CS227137B1 - Method of preparing liquid sulpho-nitrogenous fertilizers - Google Patents

Description

The present invention relates to a process for the production of sulfur-nitrogen liquid fertilizers containing 1.8 to 2.6 parts by weight of sulfur per part by weight of nitrogen.

It has been known for a long time that sulfur is an important breed of linear nutrients, but reports of sulfur deficits have only accumulated in recent years. In the past, sulfur <ranked among the so-called. secondary plant nutrients where they formed one group together with calcium, magnesium and iron. However, it is now increasingly recognized that this nutrient should be classified as a basic plant nutrient - along with nitrogen, phosphorus, and potassium / Hester B · - “Sulfur - The Fourth Major Nutrient Solutions 44-50, Nov.-Dec. / 1979 //. Long-lived plants take more sulfur from the soil than phosphorus, although the total amount of sulfur in the soil is less than half that of phosphorus.

Sulfur deficiencies are caused both by ever-increasing crop yields, by a continuously increasing concentration of used industrial fertilizers, which in most cases contain no sulfur, by limiting the use of high sulfur fuels and by increasing pressure to reduce industrial emissions, leading to a reduction in stocks. seeding compounds in the farm used by the soil fund, the decreasing use of pesticides / fungicides and insecticides / containing sulfur and the continually decreasing organic content in some stages.

Protein synthesis in plant organisms cannot take place if the plants cannot take up the required amount of sulfur and the opposite of nitrogen. This implies a relationship between plant nutrition by nitrogen and sulfur, as well as an underutilization of one

227 137 of both plant nutrients if the plant cannot receive sufficient second - deficient nutrients.

It has been shown that the concentration of soluble proteins decreased significantly in plants with a lack of sulfur and, on the other hand, increased nitrate content was determined therein / Mortvedt, J.J. - "Identifying and correcting sulfur" »deficiencies in crop plants, Crops and Soils Magazine 11-14} June-July 1981 /.

Sulfur plays another important role in the formation of chlorophyll and compounds resulting from the ongoing photosynthesis of the conversion of carbon dioxide and water using solar energy into hydrocarbons.

It follows that the lack of assimilable sulfur negatively affects not only yields, but also substantially the quality of plant agricultural production.

In countries with advanced levels of industrial fertilizer production and use, the following seed compounds are currently used as a source of assimilable sulfur: elemental sulfur, ammonium polysimide, ammonium bisulfite, ammonium sulphate, ammonium sulfate, gypsum sulfate, simple superphosphate, magnesium sulfate / so-called . Epsom's salt, magnesium-potassium sulfate, potassium sulfate, copper sulfate, iron sulfate, manganese sulfate and zinc sulfate.

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In Czechoslovakia, the main industrial fertilizer containing sulfur is simple superphosphate and ammonium sulphate. Potassium sulphate and magnesium sulphate are also used to a lesser extent. Although the above-mentioned types of fertilizers allow the fertilization of the soil, only rarely some of them (NH4 / ^ SO4, KgSO4, MgSO4) are also used in connection with extracorporeal foliar nutrition of agricultural crops. Recently, some chemical plants involved in the production of industrial fertilizers have begun to produce special types of concentrated liquid fertilizers which, in addition to the other biogenic elements, also contain assimilable sulfur and are primarily intended for off-root plant nutrition during vegetation. Foliar fertilizers of this type include the SK-sol liquid concentrate, from the ENPEKASOL series of one- and two-component liquid fertilizers, which is a concentrated aqueous solution of potassium silate and contains 250 kg of sulfur and 360 kg K ^ O and special foliar fertilizers

227 137 of the PXTOVIT type, based on the system: magnesium sulfate-urea-water. Although the use of the above mentioned liquid fertilizer fertilizers has achieved significant positive results in the past period, their disadvantage is that they cannot be freely mixed with all basic types of liquid fertilizer / nitrogen solutions e.g. Type:

28, 30 resp. 32-0-0; nitrogen-phosphorus liquid fertilizers based on ammonium monophosphates e.g. type: 7-21-0, 8-24-0, 10-30-0 and 11-33-0 and liquid NP-fertilizers containing condensed ammonium phosphates e.g. Type: 9-32-0, 10-34-0, 11-37-0, 12-40-0; type 0-20-24, 0-27-31 and similar).

This disadvantage can be eliminated by using liquid sulfur-nitrogen fertilizers prepared according to the method of the invention.

SUMMARY OF THE INVENTION The present invention is based on the fact that sulfur-nitrogen liquid fertilizers containing 1.8 to 2.6 parts by weight of sulfur per part by weight of nitrogen are prepared by chemical reaction of elemental sulfur in an aqueous medium in the presence of ammonia at a temperature of 35 to 130 ° C with oxide. sulphite and / or ammonium sulphite and / or ammonium sulphite, the dosage of the reactants is adjusted during the reaction so that the pH of the reaction mixture is higher than 5.5 ·

A detailed study of the conditions for the preparation of the nitrogen-nitrogen fertilizers according to the invention has further found that, in order to achieve maximum reactivity of elemental sulfur, it is particularly advantageous to maintain the temperature of the reaction mixture in the range of 80 to 110 ° 0.

It has also been found that tempering of the reaction mixture to the desired reaction temperature can be achieved by utilizing the released reaction, dissolution and melting heat of the reactants, thereby ensuring that the process for producing liquid NS fertilizer is fully autothermal.

The study of reaction conditions also revealed that in order to achieve optimal physico-chemical properties of the product - nitrogen-nitrogen liquid fertilizers / phase stability of liquid fertilizers at low temperatures, to achieve the highest concentration of plant nutrients in prepared liquid type fertilizers, etc. is it is expedient to maintain the pH of the reaction mixture during the reaction by dispensing ammonia

227 137 resp. the sulfur dioxide preferably ranges from pH 6.5 to 9.0.

In the preparation of a sulfur-nitrogen liquid fertilizer containing 1.8 to 2.6 parts by weight of sulfur per part by weight of nitrogen, the elemental sulfur can be introduced into the reaction medium in molten form by the method of the invention; finely dispersed in powder, ground form, or as a solution in a suitable solvent.

It has been experimentally confirmed that sulfur dioxide - SO _{2 can be used} in the liquid and / or gaseous state and / or a suitable sulfur source can be hydrosulphite and / or normal ammonium sulphite / NH 4 HSO for the preparation of the sulfur-nitrogen liquid fertilizers according to the invention. ^ resp. / NH? / GSO ^ /. In order to prepare a sulfur-nitrogen liquid fertilizer characterized by a high concentration of both basic biogenic elements and a high phase stability even at low temperatures, it has proven advantageous for the elemental sulfur in ammonia to undergo a chemical reaction with ammonium sulfites in the form of their aqueous solutions.

It has also been found that, in order to produce liquid solution fertilizers having optimum properties and to minimize the reaction time, it is expedient to work with a certain excess of elemental sulfur in the production of the nitrogen-nitrogen liquid fertilizers according to the invention. The pH of the reaction mixture and thus of the product is removed from the reaction mixture (by filtration, centrifugation, sedimentation and the like). The unreacted sulfur separated from the reaction mixture can advantageously be used in the course of the preparation of the sulfur-nitrogen liquid fertilizers according to the invention.

Liquid sulfur-nitrogen fertilizers prepared by the process of the invention have the advantage that liquid type fertilizers of the solution type as well as fertilizer suspensions containing more than 35 wt. % of pure plant nutrients (N + S), are suitable sources of assimilable sulfur in liquid form and are miscible in virtually all proportions with the base nitrogen solutions prepared on the basis of urea and ammonium nitrate / DAM type respectively. UAN / as well as unstabilized and stabilized nitrogen-phosphorous and phosphoric-potassium liquid fertilizers prepared on the basis of monophosphoric and condensed ammonium and potassium phosphates.

Unlimited miscibility of NS liquid fertilizers according to the invention with others! The basic types of liquid fertilizers allow to set the optimum desired ratio between sulfur and others! plant nutrients (especially between sulfur and nitrogen and sulfur and phosphorus) in a mixed liquid fertilizer intended for application.

Liquid soda-nitrogen industrial fertilizers prepared according to the process of the invention are suitable for the fertilization of the soil as well as for the extracorporeal nutrition of plants, in particular in the form of so-called. fungicidal efficacy was found by biological tests.

The addition of the nitrogen-nitrogen liquid fertilizers obtained according to the invention to the nitrogen-containing nitrogen-containing and nitrogen-calcium nitrate-containing liquid fertilizers significantly reduced the degree of corrosion of these industrial fertilizers towards carbon steel.

The following examples illustrate but do not limit the invention.

Example 1

To a 2,500 cnP sulfonation flask equipped with an efficient glass four-blade stirrer, a bad glass cooler, a thermometer (0-150 ° C) and two shaped glass tubes (JS 2.5 mm) for NH 4 / g feed and SOg / g feed. 1100 g of distilled water was added and 300 g of ground technical sulfur was gradually added under stirring. Then, almost simultaneously, ammonia gas and sulfur dioxide gas were metered into the aqueous sulfur suspension from steel cylinders. The instant feed rate of the gaseous reactants was monitored by two rotameter flowmeters connected between the ammonia pressure reservoirs, respectively. sulfur dioxide and reaction vessel.

The proportion of the feed gases was adjusted so that there was at least a slight excess of ammonia in the reaction space, which was controlled by a moistened litmus indicator paper at the exit of the bad cooler. During the addition of ammonia and sulfur dioxide, the reaction mixture gradually warmed from the original 25 ° 0 to 102.5 ° 0. Dosing of the gaseous reactants was terminated after 120 minutes based on

227 137 result of the control of the specific gravity of the reaction mixture / < 1300 kg ·. m.p. (and its pH (6.9)).

After cooling the reaction mixture to about 60 ° C, its pH was adjusted to about 8.0 by passing an excess of ammonia gas.

Based on the weighing results of the reaction mixture before and after the gas saturation, it was determined that its weight increased by 936 g during the reaction.

Thereafter, the reaction mixture was separated by vacuum filtration through a polypropylene filter fabric, yielding 2246 g of a clear sulfur-nitrogen liquid fertilizer. The prepared liquid fertilizer was subjected to a physico-chemical check, obtaining the following basic data:

- total nitrogen content: 11,65 wt. % N

- total sulfur content: 25,20 wt. % S o

sulfur content bound in the form of SgO, 17.72 wt. % WITH

- sulfur content bound in the form of SO., * - $ 3.24 wt. % WITH

- specific weight / << 20 ^o 0 ^: ^ - ^ 18.6 kg ·

- P ^ 25®C * 8.0.

The prepared solution type liquid fertilizer sample was used to perform precise agrochemical and agronomy experiments.

Example 2

To a sulfonation flask in a similar arrangement to Example 1, 198 g of distilled water and 1219 g of 26% ammonia water were charged. The aqueous ammonia solution was then saturated with gaseous sulfur dioxide under agitation under a reflux condenser until a virtually neutral reaction (pH 7.5) was achieved. During SO 2 / g / metering, the temperature of the reaction mixture increased from the original 15 ° C to 87 ° 0.

Then, 300 g of ground sulfur was introduced into the reaction mixture and stirred for 2 hours while the suspension was gently saturated with ammonia gas. The temperature of the reaction mixture first increased slightly during the first 45 minutes (from a flood of 55 ° C) to 75 ° C and then began to drop slightly (after 90 minutes of carbonation with ammonia, the temperature of the reaction mixture was 59 ° C).

After stirring and saturating the reaction mixture with ammonia gas for 100 minutes, its pH was 9.1 and the temperature was 57 ° 0. In the interest of lowering the pH

227 137, the reaction mixture began to saturate from this point in addition to the reduced flow of ammonia gas and sulfur dioxide gas.

After 45 minutes, the metering of the gases into the reaction mixture was stopped, the reaction mixture was cooled slightly with stirring in a water bath, and then insoluble sulfur residues were removed by filtration.

From the difference in weight of the reaction vessel at the start and after the experiment, it was found that during the saturation with sulfur dioxide and ammonia its weight increased by 774 g. Filtration of the reaction mixture yielded 2085 g of a clear viscous filtrate, a slightly yellow color that had a slight odor of ammonia. The above-described product - a sulfur-nitrogen liquid fertilizer of the solution type does not have these properties with

- total nitrogen content: 12,47 wt. %

- a total sulfur content of 25,66% by weight; %

sulfur content bound in the form of SgO: 23.04 wt. %

- sulfur content bound in the form of SO4 * -! 1.63 wt. %

- density at 20 ° 0! 1,309.3 kg.m ^

- P ^ 25 ° C * θ »θ6

- Phase stability at low temperature - clearing point j -24.9 ° C

Example 3

The experiment was performed using a similar laboratory all-glass apparatus as in the experiment δ. 1 and 2.

Past A:

The flask was charged with 1050 g of distilled water and 500 g of ground technical sulfur. The procedure was similar to that of the experiment no. 1. After two hours of carbonation with ammonia and sulfur dioxide, the temperature of the reaction mixture reached 107 ° C.

Weighing showed that the weight of the reaction mixture increased by 910 g due to the saturation with ammonia and sulfur dioxide. Separation of the reaction mixture yielded 2160 g of a clear filtrate and 257 g of a wet filter cake consisting of unreacted sulfur.

5 part B j

In another part of this experiment, 1050 g of distilled water was charged to the opSt reaction vessel and the whole amount of wet filter cake from the first part of the experiment was added with stirring.

227 137 (part A) and 300 g fresh ground technical sulfur.

The procedure was similar to that in the first part of the experiment, respectively. as in the experiment described in Example 1.

Due to the addition of ammonia gas and sulfur dioxide gas, the weight of the reaction mixture increased by 876 g.

Filtration of the crude reaction mixture yielded 2083 g of product (a clear sulfur-nitrogen liquid fertilizer) and approximately 330 g of a wet filter cake consisting predominantly of unreacted elemental sulfur.

Semi-nitrogen liquid fertilizers obtained during the first and second parts of this experiment were specified as follows:

NS - liquid fertilizer prepared during the experiment:

section A section total nitrogen content /hraot.%N/ 11.70 11.66 total sulfur content / mass./S/ 27.38 27.23 sulfur content bound in the form ^of 2 ° 3 ^{2 (} mass% S) 26.26 26.38 sulfur content bound in the form of SO ₃ 2- / wt. % WITH/ 0.20 tracks ^pH 25 ^{0 (3} o 3 8.4 8.1 density at 20 C / kg.m 1,326.6 1 323.6 phase stability of the solution at low temperature-temperature dissolves the last crystal- - 22,4 - 18, '

Example 4

In order to assess the miscibility of the nitrogen-nitrogen liquid fertilizers prepared according to the invention with nitrogen fertilizer of the type 30-0-0 (DAM-390) and nitrogen-phosphorus liquid fertilizer of the type 8-24-0 (Fostim, Pensol, Synsol and the like) were prepared mixed solutions ·:

Ingredient weight - basic liquid fertilizer / g /

Sample designation- 30-0-0 NS fertilizer / pro 8-24-0

-number (DAM-390) duct from experiment (Fostim) given in Example No. 3 (A)

227 137

3 80 20 - 4 90 10 - • 5 - 10 ’90 6 - 20 80 1 - 30 70 8 - 40 60

Inspection of the thus prepared mixed solutions after 24 hours and after their weekly storage at room temperature revealed that there was no change in storage in either of the samples, which would be manifested by a phase change or a change in the sample. change colors.

Claims (3)

1) A process for the production of sulfur-nitrogen liquid fertilizers containing 1.8 to 2.6 parts by weight of sulfur per part by weight of nitrogen, characterized in that the elemental sulfur is chemically reacted in an aqueous medium and in the presence of ammonia at a temperature of 35 to 130 ° C. sulfur dioxide and / or sulphite and / or ammonium bisulphite, the dosage of the reactants being adjusted during the reaction so that the pH of the reaction mixture is higher than 5.5, 2. Process according to claim 1, characterized in that the temperature of the reaction mixture is 80 to 110 ° C. 3. The process according to claim 1, wherein the pH of the reaction mixture is 6.5 to 9.0.