Title of Invention

A PROCESS FOR THE PRODUCTION OF HUMI GOLD (A SALT OF HUMIC ACID)

Abstract

It is well-established fact that the humus matter, arising from chemical and biological degradation of plant and animal residues in soil serves to stimulate the plant growth. Lignite is rich in humus matter. This invention provides an improved and effcient method for extraction of potassium humate from lignite. The mined out lignite is air-dried to a moisture content of 15- 20 % and crushed to less than 8 mm. Crushed lignite is mixed with Potassium hydroxide solution of concentration 1 to 5% and allowed to react at 60 to 100° C for a period of 2 to 8 hours and the pH of the reaction mixture is maintained around 8 to 12. The digested material is transferred to settling tank to separate the un-reacted material. The clear solution obtained will be made to required concentration of 2 to 4%, and then pH is adjusted to 8 to 10. This solution is further dried in electrically heated tray dryer to obtain the final solid product. The product thus obtained is potassium humate flakes, which contains 50 to 55 % humic acid- fully soluble in water.

Full Text

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 ■ • 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 ). : * 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 '» 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. The extracted liquid is further concentrated in a shell and tube evaporator to get a concentration of about 8-10 % at a temperature of about 150°C. The concentrated solution is transferred to Electrically heated / Steam heated tray-dryer at 100 to 150°C. Vacuum system is maintained continuously to evacuate the vapor to get the desired dried product which contains a residual moisture about 8-20%. The product obtained is black lustrous and fully water-soluble flake containing 50 to 55 % Humic acid content. By grinding and sieving the required size (less than 5mm) of the product is obtained. ADVANTAGES: Humic substances impart a dark brown colour to the soil that influences the warmth of the soil. The soil structure and the stability of the structure are promoted by the richness of the humus in the soil. Water retentivity and air-water relationship in the soil are governed by the amount of humus in the soil. Humus serves as a reservoir of plant nutrients and it also prevents the leaching of plant nutrients because of its high cation exchange capacity. A soil rich in humus is known to have good buffering capacity so as to prevent sudden fluctuations in soil pH. Humus is known to form chelate complexes with trace element nutrients such as iron and zinc which are rendered more easily available to the crop plants. As the humus undergoes mineralisation, organic forms of nitrogen, phosphorus and sulphur turn into inorganic forms which are utilized by the crop.plants. EXAMPLES: The product potassium humate has been tested in the test fields of CARD and" the results obtained in terms of yield for the crops, groundnut, maize and bhendi are given in the table below. Further trials were also conducted with 75% of recommended dose of NPK and this product for crops, groundnut. The Table-1 enclosed shows the results in the yield and benefit accorded. We claim: 1. A process for extraction of humic acid from Lignite which comprises the steps of, (a) The Raw Lignite is air dried and crashed to less than 8mm by conventional method and that material is added to Potassium hydroxide solution 1 to 5 % weight by weight prepared in the reaction vessel and mixed to get a uniform suspension at 25 to 30 revolutions per minute, (b) Heating the Mixture prepared as in step (a) to a temperature of 60 to 100° C by conventional method and maintaining the temperature for further duration of 2 to 8 hours in the reaction vessel to solubilise the humic acid and the pH of the solution is maintained continuously around 8 to 12, (c) Transferring the solution obtained in step (b) to a settling tank to Separate any un-reacted material by conventional method and transferring the clear liquid to the storage tank, (d)The clear liquid obtained in step (c) is a liquid with 2 to 4 % potassium humate and pH 8 to 10, and the same is dried by conventional method to get solid material, which contains 50 to 55 % humic acid, 2. Process asclaimed in claim 1 wherein the Potassium Hydroxide solution of concentration 1-2 percent weight by weight is used in step 1(a). 3. Process as claimed in claim 1 wherein lignite of size less than 8 mm with moisture content of 15 to 20 % is added in step 1(a). 4. Process as claimed in claim 1 wherein heating is by steam heating, the temperature to be maintained is 80 to 90° C and duration is 4 to 5 hours. 5. Process as claimed in claim 1 wherein settling is by gravity and drying is in electrically heated tray dryer at a temperature of 100 to 120° C to get solid material. 6. The process as claimed in claim 1 wherein approximately 20 kg of Potassium Hydroxide flakes is added to about 2000 lit. of water and mixed well to get a clear solution. To that solution about 200 kg of air- dried lignite with moisture content less than 20 % is added. Heated to BO 85° C by external steam heating and maintained at that temperature for a further duration of 4 hours. The digested material is allowed to settle in the settling tank to separate any un-reacted material. The clear liquid is stored in storage tank containing 2 to 4% potassium humate. The clear liquid is dried in electrically heated tray dryer to get solid Potassium humate which contains 50 to 55 % humic acid. 7. Process for extraction of humic acid from lignite is substantially as herein described and exemplified.

Documents:

626-mas-2000-abstract.pdf

626-mas-2000-assignement.pdf

626-mas-2000-claims filed.pdf

626-mas-2000-correspondnece-others.pdf

626-mas-2000-correspondnece-po.pdf

626-mas-2000-description(complete) filed.pdf

626-mas-2000-description(complete) granted.pdf

626-mas-2000-form 1.pdf

626-mas-2000-form 26.pdf

626-mas-2000-other documents.pdf