Phosphorite flue gas desulfurization circulating system

Abstract

The utility model discloses a phosphorite flue gas desulfurization circulating system which comprises a desulfurization tower, a slurry delivery pump, a gypsum filter, an acidolysis reactor, a phosphate concentrate filter, a magnesium removal reactor and a magnesium oxide filter which are sequentially connected through pipelines, and the magnesium oxide filter is further in loop connection with the desulfurization tower through a pipeline. According to the structure, calcium resources in phosphorite can be used for flue gas desulfurization to obtain high-purity gypsum, meanwhile, the desulfurization cost is reduced, sulfur dioxide in flue gas is used for replacing sulfuric acid to be used for phosphorite impurity removal to produce phosphate concentrate, magnesium in phosphorite is changed into a magnesium hydroxide product, the utilization rate of phosphorus resources is increased, tailings are not discharged, and the production cost is reduced. The environmental influence is reduced, phosphorus concentrate and gypsum co-production through phosphorus ore flue gas desulfurization is realized, and a multi-process integrated processing cycle is realized.

Description

Technical Field

[0001] The utility model relates to the field of phosphate rock flue gas desulfurization circulation, in particular to a phosphate rock flue gas desulfurization production phosphate concentrate co-production gypsum circulation system. Background Art

[0002] Boiler flue gas technology is divided into dry and wet methods according to the form of desulfurizer. Dry and semi-dry methods have the characteristics of low investment and low energy consumption, and occupy a certain market share in the field of small and medium-sized coal-fired boilers, but their desulfurization efficiency is not higher than 90%, and their market space is limited; wet desulfurization can achieve a desulfurization efficiency of more than 95%, which is the main development direction. According to the properties of the desulfurizer, it can be divided into limestone-gypsum method, ammonia method, double alkali method, magnesium method, organic ammonia method, etc. The most commonly used one is limestone-gypsum method, which accounts for more than 90% of the market share. Limestone desulfurization requires the mining of limestone mines, and the gypsum content produced by desulfurization is low, which cannot be promoted and applied, and requires the occupation of land for storage and causes secondary pollution.

[0003] The flotation process (including forward and reverse flotation) is used for phosphate rock beneficiation. The main problems are: 1. Only medium-grade phosphate ores with a P2O5 content of more than 20% can be floated, and low-grade phosphate ores cannot be selected, resulting in a decrease in resource utilization; 2. Tailings are discharged, and the tailings contain 5-8% P2O5, and the phosphorus utilization rate is only 85%, resulting in a huge waste of phosphorus resources.

[0004] A connected processing circulation system is designed to combine the advantages and disadvantages of each process, realize the maximum resource utilization, reduce pollution, and achieve the greatest advantage: using calcium resources in phosphate ore instead of limestone for flue gas desulfurization, reducing desulfurization costs and improving desulfurization efficiency; using sulfur dioxide in flue gas instead of sulfuric acid for phosphate ore impurity removal to produce phosphate concentrate, eliminating the cost of sulfuric acid raw materials required for phosphate concentrate production, and low-grade phosphate ore can also be valued and utilized as resources, improving the utilization rate of phosphorus resources. Flue gas desulfurization and phosphate fertilizer are coupled to solve the problems of low resource utilization, resource waste, land occupation, secondary pollution, and raw material costs in the above-mentioned processes or industries. At present, there is no phosphate flue gas desulfurization production of phosphate concentrate and co-production of gypsum circulation system. Utility Model Content

[0005] The utility model provides a phosphate rock flue gas desulfurization circulation system, which solves the existing problems.

[0006] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a phosphate rock flue gas desulfurization circulation system, which includes a desulfurization tower, a slurry delivery pump, a gypsum filter, an acid hydrolysis reactor, a phosphate concentrate filter, a magnesium removal reactor and a magnesium oxide filter, which are connected in sequence through pipelines, and the magnesium oxide filter is also connected to the desulfurization tower through a pipeline to form a loop.

[0007] The desulfurization tower, slurry delivery pump, gypsum filter, acidolysis reactor, phosphate concentrate filter, demagnesium reactor and magnesium oxide filter are interconnected through corresponding pipelines. The sulfur dioxide in the flue gas in the desulfurization tower reacts with the calcium salt solution. The desulfurization tower is provided with a delivery pipeline connected to the slurry delivery pump, and the slurry delivery pump can deliver the calcium sulfate liquid to the gypsum filter. The gypsum filter is used for filtering to generate a composite acid, and the composite acid enters the acidolysis reactor.

[0008] The desulfurization tower is used for the reaction of sulfur dioxide in flue gas with calcium salt solution to produce calcium sulfate (gypsum), and the slurry delivery pump is used for delivering gypsum slurry;

[0009] The gypsum filter is used to filter the gypsum slurry to obtain gypsum filter cake and composite acid filtrate, and the composite acid filtrate flows into the acid hydrolysis reactor;

[0010] The acid hydrolysis reactor is used for incomplete acid hydrolysis of the composite acid and the phosphate ore to remove calcium, magnesium, iron and aluminum impurities in the phosphate ore, and the acid filtrate flows into the phosphate concentrate filter;

[0011] The phosphate concentrate filter is used to filter the acid hydrolysis reaction liquid to obtain the phosphate concentrate filter cake and the calcium, magnesium, iron and aluminum salt solution, which flows into the demagnesium reactor;

[0012] The demagnesium reactor is used to react the magnesium-iron-aluminum salt solution with lime to generate magnesium-iron-aluminum hydroxide precipitate;

[0013] The magnesium oxide filter is used to filter the magnesium removal reaction slurry to obtain an iron-aluminum-containing magnesium hydroxide product and a calcium salt filtrate, and the calcium salt filtrate is recycled to the desulfurization tower to react with flue gas sulfur dioxide.

[0014] The above-mentioned phosphate rock flue gas desulfurization circulation system forms a phosphate rock flue gas desulfurization production phosphate concentrate and gypsum co-production circulation system.

[0015] Preferably, the gypsum filter comprises a reaction box, a reaction column is connected to one end above the reaction box, and a vertical plate is arranged at the other end above the reaction box. A first rotating rod is arranged inside the reaction box, a first motor is connected to one end of the first rotating rod, and a roller is arranged at the outer end of the first rotating rod, and the roller is a curved ring structure. A curved pipe is arranged inside the reaction column, one end of the curved pipe is connected to the slurry delivery pump, and one end of the curved pipe is a repeatedly bent structure, and a plurality of square holes are provided on the bent end of the curved pipe. Two first telescopic cylinders are arranged inside the vertical plate, and a filter plate is connected to the lower end of the first telescopic cylinder. A pipeline is connected below the reaction box, and a rotating bead is arranged inside the pipeline, and a through hole is opened inside the rotating bead, and a second rotating rod is connected to one side of the rotating bead, and a second motor is connected to one end of the second rotating rod. A second telescopic cylinder is arranged in the middle part above the reaction box, and a push plate is arranged near one end of the second telescopic cylinder near the vertical plate. The pipeline is arranged correspondingly below the filter plate, and the filter plate filters the calcium sulfate slurry.

[0016] The beneficial effects of the utility model are as follows: the device is provided with a desulfurization tower, a slurry delivery pump, a gypsum filter, an acidolysis reactor, a phosphate concentrate filter, a demagnesium reactor and a magnesium oxide filter which are interconnected through corresponding pipelines and connected through a delivery pipeline to form a circulation system, so that the entire system realizes the recycling of the reaction slurry, the generated filtrate is fully utilized, and has good environmental benefits.

[0017] The circulation system is operated to achieve: the calcium resources in the phosphate rock are used for flue gas desulfurization to obtain high-purity gypsum, the high-purity gypsum completely replaces natural gypsum, and all resources are utilized, while reducing the desulfurization cost and improving the desulfurization efficiency; at the same time, the sulfur dioxide in the flue gas is used instead of sulfuric acid to remove impurities from the phosphate rock and produce phosphate concentrate, eliminating the cost of sulfuric acid raw materials required for the production of phosphate concentrate, and the magnesium in the phosphate rock is converted into magnesium hydroxide products. Low-grade phosphate rock resources can also be utilized as resources, which improves the utilization rate of phosphorus resources, does not discharge tailings, avoids the waste of phosphorus resources, reduces environmental impact, and realizes the production of phosphate concentrate and gypsum from phosphate rock flue gas desulfurization, and the three processes are integrated into one for processing and recycling.

[0018] In addition, the system can utilize sulfur dioxide flue gas instead of sulfuric acid to remove impurities from phosphate ore and produce phosphate concentrate, eliminating the sulfuric acid raw materials required for phosphate ore dressing, and allowing low-grade phosphate ore to be utilized as a resource. The two processes complement each other's advantages, both reduce costs, reduce limestone resource mining, reduce environmental impact, and improve the utilization rate of phosphorus resources.

[0019] The gypsum filter structure in the system can be equipped with a slurry delivery pump to deliver calcium sulfate liquid into the reaction column, and the calcium sulfate liquid is dispersed and diffused through the square holes on the curved pipe. The calcium sulfate liquid then falls onto the drum, is fully reacted through rotation and buffering, and then flows to the pipeline. The filter plate combined with two telescopic structures are telescopic to achieve the discharge of calcium sulfate (gypsum) and composite acid, which effectively realizes the auxiliary generation of composite acid, realizes the continuity of the process, and realizes the connection between the acidolysis reactor and the desulfurization tower of sulfur dioxide flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a system schematic diagram of the utility model.

[0021] Figure 2 This is a schematic diagram of the structure of the gypsum filter of the utility model.

[0022] Figure 3 It is the left view of the gypsum filter of the utility model.

[0023] Figure 4 The utility model is a schematic diagram of the structural section of the gypsum filter.

[0024] Figure 5 It is the right view of the gypsum filter of the utility model.

[0025] Numbers in the figure: 1. desulfurization tower; 2. slurry delivery pump; 3. gypsum filter; 301. reaction box; 302. reaction column; 303. vertical plate; 304. first rotating rod; 305. first motor; 306. drum; 307. curved pipe; 308. square hole; 309. first telescopic cylinder; 310. filter plate; 311. pipeline; 312. rotating beads; 313. second rotating rod; 314. second motor; 315. second telescopic cylinder; 316. push plate; 4. acidolysis reactor; 5. phosphate concentrate filter; 6. demagnesium reactor; 7. magnesium oxide filter. 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-Figure 5A phosphate flue gas desulfurization circulation system comprises a desulfurization tower 1, a slurry delivery pump 2, a gypsum filter 3, an acidolysis reactor 4, a phosphate concentrate filter 5, a demagnesium reactor 6 and a magnesium oxide filter 7, and the desulfurization tower 1, the slurry delivery pump 2, the gypsum filter 3, the acidolysis reactor 4, the phosphate concentrate filter 5, the demagnesium reactor 6 and the magnesium oxide filter 7 are connected to each other through corresponding pipelines, the desulfurization tower 1 is used for generating a reaction to obtain calcium sulfate (gypsum), and the lower end of the desulfurization tower 1 is provided with a delivery pipeline connected to the slurry delivery pump 2 The slurry delivery pump 2 can deliver the calcium sulfate liquid in the delivery pipeline to the gypsum filter 3. The gypsum filter 3 is used to filter and generate a composite acid. The sulfur-containing flue gas is placed in the desulfurization tower 1. The sulfur dioxide in the flue gas in the desulfurization tower 1 reacts with the calcium salt solution to generate a calcium sulfite precipitate. The calcium sulfite further undergoes an oxidation reaction to obtain calcium sulfate (gypsum). The delivery pipeline is connected to the bottom of the desulfurization tower 1, and the calcium sulfate liquid obtained by the reaction is delivered to the gypsum filter 3 by the slurry delivery pump 2 for filtration.

[0028] refer to Figure 1 The acid hydrolysis reactor 4 is added with phosphate rock to react to obtain a reaction slurry, the reaction slurry enters the phosphate concentrate filter 5 to generate a filter cake and a filtrate, the filtrate enters the de-magnesiumization reactor 6, the de-magnesiumization reactor 6 is added with lime to react to obtain a reaction slurry, the reaction slurry enters the magnesium oxide filter 7 to generate a filter cake and a filtrate, the calcium sulfate liquid is filtered through the gypsum filter 3, the unfiltered filter cake is the calcium sulfate (gypsum) product, the filtered filtrate is the composite acid, enters the acid hydrolysis reactor 4 to add phosphate rock to perform an incomplete acid hydrolysis reaction to obtain a reaction slurry , and enters the phosphate concentrate filter 5 through the lower pipeline to start filtering, and obtains unfiltered filter cake phosphate concentrate product and filtrate, the filtrate enters the demagnesiumization reactor 6 through the pipeline, lime raw material is added to the inside of the demagnesiumization reactor 6 at the same time, and a double decomposition reaction occurs with the magnesium salt, aluminum salt and iron salt in the demagnesiumization reactor 6 to generate magnesium aluminum iron oxide precipitation, and then the slurry enters the magnesium oxide filter 7 through the lower pipeline for filtration, and obtains unfiltered magnesium hydroxide product and filtrate, if the filtered filtrate is a calcium salt solution, it enters the desulfurization tower 1 again through the pipeline.

[0029] The gypsum filter 3 can adopt the following structure: Figures 3 to 5The gypsum filter 3 includes a reaction box 301, one end of the reaction box 301 is connected to a reaction column 302, and the other end of the reaction box 301 is provided with a vertical plate 303, a first rotating rod 304 is provided inside the reaction box 301, one end of the first rotating rod 304 is connected to a first motor 305, and a roller 306 is provided at the outer end of the first rotating rod 304, and the roller 306 is a curved ring structure, a curved pipe 307 is provided inside the reaction column 302, one end of the curved pipe 307 is connected to the slurry delivery pump 2, and one end of the curved pipe 307 is repeatedly curved. The curved structure, the curved pipe 307 is provided with a plurality of square holes 308 on one end of the curve, two first telescopic cylinders 309 are arranged inside the vertical plate 303, the lower end of the first telescopic cylinder 309 is connected to the filter plate 310, a pipeline 311 is connected below the reaction box 301, a rotating bead 312 is arranged inside the pipeline 311, and a through hole is arranged inside the rotating bead 312, a second rotating rod 313 is connected to one side of the rotating bead 312, and a second motor 314 is connected to one end of the second rotating rod 313, a second telescopic cylinder 315 is arranged in the middle of the upper part of the reaction box 301, and The second telescopic cylinder 315 is provided with a push plate 316 at one end close to the vertical plate 303, and the pipeline 311 is correspondingly arranged below the filter plate 310. The filter plate 310 filters the calcium sulfate slurry, and the calcium sulfate slurry is transported from the curved pipe 307 to the inside of the reaction column 302 through the slurry delivery pump 2, and the calcium sulfate slurry is broken up and diffused out through the square hole 308 on the curved pipe 307. The calcium sulfate slurry flows to the drum 306, and the drum 306 is driven to rotate slowly through the first rotating rod 304. The drum 306 drives the calcium sulfate slurry to rotate, so that it can be fully buffered during the reaction. The finished calcium sulfate slurry is filtered out through the filter plate 310 to filter out the composite acid and flow to the pipeline 311 to enter the next process. The unfiltered calcium sulfate (gypsum) is placed on the filter plate 310 and is telescopically driven upward by the first telescopic cylinder 309. The filter plate 310 drives the calcium sulfate (gypsum) above to the reaction box 301. The second telescopic cylinder 315 is started to push the push plate 316 to push the calcium sulfate (gypsum) out for sorting. The push plate 316 is located between the two first telescopic cylinders 309, and the width of the push plate 316 is less than the gap between the two first telescopic cylinders 309, and can be telescopically passed through (such as Figure 5As shown in the figure, in addition to the function of pushing out, the combination of the first telescopic cylinder 309 and the second telescopic cylinder 315 can achieve another effect: the second telescopic cylinder 315 pushes the push plate 316 to push out, that is, to seal the upper opening corresponding to the calcium sulfate (gypsum) on the first telescopic cylinder 309, and the first telescopic cylinder 309 can move up and down repeatedly to achieve the first mobile extrusion effect of calcium sulfate (gypsum). When the extrusion is certain, the second telescopic cylinder 315 pushes the push plate 316 to retract. When the first telescopic cylinder 309 drives the calcium sulfate (gypsum) to rise above the outlet, the second telescopic cylinder 315 pushes the push plate 316 to push out the calcium sulfate (gypsum). The cooperation of the two telescopic cylinders can realize the extrusion filtration of calcium sulfate (gypsum), decomposition of composite acid and pushing out the filtered and extruded calcium sulfate (gypsum), integrating multiple effects into one structure. In addition, when the filter plate 310 is driven to rise, the rotating bead 312 will penetrate the air vertically into the pipeline 311 to prevent the unfiltered slurry from flowing into the pipeline 311.

[0030] The structure is novel. The calcium sulfate liquid is dispersed through the square holes on the curved pipe. The calcium sulfate liquid then falls onto the drum, fully reacts through rotation and buffering, and then flows to the pipeline. The filter plate combined with two telescopic cylinders is used for filtering to obtain calcium sulfate (gypsum) and composite acid.

[0031] The gypsum filter 3 is a preferred filter and cannot be used as the only filter. The desulfurization tower 1, slurry delivery pump 2, acid hydrolysis reactor 4, phosphate concentrate filter 5, magnesium removal reactor 6 and magnesium oxide filter 7 are existing equipment.

[0032] Working principle of the system: in the desulfurization tower 1, sulfur dioxide in the flue gas reacts with the calcium salt solution to generate calcium sulfite precipitation, and the calcium sulfite further undergoes an oxidation reaction to obtain calcium sulfate (gypsum). The calcium sulfate slurry is transported to the gypsum filter 3 for filtration through the slurry delivery pump 2, and the filter cake is a calcium sulfate (gypsum) product, and the filtrate is a composite acid, which enters the acid hydrolysis reactor 4; the raw phosphate rock and the composite acid enter the acid hydrolysis reactor 4 for incomplete acid hydrolysis reaction to obtain a reaction slurry, and the reaction slurry enters the phosphate concentrate filter 5 for filtration, and the filter cake obtained by filtration is a phosphate concentrate product, and the filtrate enters the demagnesization reactor 6; the lime raw material enters the demagnesization reactor 6, and the lime undergoes a double decomposition reaction with the magnesium salt, the aluminum salt, and the iron salt in the demagnesization reactor 6 to generate a magnesium aluminum iron oxide precipitate, and the slurry after the reaction enters the magnesium oxide filter 7 for filtration, and the filter cake is a magnesium hydroxide product, and the filtrate is a calcium salt solution and then enters the desulfurization tower 1, and is cyclically processed in sequence to realize the phosphate flue gas desulfurization circulation system, and also to realize the production of phosphate concentrate and gypsum by desulfurization of phosphate flue gas.

[0033] The circulation system is operated to achieve: the calcium resources in the phosphate rock are used for flue gas desulfurization to obtain high-purity gypsum, the high-purity gypsum completely replaces natural gypsum, and all resources are utilized, while reducing the desulfurization cost and improving the desulfurization efficiency; at the same time, the sulfur dioxide in the flue gas is used instead of sulfuric acid to remove impurities from the phosphate rock and produce phosphate concentrate, eliminating the cost of sulfuric acid raw materials required for the production of phosphate concentrate, and the magnesium in the phosphate rock is converted into magnesium hydroxide products. Low-grade phosphate rock resources can also be utilized as resources, which improves the utilization rate of phosphorus resources, does not discharge tailings, avoids the waste of phosphorus resources, reduces environmental impact, and realizes the production of phosphate concentrate and gypsum from phosphate rock flue gas desulfurization, and the three processes are integrated into one for processing and recycling.

[0034] In addition, the system can utilize sulfur dioxide flue gas instead of sulfuric acid to remove impurities from phosphate ore and produce phosphate concentrate, eliminating the sulfuric acid raw materials required for phosphate ore dressing, and allowing low-grade phosphate ore to be utilized as a resource. The two processes complement each other's advantages, both reduce costs, reduce limestone resource mining, reduce environmental impact, and improve the utilization rate of phosphorus resources.

[0035] The gypsum filter structure in the system can be equipped with a slurry delivery pump to deliver calcium sulfate liquid into the reaction column, and the calcium sulfate liquid is dispersed and diffused through the square holes on the curved pipe. The calcium sulfate liquid then falls onto the drum, is fully reacted through rotation and buffering, and then flows to the pipeline. The filter plate combined with two telescopic structures are telescopic to achieve the discharge of calcium sulfate (gypsum) and composite acid, which effectively realizes the auxiliary generation of composite acid, realizes the continuity of the process, and realizes the connection between the acidolysis reactor and the desulfurization tower of sulfur dioxide flue gas.

[0036] 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 rock flue gas desulfurization circulation system, characterized in that: The circulation system comprises a desulfurization tower (1), a slurry delivery pump (2), a gypsum filter (3), an acid hydrolysis reactor (4), a phosphate concentrate filter (5), a demagnesiumization reactor (6) and a magnesium oxide filter (7), which are connected in sequence through pipelines. The magnesium oxide filter (7) is also connected to the desulfurization tower (1) through a pipeline to form a loop.

2. A phosphate rock flue gas desulfurization circulation system according to claim 1, characterized in that: The desulfurization tower (1), the slurry delivery pump (2), the gypsum filter (3), the acidolysis reactor (4), the phosphate concentrate filter (5), the demagnesium reactor (6) and the magnesium oxide filter (7) are interconnected through corresponding pipelines. The sulfur dioxide in the flue gas in the desulfurization tower (1) reacts with the calcium salt solution. The desulfurization tower (1) is provided with a delivery pipeline connected to the slurry delivery pump (2), and the slurry delivery pump (2) delivers the calcium sulfate solution to the gypsum filter (3). The gypsum filter (3) is used for filtering to generate a composite acid, and the composite acid enters the acidolysis reactor (4).

3. A phosphate rock flue gas desulfurization circulation system according to claim 1, characterized in that: The desulfurization tower (1) is used to produce calcium sulfate by reacting flue gas sulfur dioxide with a calcium salt solution.

4. A phosphate rock flue gas desulfurization circulation system according to claim 3, characterized in that: The slurry delivery pump (2) is used for delivering gypsum slurry.

5. A phosphate rock flue gas desulfurization circulation system according to claim 4, characterized in that: The gypsum filter (3) is used to filter the gypsum slurry to obtain gypsum filter cake and composite acid filtrate, and the composite acid filtrate flows into the acid hydrolysis reactor (4).

6. A phosphate rock flue gas desulfurization circulation system according to claim 5, characterized in that: The acid hydrolysis reactor (4) is used for incomplete acid hydrolysis reaction between the composite acid and the phosphate ore to remove calcium, magnesium, iron and aluminum impurities in the phosphate ore, and the acid filtrate flows into the phosphate concentrate filter (5).

7. A phosphate rock flue gas desulfurization circulation system according to claim 6, characterized in that: The phosphate concentrate filter (5) is used to filter the acid hydrolysis reaction liquid to obtain a phosphate concentrate filter cake and a calcium, magnesium, iron, and aluminum salt solution, which flows into the demagnesiumization reactor (6).

8. A phosphate rock flue gas desulfurization circulation system according to claim 7, characterized in that: The demagnesiuming reactor (6) is used for reacting the magnesium-iron-aluminum salt solution with lime to generate magnesium-iron-aluminum hydroxide precipitate.

9. A phosphate rock flue gas desulfurization circulation system according to claim 8, characterized in that: The magnesium oxide filter (7) is used to filter the magnesium removal reaction slurry to obtain an iron-aluminum-containing magnesium hydroxide product and a calcium salt filtrate, and the calcium salt filtrate is recycled to the desulfurization tower (1) to react with flue gas sulfur dioxide.

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