FI66171B - FREEZING FOR NITRATHALTIGA GOEDSELMEDEL - Google Patents

Description

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Ma w (11'utläggningsskrift odI / 1 c Pr.icr-tSI r. ;; "nnc i * y! 0 C9 1934 ^ T ^ (51) Kv.lk. ^ IntC» .3 C 05 C 5/00 ENGLISH —FINLAND (21) Ntunnllukunw. —F * .fltuw6knln | 800967 (22) Htkemltpifvi - Araekntnpdsg 28.03.80 '' (23) Primary Cloud — GHtl | h «tadt | 0 80

Patent · och registerstyrelsen AmBkan uttagd och utl.skrift * n pubUctrad 31.05.84 (32) (33) (31) PyyJatty atuolkau * —Bajtrd priority 30.03.79

Norway-Norway (NO) 791058 Proven-Styrkt (71) Norsk Hydro as, Bygdtfy a11έ 2, Oslo 2, Norway-Norway (NO) (72) Per Fredrik Gustavsen, Skien, Olav Kjtfhl, He istad, Norway-NO (NO) ) (74) Oy Kolster Ab (54) Method for the production of nitrate fertilizers -Förfarande för framstälIning av nitrathaltiga gödselmedel

The invention relates to a process for the preparation of nitrate-containing fertilizers with reduced hygroscopicity and to a conditioning agent used in the process. The substance consists mainly of wax and mineral oil.

It has long been known that wetting fertilizers such as NP fertilizers and especially lime sludge cause problems when exposed to moisture. Over the years, a number of conditioning agents have been developed for different types of fertilizers. Such conditioning agents must partially meet different requirements depending on the fertilizer for which they are used and a substance that is suitable for one type of fertilizer may therefore not be suitable for another type of fertilizer.

British Patent No. 1,312,314 relates to a fertilizer coated with a conditioning agent containing a wax and a cationic surfactant amine and optionally a mineral oil.

2 66171 Useful waxes appear to cover most species and their effect is reported to be almost independent of wax type, while fine crystalline waxes, paraffin waxes, natural waxes, Glycerides and high melting polymers are disregarded. The amount of wax is less critical, while the wax / amine ratio can range from 100: 1 to 1: 1. In addition, the type or amount of said mineral oil is also not precisely defined.

British Patent No. 1,288,333 relates to a process for reducing the dynamic hygroscopicity of urea granules using a substance consisting of solid paraffin, animal or vegetable fat and mineral oil.

It is further known from British Patent No. 335,175 to improve the storability of fertilizers by means of a substance containing mixtures of wax and mineral oil. The wax may contain up to 20% of a substance which can be used in an amount of 0.5 to 1% of the fertilizer to provide effective protection.

None of the above substances have been shown to be useful since the current requirements for nitrate fertilizers.

The substance used in accordance with British Patent No. 1,312,314 is mainly used to prevent agglomeration of fertilizer granules, while the issue of reducing the composition of fertilizers has been disregarded. However, this substance did not appear to have a more specific effect in terms of hydration reduction.

According to British Patent No. 335,175, 0.5 to 1% should be used. The use of such large amounts of conditioning agent is unfortunate for safety reasons for substances such as ammonium nitrate. Ammonium nitrate has a maximum organic content of 0.2% and substances with 70% ammonium nitrate have a limit of 0.4%.

The substance used in accordance with British Patent No. 1,288,333 is intended for urea, which is the least wetting fertilizer. In the examples, 0.8% of the substance is shown to be used. This, as mentioned above, is not desirable and such amounts also become too expensive and make the fertilizer sticky and poorly free-flowing. The substance was used in one experiment on 3 66171 lime sludge but had no effect on reducing hydration.

Fertilizers are now transported in increasing quantities in bulk and this places special demands on its ability to withstand the stresses caused by different transport equipment without the fertilizer granules being rubbed into dust. But primarily such transport places great demands on the fertilizer's ability to withstand climate change. When switching to bulk transport, there were difficulties due to moisture uptake and problems due to dusting and agglomeration during transport and storage. In addition, there had been difficulties in applying certain types of fertilizers due to the agglomeration of the granules. Therefore, an experiment was started using various known conditioning agents, but these experiments did not give the expected results.

Lime sludge has caused the greatest hydration and caking problems, and this was expected because it is much more hygroscopic than, for example, NPK, ammonium nitrate and urea. The inventors therefore began their efforts to find a substance which would reduce the hygroscopicity of lime soda and improve its storage and handling properties and which would hopefully have a positive effect on other fertilizers as well.

A number of partly opposite factors had to be taken into account in the development of the standard agent. The substance should be acceptable for use, almost odorless and colorless, easy to apply and, for safety reasons, should have a flash point above 100 C. The substance should also not have harmful effects on plants and animals. In addition, it is hoped that the substance can be used as little as possible while the conditioning effect should be high with varying temperature and humidity. The standardized fertilizer granules should also have a coating that adheres well to the granules and is not too crumbly so that it rubs into dust under the stresses to which the granules are exposed. The coating technique and the even distribution of the substance on the granules also placed certain limitations in the choice of the substance and its components. However, the most essential properties of such a conditioning agent are that it protects the fertilizer granules from destructive hydrogenation. However, the protective film must not be so impermeable as to prevent the granules from dissolving when used.

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Mineral oils have been used with varying degrees of success, and the inventors tried to select suitable oils starting from the above-mentioned requirements for the substance. It turned out that e.g. the boiling point, viscosity, and wax content of the oil had an effect on the stabilization performance. However, none of the oils tested gave the desired effect. At that time, experiments with wax mixture and mineral oil were started. One requirement placed on the oil / wax mixture was that it should provide a flexible film that readily adheres from one granule to another during the coating process.

Contrary to the teachings of the aforementioned patents, it was surprisingly found that the choice of wax types and amounts were decisive factors. As in the tests mentioned above, it was now also found that the choice of oil type was a decisive factor.

After experimenting with a number of combinations, the inventors came up with a substance consisting mainly of three components, namely fine crystalline wax, paraffin wax and a special type of oil. In certain cases, it is advantageous that the substance also contains an emulsifier. It has been found necessary to add emulsifiers suitable for the substance to the fertilizer solutions used, for example, in a drip irrigation device. These are biodegradable and non-toxic to plants. Each component must meet certain requirements and the relationship between the components must be within certain special limits.

What is special about the process according to the invention is that a substance containing 5 to 20% by weight of fine crystalline wax, 5 to 30% by weight of paraffin wax and 60 to 80% by weight of mineral oil having a boiling point of between 300 and 30% by weight is used as the conditioning agent. 400 ° C.

In a particular embodiment of the invention, 0.01 to 0.15% by weight, based on the weight of the fertilizer, of a substance containing 10 to 20% by weight of fine crystalline wax, 10 to 20% by weight of paraffin wax and 60 to 70% by weight of mineral oil are used, which the viscosity is 2 to 70 centistokes at 50 ° C, preferably 2 to 30 centistokes, and has a solidification point between 5 and 20 ° C and a boiling point between 300 and 400 ° C.

The conditioning agent according to the invention contains 5-20% by weight of fine crystalline wax, 5-30% by weight of paraffin wax and 60-80% by weight of mineral oil with a boiling point of between 300-400 ° C.

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The most preferred composition of the substance is 15% by weight of fine crystalline wax, 15% by weight of paraffin wax and 70% by weight of mineral oil.

The substance may optionally also contain suitable emulsifiers.

To evaluate the effectiveness of such a conditioning agent, several measurement methods can be used in addition to observations and tests on hydrogenation during transport, storage, and application.

A further practical method that has proven relevant in demonstrating the hygroscopicity of a substance is its water uptake rate. This depends on a number of factors, the most important of which is the temperature of the product and the temperature and humidity of the surrounding air.

The invention will now be illustrated in more detail with reference to the following figures and examples.

Figure 1 Reduction of water uptake by cinder as a function of the composition of the substance according to the invention.

Figure 2 Reduction of water uptake by lime sludge as a function of the amount of conditioning agent used.

Figure 3 Water uptake as a function of time for lime sludge, both with and without conditioning agent.

Figure 4 Water uptake as a function of relative xoticity for lime sludge, with and without conditioning agent.

Figure 5 Water uptake of lime liquor with various conditioning agents.

Figure 6 Water uptake of NP fertilizer, with and without conditioning agent.

Figure 1 is a 3-phase diagram showing the percentage reduction in water uptake to lime soda at 25 ° C and 70% relative humidity with the addition of the conditioning agent of the invention, but to varying degrees of fine crystalline wax and paraffin wax. The third major component of the substance is a heavy oil distillate having a boiling point of 300-400 ° C and an oil content of about 100% minus the sum of the wax components per gram, i.e. between 100 and 60%. The hatched area shows the most preferred composition of the invention.

Figure 2 shows the reduction in water uptake to the lime sludge at 25 ° C and 70% relative humidity, as a function of the amount of conditioning agent used according to the invention, expressed as a% by weight of the weight of the lime sludge granules. Measurements have been made 6 66171 6 hours after standardization and clearly show that even when used only 0.05% gives the substance high potency.

Figure 3 shows the percentage of water received by the lime sage granules (g water / 100 g lime soda) when stored in air at 25 ° C and 70% relative humidity. The untreated product absorbs water at almost a constant rate throughout the 24-hour storage period. For a standardized product, the water uptake decreases sharply after only a few hours, even by only 0.05% of the conditioning agent.

With about 0.1% of the conditioning agent, water uptake is almost complete within 24 hours and is then about 8% compared to 50% for the non-standardized product, a solid line. The dotted lines show the curves for the standardized product with the amount of conditioning agent given as a percentage.

Figure 4 shows the percentage of water uptake after 6 hours of storage as a function of relative humidity at about 15 and 20 ° C. Curve 1 depicts the crude product at 20 ° C and curve 3 the conditioned lime sludge at 20 ° C to which 0.12% of the conditioning agent of the invention has been added. Curves 2 and 4 show the corresponding curves at 15 ° C.

Figure 5 shows the uptake of water by a lime sludge stored for 24 hours in air at a temperature of 35 ° C and a relative humidity of 50%. Curve 1 is for the untreated product, curve 2 is for the oil-treated lime sludge with 0.5% mineral oil, and curve 3 is for the lime sludge standardized with 0.08% of the substance of the invention.

Figure 6 shows the uptake of water by NP fertilizer as a function of time during storage in air at a temperature of 32 ° C and a relative humidity of 70%. Curve 1 shows untreated NP fertilizer and curve 2 shows NP fertilizer conditioned with 0.08% of the substance of the invention.

Example 1

A conditioning agent was added to the lime sludge in an amount corresponding to 0.2% by weight of the lime soda. The coating was done by spraying the substance against a conveyor belt carrying 35 ° C lime slag granules into a bulk storage.

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The conditioning agent consisted of 80% by weight of a heavy oil distillate with a boiling range of 300-400 ° C, a pour point of 10 ° C and a viscosity of 1.3 ° Engler at 50 ° C and 20% by weight of paraffin wax.

The water uptake percentage of the standardized lime liquor was measured at 25 ° C and 70% relative humidity. The reduction in water uptake for the standardized product compared to the non-standardized product was 15%.

Example 2

Lime soda was conditioned as in Example 1, but with only 0.08% conditioning agent. The same type of oil as in Example 1 was used in this experiment, but the material now contained 80% oil, 10% paraffin wax and 10% fine crystalline wax. The total amount of wax was thus the same as in Example 1.

The percentage of water uptake was measured as in Example 1 and the reduction in water uptake was measured to be 71%.

Example 3

Lime sludge was standardized as in Example 2. The material used in this experiment contained 60% oil, 20% fine crystalline wax and 20% paraffin wax.

The reduction in water uptake was measured to be 72%.

Example 4

Lime sludge was standardized as in the previous examples. 0.08% material containing 80% oil and 20% fine crystalline wax was used.

The reduction in water uptake was measured to be 12%.

Example 5 An NP fertilizer with 26% nitrogen and 14% P 2 O 5 was stabilized with 0.08% of the same conditioning agent as in Example 3.

The reduction in water uptake was measured to be 70%.

Example 6

The granulated ammonium nitrate was conditioned with 0.1% by weight of the same material used in Example 3.

At 25 ° C and 86% relative humidity, a 68% reduction in water uptake was achieved using a conditioning agent.

This example thus shows that ammonium nitrate also achieves a considerable reduction in water uptake.

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Fine crystalline wax and paraffin wax with melting points between 50-70 ° C were used in the experiment, preferably each type of wax should have a melting point of about 60 ° C.

the pour point of the oil which can be used in the substance according to the invention should be between 5 and 20 ° C when the temperature of the product to be conditioned is between 25 and 45 ° C. To facilitate application, the viscosity of the oil should not be too high, preferably between 2 and 30 centistokes at 50 ° C. the boiling range of the oil should be between 300-400 ° C.

Examples 2, 3, 5 and 6 show the use of a conditioning agent according to the invention. Examples 1 and 4 show that when the composition of the substance is outside the claimed composition, a very small reduction in water uptake is obtained.

The practical advantages of standardizing lime slag, ammonium nitrate and NP fertilizer according to the invention can be briefly listed as follows:

The standardized product has a substantially lower tendency to form thick moist shells in bulk storage than the non-standardized product.

Large-scale bulk shipments and bulk transport to the user will be possible without substantial problems when the product is standardized according to the invention.

When handled in transport devices, the degree of crumbling and thus the dust level becomes significantly lower when the invention is used.

The tendency to form hard lumps which adhere to the feed members of the spreaders is also substantially reduced.

Lime soda, standardized according to the invention and packaged in polyethylene bags with 3 mm holes, was free of lumps after 5 months of storage at 25 ° C and 60% relative humidity, whereas control bags with untreated product formed lumps after a short time. after a while.

Previous experience had shown that when the product was applied in adverse weather conditions, it quickly agglomerated in the feeding organs. When a standardized product with the above-mentioned substantially lower water uptake rate was used, a nearly constant dosage was obtained under similar conditions regardless of climatic conditions.

Claims (3)

9 661 71 In addition, it has been found that the storage properties of freshly produced and standardized lime soda ash in bulk and in the silo are substantially improved, since such a product has a reduced tendency to harden compared to the non-standardized product. A process for the preparation of nitrate-containing fertilizers of low hygroscopicity using a conditioning agent containing not more than 0.4% by weight of wax and mineral oil, characterized in that a substance containing 5 to 20% by weight of fine crystalline wax, 5 to 30% by weight, is used as the conditioning agent. -% paratine wax and 60-80% by weight of mineral oil with a boiling point of 300-400 ° C. Process according to Claim 1, characterized in that 0.01 to 0.15% by weight of a conditioning agent is used, which contains 10 to 20% by weight of fine crystalline wax and 10 to 20% by weight of paratin wax and 60 to 70% by weight. -% mineral oil having a viscosity of 2 to 70 centistokes at 50 ° C, preferably 2 to 30 centistokes and a pour point of 5 to 20 ° C. Conditioner for use in the process according to Claim 1 or 2, characterized in that it contains 5 to 20% by weight of fine crystalline wax, 5 to 30% by weight of paratin wax and 60 to 80% by weight of mineral oil with a boiling point of 300 to 400 ° C .