JPS5953236B2 - Method for producing stable transparent liquid fertilizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a stable transparent liquid fertilizer from wet phosphoric acid obtained by decomposing phosphate rock with sulfuric acid.

Liquid fertilizer is generally made by adding ammonia or ammonia carbonate, caustic potash, potassium carbonate, etc. to wet phosphoric acid, which is used as a phosphoric acid source, to neutralize it, and removing the insoluble metal phosphates that are generated at that time. It is manufactured by obtaining a solution or potassium phosphate solution, adjusting the concentration with water and using it as a product as it is, or by adding and dissolving nitrogen fertilizer, potassium salt, etc.

However, since the insoluble substances generated in the neutralization process are colloidal, there are various difficulties in completely removing them, and some of the metal impurities derived from wet phosphoric acid that do not precipitate are removed by liquid fertilizer. dissolved in the

When this liquid fertilizer is used for a long period of time after its production, phenomena such as the formation of new precipitates occur, which also causes clogging when the liquid fertilizer is injected through the micropores during normal liquid fertilizer application.

On the other hand, a wet phosphoric acid solution obtained by decomposing phosphate rock with sulfuric acid generally contains impurities such as sulfuric acid, silifluoric acid, calcium, magnesium, iron, and aluminum.

In order to produce a stable liquid fertilizer with as few impurities as possible using wet phosphoric acid, the sulfuric acid content is converted into calcium sulfate or barium sulfate by adding lime or calcium salts such as barium carbonate, or barium salts. Acids can be made by adding soda salts such as caustic soda or soda ash.
Precipitate and separate the silicofluoride salt, and then iron,
Aluminum, calcium, magnesium, etc. are removed by adding ammonia or the like to neutralize them, converting most of them into insoluble phosphates, and then separating them.

However, when impurities contained in a wet phosphoric acid solution are separated and removed by such a treatment method, calcium and magnesium in particular cannot be removed sufficiently. 30～
40%, 2-10% of the total magnesium will be dissolved in the liquid fertilizer.

Therefore, if liquid fertilizer containing such amounts of dissolved calcium and magnesium is stored for a long period of time, it may cause precipitation.

An object of the present invention is to provide a method for producing a stable transparent liquid fertilizer containing as little calcium, magnesium, etc. as possible.

As a result of intensive research into a method for producing a stable transparent liquid fertilizer, the present inventors discovered that a soluble fluorine compound was added to a wet phosphoric acid neutralization solution or a solution prepared by adding fertilizer components to the neutralization solution. By precipitating and separating dissolved impurities, a stable transparent liquid fertilizer can be obtained and the present invention has been achieved.

That is, the present invention involves adding a soluble fluorine compound to a wet phosphoric acid neutralized solution or a solution obtained by adding fertilizer components to the neutralized solution in the production of a liquid fertilizer using wet phosphoric acid obtained by decomposing phosphate rock with sulfuric acid. This is a method for producing a stable transparent liquid fertilizer, which consists of removing impurities.

The wet phosphoric acid neutralization solution used in the present invention is an insoluble solution obtained by adding ammonia, ammonium carbonate, caustic potash, potassium carbonate, etc. to wet phosphoric acid obtained by decomposing phosphate rock with sulfuric acid, and neutralizing it. A neutralized liquid slurry containing a precipitate or a neutralized liquid obtained by separating an insoluble precipitate from the neutralized liquid slurry.

Fertilizer components added to the neutralizing liquid or neutralizing liquid slurry include nitrogenous fertilizers such as ammonium sulfate, ammonium nitrate, and urea, and potassium fertilizers such as potassium sulfate and potassium chloride.

In the present invention, soluble fluorine compounds used as an impurity removing agent include ammonium silifluoride, sodium silifluoride, silifluoride processed, silicofluoric acid, ammonium fluoride, acidic ammonium fluoride, sodium fluoride, acidic These include soda fluoride, fluoridation processing, acid fluorination processing, and hydrofluoric acid.

The amount of these soluble fluorine compounds added is such that the molar ratio of fluorine to the total of magnesium and calcium dissolved in the wet phosphoric acid neutralization solution or the solution obtained by adding fertilizer components to the neutralization solution is 5 to 30, and The weight ratio of fluorine (as F) to phosphoric acid (as P2O5) in the liquid fertilizer product is 0.006 to 0.028.

If the amount of fluorine added is less than the above-mentioned range, the amount of calcium, magnesium, etc. to be insolubilized will be too small and the objective will not be achieved.

If it exceeds this range, the objective can be achieved, but it is not economically preferable.

If a fluorine compound is further added, the pH at the time of reaction is 4 to 7.
It is preferable to carry out within the range of .

When the fluorine compound to be added is a silicofluoride, silicon dioxide is produced and precipitated as an insoluble substance, and fluorine is used to insolubilize calcium, magnesium, etc.
The selection of pH in this case has extremely important significance.

For example, when the pH is 4 or less, silicon dioxide is not sufficiently liberated from the silicofluoride, and calcium, magnesium, etc. are not sufficiently converted to insoluble precipitates.

Moreover, if the pH is 7 or more, the solubility of silicon dioxide increases and it becomes dissolved in the liquid fertilizer, which is not preferable for long-term storage.

After removing the precipitate from the neutralized liquid slurry treated with fluorine using the method described above, the slurry may be adjusted to a predetermined concentration to produce a product, or the above-mentioned fertilizer components may be further added to produce a product. I can do it.

As mentioned above, the liquid fertilizer from which impurities have been removed according to the method of the present invention is extremely stable as a transparent liquid fertilizer and can be stored for a long period of time, since especially calcium and magnesium are almost completely separated and removed as insoluble substances. Therefore, it is very useful industrially.

The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples in any way.

Note that parts and percentages shown in Examples and Comparative Examples are based on weight unless otherwise specified.

Example 1 Add phosphoric acid to 100 parts of wet phosphoric acid having the following composition.
Fluorine (as P2O5) H2804 (as F) 30
, 81% 0.59% 0.37% silicon M
g Ca (Si02 and T) (MgO and T) (CaO
) 0.11% 0.55% 0
．． Add 215 parts of 21% water and blow in 313 parts of NH.
Neutralized up to H6 and H7.

The temperature rose to 78°C due to the heat of reaction. MgO in liquid phase
is 0.0145%, CaO is 0.0214%, F is 0,
It was 0.033%.

Next, 2 parts of acidic ammonium fluoride was added to this slurry to adjust the molar ratio of F/(MgO+Ca0) in the liquid phase to 30, and after stirring, the insoluble precipitate was separated to obtain 303 parts of a supernatant liquid.

This supernatant was treated with chloride (61% as K2O) 63 parts,
After adding and dissolving 117 parts of urea (46.5% as N) and 32 parts of water, 515 parts of liquid fertilizer having the following components was obtained.

TN AN (Total nitrogen) (Ammonia nitrogen) P2O512,
31% 1.89% 5.18% to 20
MgOCaOF 7.22% 0.0005% 0.002% or less 0.
06%F/P20. (Weight ratio) 0.011 This liquid fertilizer remained completely transparent with no precipitation observed even after storage for 6 months.

Example 2 220 parts of water was added to 100 parts of wet phosphoric acid of Example 1, and N
310 parts of H3 was blown into the solution to neutralize it to pH 4.0.

The temperature rose to 75°C due to the heat of reaction.

Next, the insoluble precipitate of this slurry was separated by sedimentation to obtain 303 parts of a supernatant.

MgO in the liquid phase is 0.0148%, CaO is 0.022%
0%, F was 0.03.

1.0 part of ammonium fluoride was added to this supernatant and F/
(MgO+Ca0) (7) The molar ratio was set to 14, and after reacting at 50°C for 2 hours, 63 parts of chloride treatment, 121 parts of urea, and 26 parts of water were added and dissolved, and the generated insoluble precipitate was separated by sedimentation. 489 parts of liquid fertilizer having the following components was obtained.

TN AN (Total nitrogen) (Ammonia nitrogen) P2O512
, 28% 1.83% 5.20% 2
0 M gOCaOF 725% 0.0004% 0.002% or less 0.
07% F/P2O5 (weight ratio) 0,013 This liquid fertilizer did not show any precipitation even after being stored for 6 months and remained completely transparent.

Comparative Example 1 216 parts of water was added to 100 parts of the phosphoric acid solution of Example 1, and NH
314 parts were blown into the solution to neutralize it to pH 5.7.

The temperature rose to 78°C due to the heat of reaction.

Next, the insoluble precipitate of this slurry was separated by sedimentation to obtain 303 parts of a supernatant.

To this supernatant, 63 parts of chloride processed (K2061%), urea (
After adding and dissolving 117 parts of N46.5%) and 32 parts of water, 515 parts of liquid fertilizer having the following components was obtained.

TN AN (Total nitrogen) (Ammonia nitrogen) P 20512, 2
8% 1.90% 5.25% to 20
MgOCaOF 3.75% 0.0088% 0.0130% 0.0
2% F/P2O5 (weight ratio) 0,0038 This liquid fertilizer showed precipitation after one week.

Example 3 34.5 parts of water was added to 100 parts of wet phosphoric acid of Example 1,
313 parts of NH was blown into the solution to neutralize it to pH 6.75.

The temperature rose to 90°C due to the heat of reaction.

(7) Mg01. t 00045
%, CaO was 0.098%, and F was 0.06%.

Next, 2.5 parts of ammonium fluoride was added to this slurry to bring the molar ratio of F/(MgO+Ca0) in the liquid phase to 22.
After stirring and separating the produced insoluble substances by sedimentation, 120 parts of liquid fertilizer having the following components was obtained.

AN (ammonia nitrogen) P2O5Mg07.4%
20.35% 0.004%CaOF
F/'P 205 (weight ratio) 0.003% 0.30
% 0.013 The liquid fertilizer did not show any precipitation even after being stored for 6 months and remained completely transparent.

Example 4 36.5 parts of water was added to 100 parts of wet phosphoric acid of Example 1,
5 parts of NH3 was blown into the solution to neutralize it to pH 5.75.

The temperature rose to 89°C due to the heat of reaction.

The insoluble precipitate of this slurry is separated by sedimentation, and the supernatant liquid 12
I got 1 copy.

The MgO in this supernatant was 0.044%, and the CaO was 0.0%.
89%, Fhao, 054% tear-').

0.8 parts of acidic ammonium fluoride was added to this supernatant and stirred to adjust the F/(MgO x Ca0) nomolar ratio to 10.
After reacting at 0° C. for 2 hours, the insoluble precipitate was separated by sedimentation to obtain 111 parts of liquid fertilizer having the following components.

AN (Ammonia nitrogen) P2O5Mg.

7.55% 20.48% 0.003%C
aOF F/P2O5 (weight ratio) 0.002%
0.42% 0.021 bottles of liquid fertilizer did not show any precipitation even after being stored for 6 months and remained completely transparent.

Comparative Example 2 34 parts of water was added to 100 parts of the phosphoric acid solution of Example 1, and NH3
14 parts were blown into the solution to neutralize the pH to 6.75.

The temperature rose to 88°C due to the heat of reaction.

After adjusting this slurry by adding 2 parts of water and separating the insoluble precipitate by sedimentation, liquid fertilizer 118 having the following components is prepared.
I got the department.

N (ammonia nitrogen) P2O5Mg07.40%
20.40% 0.021%CaOF
F/P 20s (weight ratio) 0.069% 0.06
% 0.0029 bottle of liquid fertilizer, precipitation was observed after 4 days.

Claims (1)

[Claims] 1. In the production of liquid fertilizer using wet phosphoric acid obtained by decomposing phosphate rock with sulfuric acid, soluble fluorine is added to a wet phosphoric acid neutralized solution or a solution obtained by adding fertilizer components to the neutralized solution. A method for producing a stable transparent liquid fertilizer characterized by adding compounds and removing impurities. .