Phosphate concentrate reaction system

Abstract

The utility model discloses a phosphate concentrate reaction system which comprises a phosphorite filter and is characterized in that the phosphorite filter is connected with a gypsum filter, a reaction tank and an acidolysis reactor, the gypsum filter is connected with the reaction tank through a pipeline, the reaction tank is connected with the phosphorite filter through a pipeline, and the acidolysis reactor is connected with the phosphorite filter through a pipeline. Phosphoric acid filtrate decomposed by the gypsum filter is sent to the reaction tank by the reaction tank to form phosphate concentrate slurry, the phosphate concentrate slurry flows into the phosphorite filter to form connection, phosphate concentrate and filtrate are obtained by the phosphorite filter, the phosphorite filter is connected with an acidolysis reactor through a pipeline, and the filtrate decomposed by the phosphorite filter flows into the acidolysis reactor; the acidolysis reactor is in reflux connection with the desulfurizing tower through a pipeline to form a circulating system, so that sulfur dioxide in the flue gas is effectively utilized to replace sulfuric acid for phosphorus ore impurity removal to produce the phosphate concentrate, and the cost of sulfuric acid raw materials required by the production of the phosphate concentrate is saved. Meanwhile, the desulfurization cost is reduced, and the environmental influence is reduced.

Description

Technical Field

[0001] The utility model relates to the field of phosphate concentrate processing systems, in particular to a circulation system for producing phosphate concentrate by flue gas desulfurization. Background Art

[0002] The current production and processing of phosphate concentrate requires sulfuric acid as a raw material for reaction. The cost of sulfuric acid is high, and tailings are discharged. The tailings contain 55-8% P2O and the phosphorus utilization rate is only 85%, resulting in a huge waste of phosphorus resources.

[0003] Ferrous sulfate, a byproduct of titanium dioxide, is currently mainly used in the production of cement chromium reduction agent, feed additive (monohydrate), polyferrous sulfate, sulfuric acid blending and other traditional applications. The traditional downstream is saturated; a large number of uses are used in the production of iron phosphate. Recently, due to the overcapacity of iron phosphate, the demand has been greatly reduced. There is an urgent need to develop new uses, increase consumption, and improve added value.

[0004] Ferrous sulfate is rich in iron and sulfur and is a good resource of iron and sulfur. Currently, only a small amount of ferrous sulfate is calcined to produce iron red, and the sulfur resource is simply neutralized with lime. When ferrous sulfate is processed and calcined at high temperature, the iron trioxide (containing 70% iron) produced is a high-quality iron concentrate, but it also produces a large amount of sulfur trioxide and sulfur dioxide flue gas, which brings major environmental problems.

[0005] A phosphate concentrate processing system is designed to combine the advantages and disadvantages of various processes, achieve maximum resource utilization, and reduce pollution. Based on this purpose, a circulating system for producing phosphate concentrate through flue gas desulfurization is formed, that is, a phosphate concentrate reaction system. Utility Model Content

[0006] The utility model provides a phosphate concentrate reaction system, which solves the existing problems.

[0007] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a phosphate concentrate reaction system, including a phosphate ore filter, characterized in that the phosphate ore filter is connected to a gypsum filter, a reaction tank, and an acid hydrolysis reactor, the gypsum filter is connected to the reaction tank through a pipeline, and the reaction tank is further connected to the phosphate ore filter through a pipeline, the reaction tank sends the phosphoric acid filtrate decomposed by the gypsum filter to the reaction tank to form a phosphate concentrate slurry that flows into the phosphate ore filter to form a connection, and the phosphate concentrate and filtrate are obtained from the phosphate ore filter.

[0008] The phosphate rock filter is connected to an acid hydrolysis reactor through a pipeline, and the filtrate decomposed by the phosphate rock filter flows into the acid hydrolysis reactor. The acid hydrolysis reactor is refluxed and connected to a desulfurization tower through a pipeline to form a circulation system.

[0009] The gypsum filter is also connected to a desulfurization tower via a slurry delivery pump.

[0010] The desulfurization tower is used to produce calcium sulfate (gypsum) by reacting sulfur dioxide in flue gas with calcium acid solution.

[0011] The acidolysis reactor is used for the reaction of phosphoric acid and phosphate rock to obtain a calcium-containing acidolysis solution which is refluxed into the desulfurization tower for desulfurization.

[0012] The desulfurization tower is connected with a ferrous sulfate rotary kiln.

[0013] The rotary kiln is connected to a ferrous sulfate bin via a pipeline, the rotary kiln is connected to a burner via a pipeline, and is connected to a cooler via a pipeline.

[0014] The rotary kiln is used for oxidative decomposition of ferrous sulfate to produce iron concentrate and sulfur trioxide and sulfur dioxide flue gas;

[0015] The desulfurization tower reacts with the flue gas and the calcium-containing acid solution to produce calcium sulfate (gypsum), thereby removing sulfur trioxide and sulfur dioxide from the flue gas, and the sulfur trioxide and sulfur dioxide flue gas enters the desulfurization tower;

[0016] The desulfurization tower reacts with the flue gas and the calcium-containing acid solution to produce calcium sulfate (gypsum), thereby removing sulfur trioxide and sulfur dioxide from the flue gas. The calcium sulfate is transported to the gypsum filter through a slurry delivery pump;

[0017] The slurry delivery pump is used to deliver gypsum slurry;

[0018] The gypsum filter is used to filter the gypsum slurry to obtain gypsum filter cake and phosphoric acid filtrate; the generated phosphoric acid filtrate enters the acid hydrolysis reactor to react with the phosphate rock;

[0019] The acidolysis reactor is used for the reaction of phosphoric acid and phosphate rock to obtain calcium-containing acidolysis liquid which then flows back to the desulfurization tower.

[0020] The acid hydrolysis reactor reacts and decomposes a portion of the calcium-containing acid hydrolysis liquid which flows back to the desulfurization tower.

[0021] The reaction tank is used for the reaction of phosphoric acid with phosphate ore to obtain phosphate concentrate slurry which flows into the phosphate ore filter;

[0022] The phosphate rock filter is used to filter the concentrate slurry to obtain phosphate concentrate and phosphoric acid filtrate. The phosphoric acid filtrate produced enters the acid hydrolysis reactor, and then reacts with the phosphate rock to obtain calcium-containing acid hydrolysis liquid, which is then refluxed to the desulfurization tower.

[0023] The beneficial effects of the utility model are as follows: when the system is running, the sulfur dioxide in the flue gas can be effectively used to replace sulfuric acid for the removal of impurities from phosphate ore to produce phosphate concentrate, thereby eliminating the cost of sulfuric acid raw materials required for the production of phosphate concentrate; in the overall system, sulfur trioxide and sulfur dioxide flue gas can enter the desulfurization tower to react with calcium-containing acidolysis liquid to produce calcium sulfate, the calcium sulfate is transported to the gypsum filter through a slurry delivery pump to form a filter cake as a calcium sulfate product and a phosphoric acid filtrate, a part of the phosphoric acid filtrate flows into the acidolysis reactor for reuse, and a part of the phosphoric acid enters the reaction tank; in the reaction tank, phosphoric acid reacts with phosphate ore to obtain a phosphate concentrate slurry, the phosphate concentrate slurry is filtered into phosphate concentrate and phosphoric acid filtrate through a phosphate ore filter, the phosphoric acid filtrate flows into the acidolysis reactor for reuse, the acidolysis reactor decomposes to form a calcium-containing acidolysis liquid, which then flows into the desulfurization tower for continuous and cyclic use, forming a comprehensive system for producing phosphoric acid, iron concentrate, phosphate concentrate, gypsum and flue gas desulfurization with ferrous sulfate, so that the generated filtrate is fully utilized, with good environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a system schematic diagram of the utility model.

[0025] Numbers in the figure: 1. Rotary kiln; 2. Desulfurization tower; 3. Slurry delivery pump; 4. Gypsum filter; 5. Acid hydrolysis reactor; 6. Reaction tank; 7. Phosphate ore filter; 8. Ferrous sulfate bin; 9. Burner; 10. Cooler. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0027] Reference Figure 1 A phosphate concentrate reaction system includes a phosphate ore filter 7, wherein the phosphate ore filter 7 is connected to a gypsum filter 4, a reaction tank 6, and an acid hydrolysis reactor 5. The gypsum filter 4 is connected to the reaction tank 6 through a pipeline, and the reaction tank 6 is further connected to the phosphate ore filter 7 through a pipeline. The reaction tank 6 sends the phosphoric acid filtrate decomposed by the gypsum filter 4 to the reaction tank 6 to form a phosphate concentrate slurry that flows into the phosphate ore filter 7 to form a connection, and the phosphate concentrate and filtrate are obtained from the phosphate ore filter 7.

[0028] The phosphate rock filter 7 is connected to the acid hydrolysis reactor 5 through a pipeline, and the filtrate decomposed by the phosphate rock filter 7 flows into the acid hydrolysis reactor 5.

[0029] The gypsum filter 4 is also connected to the desulfurization tower 2 through a slurry delivery pump, and the acidolysis reactor 5 is connected to the desulfurization tower 2 through a pipeline reflux to form a circulation system; the desulfurization tower 2 is used for the reaction of flue gas sulfur dioxide with calcium acidolysis solution to produce calcium sulfate (gypsum); the acidolysis reactor 5 is used for the reaction of phosphoric acid with phosphate rock to obtain calcium-containing acidolysis solution which is refluxed into the desulfurization tower 2 for desulfurization; the desulfurization tower 2 is connected to a ferrous sulfate rotary kiln 1; the rotary kiln 1 is connected to a ferrous sulfate bin 8 through a pipeline, the rotary kiln 1 is connected to a burner 9 through a pipeline, and is also connected to a cooler 10 through a pipeline.

[0030] The rotary kiln is used for oxidative decomposition of ferrous sulfate to produce iron concentrate and sulfur trioxide and sulfur dioxide flue gas; the desulfurization tower is used for reacting the flue gas with calcium-containing acidolysis solution to produce calcium sulfate (gypsum), thereby removing sulfur trioxide and sulfur dioxide in the flue gas, and the sulfur trioxide and sulfur dioxide flue gas enters the desulfurization tower; the desulfurization tower is used for reacting the flue gas with calcium-containing acidolysis solution to produce calcium sulfate (gypsum), thereby removing sulfur trioxide and sulfur dioxide in the flue gas, and the calcium sulfate is transported to the gypsum filter through a slurry delivery pump; the slurry delivery pump is used for transporting gypsum slurry; the gypsum filter is used for filtering gypsum slurry to obtain gypsum filter cake and phosphoric acid filtrate; the generated phosphoric acid filtrate enters the acidolysis reactor to react with phosphate rock; the acidolysis reactor is used for phosphoric acid to react with phosphate rock to obtain calcium-containing acidolysis solution which then flows back to the desulfurization tower.

[0031] The acid hydrolysis reactor decomposes part of the calcium-containing acid solution, which is refluxed to the desulfurization tower and reaction tank for phosphoric acid to react with phosphate ore to obtain phosphate concentrate slurry that flows into the phosphate ore filter;

[0032] The phosphate rock filter is used to filter the concentrate slurry to obtain phosphate concentrate and phosphoric acid filtrate. The phosphoric acid filtrate produced enters the acid hydrolysis reactor, and then reacts with the phosphate rock to obtain calcium-containing acid hydrolysis liquid, which is then refluxed to the desulfurization tower.

[0033] The beneficial effects of the utility model are as follows: the system is operated to effectively use sulfur dioxide in flue gas instead of sulfuric acid to remove impurities from phosphate ore and produce phosphate concentrate, thereby eliminating the cost of sulfuric acid raw materials required for the production of phosphate concentrate;

[0034] In the overall system, sulfur trioxide and sulfur dioxide flue gas can enter the desulfurization tower and react with calcium-containing acidolysis liquid to produce calcium sulfate. The calcium sulfate is transported to the gypsum filter through a slurry delivery pump to form a filter cake as a calcium sulfate product and a phosphoric acid filtrate. A part of the phosphoric acid filtrate flows into the acidolysis reactor for reuse, and a part of the phosphoric acid enters the reaction tank. In the reaction tank, phosphoric acid reacts with phosphate ore to obtain phosphate concentrate slurry. The phosphate concentrate slurry is filtered into phosphate concentrate and phosphoric acid filtrate through a phosphate filter. The phosphoric acid filtrate flows into the acidolysis reactor for reuse. The acidolysis reactor decomposes to form a calcium-containing acidolysis liquid, which then flows into the desulfurization tower for continuous and cyclic use, forming a comprehensive system for producing phosphoric acid, iron concentrate, phosphate concentrate, gypsum and flue gas desulfurization with ferrous sulfate, so that the generated filtrate can be fully utilized, with good environmental benefits.

[0035] At the same time, based on the above system, the following comprehensive processing steps of ferrous acid production of phosphoric acid, iron ore, phosphate concentrate, gypsum and flue gas desulfurization can be achieved:

[0036] These include:

[0037] A. The raw material ferrous sulfate (anhydrous) enters the rotary kiln (1), the pulverized coal is burned by the burner to provide heat for the rotary kiln, the cold air exchanges heat with the iron concentrate discharged from the rotary kiln in the cooler to recover heat and enter the burner to assist combustion, and the ferrous sulfate is oxidized and decomposed by heat in the rotary kiln to produce ferric oxide (iron concentrate) and sulfur trioxide and sulfur dioxide flue gas;

[0038] B. The raw phosphate ore and phosphoric acid enter the acid hydrolysis reactor 5, where the raw phosphate ore and phosphoric acid undergo a decomposition reaction to obtain a calcium-containing acid hydrolysis solution;

[0039] C. The calcium-containing acid solution enters the desulfurization tower 2, where calcium ions react chemically with sulfur trioxide and sulfur dioxide in the flue gas to generate calcium sulfate and calcium sulfite precipitation, wherein the calcium sulfite is further oxidized to obtain calcium sulfate, and the calcium sulfate slurry is transported to the gypsum filter 4 through the slurry pump 3;

[0040] D. The filter cake produced by the gypsum filter is a calcium sulfate product, and the filtrate is phosphoric acid, a portion of which is recycled to the acid hydrolysis reactor, and a portion of which enters the reaction tank 6;

[0041] E. Phosphoric acid reacts with phosphate ore in the reaction tank to obtain phosphate concentrate slurry, which is filtered by a phosphate filter 7, and the filter cake is a phosphate concentrate product. The filtrate is recycled to the acid hydrolysis reactor, and the acid hydrolysis reactor decomposes the calcium-containing acid solution and refluxes it into the desulfurization tower 2 for continuous desulfurization;

[0042] The overall process reaction formula is: FeSO4·7H20→FeSO4·H20+6H2O, FeSO4·7H20→FeSO4+7H20, 2FeSO4·H20→Fe2O3+SO2+SO3+H20, 2FeSO4→Fe2O3+SO2+SO3, Ca5F(PO4)3+7H3PO4→5Ca(H2PO4)2+HF, Ca(H2PO4)2+SO2+H20→CaSO3+2H3PO4, 2CaSO3+O2→2CaSO4.

[0043] The raw material of step A is anhydrous ferrous sulfate, and the rotary kiln operating conditions are: temperature 900-950° C., and reaction time 1 hour.

[0044] The concentration of phosphoric acid in step B is 35-40%, the P2O5 content of phosphate ore is 15-20%, and the process conditions of the acid hydrolysis reactor are as follows: the reaction temperature of the desulfurization tower is 60°C-80°C, the reaction time is 1 hour, and the liquid-solid ratio is 2.5-3:1.

[0045] The flue gas temperature of the desulfurization tower 2 is 130° C. to 150° C., the concentration of the calcium acid solution (as Ca) is 3 to 5%, and the liquid-to-gas ratio is 1:1000.

[0046] In the step E, the concentration of phosphoric acid is 35-40%, the content of P2O5 in the phosphate ore is 15-20%, and the process conditions controlled by the reactor are: temperature 60° C.-80° C., and reaction time 2 hours.

[0047] Right now:

[0048] High temperature calcination mechanism: The ferrous sulfate heptahydrate is treated by a two-step process of drying and calcination. The drying temperature is controlled at 400-450°C to dehydrate the ferrous sulfate heptahydrate to obtain monohydrate and anhydrous ferrous sulfate. The monohydrate and anhydrous ferrous sulfate enter the rotary kiln for high temperature calcination at a controlled temperature of 900-950°C for 60 minutes. The reactions involved are: FeSO4·7H20→FeSO4·H20+6H2O, FeSO4·7H20→FeSO4+7H20, 2FeSO4·H20→Fe2O3+SO2+SO3+H20, 2FeSO4→Fe2O3+SO2+SO3

[0049] Acid hydrolysis mechanism: phosphoric acid is used to react with phosphate rock to generate calcium-containing acid hydrolysis solution, which contains water-soluble calcium dihydrogen phosphate. The main reaction involved is: Ca5F(PO4)3+7H3PO4→5Ca(H2PO4)2+HF

[0050] Desulfurization mechanism: Calcium dihydrogen phosphate in the calcium-containing acid solution reacts chemically with sulfur dioxide in the flue gas to form calcium sulfite precipitate, which is further oxidized to obtain calcium sulfate (gypsum) precipitate. The main reactions are: Ca(H2PO4)2+SO2+H20→CaSO3+2H3PO4, 2CaSO3+O2→2CaSO4, and the gypsum filter uses general slurry placed in a storage tank with an agitator for crystal growth, with a residence time of 6 to 8 hours.

[0051] Its desulfurization tower, slurry delivery pump, gypsum filter, cooler, ferrous sulfate bin, burner, reaction tank, phosphate rock filter, rotary kiln and acid hydrolysis reactor are connected equipment, which can be directly connected to form a phosphate concentrate reaction system or a phosphate rock impurity removal system.

[0052] The above system is also a comprehensive system for producing phosphoric acid, iron concentrate, phosphate concentrate, gypsum and flue gas desulfurization based on ferrous sulfate.

[0053] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A phosphate concentrate reaction system, comprising a phosphate ore filter (7), characterized in that: The phosphate rock filter (7) is connected to a gypsum filter (4), a reaction tank (6), and an acid hydrolysis reactor (5). The gypsum filter (4) is connected to the reaction tank (6) through a pipeline, and the reaction tank (6) is further connected to the phosphate rock filter (7) through a pipeline. The reaction tank (6) sends the phosphoric acid filtrate decomposed by the gypsum filter (4) to the reaction tank (6) to form a phosphate concentrate slurry, which flows into the phosphate rock filter (7) to form a connection, and the phosphate concentrate and filtrate are obtained from the phosphate rock filter (7).

2. A phosphate concentrate reaction system according to claim 1, characterized in that: The phosphate rock filter (7) is connected to the acid hydrolysis reactor (5) via a pipeline, and the filtrate decomposed by the phosphate rock filter (7) flows into the acid hydrolysis reactor (5).

3. A phosphate concentrate reaction system according to claim 2, characterized in that: The gypsum filter (4) is also connected to the desulfurization tower (2) via a slurry delivery pump, and the acid hydrolysis reactor (5) is connected to the desulfurization tower (2) via a reflux pipeline to form a circulation system.

4. A phosphate concentrate reaction system according to claim 3, characterized in that: The desulfurization tower (2) is used for the reaction of flue gas sulfur dioxide with calcium acid solution to produce calcium sulfate gypsum.

5. A phosphate concentrate reaction system according to claim 4, characterized in that: The acidolysis reactor (5) is used for the reaction of phosphoric acid with phosphate rock to obtain a calcium-containing acidolysis solution which is refluxed into the desulfurization tower (2) for desulfurization.

6. A phosphate concentrate reaction system according to claim 2, characterized in that: The desulfurization tower (2) is connected to the ferrous sulfate rotary kiln (1).

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