KR20000031078A - Method of preparing complex fertilizer - Google Patents

Abstract

PURPOSE: A method of preparing complex fertilizer is provided which provides a complex fertilizer containing potassium sulfate and potassium nitrate by employing double decomposition reaction. CONSTITUTION: The method comprises steps of: (i) reacting oxim solution with potassiumchloride with stirring at the temperature of 40-80°C; (ii) obtaining potassium sulfate fertilizer by filtering the crystalline material from step (i); and (iii) obtaining nitrogenous potassium nitrate complex fertilizer by graduating the remainder from step(ii) and cooling it to the temperature of 0-10°C with stirring and leaving it and then filtering and drying.

Description

Manufacturing method of compound fertilizer by metathesis reaction

The present invention relates to a method for producing a complex fertilizer by a metathesis reaction, and more particularly, to a method for producing a complex fertilizer containing potassium sulfate and potassium nitrate by metathesis reaction of a waste oxim solution with potassium chloride powder. will be.

Conventionally, many methods for producing potassium sulfate using a metathesis method are known, and representative examples thereof are as follows, but none of them is satisfactory enough.

1) Langbeinite law:

_{(MgSO 4 · KCl · 3H 2} O) → K 2 SO 4 · 6H 2 O + MgCl 2 K 2 SO 4 · MgSO 4 · 6H 2 O + 2KCl → 2K 2 SO 4 + MgCl 2

The method is partially manufactured in Germany, Italy, etc., and dissolves ore, kaineite, in water at about 100 ° C. to form schoenite or leonite, and then reacts with potassium chloride (KCl). It is a disadvantage in that the method for producing potassium sulfate (K ₂ SO ₄ ) or low yield.

2) Able, Fanto method:

2KCl + CaSO ₄ → K ₂ SO ₄ + CaCl ₂

It is a disadvantage that the yield is low as a method of making gypsum and potassium chloride react.

3) Potasse etproduits chimigues method:

Gypsum and potassium chloride are reacted in a 50% aqueous ammonia solution, but they are difficult to handle and have strong pollution.

4) Tombill Mining Law:

_{4Na 2 SO 4 + 6KCl → Na} 2 SO 4 · 3K 2 SO 4 · 6NaCl

Sodium sulfate and potassium chloride are prepared in a 68 ° F. aqueous solution to form a mixture of Na ₂ SO ₄ and K ₂ SO ₄ , and a pure K ₂ SO ₄ crystal is obtained as a saturated solution of potassium chloride.

5) Buchener method:

(NH ₄ ) ₂ SO ₄ + 2KCl → K ₂ SO ₄ + 2NH ₄ Cl

As a method of reacting ammonium sulfate and potassium chloride at 300 to 345 ° F., corrosion is a disadvantage.

6) Gewerk schaft victor method:

Ammonium sulfate and potassium chloride can be reacted in aqueous ammonia solution to obtain a high yield of 97%, but the corrosion is very poor.

In addition, in the stamicarbon HSO process which is commonly used for the preparation of caprolactam, the ammonium sulfate produced as a by-product is extracted with yuan fertilizer (N-NH ₃ ammonia nitrogen 20% or more), and then the final residue As an example, a method of preparing an organic fertilizer (about 30% of nitrogen, sulfuric acid and ammonium acetate) by evaporating and concentrating an oxime solution containing C = NOH as an industrial waste is known. There is a problem in that it is difficult to practically use due to the absorption of moisture in the fertilizer particles (bonding) and deliquescent between the fertilizer particles.

In order to solve the above problems, after extensive research, the inventors have found that the oxime solution (in addition to the water content, ammonia nitrogen (N-NH ₃ ) content of about 18 to ₁₉ % by weight, nitrate) A high quality potassium sulfate fertilizer (47-51% by weight of water-soluble potassium content and 1-7% by weight of total nitrogen) and nitrogenous material by metathesis reaction of about 11-12% by weight of nitrogen (N-NO ₃ ) with potassium chloride powder It has been found that potassium complex fertilizers (15 to 19% by weight of water-soluble potassium content and 15 to 19% by weight of total nitrogen) can be extracted and produced economically, and the present invention has been completed based on this.

It is therefore an object of the present invention to provide a method for producing high quality potassium sulfate fertilizer and nitrogenous nitrogen yield ratio from the oxime solution, which is an industrial waste, without fear of water quality and air pollution.

Another object of the present invention is to provide an economical manufacturing method which can obtain a sulfur-potassium fertilizer and a nitrogen-nitrogen nitrogen yield in high purity and high yield, compared to the conventional metathesis reaction process.

The production method of the present invention for achieving the above object is by adding potassium chloride to the oxime (Oxim) solution, which is a residual industrial waste after extraction of by-product ammonium sulfate derived from caprolactam preparation as yuan fertilizer and reacted at 40 ~ 80 ℃ under stirring After completion of the reaction, the crystals were filtered to obtain potassium sulfate fertilizer. The filtrate from the filtration treatment was concentrated by evaporation, cooled to 0-10 ° C. under stirring, left to stand, and then filtered and dried to obtain a nitrogenous potassium nitrogen fertilizer. Consists of gaining.

Hereinafter, the present invention will be described in more detail.

The chemical reaction to prepare potassium sulfate fertilizer and nitrous nitrogen complex ratio by reacting ammonium sulfate and ammonium nitrate with potassium chloride in the aqueous solution with ammonium sulfate and metathesis is (NH ₄ ) ₂ SO ₄ + NH ₄ NO ₃ + 3KCl → and _{3NH 4 Cl + KNO 3 + K} 2 SO 4, while an aqueous solution at a suitable temperature ^{_{NH 4 +, K +, SO}} 4 -, NO 3 -, Cl - ions such as they are present as ions according to their respective solubility Excess ions are precipitated in each molecular state, that is, K ₂ SO ₄ , KNO ₃ , NH ₄ .

As a result, a constant parallel state exists between the solubility of the solution and the composition ratio of the precipitated solid, thereby obtaining the purity of potassium sulfate and the composition of nitrogenous potassium nitrogen yield required for the product.

Some of ammonium chloride and potassium nitrate, which are highly soluble in aqueous solution, in ammonium chloride and potassium nitrate, remain in the solution in an ionic state, and potassium sulfate, which has relatively low solubility, is precipitated at a constant ratio depending on the composition of the solution. do.

Therefore, when the amount of potassium sulfate and potassium nitrate in the oxime solution is excessive, ammonium chloride, potassium nitrate and unprecipitated potassium sulfate are present in the aqueous solution, and potassium sulfate is present in the solid phase.

In addition, when potassium chloride is excessive, unreacted potassium chloride, ammonium chloride and potassium nitrate are present in the aqueous solution, and potassium sulfate and unreacted potassium chloride are present in the solid to form a dynamic equilibrium with the solution.

On the other hand, the purity of potassium sulfate required as a product is determined by the purity in the precipitated solid phase, and potassium nitrate is determined by the NH ₄ ⁺ , NO ₃ ⁻ , K ⁺ , Cl ⁻ ions of the aqueous solution.

The production method of the present invention ion and the like of various materials in the reaction vessel, that is, _{^{K +, NH 4 +, SO}} 4 -, NO 2 - adjusting the equilibrium, such as by a known method to potassium sulfate crystals and nitrogenous potassium quality Each compound fertilizer crystal can be extracted.

The waste oxime solution generally contains about 30-50% by weight of water, about 25-15% by weight of ammonium sulfate and about 45-35% by weight of ammonium nitrate. In addition, potassium chloride reacted with the waste oxime solution contains 60% or more of water-soluble potassium (K ₂ O). The weight ratio of the oxime solution and the potassium chloride is 1: 0.5 to 1: 7.0, preferably 1: 0.6.

If the potassium chloride addition ratio is less than 0.4, the yield is lowered, which is undesirable, and if it exceeds 0.8, it is not economical and there is no increase in yield. The reaction is reacted at 50 to 80 ° C. for about 20 minutes to 2 hours with stirring at 60 rpm to 120 rpm. The mixed solution is poured and dehydrated for about 2 minutes, then rinsed with dechlorination water and dehydrated for about 3 minutes. Potassium sulfate crystals are obtained by drying this at about 40 ° C to 80 ° C for about 20 minutes to 2 hours.

On the other hand, the filtrate was concentrated by vacuum evaporation, cooled to about 0 ° C to 10 ° C with stirring at about 30 rpm, and left for about 30 minutes to obtain white crystals. The white crystals are extracted from a centrifugal dehydrator or press filter, and dried in a drier at about 40 ° C. to 80 ° C. for about 20 minutes to 2 hours to obtain a nitrogenous potassium complex fertilizer crystal. Alternatively, the filtrate other than the concentrated crystal method may be directly added to a spray dryer or a freeze dryer, and the crystal may be extracted. However, in the present invention, a concentrated crystal method has been adopted in the interest of causing pollution problems.

The potassium sulfate crystals contain 47 to 51% by weight of water-soluble potassium (K ₂ O), 1 to 7% by weight of total nitrogen, and less than 1% by weight of chlorine.

In the method of the present invention, by adjusting the equilibrium state of ions, the content of water-soluble potassium can be easily adjusted arbitrarily over a relatively wide range.

In addition, the nitrogen nitrogen potassium nitrification ratio is 15 to 19% by weight of water-soluble potassium, 15 to 19% by weight of total nitrogen, 6 to 12% by weight of chlorine, which is mainly composed of KNO ₃ , K ₂ SO ₄ and NH ₄ Cl.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

Example 1

A fully mixed pilot plant consisting of one batch reactor with a 30 L capacity and two continuous reactors was used.

The batch reactor comprises 1,000 g of an oxime solution containing 40 wt% water, 20 wt% ammonium sulfate, 40 wt% ammonium nitrate, 6.4 wt% nitrogen nitrate and 10.4 wt% ammonia nitrogen. After heating to 60 ° C., 600 g of potassium chloride having a 60 mesh particle size containing 60% by weight of water-soluble potassium (K ₂ O) was added thereto. The reaction was carried out at 30 rpm for 30 minutes with stirring. Process water was 50 weight% of potassium chloride amount, and it automatically controlled by the water level valve. Here, the mixed liquor at the end of the first reaction over 30 minutes in a batch reactor contained 25% slurry and maintained about 90% of the target purity. Subsequently, the mixture was further reacted for 10 minutes while being transferred to a continuous reactor to increase the target purity and slurry amount.

After completion of the reaction, the solution was introduced into a centrifugal filter and centrifuged for 2 minutes at 6000 × g. Then, 100 ml of chlorine removal water was added and washed again for 3 minutes at 500 × g in order to prevent a drop in purity according to the product ratio of the product. Dehydrated. The dehydrated crystals were dried at 60 DEG C for 30 minutes in dry condition to give 318.4 g of calcium sulfate crystals (26.5% yield based on the total weight ratio except water).

Analysis of this;

Water Soluble Potassium: 48.1 wt%

Total nitrogen content: 5.0 wt%

Chlorine content: 0.7 wt%

Moisture: 0.3 wt%

It was found to be a good quality potassium sulfate fertilizer.

Meanwhile, the filtrate from the centrifugal filter (filtrate of potassium nitrate) is preheated to about 50 ° C. by a heat exchanger, and then vacuum evaporated in a vacuum evaporator, then cooled to 5 ° C. in a cooling tank with stirring at about 30 rpm. The mixture was left for 30 minutes to precipitate white crystals.

The precipitated crystals were separated by a centrifugal filter as described above, and dried in a drier at 60 ° C. for 30 minutes to obtain 535.3 g of nitrogenous nitrogen yield ratio crystals (44.61% yield based on the total weight ratio except water).

Analysis of this;

Water Soluble Potassium: 19.5 wt%

Total nitrogen content: 17.4 wt%

Chlorine content: 8.6 wt%

Moisture: 0.5 wt%

It was found to be a high quality nitrogenous potassium fertilizer containing fertilizer.

As described above, the manufacturing method according to the present invention can obtain a high quality potassium sulfate fertilizer and a high quality potassium fertilizer ratio of the oxime solution, which is an industrial waste, without the concern of water quality and air pollution. It is economically obtainable with high purity and high yield, and unlike the Mannheim method, it has the advantage of easily reducing the Cl content in potassium sulfate fertilizer to less than 1% by weight.

Claims (5)

Potassium chloride was added to the oxime solution, which is a residual industrial waste after extraction of by-product ammonium sulfate derived from caprolactam preparation, as a fertilizer and reacted at 40 to 80 ° C. under stirring. After completion of the reaction, the crystals were filtered to give sulfuric acid. Potassium fertilizer was obtained, the filtrate from the filtration treatment was concentrated by evaporation, cooled to 0 to 10 ° C. under stirring, left to stand, and filtered and dried to obtain a nitrogenous potassium nitrogen fertilizer. Manufacturing method. The method for producing a composite fertilizer by metathesis according to claim 1, wherein the weight addition ratio of the oxime solution and potassium chloride is 1: 0.5 to 1: 0.7. The metathesis reaction according to claim 1, wherein the potassium sulfate fertilizer contains 47-51 wt% of water-soluble potassium (K ₂ O), 1-7 wt% of nitrogen, and less than 1 wt% of chlorine. Method for producing complex fertilizer by The method of claim 1, wherein the nitrogenous potassium nitrile ratio comprises 15 to 19% by weight of water-soluble potassium, 15 to 19% by weight of total nitrogen, and 6 to 10% by weight of chlorine. Manufacturing method of compound fertilizers. 2. The metathesis of claim 1, wherein the filtrate obtained after the separation of the potassium sulfate crystal is not concentrated and cooled, and the filtrate is subjected to a spray dryer or a freeze-dryer treatment to obtain nitrogen-nitrogen nitrogen complex ratio crystals having the same conditions as above. Method for producing complex fertilizer by reaction.