阅读说明：本技术 一种磷肥的制备方法 (Preparation method of phosphate fertilizer ) 是由 张传成 何翔 贺战文 刘杰胜 于 2020-06-30 设计创作，主要内容包括：本发明公开一种磷肥的制备方法,涉及废弃物回收利用技术领域。所述磷肥的制备方法包括以下步骤：将污泥灰置于硫酸溶液中,搅拌至反应形成混合物；对所述混合物固液分离,收集滤液；向所述滤液中加入碱性铝溶液使发生络合反应以生成络合混合溶液；将所述络合混合液过滤,取沉淀物造粒、烧结后,得磷肥。本发明实现了将污泥灰变废为宝,从而减少了污泥灰处理成本,并为污泥灰提供了新的应用途径,为磷肥提供了新的制备方法。(The invention discloses a preparation method of a phosphate fertilizer, and relates to the technical field of waste recycling. The preparation method of the phosphate fertilizer comprises the following steps: putting the sludge ash into a sulfuric acid solution, and stirring until a mixture is formed; carrying out solid-liquid separation on the mixture, and collecting filtrate; adding an alkaline aluminum solution into the filtrate to perform a complexing reaction so as to generate a complexing mixed solution; and filtering the complex mixed solution, taking the precipitate, granulating and sintering to obtain the phosphate fertilizer. The invention changes the sludge ash into valuable, thereby reducing the treatment cost of the sludge ash, providing a new application approach for the sludge ash and providing a new preparation method for phosphate fertilizer.)

1. A preparation method of a phosphate fertilizer is characterized by comprising the following steps:

putting the sludge ash into a sulfuric acid solution, and stirring until a mixture is formed;

carrying out solid-liquid separation on the mixture, and collecting filtrate;

adding an alkaline aluminum solution into the filtrate to perform a complexing reaction so as to generate a complexing mixed solution;

and filtering the complex mixed solution, taking the precipitate, granulating and sintering to obtain the phosphate fertilizer.

2. The method of claim 1, wherein the step of placing the sludge ash in a sulfuric acid solution and stirring the sludge ash until the sludge ash reacts to form a mixture comprises:

mixing the sludge ash, a sulfuric acid solution and water, and uniformly stirring to form mixed sludge with the pH value of 1.5-2.2;

and stirring the mixed mud for 20-30 h under the condition that the pH value is 1.5-2.2, so that a mixture is formed.

3. The method for preparing a phosphate fertilizer as claimed in claim 1, wherein the step of placing the sludge ash in a sulfuric acid solution and stirring the sludge ash until the sludge ash reacts to form a mixture, wherein the concentration of the sulfuric acid solution is 0.5-2 mol/L.

4. The method of producing a phosphate fertilizer according to claim 1, wherein the step of adding an alkaline aluminum solution to the filtrate to cause a complexation reaction to occur to produce a complexed mixed solution comprises:

and adding an alkaline aluminum solution into the filtrate, and adjusting the pH value to 3.8-4.3 so as to generate a complex mixed solution through a complex reaction.

5. The method for producing a phosphate fertilizer according to claim 1, wherein in the step of adding an alkaline aluminum solution to the filtrate to cause a complexing reaction to occur to produce a complex mixed solution, the alkaline aluminum solution is a mixed solution of one or both of alumina and aluminum hydroxide and sodium bicarbonate.

6. The method for producing a phosphate fertilizer according to claim 5, wherein in the step of adding an alkaline aluminum solution to the filtrate to cause a complexing reaction to generate a complex mixed solution, the alkaline aluminum solution is a mixed solution of alumina, aluminum hydroxide and sodium bicarbonate.

7. The method for preparing a phosphate fertilizer according to claim 6, wherein the mass ratio of the alumina, the aluminum hydroxide and the sodium bicarbonate in the mixed solution is (1-2): (1-2): (2-3).

8. The method for preparing a phosphate fertilizer according to claim 1, wherein in the step of filtering the complex mixed solution, taking out the precipitate, granulating, and sintering to obtain the phosphate fertilizer, a filter membrane used in the filtering has a size of 3 to 4 μm.

9. The method for producing a phosphate fertilizer according to claim 1, wherein in the step of obtaining a phosphate fertilizer by filtering the complex mixture, taking out a precipitate, granulating the precipitate, and sintering the precipitate, the sintering temperature is 800 to 1200 ℃.

10. The method for producing a phosphate fertilizer according to claim 1, wherein in the step of obtaining a phosphate fertilizer by filtering the complex mixture, taking out a precipitate, granulating, and sintering, the phosphate fertilizer has a water content of not more than 1.0 (w/w)%.

Technical Field

The invention relates to the technical field of waste recycling, in particular to a preparation method of a phosphate fertilizer.

Background

Municipal sludge is an extremely complex heterogeneous body which contains a large amount of toxic, harmful and carcinogenic substances, such as dioxin, parasitic ova, pathogenic bacteria and the like. The sludge treatment method is mainly an incineration treatment method. The final product after sludge incineration is sludge ash which contains a large amount of beneficial substances such as phosphorus, nitrogen and the like and a large amount of toxic, harmful and carcinogenic substances.

At present, sludge ash is generally treated by landfill, but the landfill method needs a wide field, the sludge ash yield is huge, a large amount of cost is required to be invested for treating the sludge ash, and in addition, beneficial substances in the sludge ash are not fully utilized, so that great waste is caused.

Disclosure of Invention

The invention mainly aims to provide a preparation method of a phosphate fertilizer, and aims to solve the problem that phosphorus contained in sludge ash is not fully utilized at present.

In order to achieve the purpose, the invention provides a preparation method of a phosphate fertilizer, which comprises the following steps:

putting the sludge ash into a sulfuric acid solution, and stirring until a mixture is formed;

carrying out solid-liquid separation on the mixture, and collecting filtrate;

adding an alkaline aluminum solution into the filtrate to perform a complexing reaction so as to generate a complexing mixed solution;

and filtering the complex mixed solution, taking the precipitate, granulating and sintering to obtain the phosphate fertilizer.

Optionally, the step of placing the sludge ash in a sulfuric acid solution and stirring until reacting to form a mixture comprises:

mixing the sludge ash, a sulfuric acid solution and water, and uniformly stirring to form mixed sludge with the pH value of 1.5-2.2;

and stirring the mixed mud for 20-30 h under the condition that the pH value is 1.5-2.2, so that a mixture is formed.

Optionally, the sludge ash is placed in a sulfuric acid solution, and is stirred until the sludge ash reacts to form a mixture, wherein the concentration of the sulfuric acid solution is 0.5-2 mol/L.

Optionally, the step of adding an alkaline aluminum solution to the filtrate to cause a complexation reaction to occur to generate a complexed mixed solution includes:

and adding an alkaline aluminum solution into the filtrate, and adjusting the pH value to 3.8-4.3 so as to generate a complex mixed solution through a complex reaction.

Optionally, in the step of adding an alkaline aluminum solution to the filtrate to perform a complexation reaction to generate a complex mixed solution, the alkaline aluminum solution is a mixed solution of one or both of aluminum oxide and aluminum hydroxide and sodium bicarbonate.

Optionally, in the step of adding an alkaline aluminum solution to the filtrate to perform a complexation reaction to generate a complex mixed solution, the alkaline aluminum solution is a mixed solution of aluminum oxide, aluminum hydroxide and sodium bicarbonate.

Optionally, in the mixed solution, the mass ratio of the aluminum oxide to the aluminum hydroxide to the sodium bicarbonate is (1-2): (1-2): (2-3).

Optionally, in the step of filtering the complex mixed solution, taking out the precipitate, granulating and sintering to obtain the phosphate fertilizer, the size of the filter membrane adopted during filtering is 3-4 μm.

Optionally, in the step of filtering the complex mixed solution, taking out a precipitate, granulating and sintering to obtain the phosphate fertilizer, the sintering temperature is 800-1200 ℃.

Optionally, in the step of filtering the complex mixed solution, taking out the precipitate, granulating and sintering to obtain the phosphate fertilizer, the water content of the phosphate fertilizer is not more than 1.0 (w/w)%.

According to the technical scheme provided by the invention, the sludge ash is used as a raw material, the sludge ash is reacted with sulfuric acid to extract phosphorus in the sludge ash and remove other harmful substances, and then the phosphorus and aluminum are separated after forming a complex compound through reaction with an alkaline aluminum solution, so that the phosphate fertilizer is prepared. The phosphate fertilizer can be used for cultivating plants and providing phosphorus elements for the plants, and the invention realizes the purpose of changing sludge ash into valuable, thereby reducing the sludge ash treatment cost, providing a new application approach for the sludge ash and providing a new preparation method for the phosphate fertilizer.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other related drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic flow chart of an embodiment of a method for producing a phosphate fertilizer according to the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments.

It should be noted that those whose specific conditions are not specified in the examples were performed according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The sludge ash contains a large amount of beneficial substances such as phosphorus, nitrogen and the like and a large amount of toxic, harmful and carcinogenic substances.

At present, sludge ash is generally treated by landfill, but the landfill method needs a wide field, the sludge ash yield is huge, a large amount of cost is required to be invested for treating the sludge ash, and in addition, beneficial substances in the sludge ash are not fully utilized, so that great waste is caused.

In view of the above, the invention provides a preparation method of a phosphate fertilizer, which takes sludge ash as a raw material, can prepare the phosphate fertilizer, solves the problem that phosphorus contained in the sludge ash is not fully utilized at present, and realizes the purpose of changing the sludge ash into valuable, thereby reducing the sludge ash treatment cost, providing a new application approach for the sludge ash and providing a new preparation method for the phosphate fertilizer. FIG. 1 shows an embodiment of a method for producing a phosphate fertilizer according to the present invention.

Referring to fig. 1, in this embodiment, the method for preparing the phosphate fertilizer includes the following steps:

and step S10, placing the sludge ash into a sulfuric acid solution, and stirring until the sludge ash reacts to form a mixture.

In this example, the sludge ash is ash formed by burning sludge. The sludge ash contains a large amount of phosphorus in the form of calcium phosphate, which is in this embodiment immersed in a sulfuric acid solution to react with the sulfuric acid sufficiently to form water-soluble phosphoric acid and water-insoluble calcium sulfate.

In order to make the calcium phosphate fully react to generate the phosphoric acid, the pH environment of the reaction system can be controlled within the range of 1.5-2.2. In specific implementation, the method can be realized according to the following steps:

step S110, mixing the sludge ash, a sulfuric acid solution and water, and uniformly stirring to form mixed sludge with the pH value of 1.5-2.2;

and S120, stirring the mixed mud for 20-30 hours under the condition that the pH value is 1.5-2.2 to react to form a mixture.

In step S120, since the reaction is proceeding and the pH environment of the reaction system changes, the pH of the reaction system needs to be controlled so as to be stabilized within a range of 1.5 to 2.2.

Meanwhile, in order to adjust and control the pH value, in the embodiment, the concentration of the sulfuric acid solution is 0.5-2 mol/L, so that the pH value can be controlled quickly and accurately.

In addition, the stirring can be mechanical stirring, and in order to fully and uniformly mix the sludge ash, the sulfuric acid solution and the water, a plow-shaped tooth stirrer can be used for stirring.

And step S20, carrying out solid-liquid separation on the mixture, and collecting filtrate.

The sludge ash contains a large amount of toxic and harmful heavy metal components, and after the step S10, the heavy metal components enter the solid part of the mixture. The solid-liquid separation can be carried out by various methods, such as filtration, centrifugation, or filter pressing.

And step S30, adding an alkaline aluminum solution into the filtrate to perform a complexing reaction so as to generate a complexing mixed solution.

The filtrate obtained by the solid-liquid separation contains most of the phosphorus contained in the sludge ash. In this example, an alkaline aluminum solution was added to the filtrate, and phosphoric acid in the filtrate and the alkaline aluminum solution were subjected to a complex reaction to form a water-insoluble aluminum phosphate complex. The alkaline aluminum solution is an alkaline solution of an oxide or salt of aluminum, for example, an alkaline aluminum solution formed by dissolving aluminum oxide in an alkaline solution such as sodium hydroxide or sodium bicarbonate; or an alkaline aluminum solution in which aluminum chloride is dissolved in sodium hydroxide, and the like.

The complex reaction of the phosphoric acid and the alkaline aluminum solution needs to be carried out in a proper pH environment, so that the aluminum and the phosphorus can be fully complexed and precipitated, and in the embodiment, the pH of the reaction system is controlled to be 3.8-4.3. Specifically, step S30 is implemented by the following steps: and adding an alkaline aluminum solution into the filtrate, and adjusting the pH value to 3.8-4.3 so as to generate a complex mixed solution through a complex reaction.

It is understood that the solution for adjusting the pH of the reaction system may be selected from commonly used acids and bases, such as sulfuric acid, sodium hydroxide, sodium bicarbonate, etc.

Further, in this embodiment, the alkaline aluminum solution is a mixed solution of one or both of aluminum oxide and aluminum hydroxide and sodium bicarbonate. That is, the alkaline aluminum solution may be a mixed solution of aluminum oxide and sodium bicarbonate, a mixed solution of aluminum hydroxide and sodium bicarbonate, or a mixed solution of aluminum oxide, aluminum hydroxide and sodium bicarbonate.

When the alkaline aluminum solution is a mixed solution of aluminum oxide and sodium bicarbonate, the mass ratio of the aluminum oxide to the sodium bicarbonate is (1-2): 1; when the alkaline aluminum solution is a mixed solution of aluminum hydroxide and sodium bicarbonate, the mass ratio of the aluminum hydroxide to the sodium bicarbonate is (1-2): 1.

further, when the alkaline aluminum solution is a mixed solution of aluminum oxide, aluminum hydroxide and sodium bicarbonate, which reacts with phosphoric acid more sufficiently, more aluminum phosphate complex can be generated. And when the mixed solution is prepared, the mass ratio of the aluminum oxide to the aluminum hydroxide to the sodium bicarbonate is (1-2): (1-2): (2-3), the mixed solution of aluminum oxide, aluminum hydroxide and sodium bicarbonate can realize the optimal reaction environment for the reaction with phosphoric acid, and the reaction yield is further improved.

And step S40, filtering the complex mixed solution, taking the precipitate for granulation and sintering to obtain the phosphate fertilizer.

In this embodiment, the complex mixture is filtered, the precipitate contains an aluminum phosphate complex, the precipitate is placed in a granulator for granulation to obtain coarse granules of the phosphate fertilizer, and then the granules are sintered to obtain the phosphate fertilizer containing high effective phosphorus content.

In order to filter out other impurities, in this embodiment, the specification of the filter membrane is limited, and the filter membrane with the specification of 3-4 μm is selected, i.e. the aperture of the filter membrane is 3-4 μm.

In addition, in order to further remove ineffective impurities in the coarse phosphate fertilizer particles and fully oxidize phosphorus in the particles to form effective phosphorus which can be effectively absorbed by plants, sintering is carried out at 800-1200 ℃ in the embodiment.

In the embodiment, the water content of the phosphate fertilizer is not more than 1.0 (w/w)%, and the standard of GB/T20412-.

In addition, the filtered filtrate still contains some harmful heavy metal components, so in this embodiment, after step S40, the following steps are further included: collecting the filtrate, adjusting the pH of the filtrate to be alkaline, filtering, collecting the secondary filtrate, adjusting the pH of the secondary filtrate to be neutral, and discharging. Therefore, most heavy metal harmful components can be removed, and the environment pollution caused by the filtrate is avoided.

The technical solutions of the present invention are further described in detail below with reference to specific examples and drawings, it should be understood that the following examples are merely illustrative of the present invention and are not intended to limit the present invention.