SU1659387A1 - Method of producing liquid nitrogen fertilizer with nitrification inhibitor - Google Patents

Abstract

The invention relates to the technology of liquid mineral fertilizers with the simultaneous synthesis of a nitrification inhibitor and contributes to a decrease in the crystallization temperature of the fertilizer while reducing the cost of the process. According to the invention, technical calcium cyanamide is subjected to hydrolysis to form an acidic salt of calcium cyanamide and neutralization with the last nitric acid to a pH of 4.5-5.5, followed by the introduction of ammonia or ammonia water into the resulting solution to pH 9-10, heating the latter for 10-15 minutes to a temperature of 45-50 ° C and the introduction of nitric acid to a neutral medium followed by the introduction of an unconditioned part of urea and ammonium nitrate in a ratio of 1: (1-1.22), respectively. Hydrolysis of technical calcium cyanamide is carried out at ratios Ж-Т (3-4) 1, temperature 25-35 ° C and time 1 hour. The proposed fertilizer has a crystallization temperature of -20 ° C while maintaining the quality of the product. 1 з п ф-лы, 1 table С с

Description

The invention relates to the technology of mineral fertilizers and can be used to obtain liquid nitrogen fertilizers based on substandard parts of urea and ammonium nitrate with simultaneous synthesis of a nitrification inhibitor.

The purpose of the invention is to reduce the crystallization temperature of the fertilizer while reducing the cost of the process f. The invention is illustrated by the following examples.

Example 1: To 300 ml of water, 100 g of technical calcium cyanamide are added in portions. The hydrolysis is carried out with vigorous stirring for 1 h and a temperature of 35 ° C, the insoluble part of the suspension is separated in the form of calcium hydroxide, iron, aluminum and free carbon, the precipitate is washed with water twice

75 ml. 477.72 ml of acidic salt of calcium cyanamide with a concentration of 8.3% Ca (HCN2) 2 is formed. The resulting solution is neutralized, 73.3 ml of 56% HMO, a pH of 4.5-5.5, forms a mixture of calcium nitrate and free cyanamide in an amount of 551 ml, where 25% ammonia water is introduced in an amount of 40 ml to create a pH of 9-10. The heated solution to 45 ° C is kept slightly stirred for 15 minutes, then neutralized again with 32.14 ml of 56% HNM03 to neutral (pH 6-7) medium on indicator paper. A solution is formed containing NH-qNOA 22.86 g. H4C2N, 27.4 g Ca (N03) r 43.46 g, the concentration of which is 18.25 mas.%. Sub-standard carbamide and ammonium nitrate are added to this solution in the amount of 1277 g (of which urea is 585 g, ammonium nitrate is 692.0 g) Ratio 55% МН4МОз

with

h

with about

N

- 45% CO (NH2) 2 1: 1.2-1.275. The crystallization temperature of this solution is -20.9 ° C. p 1183 mPa sr 1167 1 (G3 kg / m3. Concentration of LCS solution 72.68 wt.%. Nutrient content, wt.%:, 81, 16, MdTSda 0.48, H4C2N4 2.82, 02, The sum of nutrients 30,16.

PRI mme R 2. Similarly to Example 1, to the obtained 623.14 ml of a solution of Ca (NO3) 2 + H2CN + MH4Moz with a concentration of 18.3% by weight, substandard urea and ammonium nitrate are added in an amount of 1577 g ( of these, 720 g of carbamide and 857 g of ammonia nitrate). The ratio of CO (NH2) 2 45%: MN / ZMOZ, 2. The crystallization temperature of the obtained JAU is 18.9 ° C. JU 1271 MPa.s. 1198-Ю 3 kg / m3, solution concentration 76.4 wt.%, Nutrient content, wt.%:, 34,, 75, 43, MDCda 0.43, P4C2N4 2; 43. The amount of nutrients 32.77.

Example 3. To 300 ml of water 100 g of technical calcium cyanamide are added in portions. The hydrolysis is carried out with vigorous stirring for 1 h, a temperature of 30 ° C, the insoluble is separated, part of the suspension in the form of hydroxides of Ca, Al, Fe, silicon and free carbon and washed the precipitate twice with 75 ml of water. 477.72 ml of a solution of the acidic salt of calcium cyanamide with a concentration of 8.3% Ca (HCN2) a is formed. The resulting solution neutralizes 82.14 ml of 50% HNOs to a pH of 4.5-5.5 in universal indicator paper, forming a mixture of calcium nitrate and free cyanamide in an amount of 560 ml (14.44% solution), 40% ammonia water was added in an amount of 40 ml to create a pH of 9-10 (control was carried out on universal indicator paper). The whole mass is heated at 50 ° C for 10 minutes to convert free cyanamide to dicyandiamide (2HaC). Next, neutralize again 36 ml of 50% HNO $ to a neutral (pH 6-7) medium. In this case, 627 ml of a 18, 13% solution is formed. Substandard urea and ammonium nitrate are added to this solution in the amount of 1277 g (of which 585 g of urea, 692 g of ammonium nitrate). The ratio of 45% CO (NH2) 2: 55% NH4N03 is 1: 1.2. The crystallization temperature of the obtained LPA is -21.0 ° C, / and 1376-10 3 mPa.s, p 1217-10 3 kg / m3. The concentration of the solution is 72.53 wt.%. The content of nutrients, wt.%:, 75,, 38, CaO2.81, Mdtsda 0.96, H4C2N4 2.81. The amount of nutrients 31,56. LCS concentration is 72.53 wt.%.

PRI me R 4. Similar to example 3 to the resulting 627 ml of solution

(Ca (N03) 2 + H2CN2 + NH4) with a concentration of 18.1% add unconditioned urea and ammonium nitrate in the amount of 577 g, of which 45% CO (МН2) 2 720 g, NH4N03 55% 857 g), the ratio is 1: 1,2.

The crystallization temperature of such a solution is -18.1 ° C, 1201-U 3 mPa.s; p1151 10 kg / m3. The content of nutrients, wt.%:, 28,, 14, 43,, 43.

The amount of nutrients 32.71 wt.%. The concentration of the resulting JAR is 76.27 wt.%.

Example 5. To 300 ml of water 100 g of technical cyanamide are added in portions

calcium. The hydrolysis is carried out with vigorous stirring for 1 h, a temperature of 25 ° C, the insoluble part of the suspension is separated in the form of Ca hydroxides. Al, Fe. silicon and free carbon washed

twice with 75 ml each. The washings are added to the filtrate. 477.72 ml of a solution of the acidic salt of calcium cyanamide with a concentration of 8.3% Ca are formed (HCN2h. The resulting solution is neutralized 82.14 ml.

50% nitric acid to pH 4.6-5.5 on universal indicator paper, thus forming a mixture of calcium nitrate and free cyanamide in the amount of 560 ml, i.e. 14.4%. For the polymerization of free

cyanamide in dicyandiamide, 10% ammonia water is added to the solution in an amount of 100 ml and a pH of 9-10 (control of which is carried out on indicator paper). 660 ml of a 13.8% solution is kept for 15 minutes at a temperature of 50 ° C. After that, 36 g of 50% HNOs are added to the solution to obtain 696 ml of a 16.3% solution (Ca (MO3) 2 + H4C2M4-MH4Moz). Sub-standard carbamide and ammonium nitrate are added to the latter in the amount of 1277 g (of which urea is 585 g, ammonium nitrate is 692 g). The ratio of 45% CO (MH2) 2: 55% MN4Moz 1: 1.22. The crystallization temperature is 20, 2 ° С, and 1478-10 3 mPa.s, / 51206-10 3

0 kg / m. The content of nutrients, wt.%:, 26, .26: MdTSDa 0.94, 76, H CiN4-1,42. The amount of nutrients 31.02. The concentration of HAA obtained is 71.3

5 wt.%.

Example 6. Similarly to Example 5, to the obtained 696 ml of a 16.3% solution of (Ca (N03) 2 + H4C2N + NH4N03) was added 1577 g of substandard urea and ammonium

saltpeter. The ratio of 45% CO (NH2) 2: 55% MH4Moz 1: 1.22. Crystallization temperature -17.8 ° C; C 1570-10 3 mPa.s; /) 120-i kg / m3, solution concentration 75.14%. The amount of nutrients, wt.%:, 84, Mam-Mnit-14.92. Nfllwa 0.82, 4 H4l2N4 1.23. The amount of nutrients 32,24.

The table presents data confirming the appropriateness of the selected parameters. The product obtained by a known method is a liquid fertilizer with a nitrification inhibitor based on nitrogen compounds with an admixture of phosphates and potassium salts, which contains dicyandiamide in an amount of 10% by weight of other nitrogen compounds, which are introduced in solid form into a solution of these nitrogen compounds and has the following physico-chemical characteristics:

Mom Mnitr 6.65

,five

, 7

,five

YDTSda 4.0

Thus, the proposed fertilizer has a lower crystallization temperature of -20 ° C while maintaining

salts 73.0

t crista 6,2 С

fi 1,337 -1 (G3mPa-s p 1.184 g / cm3

product quality. The use of dicyandiamide intermediate in the production of fertilizers is more economically advantageous. five

Claims (2)

Claims 1. Method for producing liquid nitrogen fertilizer with a carbamide-based nitrification inhibitor, nitrate compounds Ammonia nitrogen and salts of cyanic acid, characterized in that, in order to reduce the crystallization temperature of the fertilizer while reducing the cost of the process, technical calcium cyanamide is subjected to hydrolysis to form the acidic salt of calcium cyanamide and neutralization with nitric acid to a pH of 4.5-5.5 followed by the introduction of ammonia or ammonia water in the resulting solution to pH 0 9-10, heating the latter for 10-15 minutes to a temperature of 45-50 ° C, introducing nitric acid to a neutral medium by introducing into the mixture of urea and ammonium nitrate in the mass 5 ratio 1: (1 -1,22), respectively. 2. The way pop. 1, characterized in that the hydrolysis of technical calcium cyanamide wire with a ratio W: T (3-4): 1, a temperature of 25-35 ° C and a time of 1 hour. 0