignite is mixed with 70 to 95 % of solution containing 1 to 5 % of Potassium hydroxide. The contents are allowed to react at a range of temperature 60-100° C, for about a period of 2 to 6 hours with continuous stirring or as and when required, so that the material is in suspension. The required process temperature is to be maintained by external steam heating. The pH (8 to 12) of the medium is to be adjusted continuously during the process, to obtain desirable extraction. After the digestion period the solution is to be agitated for uniform dispersion for about 2 to 3 hours. Then it is transferred to a settling tank for separation of final sludge. After 24 hours the clear solution obtained is made up to required concentration of 2-4 %. After checking pH and correction (8 to 10.5) it is transferred to main storage tank. The un-reacted lignite portion is discarded.