WO2020088273A1

WO2020088273A1 - Method for improving glass-like feel of surface of diammonium phosphate

Info

Publication number: WO2020088273A1
Application number: PCT/CN2019/111879
Authority: WO
Inventors: 王仁宗; 杨慧萍; 田楠; 李淑华
Original assignee: 湖北富邦科技股份有限公司
Priority date: 2018-10-31
Filing date: 2019-10-18
Publication date: 2020-05-07
Also published as: CN109264689A

Abstract

A method for improving the glass-like feel of the surface of diammonium phosphate, comprising the following steps: in a conventional method for producing diammonium phosphate from phosphoric acid, adding to a neutralization tank boric acid that accounts for 0.05-0.10% of the mass of phosphoric acid in the neutralization tank; and adding to a granulator of a sodium-containing substance that accounts for 0.02-0.08% of the mass of a slurry in the neutralization tank, the sodium-containing substance being one from among or a mixture of two or more from among sodium carbonate, sodium bicarbonate and sodium oxide. The described method may improve the transparency, gloss, strength and like properties of diammonium phosphate particles, while the pH value of diammonium phosphate may be adjusted, and the granulation rate of diammonium phosphate may be increased.

Description

Method for improving surface glass feeling of diammonium phosphate

Technical field

The present invention relates to the production field of diammonium phosphate, specifically, to the production field of diammonium phosphate granulation.

Background technique

With the continuous development of the market, the quality requirements of users for diammonium phosphate products have also been continuously improved. In particular, the appearance quality of diammonium phosphate is very high, and it will become an intuitive standard for the quality of diammonium phosphate to control the product particle size, roundness, color and crystallinity.

Improving the appearance quality of DAP products is one of the important means to establish the product image and user texture. Under the premise of ensuring the internal quality, the appearance quality of DAP product particles is usually tested and determined by the following indicators:

1. Particle size: Use a test sieve with a pore size of 1.00-4.00mm to sieve the sample to calculate its fraction; and the degree to which the particle size tends to be consistent is called particle uniformity. At present, the particle size of diammonium phosphate is 90-92%

2. Roundness: the degree to which the external arc of the particles is spherical. A few companies use the screening method to classify the particles with a sample size of 2.5-3.5mm, and then randomly take dozens of particles from them, and the number of the particles that freely roll down to the preset reference distance on the smooth surface of the inclined plate accounts for the sampling. The fraction of the number (usually, the distance of the rounder particles free to roll off is relatively longer) is used as a measurement standard, and the value is generally 60% -80%. The larger the value, the more round the particles. The roundness is the degree to which the particles visually feel their spherical shape and oiliness under light.

3. Particle strength: Use a particle strength meter to measure the crushing pressure of particles. At present, the particle strength of DAP particles is 40-80 Newtons.

4. Translucency: Pure ammonium phosphate is white crystals, and the product particles can intuitively feel its crystal clearness under the light. There is currently no quantitative standard to measure.

Many domestic research institutes and enterprises have done a lot of work. Based on the granulation (granulation) mechanism of diammonium phosphate (DAP), the factors influencing the granulation of DAP are analyzed from the raw material, process and equipment of the granulation process. From the slurry neutralization degree, neutralization temperature, water content, viscosity, granulation process return ratio, washing liquid, masterbatch particle size distribution, spray volume and ammonia flux, and the slurry distributor in the granulator , Ammonia distributor and rubber liner etc. discussed the impact on granulation, and achieved certain results.

Patent "CN101891169B" is a method of using aluminum ions to improve the crystallinity of diammonium phosphate. It discloses that during the process of decomposing phosphate rock to phosphoric acid, the aluminum element accounts for 0 to 2.5% of the weight of the phosphate rock or has been generated. Adding 0 to 1.25% of aluminum by weight to phosphoric acid, and the addition amount of aluminum is not 0, so that the content of metal sesquioxide in diammonium phosphate is 1.5 to 3%, and phosphoric acid with good crystallinity can be obtained Diammonium particles. Although the appearance of diammonium phosphate is improved and the particle strength is enhanced, due to the addition of aluminum, the sesquioxide content is high, which reduces the total nutrients of diammonium phosphate and affects the quality of diammonium phosphate. There are certain requirements for quality, and the use of phosphate rock is restricted to a certain extent.

The patent "CN1765734A" uses phosphoric acid with a high magnesium content to produce diammonium phosphate, which discloses the rapid neutralization of phosphoric acid and ammonia in the reactor: the phosphoric acid entering the tubular reactor to produce diammonium phosphate is non-neutralizing Phosphoric acid, the phosphoric acid that enters the pre-neutralization tank is washing acid. The production load of the tubular reactor is controlled above 80% of the total production volume, and the production volume of the pre-neutralization tank is controlled below 20% of the total production volume. This method can produce qualified diammonium phosphate products using wet-process phosphoric acid with a magnesium content of 1.5% to 2.5%, thereby broadening the application path of phosphate ores with high magnesium oxide content, and the produced products have a good crystallinity. Although the crystallization is very good, the product is not rounded, which makes the product easier to agglomerate, and it is limited to a specific process.

The patent "CN104193453A" discloses a production method containing trace elements of ammonium phosphate, which is characterized in that in the production process of ammonium phosphate, the method adopts the method of dissolving phosphoric acid and fully ammonizing the reaction of trace element oxides or salts, which will contain trace amounts The oxides or salts of the elements are added to the acidolysis tank, the washing liquid from the ammonium phosphate washing system, phosphoric acid, and water are mixed and stirred to fully decompose the oxides or salts of trace elements into ions or complexes to form trace elements. The phosphoric acid solution is transported by the feed pump into the tube counter acid tank, added with phosphoric acid, washing liquid, and process water to mix, rapidly ammoniated in the tubular reactor, sprayed and granulated in the granulator, and then dried , Sieving, cooling and wrapping to obtain ammonium phosphate compound fertilizer containing trace elements. The ammonium phosphate compound fertilizer containing trace elements obtained by the method of the invention has good solubility.

In the production method of the trace element-containing ammonium phosphate according to claim, the oxide or salt of the trace element is borax pentahydrate (Na ₂ B ₄ O ₇ .5H ₂ O), borax decahydrate (Na ₂ B ₄ O ₇ .10H ₂ O), zinc oxide (ZnO), zinc sulfate (ZnSO _4), zinc phosphate _{_{_{(Zn 3 (PO 4) 2}}} ), copper sulfate (CuSO ₄ .5H ₂ O), copper phosphate (Cu ₃ (PO ₄ ) ₂ ), sodium phosphate (Na ₃ PO ₄ ), sodium selenite (Na ₂ SeO ₃ ), sodium selenite (Na ₂ SeO ₄ ), molybdenum trioxide (MoO ₃ ), selenium oxide (SeO ₂ ), Iron sulfate (Fe ₂ (SO ₄ ) ₃ ), iron phosphate (FePO ₄ ), iron oxide (Fe ₂ O ₃ ), manganese sulfate (MnSO ₄ ), manganese oxide (MnO), sodium sulfate (Na ₂ SO ₄ ), One or more of sodium iodide (NaI) and sodium iodide (NaIO ₃ ).

The patent "CN101723733B" method for producing crystals of diammonium phosphate with added trace elements is to add proportionally to the diammonium phosphate product the soluble salt containing iodine, cobalt, selenium, zinc, copper, iron, manganese, boron. One or more kinds, mixed with diammonium phosphate slurry, made by conventional granulation and drying. The soluble salts containing iodine, cobalt, selenium, zinc, copper, iron, manganese, and boron are sodium iodide or potassium iodide, cobalt oxide, selenium oxide, zinc oxide, copper sulfate, iron sulfate, or ferrous sulfate, sulfuric acid Manganese, borax.

Phosphate Fertilizer and Compound Fertilizer, Volume 30, Issue 4, April 2015, "Study on Controlling Appearance Quality of Diammonium Phosphate Products with Ternary Phase Diagram", explores the relationship between mineral impurity content and product appearance quality crystallinity, through the AI ₂ O ₃ , CaO, MgO, SiO ₂ , and Fe ₂ O ₃ impurities constitute a ternary phase diagram, and the most suitable control interval is found for AI ₂ O ₃ content of 1.65-2.20%; MgO content is not greater than 1.44% ; SiO ₂ content is not more than 0.55%, in order to achieve the purpose of improving product appearance quality.

Sulphur and Phosphorus Design and Powder Engineering The third issue of 2016, "Analysis of Factors Affecting the Crystallinity of DAP Products", the article analyzes the main factors affecting the crystallinity of DAP products, and proposes AI ₂ O ₃ in phosphate rock and phosphoric acid. The main control parameters of MgO impurities and solid content (silt content).

Summary of the invention

The purpose of the present invention is to provide a method for improving the surface glass feel of diammonium phosphate on the basis of the existing technology, improve the permeability, gloss, strength and other properties of diammonium phosphate particles, and improve the surface appearance of diammonium phosphate At the same time, the PH value of diammonium phosphate can be adjusted, and the selectivity to crops is broader.

The technical solution of the present invention is:

A method for improving the surface glass feel of diammonium phosphate. In the conventional method for producing diammonium phosphate by phosphoric acid, it is characterized by adding a boric acid that accounts for 0.05 to 0.10% of the mass of the phosphoric acid in the neutralization tank. Add a 0.02-0.08% sodium-containing substance to the pelletizer mass in the granulator.

The substance containing sodium element is one or a mixture of two or more of sodium carbonate, sodium bicarbonate and sodium oxide.

In the neutralization tank, boric acid forms a mixture of boric acid and ammonium borate. The ammonium borate contains crystalline water and its molecular formula is NH ₄ HB ₄ O ₇ · 3H ₂ O. The mixture of boric acid and ammonium borate in diammonium phosphate The surface forms dense glass fibers and the crystallization mechanism of boric acid and borate systems; sodium carbonate, sodium bicarbonate, and sodium oxide form sodium dihydrogen phosphate in the granulator, and release heat to promote a part of the sodium ion Metal impurities form crystals, and nonmetallic impurities form crystals and a mixture of sodium dihydrogen phosphate forms glass fibers and crystal structures on the surface of diammonium phosphate. From the neutralization tank to the granulation process, a dense fiber structure and crystals are continuously formed, thereby enhancing the gloss and firmness of the surface of the diammonium phosphate and improving the strength of the diammonium phosphate particles, so that the surface of the diammonium phosphate has a clear glass feel. At the same time, sodium carbonate, sodium bicarbonate or sodium oxide can effectively adjust the PH value of the slurry in the granulator, thereby more effectively promoting the granulation of diammonium phosphate.

The method of the invention mainly improves the roundness, strong crystal sense, obvious glass feeling, high strength and other properties of the diammonium phosphate particles, and at the same time can adjust the PH value of the diammonium phosphate and increase the granulation rate of the diammonium phosphate. The present invention can achieve the following points through the following tests:

1. Particle size: Use a test sieve with a pore size of 2.00 to 4.00mm to sieve the sample to calculate its fraction; and the degree to which the particle size tends to be consistent is called particle uniformity. The particle size of the diammonium phosphate prepared by the invention reaches more than 95%.

2. Roundness: the degree to which the external arc of the particles is spherical. The diammonium phosphate prepared by the present invention randomly takes dozens of particles from it, and the number of free rolls on a smooth surface inclined plate to a preset reference distance accounts for the fraction of the number of samples (usually, it is more round The distance at which the particles are free to roll off is relatively long) As a measure, the value is generally greater than 80%. The larger the value, the more round the particles. The roundness is the degree to which the particles visually feel their spherical shape and oiliness under light.

3. Particle strength: A particle strength meter is used to measure the crushing pressure of the particles, and the particle strength of the diammonium phosphate particles prepared by the present invention is 80-100 Newtons.

4. Translucency: Ammonium phosphate is a crystal structure. The diammonium phosphate product particles prepared by the present invention are visually clear and transparent under the light, and the glass feels strong.

detailed description

The following further describes the present invention through specific implementation cases.

Implementation Case 1

A diammonium phosphate enterprise in Hubei uses the traditional pre-neutralization-drum ammonia granulation method for production. The specific process flow is: in the pre-neutralization tank, concentrated phosphoric acid and liquid ammonia are reacted at 120 ° C to produce a slurry with an N / P of 1.5, and the slurry is pumped into the granulator. In the granulator, the slurry and ammonia are further reacted to produce DAP with an N / P of 1.8 to 1.9 and a moisture content of 3 to 4%, which is fed into a co-current rotary dryer and dried into a finished product. Due to the influence of impurities such as magnesium oxide phosphate, the produced diammonium phosphate particles have insufficient roundness, no glossiness, low strength, and easy agglomeration.

By adopting the method of the invention, 0.08% purity 95% boric acid in the phosphoric acid pre-neutralization tank is added to the phosphoric acid pre-neutralization tank, and the reaction is performed to generate a slurry with an N / P of 1.4-1.6, and then the slurry is pumped into the granulator In the granulator, add 0.02% sodium oxide powder with a purity of 99% to the mass of the neutralizing tank slurry, and the diammonium phosphate particles produced under the same conditions of other processes and the same situation as a diammonium phosphate enterprise in Hubei Roundness, strong crystal sense, obvious glass feeling, high strength, and good fluidity of diammonium phosphate particles. The tested particle size reaches 96%, the roundness reaches 82%, and the particle strength reaches 90 Newtons.

Implementation Case 2

A diammonium phosphate enterprise in Gansu province uses the pre-neutralization + tube reactor mixing process for production. The specific technological process is: the concentrated acid and washing liquid (N / P is about 0.6) in the wet-process phosphoric acid storage tank are prepared into a certain concentration of dilute phosphoric acid (N / P≤0.6), and then the prepared dilute phosphoric acid and The liquid ammonia in the integrated tank area reacts in the pre-neutralization reactor (120 ° C) + tubular reactor (140 ° C) to produce a diammonium phosphate slurry (N / P is about 1.5), and the slurry is sprayed to the The granulation is carried out in the granulator. In the granulator, the slurry and ammonia are further reacted to produce DAP with an N / P of 1.9. The material granulated by the granulator enters the dryer to dry the material into a finished product. The tubular reactor can produce 60-70% of the total ammonium phosphate slurry required, and the remaining 30-40% is produced by the neutralization tank. Due to the limitation of ore quality, the produced sesquioxide phosphate has a high impurity content, and the produced diammonium phosphate particles have insufficient roundness, lack of permeability, and low strength. With the patent "CN101891169B", the product's nutrients are not up to the standard; with the patent "CN1765734A", the capacity of the tubular reactor is limited.

Using the method of the present invention, 0.06% purity 96% boric acid, which accounts for the mass of phosphoric acid in the neutralization tank, is added into the phosphoric acid pre-neutralization tank, and the reaction is performed to generate a slurry with an N / P of 1.4-1.6, which is then pumped into the granulator In the granulator, add 0.02% purity 99% sodium oxide and 0.02% purity 99% sodium carbonate powder, which account for the mass of the neutralization tank slurry. The other process conditions remain unchanged and the same as a diammonium phosphate enterprise in Gansu In the case, the produced diammonium phosphate particles are round, strong in crystallization, have obvious glass feeling, high in strength, and have good fluidity. The tested particle size reaches 96%, the roundness reaches 81%, and the particle strength reaches 80 Newtons.

Implementation Case 3

A diammonium phosphate enterprise in Guizhou, using pre-neutralization + tube reactor mixed process production. The specific technological process is as follows: the concentrated acid and washing liquid (N / P is about 0.8) in the wet phosphoric acid storage tank are prepared into a certain concentration of dilute phosphoric acid (N / P≤0.6), and then the prepared dilute phosphoric acid and The liquid ammonia in the integrated tank area reacts in the pre-neutralization reactor (120 ° C) + tubular reactor (140 ° C) to produce a diammonium phosphate slurry (N / P is about 1.5), and the slurry is sprayed to the The granulation is carried out in the granulator. In the granulator, the slurry and ammonia are further reacted to produce DAP with an N / P of 1.9. The material granulated by the granulator enters the dryer to dry the material into a finished product. The tubular reactor can produce 60-70% of the total ammonium phosphate slurry required, and the remaining 30-40% is produced by the neutralization tank. Due to the limitation of ore quality, the produced sesquioxide phosphate has a high impurity content, and the produced diammonium phosphate particles have insufficient roundness, lack of permeability, and low strength. With the patent "CN101891169B", the product's nutrients are not up to the standard; with the patent "CN1765734A", the capacity of the tubular reactor is limited.

By adopting the method of the invention, 0.05% purity 97% boric acid with a mass of phosphoric acid in the neutralization tank is added into the phosphoric acid pre-neutralization tank, and the reaction is performed to generate a slurry with an N / P of 1.4-1.6, and then the slurry is pumped into the granulator In the granulator, add sodium carbonate powder with a purity of 0.07% and a purity of 99%, which accounts for the mass of the slurry in the neutralization tank. Under the same conditions of other processes and the same situation as a diammonium phosphate enterprise in Guizhou, the produced diammonium phosphate particles are round, strong crystalline, obvious glass, high strength, and good flowability of the diammonium phosphate particles. The tested particle size reaches 96%, the roundness reaches 80%, and the particle strength reaches 90 Newtons.

Implementation Case 4

A diammonium phosphate enterprise in Hubei uses the traditional pre-neutralization-drum ammonia granulation method for production. The specific process flow is: in the pre-neutralization tank, concentrated phosphoric acid and liquid ammonia are reacted at 110-120 ° C to produce a slurry with an N / P of 1.5-1.8, and the slurry is pumped into the granulator; in the granulator In the process, the slurry further reacts with ammonia to form DAP with N / P of 1.8 to 1.9 and moisture content of 3 to 4%, and enters the co-current rotary dryer to dry it into finished products. Due to the influence of impurities such as magnesium oxide phosphate, the produced diammonium phosphate particles have insufficient roundness, no glossiness, low strength, and easy agglomeration.

Using the method of the present invention, 0.10% purity 96% boric acid in the phosphoric acid pre-neutralization tank is added to the neutralization tank phosphoric acid, and 0.08% purity 99% sodium bicarbonate in the granulator is added to the neutralization tank slurry mass. In the same conditions as other diammonium phosphate enterprises in Hubei, the produced diammonium phosphate particles are round, strong crystalline, obvious glassy, high strength, and good flowability of diammonium phosphate particles. The tested particle size reaches 95%, the roundness reaches 81%, and the particle strength reaches 85 Newtons.

The above is only an embodiment of the present invention, and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention without departing from the technical solution content of the present invention And modifications are still within the scope of the technical solution of the present invention.

Claims

A method for improving the surface glass feel of diammonium phosphate. In the conventional method for producing diammonium phosphate by phosphoric acid, it is characterized by adding a boric acid that accounts for 0.05 to 0.10% of the mass of the phosphoric acid in the neutralization tank. Add a 0.02-0.08% sodium-containing substance to the pelletizer mass in the granulator.
The method for improving the surface glass feel of diammonium phosphate according to claim 1, wherein the substance containing sodium element is one or a mixture of two or more of sodium carbonate, sodium bicarbonate, and sodium oxide .