SU1096261A1 - Method for reducing caking of mineral fertilizers - Google Patents

Abstract

The method of suppressing the traceability of MHEPAL FERTILIZERS by treating them with a conditioning additive including calcium carbonate and G silica, characterized in that, in order to increase the effectiveness of the conditioning additive, sapropel, previously dried to a moisture content of 10–20%, is used as the last additive.

Description

1 The invention relates to the production of mineral fertilizers and can be used in plants producing caking-prone fertilizers. There is a known method for preventing caking of fertilizers by coating the granules with a conditioning additive - mineral profillite, co. The latter is used in an amount of 0.052, 5, preferably 0.5-1 wt.%. At the same time, the caking of powdered ammonia seligers is 0.15 kg / cm (15 kPa) lj. When used as a conditioner of profillite (aluminosilicate mineral), the fertilizer contains up to 1% by weight of the ballast material, which is not used by the plant. In addition, it has insufficient adhesion properties when processing difficult-mixed fertilizers (nitphos, nitroammophosca, etc.). The closest to the proposed technical essence and achievable result is the method of reducing the caking of mineral fertilizer (ammonium nitrate) by treating the condensation supplements with a homogeneous mixture of calcium carbonate and amorphous silica (in a molecular ratio of 1: 1), obtained by carbonization of calcium metasilicate 21. The carbonated calcium metasilicate investigated as a conditioning additive contains a significant amount (36.15%) of the ballast element - silica. In addition, this conditioner almost does not interact with ammonia seed even with SOC and a moisture content of 1.5-2%. As a result, the anti-caking effect is mainly due to the formation of a protective sheath of calcium carbonate compounds not bound to the surface of the fertilizer. Silica B, thus obtained, in the shell serves as an inert filler. This shell has discontinuities in the form of cracks, through which the fertilizer contacts directly with the atmosphere, absorbing moisture. 61 The aim of the invention is to increase the effectiveness of the conditioning additive. This goal is achieved by the fact that according to the method of reducing the traceability of mineral fertilizers by treating it with a conditioning additive, including calcium carbonate and silica, saprapel, previously dried to a moisture content of 10–20%, is used as the latter. Sapropel - bottom sediment of freshwater lakes, the content of organic substances in which no less. 15%. The composition of sapropel also includes mineral macro- and microelements. As a conditioning additive, predominantly sapropel is used with a calcium carbonate content of at least 20% by weight. The sapropel used has the following composition, wt%; the residue from calcination at 830 ° С is 35-65, incl. SiO 0.3-35, CaO 12-48, the remaining mineral components (Fe.0 ,,, SOj, P.Og, 1.5-10.0, organic matter 15-40, nitrogen 0.2-3, trace elements Sapropel is an active ion exchanger and not only creates a protective hydrophobic coating that is chemically and physically sorbed onto the surface of mineral fertilizers, but also interacts with their components. In particular, it neutralizes the functionally acidic components of the fertilizer, for example, excess phosphoric acid, reducing the total the acidity of the conditioned mineral tusks. The ability of nutrients to be exposed to atmospheric moisture and reduces the caking of the fertilizer as a whole. The ion-exchange and adhesion properties of sapropel show up best at its moisture content of 1020%. At a moisture content of more than 20%, the aggregate state of the crushed sapropel is unstable due to its tendency to coarsen. This greatly impedes the formation of a uniform and dense coating of fertilizer granules without discontinuities and entails an increase in the consumption of conditioning additives. In addition, at this humidity, the sapropel makes an unnecessary amount of moisture, which reduces the effect of reducing caking. When using sapropel, dried to, less than 10% of dryness, adhesion of sapropel to the surface of the granules is reduced. Example. In order to condition the mineral fertilizers of nitrophos and nitroammophoska, in order to reduce their tracking, they take 50% sapropel, obtained in accordance with the existing technology of preparation of sapropel fertilizers, dried it to a moisture content of 10-20% and crushed on hammer crushers to a state that corresponds to the following sieve composition: residue on sieve +1 mm not more than 10%. , 50 kg of nitrophos are thoroughly mixed with 250 g of sapropel, a sample is taken according to GOST 21560.0-76 mass 50.0 g, and the tracking is carried out in accordance with GOST 21560.4-76. The sample is loaded into a mold and placed in a thermostat, inside which a constant temperature of 50t2 ° C is maintained. A load of 2.810.5 kg is placed on the platform and seized 24 hours, after which the image is subjected to a fracture test. Similarly, samples are prepared with different doses of sapropel, corresponding to 0.3-6 wt.%, And a control sample of the fertilizer is taken without the sapropel being fertilized and subjected to the same tests. Along with this, testing is carried out according to GOST 21560.5-76 , for which 50 kg of nitrophos, thoroughly mixed with 250 g of sapropel (0.5%), are packed in a standard container (five-ply bituminous bituminous paper bags) and placed in a template in the second layer below, under a ballast weighing 450 kg. After six months of storage, the product is tested for friability. The effectiveness of the conditioning additive is also assessed by the maximum hygroscopicity (W) according to the Mitscherlich method, which is based on establishing the equilibrium state of the material's moisture content in the air completely saturated with water vapor and the stability (c) of nutrients to leaching out when the fertilizer is in the aqueous medium. Resistance (B) is characterized by the amount of nutrients transferred from the granules to the solution for 10 minutes in the aquatic environment as a percentage of their total content in the granules. The results of measurements of these parameters are presented in the table.

Air conditioning additive - sapropel

1.0 1.0 1.0 1.0 1.0 0.5

Nitrophos

l

30 10 10

100

100

100

10 25 15

100

95

100

Thus, the data in the table confirm the higher efficacy of sapropel as a conditioning additive as compared to the known carbonated metasilica TdM calcium. The most effective treatment is sapropel, dried to 10-20% vts nost. This is due to the fact that when using sapro dried up to a moisture content of less than 10%, the adhesion of sapropel to the surface of the granules is reduced. When the humidity is greater than 20%, the aggregate state of the crushed sapropel is unstable due to the tendency due to, obviously, cohesive forces to

enlargement of particles. This entails an increase in the consumption of the conditioning additive and makes it difficult to form a continuous and dense coating of fertilizer granules. In addition, an undesirable amount of moisture is introduced, which reduces the effect of caking reduction.

The application of the proposed method in agriculture allows reducing the caking of mineral fertilizers during storage, improving their physicochemical properties, enriching the organic component and microelements, and thereby increasing the efficiency of mineral fertilizers.

Claims (1)

METHOD FOR REDUCING THE FOLLOWABILITY OF MINERAL FERTILIZERS by treating them with a conditioning additive, including calcium carbonate and / silica, characterized in that, in order to increase the effectiveness of the conditioning additive, sapropel is used as the latter, previously dried to a moisture content of 10-20Z.