WO2022025779A1

WO2022025779A1 - A method for the production of functional humic and fulvic products from natural organic raw materials

Info

Publication number: WO2022025779A1
Application number: PCT/PL2020/050056
Authority: WO
Inventors: Józef Hoffmann; Marta Huculak-Mączka; Dominik NIEWEŚ; Krystyna Hoffmann; Ewelina Klem-Marciniak; Jakub Zieliński; Maciej Kaniewski; Magdalena Braun-Giwerska; Marcin Biegun
Original assignee: Politechnika Wroclawska
Current assignee: Politechnika Wroclawska
Priority date: 2020-07-30
Filing date: 2020-08-03
Publication date: 2022-02-03
Anticipated expiration: 2023-01-30
Also published as: PL241814B1; PL434853A1

Abstract

The subject of the invention is a method for the production of functional humic and fulvic products enriched with N, P, K nutrients, characterized in that in the first stage, the raw carboniferous material is activated with an H3PO4 solution or an HNO3 solution until the pH level of the mixture is lower than 3; in the second step, an H3PO4 solution or an HNO3 solution is added, while the ratio of the input material to the total amount of added solutions is maintained within in the range of 1:5-1:15; next the mixture is neutralized with a KOH solution or an ΝΗ3'H2Ο solution and extracted with a KOH solution or an ΝΗ3'H2Ο solution; next the sediment is separated from the actual extract of humic substances enriched with nutrients such as N, P, K, from which humic acids are precipitated by adding H3PO4 or HNO3 acid with the concentration of up to 50 wt.%, and the products in the form of humic and fulvic acids are separated, wherein the activation and/or extraction process is aided with ultrasounds.

Description

A method for the production of functional humic and fulvic products from natural organic raw materials

The object of the present invention is a method for the production of functional humic and fulvic products from carboniferous materials in an aided process of their extraction, having a role especially in agriculture, chemistry, pharmacy, medicine and generally understood food industry in composing functional food.

Due to numerous and valuable properties of humic substances, preparations produced from alternative organic materials, a rich source of these, such as carboniferous materials with various levels of carbonization, have been widely used in various industries. However, it is the humic acids fraction in agriculture that is the most widely used. In patents, one can find documents concerning both the method of the production of fertilizing preparations with the use of humic substances as a product of chemical modification of raw material being their source, as well as the direct method of obtaining humic preparations used in soil fertilization process or in fertilizers production.

Alkaline extraction is the basic action undertaken in the process of the production of humic substances from various organic materials. The individual patents pertaining to the acquisition of these usually show modifications of the method using an alkaline agent, carried out in different combination of physical, chemical or biological parameters. These agents can intensify the extraction of humic acids from the said organic material both due to their addition prior and following the proper alkaline extraction.

In American patent application No. US5004831 (Al), a method of obtaining humic acids from previously oxidized materials is shown. The method comprises a stage of mixing oxidized coal with an alkaline solution, in particular, with a sodium base solution, following by warming the mixture to a temperature in the range of 100-180°C in a proper pressure to avoid water vaporization; the mixture is kept at higher temperature, usually for a period not longer than 2 hours, which, according to the description, is enough to separate a considerable amount of available humic acids from the oxidized material. The authors of the patent have suggested precipitation of humic acids with strong mineral acids like HC1 or H2SO4. The method of oxidizing coal, i.e. the initial material in the process of acquiring humic acids, according to the application above is the object of other patents, including patent No. ZA899232B. The oxidization process, in this case coal oxidization, is performed in the dry phase and in oxygen or oxygen and nitrogen atmosphere in a fluidized bed reactor. Coal, with particles sizes ranging from 100 pm to 3 mm, can be heated up to a temperature from 150 to 300°C within 30 to 600 minutes. The procedure of oxidizing coal in the dry phase with pure oxygen or air has been also disclosed in the description in European patent No. EP0272737 (Bl).

Polish patent No. PL166644 (Bl) discloses a method of obtaining humic acids from coal, according to which in the dry phase, coal, its particles being up to 3 mm in size, is oxidized in the presence of oxygen or oxygen/nitrogen mixture, especially air, in a fluidized bed reactor, at 150-300°C, oxygen partial pressure at 68.7-490.5 kPa and time of contact of 30-600 minutes, wherein some part of the exhaust from the reactor is returned to the reactor after cooling down to 50-100°C. Referring to the subject of regenerated humic acids obtained from coal, according to European patent No. EP0364025 (A2), the extraction of essentially aliphatic, low-molecular-weight fraction of humic acids requires the use of methanol under supercritic conditions. Coal oxidation with oxygen in water phase, in acidic environment is the object of European patent application No. EP0786491 (A2), showing a method of production of oxidized humic acids by an oxygen-alkali process. The method comprises reacting humic acids bearing materials with oxygen under alkaline conditions at a temperature between 100 and 200°C for at least 1/2 hour, but usually for 1-2 hours, to produce oxidized humic acids which are soluble at pH as low as 2.9 and which are formed in yields of at least 70%.

However, the proposed humic acids production methods are characterized by high reagent cost in comparison to the amount of the product, long processing time and low selectivity of the humic acids extraction process. Moreover, conducting the process in a higher temperature or thermal processing of the initial material generates additional processing cost, and in many cases, using a temperature too high a can result in destruction of the structure of produced fractions and its deactivation.

European patent No. EP0117223 (Bl) discloses a complex production process of both humic and fulvic acids and intermediates from peat, peat soil and humic organic materials for use in agriculture, chemistry, pharmacy, medicine and generally considered industry as well as in other commercial branches. The process according to the invention comprises of two cycles. The first one, comprises the production of humic and fulvic acids as well as liquid and solid fertilizers or materials used in the fertilizers production. The second one, pertains to the process of production of a substance rich in humic acids and free from mineral substances (iron, aluminium, etc.). Patent No. EP3135655 (Al) discloses a complex method of processing coal caustobiolites, predominantly lignite and leonardite, into organic and organomineral humic fertilizers, as well as preparations needed to produce briquettes in a continuous flow with the efficiency of the key processes. According to the description, the technological process comprises of leaching processes based on aqueous solutions with the ratio of liquid: solid close to 2, carrying out acidification processes with the precipitation of humic acids from liquid phase into coagulated pulp, carrying out mechanical phase separation processes in a centrifugal field, carrying out the liquid-phase mechanoactivation and the dispersion of reaction compositions via grinding, with recycling residual “water”, and including the production of water-soluble humic acids and fuel briquettes used to produce process heat, and allowing for the production of a wide range of products. In the embodiment of the invention, mechanoactivation and/or mechanochemical activation is used together with dynamical exposition of processed media to sonic and infrasonic frequencies. Another known method of producing organomineral fertilizers based on humic substances with the use of ultrasounds, disclosed in patent application No. RU2350587 (Cl), in which a mixture consisting of an alkali liquor with a minimum pH of 12 and a humic substance is processed by cavitational dispersion due to exposure to ultrasonic radiation for 5-15 minutes, the specific wattage consumption being 1-4 W per 1 cm³. After that, phosphoric acid is added to the mixture in an amount sufficient for pH to decrease to the level of 2-1 and the mixture is again exposed to ultrasonic radiation, the treatment duration and intensity being as specified above; next the resultant solution is mixed with alkali in an amount sufficient for the solution neutralisation to pH of 7-7.5, and nutrient microelements are added to the liquid humic fertiliser. The process results in just one type of product: a ballast solution of humic acids (in a form of suspension, gel of various humic substances forms) with microelements. Patent No. RU2473527 (C2) discloses a method for the production of humic acids concentrate from lignite. This method comprises lignite grinding to the extent of obtaining microparticles, the suspension preparation in a diluted solution of alkali solution and extracting humic acids. In this method, coal is subjected to two-stage grinding, and during the mechanical stirring, the coal-microparticle suspension in the extraction is simultaneously processed with ultrasounds for 7-15 minutes; next the solid phase is separated from the liquid phase by sedimentation of insoluble coal residue and to the liquid phase hydrochloric acid is added; after at least 24 hours, the system separates to the liquid phase, then returned to the mixer, and humic acids of 90 wt.%, 70 wt.% and 40 wt.%. Russian patent No. RU2316227 (Cl) discloses the method for preparation of liquid feeds that comprises the production of humic acids and their salts from peat or lignite, previously dried to 20-35 wt.%, by cavitational dispersion of the material, in aqueous alkali solution until full yield of humic acids is obtained, followed by the production of their salts through cavitational dispersion with carbonates, and sodium and potassium hydroxides, until the temperature of mixture reaches 80-90°C. However, this technological process does not provide the ability to control the composition and amount of nutrients in obtained product, and consequently it is not possible to obtain a high-quality product with stable consumer properties. Moreover, it requires high energy and economic expenditure. Patent No. RU2491266 (C2) discloses another process using ultrasonic dispersion for the production of humic preparations, in which a material rich in humic substances is processed without the use of chemicals in a stream of air or vapour using a jet-edge generator with an ultrasonic radiation intensity above 10 W/cm.². As a result, so-called ultrahumic preparation is produced, which contains water-soluble both fulvic and humic acids, and possibly nutrients contained in the raw material itself, the amount of which is insufficient and the form is not available for plants when the aforementioned preparations are used in fertilization.

The invention addressed the need of developing an efficient technology to process carboniferous raw materials with the use of ultrasounds into functional humic products, constituting separate fractions of humic and fulvic acids, and their salts enriched with nutrients such as: N, P, K.

Due to their lower molecular weight, higher content of functional groups, and therefore greater biological activity than in humic acids, fulvic acids are characterised by great application potential in various industries, including agriculture, although they usually appear as a minor component of humic preparations. Humic substances are now also used in peloid baths, cosmetics and as components in dietary supplements and feed preparations. In this case, fulvic acids play a significant role and, owing to their potentially antiviral, anticancer, antioxidant and anti-inflammatory properties, they constitute a valuable medical substance and component of functional food. A comprehensive approach to the efficient process of the production of both valuable fractions is therefore extremely important, and the combination of the process of producing them from coal raw materials with the use of various configurations of fertilizing components allows the enrichment of this type of preparations with the necessary nutrients.

With regard to sustainable fertilization concept, the need to increase the degree of absorption of nutrients, and at the same time, taking into account the need for rational management of mineral resources, the development of new formulas of preparations using natural organic materials as a source of humic substances enriched with fertilizing ingredients is the desired course of action. The essence of the invention is a method for the production of functional humic and fulvic products enriched with N, P, K nutrients, characterized in that in the first stage, the raw carboniferous material is activated with a H₃PO₄ solution or an HNO₃ solution until the pH level of the mixture is lower than 3; in the second step, an H₃PO₄ solution or an HNO₃ solution is added, while the ratio of the initial material and the total amount of added solutions is maintained within in the range of 1:5-1:15; next the mixture is neutralized with a KOH solution or an NH₃Ή₂O solution and extracted with a KOH solution or an NH₃Ή₂O solution; next the sediment is separated from the actual extract of humic substances enriched with nutrients such as N, P, K, from which humic acids are precipitated by adding H₃PO₄ or HNO₃ acid with the concentration of up to 50 wt.%, and the products in the form of humic and fulvic acids are separated, wherein the activation and/or extraction process is aided with ultrasounds.

Preferably, the coal material is selected from the group consisting of: lignite, leonardite, peat or bituminous coal with initial particle size not exceeding 30 mm. Most preferably, the initial size of particles of coal material is 15 mm.

Preferably, in the first stage, during the activation process, a 5 to 30 wt.% H3PO4 solution or a 3 to 30 wt.% HNO3 solution is used in the activation process.

Preferably, a 1 to 5 wt.% H3PO4 solution or a 0.5 to 3 wt.% HNO3 solution is used in the second step of the activation process, so that the ratio of the initial material and the total amount of H3PO4 solution or HNO3 solution added equals 1:10.

Preferably, a 3 to 10 wt.% KOH solution or a 2 to 10 wt.% NH₃Ή₂O solution is used to neutralize the mixture. Most preferably, a 3 wt.% KOH solution or 5 wt.% NH₃Ή₂O solution is used to neutralize the mixture.

Preferably, a 0.5 to 3 wt.% KOH solution or a 0.3 t 2 wt.% NH3Ή2O solution is used in the extraction process, in an amount needed to produce a mixture with pH of from 10 to 13.5.

Preferably, the activation and/or extraction process is performed with the aid of ultrasounds characterized by 25-60 kHz frequency and 5 to 300 W power.

Preferably, the ultrasonic-aided activation or extraction time remains within 5 to 60 minutes.

An advantage the invention provides is that the solutions used have been selected and introduced in such a sequence that in the end salt solutions that allow the production of humic and fulvic products with an appropriate yield are formed, and both can be used as a source of plant nutrients. In accordance with the idea of the invention, carboniferous raw materials, depending on their position in the coalization process and, consequently, technical and chemical parameters and predisposition to use them for non-energetic purposes, should, if necessary, undergo an appropriate treatment before processing them into humic and fulvic products. Fragmentation of the raw material to a larger extent makes it possible to increase its active surface and porosity of the mass subjected to physicochemical processes, which in turn results in an increase in the contact area between the material and the solutions used. The process of grinding the raw material that requires fragmentation is carried out in the liquid phase, during the first stage of the process, within the solutions of mineral acids, and the material itself is not subjected to the energy-consuming drying process before processing. It has been established that pre-drying of coal raw materials, most of which have a high natural humidity, and thus are sticky, and therefore difficult to grind as the material sticks to the surface of the equipment and clogs crushers and mills, can be successfully replaced by wet grinding at the stage of activation.

Moreover, it turned out that the ultrasonic-aided extraction is a fast process that does not require elevated temperature and when compared to the conventional extraction, it offers, in a short time, a high reproducibility, while the consumption of reagents is reduced and energy requirements are lowered, and good process efficiency is maintained. The use of modern techniques in the extraction of humic acids from potential organic materials allows to improve and reduce the cost of this process and shorten its duration, and by using the appropriate configuration of solutions constituting a source of phosphorus, potassium, and nitrogen in the process, it contributes to the enrichment of the final product with components that have, amongst others, a beneficial effect on plant growth and development. By the method according to the invention, humic and fulvic acids enriched with nutrients, depending on the used configuration of solutions, can be used, directly or after prior treatment, in agriculture, chemistry, pharmacy, medicine and generally understood food industry to compose functional food.

The subject of the invention has been presented in the examples of obtaining functional humic and fulvic products from carboniferous materials using components being the source of N, P, K in an ultrasonic-aided process.

Example 1

Raw peat is activated by the introduction of 10 wt.% H3PO4 solution into the reactor, in which the components are mixed and after the acidity of the mixture has been established, a 1 wt.% H₃PO₄ is added so that the ratio of the initial material and the total amount of introduced solutions is 1:5; then the system is neutralized with a 10 wt% N¾ H₂O solution and extracted with a 1.5 wt% KOH solution at pH level close to 13. The extraction process is carried out for 15 minutes in an ultrasonic environment characterized by 45 kHz frequency and 200 W power. Then the extract is separated from the post extraction residue, and humic acids, which are one of the products enriched with nutrients, are precipitated by acidifying the medium to pH of about 2 using a 10 wt.% H₃PO₄ solution. After the separation of humic acids by one of known phase separation methods, the post- extraction solution constitutes a finished product containing fulvic acids or an intermediate for further processing.

Example 2

Raw peat and a 7 wt.% HNO₃ solution are introduced into the reactor in such a way that the system's pH level is close to 2; next as much as of a 2 wt.% HNO₃ solution is added, so that the ratio of the initial material and the added total amount of HNO₃ solutions equals 1:5. After the reactants are thoroughly mixed, a 7 wt% KOH solution is introduced into the reactor to neutralize the mixture; and next, within 15 minutes an extraction with 3 wt.%. KOH solution is performed under normal pressure in an ultrasonic environment characterized by 40 kHz frequency and 150 W power. Next, the produced humic extract is separated from the post -extraction residue, and humic acids are precipitated by acidifying the medium to about pH = 1.5 using a 15 wt.%. H₃PO₄ solution. After 6 h, the reaction mass is separated to obtain humic acids in a form of gel or a solid product, having previously dehydrated it, and a solution of fulvic acids ready to be concentrated to obtain the desired properties.

Example 3

Raw lignite, with the step of unnecessary drying omitted and the initial size of particles not exceeding 30 mm, is subjected to simultaneous activation and grinding, while introducing a 20 wt.% H₃PO₄ solution into the reactor in which the ingredients are mixed; and after adjusting pH level to 2, a 5 wt.% H₃PO₄ solution is added to the mixture, so that the ratio of the initial material and the introduced total amount of solutions equals 1 :7. Next, the mixture is neutralized with a 10 wt.% KOH solution and in order to extract humic substances consisting of humic and fulvic acids and their salts, as much as a 3 wt.% KOH solution is added to the extraction reactor until the system's pH level becomes close to 13. The ingredients are mixed for 30 minutes in an ultrasonic environment, characterized by 60 kHz frequency and 200 W power. After separation of the reaction mass into an insoluble part and an extract of humic substances enriched with 2 out of 3 nutrients introduced during the process, a 20 wt.% HNO3 solution is being introduced into the liquid phase, until pH of the solution is below 2; the solution is allowed to rest for 3 hours. Precipitated humic acids are separated from the fulvic acids solution, thus obtaining two separate products with various properties and possible applications.

Example 4

Raw peat is activated by the addition of a 10 wt.% H₃PO₄ solution so that pH of the system becomes close to 2. Next, such an amount of a 4 wt.% H₃PO₄ solution is added to keep the mass ratio of peat raw material and the total amount of solutions used equal 1:10. The raw material activation process is carried out for 20 minutes in an ultrasonic field characterized by 25 kHz frequency and 100 W power. The system is then neutralized with a 10 wt.% NH₃Ή₂O solution. In the next step, a 2 wt.% KOH solution is being added to the system until it reaches pH of at least 11 , and 40 minute-long ultrasonic extraction of individual fractions of humic substances in an environment characterized by 50 kHz frequency and 200 W power is carried out, after which the system is neutralized with a 8 wt.%. NH₃Ή₂O solution. Next, using known methods, the solution of humic substances is separated from the post-extraction residue. The liquid phase is acidified with a 15 wt.% HNO₃ solution until its pH is below 3, thus precipitating the humic acids fraction, and allowed to rest for 12 hours. The last step comprises of the separation of the mixture into 2 useful fractions: humic acids and fulvic acids, each of them enriched with N, P, K fertili er components.

Example 5

Peat raw material, with the step of unnecessary drying omitted, is treated with a 15 wt.% HNO3 solution until its pH value equals 2. In the next step, a 3 wt.% H3PO4 solution is added to the system to achieve the ratio of the raw material and the introduced liquid phase equal 1:5. The activation process of the carboniferous raw material is carried out by vigorous, mechanical mixing of the system for 45 minutes, after which the system is neutralized with a 5 wt.% KOH solution. In the next step, a 2 wt.% NH3H2O solution is added to the system, to achieve the final mass ratio of the raw material and the total amount of aqueous solutions equal 1:10. The extraction of individual fractions of humic substances from the raw material is carried out for 45 minutes in an ultrasonic-aided process, where the ultrasounds are characterized by 40 kHz frequency and 175 W power. Next, after performing a phase separation by known methods, a 10 wt.% H3PO4 solution is introduced to the solution, until its pH becomes of 2, in order to precipitate the humic acids fraction, and the solution is allowed to rest for 4 hours. The last step is to separate humic acids gel from the fulvic acids solution, wherein individual products are enriched with fertilizing nutrients.

Example 6

Lignite, crushed into particles not larger than 30 mm, is added to a 20 wt.% HNO3 solution, until pH of the mixture reaches 2. Next, a 5 wt.% H3PO4 solution is introduced to the system, so that the ratio of the raw material and the liquid phase is not lower than 1:5. The activation of raw coal is carried out for 60 minutes in an ultrasonic-aided process, where the ultrasounds are characterized by 30 kHz frequency and 150 W power. At the next stage, a 10 wt.% NH₃Ή₂O solution is added to the system until pH level reaches 6, preferably 7. In order to separate individual fractions of humic substances, a 2 wt.% KOH solution is added to the reaction system to adjust pH to 12. The extraction is carried out by vigorously mixing the system at ambient temperature for 60 minutes. Next, the solution is separated from the post-extraction residue, which is acidified with a 30 wt.% H3PO4 solution to isolate the humic acids fraction, until pH is adjusted to 2 and the solution is allowed to rest for at least 10 hours. The precipitated humic acids gel is separated from the solution containing fulvic acids, both products being a source of organic matter enriched in nitrogen, phosphorus and potassium.

Example 7

Lignite is simultaneously ground and activated with the addition of a 25 wt.% H3PO4 solution to the raw material to acidify it to pH of 2; next a 3 wt.% HNO3 solution is introduced into the reactor in order to achieve the weight ratio of feedstock to liquid phase equal 1:6. After carrying out the activation process, using methods allowing the intensive, mechanical agitation of the system for 30 minutes, a 7 wt.% NH₃Ή₂O solution is added to the system to adjust pH of 6, preferably 7. Next, a 8 wt.% KOH solution is added to the system, in order to achieve pH of at least 11, wherein it is preferable to achieve pH of 13. The extraction of humic substances is carried out for 60 minutes at ambient temperature in an ultrasonic-aided process, where the ultrasounds are characterized by 40 kHz frequency and 200 W power. After the extraction residue has been separated from the solution by known phase separation methods, a 25 wt.% HNO3 solution is introduced into the extract to acidify it to pH of around 2. The system is allowed to rest for 8 hours. After the phase separation, a humic acids fraction is obtained, as well as a solution containing the fulvic acids fraction, the products being enriched with nutrients N, P, K.

Claims

1. The method for the production of functional humic and fulvic products enriched with N, P, K nutrients, characterized in that in the first stage, the raw carboniferous material is activated with H₃PO₄ solution or HNO₃ solution until the pH level of the mixture is lower than 3; in the second step, H₃PO₄ solution or HNO₃ solution is added, while the ratio of the input material and the total amount of added solutions is maintained within in the range of 1:5-1:15; next the mixture is neutralized with a KOH solution or an NH₃H₂O solution and extracted with a KOH solution or an NH₃Ή₂O solution; next the sediment is separated from the actual extract of humic substances enriched with nutrients such as N, P, K, from which humic acids are precipitated by adding H₃PO₄ or HNO₃ acid with the concentration of up to 50 wt.% and the products in the form of humic and fulvic acids are separated, wherein the activation and/or extraction process is aided with ultrasounds.

2. The method according to Claim 1, characterized in that the coal material is selected from the group consisting of: lignite, leonardite, peat or bituminous coal with output particle size not exceeding 30 mm.

3. The method according to Claim 2, characterized in that the initial size of particles in coal material is 15 mm.

4. The method according to Claim 1, characterized in that in the first stage, during the activation process, a 5 to 30 wt.% H3PO4 solution or a 3 to 30 wt.% HNO3 solution is used in the activation process.

5. The method according to Claim 1, characterized in that a 1 to 5 wt.% H3PO4 solution or a 0.5 to 3 wt.% HNO3 solution is used in the second step of the activation process, so that the ratio of the input material and the total amount of an H3PO4 solution or an HNO3 solution added equals 1:10.

6. The method according to Claim 1. characterized in that a 3 to 10 wt.% KOH solution or a 2 to 10 wt.% NH₃Ή₂O solution is used to neutralize the mixture.

7. The method according to Claim 6, characterized in that a 3 wt.% KOH solution or a 5 wt.% NH₃Ή₂O solution is used to neutralize the mixture.

8. The method according to Claim 1 , characterized in that a 0.5 to 3 wt.% KOH solution or a 0.3 to 2 wt.% NH₃Ή₂O solution is used in the extraction process, in an amount needed to produce a 10- to 13.5-pH-level system.

9. The method according to Claim 1, characterized in that the activation and/or extraction process is performed with the aid of ultrasounds characterized by 25-60 kHz frequency and 5 to 300 W power.

10. The method according to Claim 1 and 9, characterized in that the ultrasonic-aided activation or extraction time remains within 5 to 60 minutes.