UCHRIN, János (Mezei Mária u. 9, Budakeszi, H-2092, HU)
UCHRIN, Jánosné (Mezei Mária u. 9, Budakeszi, H-2092, HU)
UCHRIN, János (Mezei Mária u. 9, Budakeszi, H-2092, HU)
| Claims 1. An improved process for the preparation of a humate-containing composition with an enhanced yield of water-soluble lower molecular humate substances which have higher concentration of oxygen-containing functional groups, from a humic-containing starting material by a first mechanochemical treatment comprising hydrolysis and depolymerization of the powdered and moisturized starting material in the presence of an alkali under mechanical effect characterized in that the first mechanochemical treatment, carried out in the presence of 5 to 25 % by weight of alkali based on the total amount of the moisturized starting material in a ball mill with balls accelerating at from 60 to 180 m/s2, is supplemented with a second mechanochemical treatment comprising oxidation and depolymerization by an ozone- containing gaseous oxidant under mechanical effect, simultaneously with or subsequently to the first mechanochemical treatment. 2. The process according to claim 1, characterized in that the second mechanochemical treatment is carried out subsequently to the first mechanochemical treatment. 3. The process according to claim 1, characterized in that the first and the second mechanochemical treatment are carried out simultaneously in planetary vibration ball mill with balls accelerating at from 60 to 180 m/s2 in a period of from 0.5 to 2.0 minutes. 4. The process according to claim I3 characterized in that the concentration of ozone in the gaseous oxidant is between 0.1 and 3.0 percent by weight based on the weight of the staring material. 5. The process according to claim 2, characterized in that the second mechanochemical treatment is carried out - in planetary vibration ball mill with balls accelerating at from 9.8 to 60 m/s in a period of from 0.5 to 2.0 minutes, or - in impeller mill and in breaking mill with impeller blades rotating at a speed from 10 to 120 m/s in a period of from 0.2 to 2.0 minutes, or - in pneumatic and vortex mill with flow rate ranging from 10 to 120 m/s in a period of from 0.2 to 2.0 minutes. 6. The process of claim 2, characterized in that ozone is used as a blend with air, ozone content of the gas mixture is 0.1 to 2.0 %, preferably 0.9 % by volume, at a temperature of from 0 to 60 0C and at a degree of humidity ensuring more than equimolar ratio of water to ozone content. 7. The process according to claim 1 or 2, characterized in that the humic-containing starting material is selected from the group consisting of brown coal, peat, oil shale and sapropel or a mixture thereof. 8. A humate-containing composition having enhanced biological activity obtainable by the process according to any one of claims 1 to 7. 9. Use of the humate-containing composition according to claim 8 in farm breeding as fertility and growth enhancer feed additive; in plant growing as seed-dressing or watering additive for increasing germination, growth of above-ground shoots and rooting and enhancing plant's fertility; in environment protection for land recultivation, amelioration of soils and for reconstruction of heavy metal polluted lands and water resources; and in oil and gas exploitation industry as stabilizing component of drilling solutions as well. 10. A humate-containing composition according to claim 8 for use in combination with a nitrogen fertilizer (either solid or liquid one) in plant growing to improve plant growth and production potential of soils, and to increase efficiency of the fertilizer. |
Field of the invention
The present invention relates to an improved process for the preparation of a composition with enhanced content of biologically useful, water-soluble humate compounds. The composition obtained by the process of the present invention can be used in plant growing, farm breeding as biologically active agent; in environment protection for land recultivation and for reconstruction of heavy metal polluted lands and water resources; and in oil and gas exploitation as well.
Background of the invention
Water-soluble, high-molecule polyphenolic compounds (so called humic acids and their salts, humates) can be recovered from natural insoluble humic compounds. These humic acids and humates have significant commercial value, as they can be used in numerous fields. The quality of natural based humate compounds can be measured by the water-soluble fraction contained therein. Water-solubility of humates depends on the size of humate polymer molecules and on the presence of oxygen-containing groups (primarily phenolic - OH and acidic -COOH groups) in the molecule.
Brown coal comprises 30-90 percent by weight of humic acids, peat comprises 30-70 percent by weight of humic acids, and oil shale and sapropel comprise 40 percent by weight of the same. Further chemical components of brown coal include amorphous carbon, bitumens, inorganic materials (ash), while in the case of peat such components include cellulosic compounds, lipids and inorganic materials.
Humic acids are complex mixtures of high molecular polyphenolic compounds having 1,000,000 to 1,000 Da molecular mass. The lowest (below 10,000 Da) molecular weight fraction of humic acids is called fulvic acid [Stott D.E. Martin J.P.: Synthesis and degradation of natural and synthetic humic material in soils, in "Humic substances in soil and crop sciences: selected readings", American Society of Agronomy, Soil Science of America. Madison, p. 37-63 (1990)]. Mixtures of humic and fulvic acids can be separated by their solubility.
In general, by heating brown coal in steam chamber at 130 0 C with concentrated alkali solution a mixture of humic salts (humates) can be obtained. By the alkali treatment humic compounds are depolymerized as a result of hydrolysis of etheric bonds and formation of humic acids. Alkali, at the same time, neutralizes the acidic groups of humic acids, thereby generating water-soluble humic salts (humates). Addition of an acid to a solution of humates results in humic and fulvic acids in the form of dark brown precipitate.
Humic compounds are widely used, primarily in agricultural production and in environment protection [Kim H. Tan. Humic matter in soil and the environment. Principles and controversies, New York, Marcell Dekker, Inc. Chapt 8 and 9 (2003)].
As described above, the properties of humic acids essentially depend on two parameters: the -size of the polymeric molecule and the presence of oxygen-containing phenolic and acidic groups in the molecule. For example, high molecule humic acids can not penetrate through the cell membrane of plants, so they don't affect directly plant's growth. For activation, their macromolecules must be broken down to 10,000 Da sized units [F. Pospisil, M. Cvirkova, M. Grubcova. Growth and differentiation of plants. Moscow, Nauka, 1981, 150-162 (in Russian)]. Increasing the amount of oxygen-containing groups leads to more hydrophilic nature and increased water-solubility of the polymer [Stevenson FJ.: Humus chemistry. Genesis, composition, reactions. John Wiley and Sons (1982)].
Various chemical substances can be used for the fragmentation (i.e. depolymerization) of insoluble humic compounds. In the huge molecule of humin, polyphenol parts of humic acids are linked to the other components via polysaccharides, lipids and etheric ,,carbon- oxygen-carbon" (-C-O-C-) bonds. These bonds are broken by hydrolysis in alkaline, acidic, oxidative and reducing media. Therefore, in various methods for producing humate compositions, alkali treatment is used for the depolymerization of humic compound molecules and for the preparation of well-soluble humic salt compounds (i.e. humates).
If humic acids are comprised of extremely large molecules in the natural starting material, ,,carbon-carbon" bonds (-C-C- and -C=C-) must be ,,destructed" within the humic acid. Basic or acidic hydrolysis of such bonds is virtually impossible, thus oxidative hydrolysis must be used.
In the presence of oxidative agent not only depolymerization reactions take place but oxidation of polymer molecules without decomposition of the polymer chain. In such cases, oxygen-containing (phenolic -OH, ketone i.e. -C(=O)- and acidic -COOH) groups appear in the polymer. The change in the composition of humate macromolecule significantly affects its properties. In particular, this improves the solubility of the macromolecule. The humates' principal property, the chelating capability is proportional with the number of adjacent oxygen-containing groups located on the aromatic ring (e.g. phenolic groups, see Figure 1).
It is also known that humic acids exert their biological activities by forming salts and complexes (chelates) with metals ions, metal oxides, silica, phosphorus salts and micro elements, etc., turning them into readily absorbable bio-available forms. Humates play a direct role in determining the production potential of a soil, and sharply increase efficiency of mineral fertilizers [Bochter, R. Boden und Bodenuntersuchungen. Praxis Schriftenreihe Chemie, Band 53, Aulis Verlag, 1995, 273 S (in Germain)]. Namely, in admixture with nitrogen fertilizers (either solid or liquid ones) humates are able to bind nitrogen content of the fertilizer via ammonium salt formation or chelating to prevent thereby nitrogen loss from the soil into the air [Seyedbagheri, Mir-M, Torell, J. M. Effects of Humic Acids and Nitrogen Mineralization on Crop Production in Field Trials in "Humic Substances Structures, Models and Functions". Edited by Elham A. Ghabbour and Geoffrey Davies, Northeastern University, Boston, USA, The Royal Society of Chemistry, 2001, p. 355 - 360].
Oxidation of coal containing humic compounds (by oxygen present in air at 100 to 300 0 C in a period ranging from 5-600 minutes) is used to produce humic acids (Cronje, US Patent 4,912,256, 1990). Humic acids prepared by this method are insoluble in water, so they have limited applicability.
Soluble humic acids can be prepared by treating humic-containing starting material with aqueous ammonia solution (Subert, et. al. US Patent 4,918,059, 1990). Because of the low soluble humic acid content of coal (up to 10 % in the prevalent leonardite type coal), the yield of soluble humic acids is limited in this case as well.
Treatment with aqueous ammonia solution at 100-300 °C (Dekker et. al. US Patent 5,004,831, 1991) is associated with the use of autoclave, but only a portion of soluble humic acids present in base coal can be recovered this way.
Increase of the yield is ensured by oxidation of a portion of insoluble floating humic acids with oxygen present in air, which makes humic acid soluble in aqueous alkali solution (Calemma, et al. US Patent 5,248,814, 1993). Combining oxidation process with alkali treatment facilitates increasing the yield of dissolved acid by 70 %, compared to the mass of humic acids present in coal (Lebo, Jr, et al. US Patent 5,688,999, 1997). In carrying out state of the art processes, the known sequence of operations is preserved, the essence of which is to disintegrate humic-containing base material and to mix it with aqueous alkali solution in order to cause hydrolysis of humic compound at a pH ranging from 6.5 to 8.0 (Shulgin et al. US Patent 7,204,660, 2007).
Reaction between the humic compound and the liquid and solid reagents can be accelerated by mechanical treatment. A method is known for producing humic compositions by the treatment of peat with strong acid and base [Solid Fuel Chemistry, 1993, Vol. 1 (in Russian)]. In this method the peat/base ratio is 1:0.5-1.0 (50-100 % by weight), and the pH is 10-12. Disintegrating peat for 360 minutes in gravitational ball mill (with ball acceleration of 10 m/s 2 ) doubles the yield of humic compounds [TJ. Kasinskaya, A.P. Gavriltsik, L.P. Kalilec: Change of peat's chemical composition during dispersion, Solid Fuel Chemistry, 1997, Vol. 6, pages 14-24 (in Russian)]. Disadvantage of the above-mentioned methods is the excessive basicity of the product that prevents its agricultural use in concentrated form. Additional disadvantages are the presence of high concentration of high molecule humic fractions in the composition and the long duration (120-160 minutes) of the treatment.
RU Patent No. 2007376 (IPC 7 C 05 F 11/00, publication date: 15. 02. 1994, BI No 3A) describes a method for plant growth stimulation comprising: as Stage 1 - disintegrating humic-containing base material (brown coal, peat, oil shale, sapropel and vegetable compost); as Stage 2 — saturated alkaline/aqueous treatment; as Stage 3 — treating dilute suspension and slurry with nitrogen-containing salts; as Stage 4 - evaporation. Disadvantages of this method are the too long processing time and increased basicity of the product.
According to the method for producing humic-containing artificial fertilizer as described in RU Patent No. 2104988 (IPC 6 C 05 F 11/02, publication date: 20. 02. 1998., BI No 5), which may be considered as being the most similar to the presently proposed method, super-finely disintegrated coal mixed with chemical additive is used for preparing the composition. The base mix is preconditioned and moisture-content is adjusted to 6-12 % by weight. Dry alkali metal hydroxides and/or urea is used as chemical additive, while keeping carbon:hydroxide ratio at 1:0.20-0.35. Disadvantage of this method is that producing water- soluble compounds requires the use of alkali and solid compounds. The yield of water-soluble fraction can be increased by increasing the amount of alkali and by depolymerization of high molecule fraction of humic compounds. On the other hand, by this method it is impossible to increase the number of oxygen-containing groups. Treatment of huniate and other compounds of polyphenolic origin with ozone is applicable for oxidative depolymerization and to increase the number of oxygen-containing groups in polymer molecule, as well. Ozone, as an oxidant, has the advantages of excellent reactivity and selectivity, which allows gentle oxidation and elimination of using high temperature and pressure, respectively [M.M. Ksenofontova, A.V. Kudryavtsev, A.N. Mitrofanova et al., Ozone application for modification of humates and lignins. In ,,Use of Humic Substances to Remediate Polluted Environments: from theory to practice", Netherlands, Springer, p. 473-484 (2005)]. Molecular ozone oxidizes primarily the electron- excess parts of macromolecules like double and aromatic C-C bonds, aromatic phenolic groups and saturated structures [J. Hoighe, H. Bader. Rate constants of reactions of ozone with organic and inorganic compounds in water 1 - non-dissociating organic compounds. Water res., Vol. 17, p. 173-183 (1983)].
It is also known that in aqueous solutions ozonation generates hydroxyl radicals (OH) having excellent reactivity [J. Staehelin, Heughe. Decomposition of ozone in water in the presence of organic solutes acting as promoters and inhibitors of radical chain reactions. Environ. Sci. TechnoL, Vol. 9, No. 12, p. 1206 - 1213 (1985)]. Generation of ozone is resulted from a reaction between ozone and water or between ozone and the organic compound. Reaction with OH radical significantly alters the polymer structure; its depolymerization occurs and phenolic and acidic groups appear. Oxidized polymers are less aromatic, rather hydrophilic, and become water-soluble (A. Kerc, M. Bekbolet, A. M. Saatci. Sequential oxidation of humic acid by ozonation and photocatalysis, Proceeding of the Intern. Conf. On Ozone and Global Water Sanitation, 1 - 3 October 2002, Amsterdam, the Netherlands). Ozonization of humic acids is characterized by reduction of molecular weight; hydrophobic structures of acids containing C-C double bond become hydrophilic [Ying-Shih, Reaction mechanism for DBPS reduction in humic acid ozonation. Ozone: Science and Engineering, Vol. 26. No. 2, p. 153-164 (2004)].
Characteristics of the photochemical reaction occurring radically, similar to the humic acid ozonation reaction described above, in humic acids have also been studied. Ozone penetrates easily through humic acid layer, and the reaction proceeds by photochemical activation but is rapidly slowed down by the elimination of light (S. Fahrni, K. Stemmler, M. Birrer, M Amniann. Reactions of ozone on photochemically activated humic acid surfaces. 15th Radiochemical Conf., Marianske Lazne. Czeh Rep. 23 - 29 April 2006). In the presence of alkali, ozonation of humates is accelerated (B. Danna, A Jammoul, C. George et al. Photoenhanced ozone uptake onto humic acid films and aerosols. Geophysical Research Abstracts, V. 9, 11131, 2007).
Accordingly, despite of the substantial endeavors in this field, there remains a need for an effective process of preparing a composition which contains a high proportion of water- soluble humate compounds having lower molecular weight and higher concentration of oxygen-containing functional groups, without excessive basicity of the product, in a relatively short time.
Object of the invention
The objects of the present invention are to increase the yield of water-soluble humate substances starting from natural humic-containing substances; to increase the proportion of water-soluble humate compounds in the humate composition; to enhance the biological activity of the composition; and to decrease the reagent demand and processing time.
The above-mentioned objects were achieved according to the present invention by a process comprising mechanochemical treatment of a mixture of the humic-containing starting material and alkali wherein the mechanical treatment is carried out at high intensity and the chemical treatment is supplemented by oxidation and further depolymerization under ozone- containing gaseous oxidant atmosphere.
The humate compositions obtainable by the process of the invention contain higher proportion of water-soluble humate compounds having lower molecular weight and higher concentration of oxygen-containing functional groups than those obtained by any process described in the prior art.
These and other objects of the invention will become apparent from the detailed description which follows.
Brief description of the drawing
Figure 1 represents the model structure of humic acid. Bonds between polyphenol parts of the molecule and unsaturated bonds can be broken by oxidative hydrolysis. Chelating groups (comprised of adjacent oxygen-containing groups) are indicated by brackets. Increase of the number of oxygen-containing groups improves solubility and biological activity.
Figure 1
Summary of the invention
In one aspect, the invention is directed to a process for the preparation of a humate- containing composition with an enhanced proportion of water-soluble lower molecular humate compounds having higher concentration of oxygen-containing functional groups, from a humic-containing starting material by a first mechanochemical treatment comprising hydrolysis and depolymerization of the powdered and moisturized starting material in the presence of an alkali under mechanical effect, wherein enhanced technical efficiency of the process is achieved in such a manner that the first mechanochemical treatment is carried out under a mechanical effect of high intensity, and is supplemented with a second mechanochemical treatment comprising oxidation and depolymerization by an ozone- containing gaseous oxidant under mechanical effect simultaneously with or subsequently to the first mechanochemical treatment.
In a further aspect, the invention is directed to a humate-containing composition having enhanced biological activity due to the enhanced proportion of water-soluble humate compounds having lower molecular weight and higher concentration of oxygen-containing functional groups therein, obtainable by the process af the invention.
In a further aspect, the invention is directed to the use of the composition according to the invention in farm breeding as fertility and growth enhancer feed additive, in plant growing, as seed-dressing or watering additive for increasing germination, growth of above- ground shoots and rooting and enhancing plant's fertility, and in combination with a nitrogen fertilizer (either solid or liquid one) to improve plant growth and production potential of soils, and to increase efficiency of the fertilizer; in environment protection for land recultivation, amelioration of soils and for reconstruction of heavy metal polluted lands and water resources; and in oil and gas exploitation industry as stabilizing component of drilling solutions as well.
Detailed description of the invention
In one aspect, the invention is directed to a process for the preparation of a humate- containing composition with an enhanced proportion of water-soluble humate compounds having lower molecular weight and higher concentration of oxygen-containing functional groups, from a humic-containing starting material by a first mechanochemical treatment comprising hydrolysis and depolymerization of the powdered and moisturized starting material in the presence of an alkali under mechanical effect, wherein the first mechanochemical treatment, carried out in the presence of 5 to 25 % by weight of alkali based on the total amount of the moisturized starting material in a ball mill with balls accelerating at from 60 to 180 m/s 2 , is supplemented with a second mechanochemical treatment comprising oxidation and depolymerization by an ozone-containing gaseous oxidant under mechanical effect, simultaneously with or subsequently to the first mechanochemical treatment.
In the context of the present invention the term "mechanochemical treatment" means a chemical treatment e.g. hydrolysis in alkaline or acidic medium or oxidation which is carried out under a mechanical effect, e.g. impact, shear or combination thereof.
The term "lower molecular weight" or "lower molecular" as used in connection with humate compounds means a humate compound of molecular weight from about 1000 to about 10000 Da.
The term "higher concentration of oxygen-containing functional groups" as used in connection with humate substances is intended to mean that the humate compounds of the composition obtained by the process of the invention contain more oxygen-containing functional groups i.e. carboxyl, phenolic OH and carbonyl groups in their molecules than those obtained by prior art processes, such as the process disclosed in RU Patent No. 2104988.
Ozone treatment can be carried out simultaneously with the first mechanochemical treatment, by carrying out the alkaline hydrolysis and depolymerization of the starting material under mechanical effect in the presence of ozone. Alternatively, oxidation and depolymerization of the reaction mixture by ozone under mechanical effect can be carried out subsequently to the first mechanochemical treatment. Ozone results in oxidative depolymerization of humic compounds, generation of humates, as well as an increased concentration of oxygen-containing groups of humates leading to an enhanced biological activity of the composition obtained by the process of the invention.
In the process of the invention any humic-containing natural substances can be used including brown coal, peat, sapropel, oil shale and the like as starting material. Preferably brown coal type leonardite is used as starting material in the process of the invention, which has the following composition: humic compounds: 65 % by weight; other substances (mostly inorganic oxides): ash - 30 % by weight, carbon: 15 % by weight. Other components (in % by weight): nitrogen - 0.18, phosphorus (in P 2 O 5 equivalent) - 0.05, potassium (in K 2 O equivalent) - 0.06, magnesium - 0.37, iron - 0.67, manganese - 0.01.
In the following description, for the sake of simplicity, the process of the invention is described when brown coal is used as starting material. It is understood, however, that the process of the invention is useful when any other humic-containing substance is used as starting material.
Brown coal is disintegrated to a particle size below 3 mm and conditioned to a moisture content of 8 to 16 % by weight based on the wet weight of coal. As an alkali, hydroxides of metals having particle size below 3 mm and at least 90 % main component content, preferably sodium hydroxide, or carbonates of metals, preferably sodium and potassium carbonate can be used.
Ozone is used as a mixture with air; ozone content of the gas mixture is 0.1 to 2.0 %, preferably 0.8 to 1.0 %, more preferably 0.9 % by volume.
Alkali content of the mixture of brown and alkali is determined by the amount of alkali needed to neutralize humic acid and to catalyze basic depolymerization of humic compound and ranges from 5 to 25 % by weight, based on the total weight of mixture. An alkali content below 5 % by weight is not enough for increasing solubility of coal. Alkali content above 25 % by weight, on the other hand, enhances the solubility of coal, but it significantly raises the cost of the process and increases the pH of the solution to 9 to 10, which does not permit its conventional usage.
The amount of ozone used in the process of the invention is specified by the number of oxygen-containing groups needed to increase the solubility of humate, and ranges from 0.1 to- 3.0 % by weight, based on the weight of the starting material fed in the process. Ozone introduced in an amount below 0.1 % by weight does not increase the solubility of the product, while ozone used in an amount above 3.0 % by weight oxidizes humic acids and leads to the generation of low molecular weight, oxidation-resistant mono- and di-carboxylic acids, decreasing thereby the yield of humic acids. Generation of ozone can be carried out by the following ozone generators: Ionic Zone Ozone Generators, Ionic Zone LLC 5 Las Vegas, USA - but other industrial ozone generators may be used as well.
The following activators and mills can be used for mechanochemical conversion of powdered reagent mixture of brown coal and alkali:
- equipments working at high intensity such as ball mills e.g. planetary and vibration ball mills or centrifugal vibration ball mills, in which balls accelerating at from 60 to 180 m/s 2 are needed to reach mechanical effect with suggested intensity in the starting material;
- equipments working at lower intensity for supplementary treatment of the reaction mixture (i.e. for the second mechanochemical treatment carried out subsequently to the first one) in ozone-containing medium, like gravitational ball mills, as well as disintegrator-type breaking mills, jet and vortex mills, which can be used in the following operating modes:
- in impeller mill and in breaking mill with impeller blades rotating at a speed from 10 to 120 m/s, in a period of from 0.2 to 2.0 minutes,
- in pneumatic and vortex mill with flow rate ranging from 10 to 120 m/s, in a period of from 0.2 to 2.0 minutes.
Ozonation under various conditions is determined by known features of mechanochemical reactions occurring between gases and solids (Awakumov J. G.: Mechanical Methods of Activation of Chemical Processes. Novosibirsk: Nauka, Siberian branch of Publishing House Nauka, 1986, page 201). Chemical processes not only take place at active centers of newly developed surfaces but also on already existing surfaces, where active centers are generated as a result of friction between particles.
The lower threshold value of intensity of the mechanical effect (ball acceleration of 60 m/s 2 ) is determined by the threshold value of the mechanical effect required for a mechanochemical reaction to take place (Awakumov J.G.: Mechanical Methods of Activation of Chemical Processes. Novosibirsk: Nauka, Siberian branch of Publishing House Nauka, 1986, page 303). The upper threshold value of the said intensity is limited by the onset of degradation reaction of humic compounds, as well as by their conversion to amorphous carbon structure. The lower threshold value of water content of the reaction mixture can be determined by the stoichiometry of humic compounds' hydrolysis; this threshold value is dependent of the molecular weight of the initial and the generated molecules and amounts to about 8 % by weight based on the weight of the reaction mixture. The upper threshold value of water and liquid content of the treated feedstock can be determined by rheological characteristics (liquidity) of the treated mixture, and in the case of various starting materials it has a numerical value of 16 to 24 % by weight. Auxiliary liquid reagents can be added to the mixture with the proviso that the total concentration liquids will not exceed the indicated threshold value.
The temperature of processing is not critical, it may range from 0 to about 60 0 C 5 it is preferably about ambient temperature i.e. no extra heating or cooling is required either in the first or the second mechanochemical treatment.
The pressure of processing is not critical, it is preferably about atmospheric pressure (1 atm) although lower and higher pressures from 0.9 atm to 1.1 atm may also be used both in the first and the second mechanochemical treatment.
The main advantage of the process of the invention is that the whole processing time is shortened to a few minutes compared to several hours needed in the prior art processes. In addition, unlike to the prior art processes, it avoids the use of excessive alkali to increase water-solubility of the product, therefore the composition obtained by the process of the invention can be used directly for various agricultural purposes as disclosed herein.
In a further aspect the invention is directed to a humate-containing composition having enhanced biological activity due to the enhanced proportion of water-soluble humate compounds having lower molecular weight and higher concentration of oxygen-containing functional groups therein, obtainable by the process af the invention.
The composition obtained by the process of the invention in powder form can be used directly in farm breeding as fertility and growth enhancer feed supplement for cattle, pigs and poultry.
Furthermore, the composition, can be used in plant growing as plant growth enhancer, being added during seed-dressing or watering, and it is useful for increasing germination, growth of above-ground shoots and rooting, and for enhancing plants' fertility in general. In addition, said composition in combination with a nitrogen fertilizer (either solid or liquid one) can be used in plant growing to improve plant growth and production potential of soils, and to increase efficiency of the fertilizer. As used herein, ,,nitrogen fertilizer" refers to any conventional artifical fertilizer supplying plants with nitrogen essential for plant growth including, without limitation, ammonium nitrate, ammonium sulfate, calcium nitrate, ammonium hydroxide, anhydrous ammonia, urea, etc. In these combined uses, the product obtained by the process of the invention and the fertilizer can be applied to the soil simultaneously or separately, either in a single composition or in the form of different compositions in their usual effective doses which can easily be selected by a skilled person.
A further advantage of the powdered composition obtained by the process of the invention versus liquid compositions is the ease of shipping and storage. The powdered composition may be extracted, if necessary, whereby higher yield prime quality composition is obtained which has a higher concentration of solutes.
The method of the invention is further illustrated by the following examples.
Example 1
Brown coal type leonardite (with moisture content of 15 % by weight ) derived from a deposit in Dudar (Hungary) is disintegrated to a particle size below 1 mm, mixed with ,,pure" or ,,technical pure" sodium hydroxide (NaOH) in the amounts indicated in Table 1, and treated in centrifugal vibration ball mill (activator) (Type: CEM20, Novic, Novosibirsk, Russia) at 120 m/s 2 ball acceleration for 1 minute.
Proportion of water-soluble materials (represented primarily by humates) and of lower molecular weight fractions containing humic acids and fulvic acids is analyzed independently in the obtained powdered composition.
Assay method
Samples (5.0 g) were kept in water at room temperature for 15-16 hours in order to transfer water-soluble materials from the activated mixture to the solution (L:S = 4, i.e. weight-to-weight ratio of liquid and solid phase must be 4:1). Subsequently, aqueous extraction was carried out in a Soxhlet equipment mounted with conventional cooler at 60 °C until soluble materials were extracted entirely from the samples (8-10 hours). Yield of water-soluble materials was determined by two methods:
1) by the amount of dissolved material;
2) by the amount of remaining undissolved portion. Determination of the yield of water-soluble materials by method 1 During the assay a solution and wet, washed sediment were obtained. The solution (400 ml) was filtered and after pH determination it was evaporated to dryness at 60 °C. The remaining dry residue represented the dry extract (water-soluble material extracted from the starting material). The water-soluble powder was weighed.
Determination of the yield of water-soluble materials by method 2
Sediment was dried at 60 °C. The yield of water-soluble materials (in % by weight) was determined in each experiment as the difference between the natural starting material content of starting reaction mixture (having regard to its moisture content at 60 °C) as dry residue and the washed dried sediment.
According to method 2, the humic compound was quantified by dissolving the dry extract obtained by precipitation with 1% hydrochloric acid. The precipitate was filtrated and weighed. Low molecule fractions containing fulvic acids determined as the difference between the weight of starting sample and humic fractions. For the calculations the weights of reagents and soluble salts participating in the reaction and generated during conversion of humates to humic acid, respectively, were taken into account.
Accuracy of the method is 3 %.
Table 1: Amount of soluble humates as a function of introduced alkali in samples after the first mechanochemical treatment
It can be seen that the proportion of soluble humates increases by increasing the amount of introduced alkali. Amount of alkali below 5 % by weight significantly reduces the yield of water-soluble materials.
Biological activity of the obtained compositions (as weight enhancing feed supplement) was tested in groups of 15 Holstein steer calves each. Testing was started with 6- month steer calves having 150 kg initial weight. Feeding was continued for 150 days. All animals were fed with 150 mg/kg live weight /day powdered composition in addition to basic feed. Animals receiving feed supplement showed better results in live weight gain. In steer calf control group the average daily live weight gain was 600 g. In the group receiving composition with 3 % alkali the weight gain was 400 g, in the group receiving humate with 5 % alkali the weight gain was 660 g, while the group receiving humate containing 10 % alkali exhibited 650 g weight gain.
Animals belonging to the experimental group had better meat indices then those of control groups. Morphological and biochemical blood parameters indicating the quality of metabolism remained below physiological threshold values in each animal.
Example 2
Brown coal type leonardite (with moisture content of 15 % by weight) derived from a deposit in Dudar (Hungary) is disintegrated to a particle size below 1 mm, mixed with ,,pure" or ,,technical pure" sodium hydroxide (NaOH) in the amounts indicated in Table 2, and treated in centrifugal vibration ball mill (Type: CEM20, Novic, Novosibirsk, Russia) at 120 m/s 2 ball acceleration under ozone-containing atmosphere in the presence of 0.8 % by weight of ozone for 2 minutes.
Proportions of water-soluble materials (represented primarily by humates) and of low molecular weight fractions containing humic acids and fulvic acids in the powdered composition obtained are analyzed as describe d in Example 1. Results are shown in Table 2 below.
Table 2: Dissolved humate content of compositions prepared from coal by ozone oxidation
The biological activity of the obtained compositions (as feed supplements) was assayed during feeding poultry stock.
Compositions No. 1 and 2 added to 6 groups of 40 quails each. Experiment was started with 40-70 day old quails. Control group received basic feed with balanced nutritive value. In the case of the other two groups, 1 kg of feed was supplemented with 250 g composition. Results are illustrated in Table 3. Table 3: Effect of coal composition on fertility of quails
From the data of Table 3 it can be seen that adding a composition prepared from brown coal according to the invention to the feed of quails has positive effect on their productivity: egg-laying capacity is increased by 9 %, feed consumption is decreased by 34 % (compared to control), and live weight gain is increased by 16 %.
Example 3
The process of Example 1 was repeated by using alkali in an amount of 15 % by weight. Then supplementary ozonation was carried out in impeller mill (manufacturer: Disintegrator, Tallinn, Estonia) at a speed of 55 m/s under ozone-containing atmosphere in the presence of 1.0 % by volume of ozone for 2 minutes.
The amount of dissolved humates in composition 1 (obtained before ozonation) was 25 % by weight, while in composition 2 (following ozone treatment) it was 40 % by weight.
Biological effect of composition 1 and of composition 2 on germination and on growing of cereal shoots was assayed in vegetation experiments according to a known method (M.K. Firsova: Seed corn control. Moscow, Kolos, 1969, page 295).
Grains were placed in rolled filter paper and germinated in beaker glass filled with test solutions. The amount of growth stimulation supplement (i.e. either composition 1 or composition 2) in the solution was 10 mg/1. Control contained no growth stimulation supplement. Height of shoots and length of roots was measured on days 2, 6 and 10. At the end of the assay shoots were weighed. Results are shown in Table 4 below.
Table 4: Stimulation effect of the compositions obtained from coal on growth of cereal shoots
It can be seen that both composition 1 and 2 stimulate growth of plants, increase growth rate of roots, as well as height of shoots and mass of germinated part. The composition obtained by mechanochemical treatment with ozonation according to the process of the invention is more active than the one treated only with alkali.
Biologically active composition obtained using ozone has increased dissolved humate content. Compositions prepared according to the invention also have higher biological activity than other compositions prepared according to known methods.
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