RU2121969C1 - Method of preparing porous granular ammonium nitrate - Google Patents

Abstract

FIELD: manufacture of porous and explosion-proof explosives. SUBSTANCE: in concentrated of formula: NH₄NO₃ prior to granulation stage, is added sugar production waste, namely saccharose containing sugar beet molasses. In order to prepare porous ammonium nitrate, 0.05-0.15 wt % (calculated in terms of saccharose) molasses solution should be added to obtain product. Characteristics of the product: imbibing capacity of granules is 9.7-13.5 g/100 g; retaining capacity is 5.5+-0.5%; H₂O content is 0.35-0.60%; strength of granules is 500-700 g per granule. The resulting granules have high strength and are explosion-proof. EFFECT: more efficient preparation method. 2 tbl

Description

 The present invention relates to the technology of inorganic substances and can be used for the manufacture of simple, relatively cheap, affordable and explosion-proof explosives - granulites M, igdanites, as well as emulsion explosives used in mining, mining, coal and other industries.

A known method of producing porous ammonium nitrate (PAS) by introducing into the melt NH ₄ NO ₃ before granulation of the NF dispersant in an amount of 0.01 - 0.1 wt. % by weight of the finished product. According to this invention, the finished product has an absorbent capacity of granules up to 13 g / 100 g and a strength of 300 g / g. However, this fairly simple method, which does not require, in fact, the installation of additional equipment, has not found application in industry. This is because the obtained product, having a relatively high absorbent ability of the granules, retains only 1-1.5 wt.% Diesel fuel (DT) or other oils, while to achieve zero oxygen balance, ensuring full blasting , retention of 5.5 ± 0.5% DT is necessary. According to the above invention, when processing PAS granules with such a quantity of diesel fuel, the granules are oily and non-flowing, and the oil drains from them within a few hours.

 To achieve the technical result, a new method for producing PAS is proposed, which has the ability to hold 5.5 ± 0.5% for six to seven days using waste from the sugar industry - beet molasses (hereinafter referred to as molasses) according to OSTU 18-395-82, which includes sucrose (at least 43 wt.%). The latter has a guaranteed shelf life of nine months and is soluble in water. Moreover, with the introduction of this additive is obtained PAS with high strength granules.

After granulation of the melt, a product is obtained that has the following characteristic: the absorbency of granules 9.0 - 13.0 g / 100 g, the retention capacity of 5.5 ± 0.5% DT, the strength of the granules 500 - 750 g / g, soda. H ₂ O 0.3 - 0.6 wt.% (Fischer method).

Thus, a method for producing porous granular ammonium nitrate with high strength granules by introducing NH ₄ NO ₃ into a concentrated melt before the granulation stage of a liquid pore-forming additive is proposed, characterized in that molasses is introduced in an amount of 0.05 - 0.15 wt.% (in terms of sucrose). Moreover, molasses is introduced in the form of a sucrose solution diluted 1.2-2 times and contains 35-29 wt.% Sucrose in order to reduce the viscosity of the injected solution.

 In this case, a reaction occurs.

Получившийся в результате реакции углерод объясняет светло-коричневый цвет готового продукта. Необходимо отметить, что его количество находится в пределах допуска в аммиачной селитре (при введении 0,1 мас.% сахарозы его содержание 0,025 мас.%).

The resulting carbon explains the light brown color of the finished product. It should be noted that its amount is within the tolerance in ammonium nitrate (with the introduction of 0.1 wt.% Sucrose, its content is 0.025 wt.%).

Investigation of the pore structure of PAS obtained by the prior art (sample 1) and the present invention (obr.2) showed that in the first case the pore volume was 0.037 cm ³ / g (V _macropores - 0.019 cm ³ / g, V _{the Transitional} - 0.018 cm ³ / g), i.e. their percentage is 50:50. At the same time the pore volume of the second sample was 0.160 cm ³ / g (V _macropores - 0.128 cm ³ / g, V _{the Transitional} - 0.032 cm ³ / g), ie their percentage ratio 80:20... It was found that transition pores practically do not participate in the process of sorption of diesel fuel, because Due to the length of the molecule of the latter, DT does not penetrate into the pores, not exceeding their diameter by a factor of three, which, as shown by our studies, accounts for the bulk of the transition pores.

 In the table. 1 shows the results of measuring the parameters of the porous structure of these two samples.

As follows from the table. 1, the volume of the caverns in the sample PAS according to the invention is ≃ 30% of the total pore volume and the granules are able to hold 5.5% + 0.5% DT. PAS granules obtained using a NF dispersant, although they have a high total porosity, practically do not absorb oil because of the large volume of caverns, which is 89.0% of the total pore volume. According to our studies, the NF dispersant, without reacting with amcelite melt, is practically necessary to facilitate the diffusion process and more uniform distribution of gas bubbles generated during the melt granulation, reducing the energy barrier at the gas-liquid interface. In other words, the presence of an NF dispersant in the NH ₄ NO ₃ melt reduces the rate of gas evolution that takes part in the formation of pores in the melt droplets until they solidify. At the same time, as a result of the interaction of molasses with a melt of NH ₄ NO ₃ , as shown above, carbon dioxide, nitrogen and oxygen are released, which participate in the formation of pores at the time of formation of the granules.

 Thus, the introduction of molasses into the melt (in contrast to the NF dispersant) resulted in a porous product absorbing 5.5 ± 0.5% DT.

 The quantitative content of the molasses introduced was selected experimentally, taking into account the quality of the obtained product, which also has the highest strength of the granules.

 The molasses content <0.5 wt.% (In terms of sucrose) resulted in a non-porous product, and> 0.15 wt.% Did not significantly change the characteristics of PAS. The limits of the introduced dispersant of the prototype were selected earlier.

Example. In a concentrated melt of NH ₄ NO ₃ (with a granulator capacity of 30 t / h), various amounts of sucrose contained in molasses are introduced. Data regarding the quality indicators of the finished product are summarized in table. 2. For comparison, the data according to the prototype.

 As follows from the table. 2, with the introduction of molasses containing <0.05 wt.% Sucrose, a non-porous product is obtained. The introduction of molasses> 0.15 wt.% Sucrose practically does not change the quality indicators of the finished product. The strength of the granules of the obtained product lies in the range of 500-700 g / g, which is 1.3 - 2 times more than that of the granules of the prototype.

It should be noted that in the case of introducing into the melt a deliberately overestimated amount of molasses, the temperature of the melt NH ₄ NO ₃ practically did not change (179-182 ^o C).

 The explosion safety of the obtained product in comparison with ordinary granular ammonium nitrate was proved by special studies. organizations. In particular, it was found that igdanite prepared on the basis of this PAS is stable for six days and detonates in a strong shell with a diameter of 40 mm from the intermediate detonator.

 Its use in wells with a diameter of ≃ 150-320 mm is recommended.

Claims (1)

A method of producing porous granular ammonium nitrate by introducing liquid pore-forming additives into a concentrated melt of NH ₄ NO ₃ , characterized in that beet molasses is introduced as a pore-forming additive, introduced in an amount of 0.05 - 0.15 wt.% In terms of sucrose to obtain finished product with granular strength up to 700 g / g.

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