RU2763050C1 - Method for producing carbon fertilizer - Google Patents

Abstract

FIELD: agriculture.SUBSTANCE: invention relates to agriculture, namely to the production of a complex fertilizer containing carbon dioxide. The method provides for obtaining a complex fertilizer containing carbonic acid and a component based on bulk material, including nutritional ingredients. As the specified component, a natural mineral is used - serpentinite, wet milled in a carbonic acid medium. Before the specified grinding, the serpentinite is first subjected to crushing to achieve a size acceptable for equipment used for wet grinding, then it is poured with carbonic acid and kept for at least 7 hours. In this case, wet grinding is carried out at the initial mass ratio of solid and liquid phases in the processed material S:L from 1.2:1 to 1.4:1 and is carried out until the resulting product reaches a pasty consistency with a particle size of not more than 0.02 mm.EFFECT: ensuring the possibility of obtaining fertilizer as a single material applicable by directly introducing it into the soil during plowing or pre-sowing preparation while maintaining the properties due to the presence of carbon dioxide, as well as ensuring the gradual release of the latter.4 cl, 1 dwg, 4 ex

Description

The invention relates to agriculture, more specifically to the production of fertilizers for agriculture, namely, to obtain a complex fertilizer containing carbon dioxide.

At present, considerable attention is paid to feeding cultivated plants with carbon dioxide, including intra-soil feeding.

Carbon dioxide, as you know, refers to natural biological ingredients that are an integral part of soil biomass and, in particular, humus. On the other hand, CO ₂ is an excellent nutrient medium for beneficial soil microflora, which is concentrated mainly in the 0-15 cm layer and partially in the 15-25 cm layer. Microorganisms process part of CO ₂ and not only break off natural carbon - the basis the vital activity of microflora, but also process it. Along with this, the detached oxygen O ₂ is an oxidizing agent of biological material, which contributes to the acceleration of its decomposition. As a result, the content of nutrients in the soil increases, including compounds of phosphorus Р ₂ О ₅ , potassium K ₂ O and nitrogen, containing the anion NO ₃ ^- and the cation NH ₄ ⁺ , and these substances are in the soil in a form that is easily assimilated by the root system plants, as noted in RF patent No. 2318306 (publ. 03/10/2008) [1].

Deficiency of CO ₂ is a more serious problem than the deficiency of mineral nutrients for plants. On average, a plant synthesizes 94% of the dry matter mass from water and carbon dioxide. Carbon dioxide, formed as a result of the decomposition of carbonic acid H ₂ CO ₃ , comes out to the surface and is absorbed by the green mass of plants during photosynthesis. A new understanding of the reactions of photosynthesis shows that the oxidation of water in the enzymatic center of a plant does not occur in the form of H ₂ O or OH ^- , but in the form of molecules obtained as a result of the dissociation of H ₂ CO ₃ , which is oxidized by the enzymatic center of the water-oxidizing complex of plants (V.M. Stepanov, Molecular Biology, Moscow, VSh, 1996, pp. 105-106, 561 S. [2]). This leads to the release of the O ₂ molecule and the release of the CO ₂ molecule, which involves new water molecules in the oxidation process. Thus, the process of plant tissue formation occurs, the intensity of which directly depends on the concentration of carbonic acid in the physiological cycle of plants, as emphasized in the patent [1].

Known, in particular, technologies that provide for watering plants with water saturated with carbon dioxide (see, for example, RF patent No. 2527065 (publ. 08/27/2014) [3], the direct supply of liquid carbonic acid or gaseous carbon dioxide into the soil (see. , for example, the aforementioned patent [1], RF patent No. 2338363, publ. 20.11.2008 [4]).

Such technologies are characterized by the need to equip plant growing areas with special equipment for the implementation of the specified supply.

Along with such technologies, technical solutions are being developed related to fertilizers intended for application to the soil.

So, in the patent document of the PRC No. 111333435 (publ. 06/26/2020) [5], a complex fertilizer based on carbon dioxide hydrate with the addition of various microelements and a method for its production are proposed. This fertilizer can be used in traditional ways, but it requires the use of negative temperatures during its production and temperatures of about -5 ° C during storage.

RF patent No. 2321573 (publ. 10.04.2008) [6] proposes a complex fertilizer containing liquid and bulk components. As the latter, when obtaining fertilizer, a sludge is used that occurs during the biological treatment of domestic wastewater, which is subjected to disinfection, decontamination and drying, and as a liquid component, carbonic acid H ₂ CO ₃ . The fertilizer contains a number of nutritious ingredients and, due to the presence of carbonic acid, as noted in the patent [6], contributes to an increase in humus formation and soil fertility. This fertilizer is applied by applying it simultaneously with plowing the soil.

Although the patent [6] emphasizes that the above result is due to the combined effect of the named components, this fertilizer is actually a two-component fertilizer, since the said bulk and liquid components must be stored and applied separately from one another. In this case, the introduction of fertilizer requires the implementation of specific techniques that make up the content of the method, which is the subject of another invention of the same patent and provides for the features of the implementation of plowing with the introduction of components at different depths. Since the liquid component of the fertilizer, which is carbonic acid, comes into direct contact with the soil, an accelerated release of carbon dioxide occurs. However, this feature noted in the patent [6], at the same time, can be the reason for the too rapid loss of the properties of the fertilizer as a source of carbon dioxide.

The method for obtaining a complex fertilizer according to the patent [6] is the closest to the method according to the proposed invention.

The invention according to the proposed method is aimed at achieving a technical result, which consists in providing the possibility of using the fertilizer obtained during its implementation as a single material by directly introducing it into the soil during plowing or pre-sowing preparation while maintaining the properties due to the presence of carbon dioxide and ensuring its gradual release into the soil.

Along with this, other types of technical result can be achieved, which will be named and explained in the future when disclosing the essence of the invention, as well as when describing examples of using the resulting fertilizer, and manifested both in the process of implementing the method and in the properties of the resulting product, regardless of the properties of the closest known method and the product obtained with its help.

The proposed method for producing a complex fertilizer containing carbonic acid, as well as the closest known to it, includes the use, along with carbonic acid, of a component based on bulk material containing nutritive ingredients.

To achieve the above technical result in the method according to the invention, in contrast to the closest known to it, a natural mineral, serpentinite, is used as the specified component, subjected to wet grinding in a carbonic acid medium H ₂ CO ₃ . Before the specified grinding, the serpentinite is first subjected to crushing to achieve a particle size acceptable for the equipment used for wet grinding, then it is poured with carbonic acid and held for at least 7 hours, and the wet grinding process is carried out at the initial mass ratio of solid and liquid phases in the processed material S: W from 1.2: 1 to 1.4: 1 and lead it until the resulting product reaches a pasty consistency with a solid particle size of not more than 0.02 mm.

Fertilizers using serpentinite are widely known, and in most cases, serpentinite acts as a magnesium-containing component of the fertilizer produced, to which other useful components are added (such as potassium, phosphorus, trace elements, in particular, contained in drilling water, etc.), see. , for example: USSR author's certificate No. 245144 (publ. 06/04/1969) [7]; RF patent No. 2046785 (publ. 27.10.1995) [8]; RF patent No. 2151132 (publ. 05/07/1999) [9]. At the same time, in all the above-mentioned inventions, serpentinite is subjected to roasting at a temperature of the order of 600-800 ° C, which, as explained in documents [8], [9], has the goal of activating its surface.

Preparation of the proposed fertilizer as a single material, without high-temperature roasting, requiring only the above-mentioned operations, can significantly reduce energy consumption during its production.

As the studies have shown, wet grinding of serpentinite in a carbonic acid medium favorably differs from similar grinding in water with an equal mass ratio of solid and liquid phases in that the sizes of solid particles of serpentinite are on average 7-10 times smaller. Due to this, there is a significant increase in the contact surface of the phases - by almost two orders of magnitude. Such an increase, achieved with a particle size not exceeding = the above value of 0.02 mm, in combination with the porosity of serpentinite, ensures the absorption of the liquid phase, which determines the "capacity" of the fertilizer for carbonic acid and the gradual release of it with the release of CO ₂ when the fertilizer is used.

A consequence of the noted increase in the degree of grinding and growth of the contact surface of the phases is also the greater availability of inclusions of the crushed mineral blocked by waste rock. Due to this, as a result of the reaction with carbonic acid, the magnesium silicate contained in the initial serpentinite raw material is carbonized to magnesium carbonate, a valuable substance for plant nutrition.

The intensity of the described processes occurring during grinding, as shown by the results of experimental studies, significantly increases if the crushed serpentinite is kept in carbonic acid before grinding. After such aging, in combination with the above initial S: L ratio (from 1.2: 1 to 1.4: 1), the grinding time until a grinding degree of 0.02 mm is achieved, with the possibility of achieving a pasty state of the material upon completion of grinding, can be shortened several times. Experiments have shown that aging for 7 hours in combination with the initial S: L ratio within the above limits is sufficient. A further increase in the holding time leads only to a slight increase in the noted effects. At the same time, an increase in the initial S: L ratio in comparison with 1.4: 1 affects in the same way as a decrease in the holding time, and prevents the achievement of these effects, and its decrease in comparison with 1.2: 1 leads to an undesirable decrease in the density of the resulting pasty masses.

The noted reduction in grinding time due to preliminary holding of crushed serpentinite in carbonic acid can significantly increase the productivity of the process as a whole, since the time during which complex mill equipment is employed to obtain each portion of the product is correspondingly reduced.

When using the fertilizer obtained by the proposed method, the properties of serpentinite are also realized, which it manifests in the composition of other fertilizers containing it.

So, serpentinite, along with the main properties, due to which it contributes to the normalization of soil acidity, has anion exchange properties (see, for example, RF patent No. 2316479, publ. 10.02.2008 [10]). Its inherent anion exchange capacity helps to retain useful anions: phosphates, nitrates and sulfates, preventing them from being washed out by soil water. In addition, serpentinite itself is a proven and used fertilizer containing magnesium, calcium, iron and useful microcomponents. In particular, it is this circumstance that determines the complex nature of the fertilizer obtained by the proposed method.

Serpentinite, which is part of the resulting fertilizer, also has bactericidal properties. The fertilizer is at the same time a good ameliorant due to the properties of the crushed serpentinite that constitutes its basis, which helps to improve the structure of the soil and its drainage properties, increase water retention (due to the high content of micro- and nanopores in serpentinite) and create a favorable water-air regime for plants.

The fertilizer obtained by the proposed method is convenient for storage, packaging and transportation, as well as for practical use in agriculture with the addition, if necessary, of other components.

In a particular case, such a component can be brown coal. In this case, the fertilizer additionally contains brown coal in the resulting pasty mass, which is subjected to the specified grinding together with serpentinite, adding it in an amount of 15 to 30% of the mass of serpentinite to be ground, aged in carbonic acid. Like serpentinite, brown coal is preliminarily subjected to crushing to achieve a particle size acceptable for equipment used for wet grinding.The component brown coal contains humic substances in a bound state and is a source of organic matter, and, therefore, such a complex fertilizer will be organomineral.

It is known that brown coals are a layered structure in which organic and aqueous layers alternate and form a spatial "polysandwich". The share of water in brown coal is 45-65%, the water layers can be replaced with other substances that are widely used in agriculture. The content of humic acids in brown coal reaches more than 60%, the complexity of the structure of humic substances determines a wide range of their use as growth stimulators, micronutrient fertilizers, to combat chemical pollution, improve soil structure, etc. (SI Zherebtsov, NV Malyshenko, S.Yu. Lyrshchikov and others. Composition and biological activity of brown coal humates as stimulators of crop growth / Bulletin of the Kuzbass State Technical University. - 2014. - No. 5 (105). - pp. 102-106 [11]).

In a number of works, the effect of humic substances of brown coals on the accumulation of organic matter, the water-physical properties of the soil, an increase in the yield of grain, fodder and vegetable crops, an increase in the resistance of plants to diseases, frosts and drought are noted. Information is given that brown coals bind heavy metals and cleanse the soil from harmful chemical and biological components (S.I. Zherebtsov, N.V. Malyshenko, S.Yu. Lyrshchikov and others. Functional composition of brown coal humates and their stimulating activity / International scientific-practical conference. Comprehensive approach to the use and processing of coal. - Dushanbe, 2013. - pp. 96-97 [12]).

When brown coal is added for joint grinding with serpentinite in an amount of less than 15% of the mass of serpentinite kept in carbonic acid, the humification provided by brown coal turns out to be too weak, and when more than 30% is added, the acidity of the fertilizer increases.

The fertilizer obtained by the proposed method, including in the case described above, when it additionally contains brown coal, can be used both in the form of a pasty mass, which it is immediately after wet grinding, and in the form of a loose crumbly material obtained by tedding dried naturally pasty mass.

The high content of various resins and wax in brown coal, in the case of using the latter, gives the fertilizer plasticity and makes it possible to efficiently granulate or briquett it into molds of various configurations and sizes.

The resulting complex fertilizer can be applied locally for cereals in the amount of 250-300 kg / ha, in protected ground - for cucumbers, tomatoes 0.3-0.4 kg / m ² , as mulch - for root crops, onions, garlic, lettuce, dill, radish - 1.0-0.5 kg / m ² .

The implementation of the proposed method is illustrated in Fig. 1, which schematically shows the sequence of its operations. The circuit elements of FIG. 1, shown by dashed lines, relate to special cases of the method using brown coal and obtaining fertilizer in the form of loose friable material, granules or briquettes.

It is advisable to organize fertilizer production near the deposit of the mineral used - serpentinite.

At the grinding and concentration section of the deposit, serpentinite is crushed (position 1 of Fig. 1) to the size specified for the equipment used for the upcoming wet grinding in accordance with its technical characteristics (for example, for the vertical mills of Metso Outotec mentioned below - no more than 6 mm (Yu Smirnov. Vertical mills Vertimill®: efficient and affordable. Magazine "Mining Industry", No. 2, 2013, p. 82 [13]).

Then serpentinite is loaded into containers, which are filled with carbonic acid (item 2 of Fig. 1). After keeping under such conditions for 7 hours (item 3 of Fig. 1), the serpentinite is unloaded from the containers and transferred to the production site for fine grinding.

Crushed serpentinite, aged in carbonic acid, is loaded into the grinding tank of the mill, carbonic acid is poured there (position 4 of Fig. 1) to ensure the mass ratio of the solid and liquid phases S: L within the above limits (from 1.2: 1 to 1 , 4: 1).

In a particular case, together with serpentinite, crushed brown coal (item 4A in Fig. 1) can be loaded into the grinding tank of the mill at the above ratio by weight with serpentinite previously aged in carbonic acid.

Next, wet grinding of the material loaded into the grinding tank is carried out (item 5 of Fig. 1). With fine grinding, the destruction of the material begins in its most weakened places - at the joints between material particles, in pores, cracks, etc. Grinding of the material in an H ₂ CO ₃ environment accelerates this process. As noted above, preliminary holding of serpentinite in carbonic acid further accelerates it. The high hydrophilicity of serpentinite and brown coal in the case of using the latter (ultimately, the original H ₂ CO ₃ in an amount of up to 25% of the mass of the ground material is in its micro- and nanopores) contributes to the fact that acid molecules quickly wet the newly formed during the destruction of the surface particles, helping to grind. A two-dimensional pressure is created in microcracks, directed deep into the particle, which, acting simultaneously with a decrease in the free surface energy of the particles, accelerates their destruction.

The duration of the wet grinding cycle is 1.5-2.5 hours. Under the conditions of a specific production, the duration of this cycle is selected empirically at the stage of debugging the production process, performing control tests with checking the consistency of the resulting product and the fineness of grinding. The characteristic size of solid particles after grinding is no more than 0.02 mm.

The process of wet grinding (position 5 of Fig. 1) ends with the unloading of the pasty mass on special trays. It is stored in a production room, then transferred for further use as a finished fertilizer, or for use after transformation into a loose friable material obtained by tedding a dried pasty mass (item 6 of Fig. 1).

In special cases involving the production of the proposed fertilizer using brown coal in the form of granules or briquettes made from a pasty mass (position 7 of Fig. 1), well-known standardized technologies for granulating and briquetting substances in industry can be used (see, for example: GOST 22834 -87 "Compound feed granulated" [14], GOST R 57016-2016 "Coal briquettes for energy and household needs" [15]).

The preferred type of mill equipment in a large-scale production is vertical gravity mills [13]. Such mills, occupying a smaller area and providing an acceptable grinding fineness indicated above, simultaneously provide a greater granulometric uniformity of the grinding result, while they are characterized by lower energy consumption and a lower wear rate of the grinding bodies.

To assess the effectiveness of the resulting complex carbon dioxide fertilizer, an experimental study of its use was carried out.

Example 1.

Experimental studies with seeds and plants were carried out in the experimental farm of JSC "Scientific and Production Enterprise" Radiy "(the village of Knyazhyi Gory, Zubtsovsky District, Tver Region).

Four batches of white cabbage were planted in the sod-podzolic soil of the experimental plot. The experiment was carried out in the period from 08.05 to 29.05.2021.

The first pilot batch of twenty seeds was planted in holes with fertilizer obtained by the proposed method without the addition of brown coal, in the form of a pasty mass in the amount of 9 grams.

The second same pilot batch of seeds was planted in holes with fertilizer obtained by the proposed method with the addition of brown coal in the amount of 30% in relation to the mass of serpentinite after keeping the latter in carbonic acid, in the form of a pasty mass in the amount of 9 grams.

The third pilot batch of twenty seeds was planted in holes together with cylindrical granules (one granule 16 mm long and 9 mm in diameter in a separate hole) containing fertilizer obtained by the proposed method with the addition of brown coal in an amount of 30% in relation to the mass of serpentinite after keeping the latter in carbonic acid.

A fourth batch was formed with control seeds planted in empty wells.

All wells were watered in the same mode, three times a day, with ordinary tap water.

In the course of the experiment, the rate of gain of the plant mass of the experimental plants from the first batch exceeded the same indicator for the control plants by 1.5 times, the experimental plants from the second and third batches - 2 times. The root system of the experimental plants was significantly more developed than that of the control ones.

These experiments indicate that the use of the fertilizer obtained by the proposed method in the sowing process can significantly improve the quality and efficiency of plant mass growth and contributes to a reduction in the total amount of agricultural work.

Example 2.

Studied the change in the quality of barley grain when using a complex fertilizer, obtained in accordance with the proposed method. The place of the experiment is the experimental farm of the Scientific and Production Enterprise Radiy JSC (the village of Knyazhyi Gory, Zubtsovsky District, Tver Region).

Two plots of 0.2 hectares were prepared. Used a complex fertilizer obtained by the proposed method (without the addition of brown coal). Fertilizer was applied to the soil (evenly scattered at the rate of 0.8 kg / m ² ) immediately before plowing the soil in the form of a loose crumbly material obtained after drying the pasty mass.

After plowing, the soil in both plots was cultivated with subsequent sowing of barley.

At the end of the growing season, plant samples were collected from all plots. The amount of green mass of barley from 1 m was 5.1 kg for the experimental plot and 3.9 kg for the control plot.

Comparison of the harvested barley crop after the crops ripened showed a significant (by 20-30%) increase in the yield on the experimental plot compared to the control, from which it can be concluded that the complex fertilizer obtained by the proposed method increases the quality and yield of barley grain.

Example 3.

The research was carried out on the experimental field of the "Starokuvinsky" farm, located in the floodplain of the Bolshoi Zelenchuk river, near the Vedensky deposit of natural serpentinite in the Karachay-Cherkess Republic. The object of the study was sunflower. The time of the experiment is March-May 2021.

The aim of the work was to experimentally verify the effectiveness of the use of a complex fertilizer obtained in accordance with the proposed method, in the case when it additionally contains brown coal in an amount of 20% in relation to the mass of serpentinite after keeping the latter in carbonic acid, i.e. is actually organomineral. The soil of the experimental plot is ordinary chernozem, calcareous, medium-thick, low-humus. The area of the experimental plot is 0.3 hectares, the control plot is 0.2 hectares.

A complex fertilizer in the form of a loose crumbly material obtained after drying the pasty mass was preliminarily scattered on the experimental plot at the rate of 0.3-0.5 kg / m ² .

In field experiments, the dynamics of the accumulation of dry matter and the development of the leaf area of plants were studied.

There was a positive effect of fertilization on the growth and development of the stem and leaves of sunflower. In the experimental field, the accumulation and average daily gain of dry matter significantly increase. Fertilization helps to reduce the coefficient of water consumption by the plant, in contrast to the control plot, the height of the plants and the amount of green mass increase in the experimental plot. As a result of the presowing application of complex fertilizer, the sunflower caps in the experimental field look brighter and more powerful than in the control field.

The positive effect of complex fertilization on the resistance of plants to unfavorable weather conditions has been determined. In mid-May, hail fell in the area of the experiment, which severely damaged the plants. I was surprised that almost all sunflower in the experimental field recovered to its normal state within 2-3 days, while half of the plants in the control field died completely, and the remaining half of the sunflower did not recover to its original state.

Example 4.

This example relates to the use of fertilizer obtained by the proposed method with the addition of brown coal, in the case when the pasty mass is subjected to briquetting.

Briquetted fertilizers are mainly used for planting plants in poor soil. Individual or block use of briquettes of various sizes and shapes is possible. The seeds, immediately before planting, are placed inside the briquette, which, gradually disintegrating, lets the roots of the plant pass through itself.

The place of the experiment is SNT "Skala-3", near the town of Protvino in the south-west of the Moscow region.

In the fall of 2019, 10 control beans of the Lastochka variety were planted in holes formed in sandy soil. 10 seeds from a pilot batch were preliminarily placed in cylindrical hollow briquettes 50 mm long with an inner diameter of 9 mm and a wall thickness of 5 mm and were also embedded in prepared holes.

Until the spring of 2020, no work was carried out on the plot. The first shoots in the experimental group of plants appeared in mid-April, and in the control group only by May weak shoots appeared in two holes out of 10, the rest of the seeds died. By the end of summer, 7 out of 10 test plants had yielded, all control plants had died.

The results of this experiment make it possible to judge the possibility of using briquetted fertilizer obtained by the proposed method for growing plants even in conditions not adapted for their cultivation.

Thus, the complex fertilizer obtained by the method in accordance with the invention can be used in agriculture for intensive crop production, including for growing crops in difficult climatic conditions. An important feature of this fertilizer lies in the possibility of traditional methods of its use as a single material by direct introduction into the soil during plowing or simultaneously with sowing.

Sources of information

1. RF patent No. 2318306, publ. 10.03.2008.

2. V.M. Stepanov. Molecular biology, p. 105-106, Moscow, VSh, 1996, 561 pp.

3. RF patent No. 2527065, publ. 27.08.2014.

4. RF patent No. 2338363, publ. 20.11.2008.

5. Patent document of the PRC No. 111333435, publ. 06/26/2020.

6. RF patent No. 2321573, publ. 10.04.2008.

7. USSR author's certificate No. 245144, publ. 06/04/1969.

8. RF patent No. 2046785, publ. 10/27/1995.

9. RF patent No. 2151132, publ. 05/07/1999.

10. RF patent No. 2316479, publ. 10.02.2008.

11. S.I. Zherebtsov, N.V. Malyshenko, S.Yu. Lyrshchikov et al. Composition and biological activity of brown coal humates as stimulators of agricultural crops growth / Bulletin of the Kuzbass State Technical University. - 2014. - No. 5 (105). - With. 102-106.

12. S.I. Zherebtsov, N.V. Malyshenko, S.Yu. Lyrshchikov et al. Functional composition of brown coal humates and their stimulating activity / Mezhdunar. scientific and practical. conf. An integrated approach to the use and processing of coal. - Dushanbe, 2013 .-- p. 96-97.

13. Yu. Smirnov. Vertimill® vertical mills: efficient and affordable. Mining Industry Magazine, No. 2, 2013, p. 82.

14. GOST 22834-87. Compound feeds granulated.

15. GOST R 57016-2016. Coal briquettes for energy and household needs.

Claims (4)

1. A method of obtaining a complex fertilizer containing carbonic acid and a component based on bulk material, including nutritive ingredients, characterized in that the specified component is a natural mineral - serpentinite, wet-milled in carbonic acid, which is first subjected to wet grinding crushing until a particle size acceptable for the equipment used for wet grinding is reached, then it is poured with carbonic acid and held for at least 7 hours, and said wet grinding is carried out at the initial mass ratio of solid and liquid phases in the material being processed S: W from 1 , 2: 1 to 1.4: 1 and lead it until the resulting product reaches a pasty consistency with a solid particle size of not more than 0.02 mm. 2. The method according to claim 1, characterized in that the specified wet grinding together with serpentinite aged in carbonic acid is additionally subjected to brown coal, previously crushed to achieve a particle size acceptable for equipment used in wet grinding, in an amount of 15 to 30% from the mass of the specified serpentinite. 3. A method according to claim 1 or 2, characterized in that the resulting product having a pasty consistency is dried and, by tedding it, is transferred to the state of a loose friable material. 4. A method according to claim 2, characterized in that the resulting product having a pasty consistency is granulated or briquetted.

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