CN213416277U

CN213416277U - Sewage recycling system for preparing hydrogen fluoride from fluosilicic acid

Info

Publication number: CN213416277U
Application number: CN202022076434.3U
Authority: CN
Inventors: 宋志伟; 刘大鹏; 黄弘; 刘文超
Original assignee: Hubei Wengfu Lantian Chemical Co ltd
Current assignee: Hubei Wengfu Lantian Chemical Co ltd
Priority date: 2020-09-21
Filing date: 2020-09-21
Publication date: 2021-06-11
Anticipated expiration: 2030-09-21

Abstract

The utility model relates to a fluosilicic acid prepares sewage recycling system of hydrogen fluoride, including the acidolysis pond, the acidolysis pond passes through pipeline and first filter, sedimentation reaction pond and second filter communicate in proper order through the pipeline, the sedimentation reaction pond still is equipped with the dilute sulphuric acid admission pipe, second filter filtrating discharge port and first neutralization tank, deposit the settling tank, filter the feed pump, first filter, the second filter, neutralization tank in the second, concentrated feed pump, first evaporimeter and second evaporimeter communicate in proper order through the pipeline, first evaporimeter and second evaporimeter bottom pass through pipeline and crystallizer tank, the crystal slurry groove, centrifuge communicates in proper order, centrifuge's liquid discharge port passes through pipeline and crystallizer tank intercommunication, centrifuge discharge port still communicates in proper order through pipeline and wet hopper and wet material spiral feeder. The utility model discloses directly retrieve the thin sulphuric acid of fluosilicic acid byproduct and be used for the preparation of wet process phosphoric acid, the thin sulphuric acid solution does not need extra treatment, reducible sewage treatment cost.

Description

Sewage recycling system for preparing hydrogen fluoride from fluosilicic acid

Technical Field

The utility model belongs to the technical field of fluosilicic acid, a sewage recycling system of hydrogen fluoride is prepared to fluosilicic acid is related to.

Background

93-99% of H is used to prepare hydrogen fluoride from fluosilicic acid₂SO₄Contacting with fluosilicic acid solution to dehydrate fluosilicic acid, then decompressing and separating the mixture, and using H to distill HF₂SO₄And (4) absorbing. Heating and resolving to obtain hydrogen fluoride, purifying and rectifying to obtain anhydrous hydrofluoric acid. Silicon tetrafluoride reacts with water in the fluosilicic acid to generate high-concentration fluosilicic acid for recycling. In the process, a large amount of by-product dilute sulfuric acid is generated, a large amount of sewage can be generated if the by-product dilute sulfuric acid is not recycled, and meanwhile, a small amount of fluorine can be contained in the sewage, so that the sewage treatment cost is high.

Disclosure of Invention

In order to solve the technical problem, the utility model provides a sewage recycling system for preparing hydrogen fluoride from fluosilicic acid.

The scheme of the utility model is that:

a sewage recycling system for preparing hydrogen fluoride from fluosilicic acid comprises an acidolysis tank, wherein the acidolysis tank is sequentially communicated with a first filter through a pipeline, a precipitation reaction tank and a second filter through a pipeline, the precipitation reaction tank is further provided with a dilute sulfuric acid inlet pipe, a filtrate outlet of the second filter is sequentially communicated with a first neutralization tank, a precipitation clarification tank, a filtration feed pump, a first filter, a second neutralization tank, a concentration feed pump, a first evaporator and a second evaporator through pipelines, the bottoms of the first evaporator and the second evaporator are sequentially communicated with a crystallization tank, a crystal slurry tank and a centrifuge through pipelines, a liquid outlet of the centrifuge is communicated with the crystallization tank through a pipeline, a filter residue outlet of the centrifuge is sequentially communicated with a wet hopper and a wet material spiral feeder through a pipeline, a cyclone separator and a finished product conveyor are arranged above a discharge port of the wet material spiral feeder through an airflow drying pipe, The finished product hopper is communicated with the packaging machine in sequence.

Preferably, the top of the cyclone separator is sequentially communicated with a bag-type dust collector and a tail gas fan through pipelines, and a discharge hole at the bottom of the cyclone separator is communicated with a wet material spiral feeder through a pipeline.

Preferably, the discharge port at the bottom of the wet material spiral feeder is also provided with a breaker and is communicated with the hot blast stove through a pipeline.

Preferably, the second filter, the first neutralization tank, the sedimentation and clarification tank, the first filter, the second neutralization tank and the crystallization tank are also communicated with a liquid collecting tank through pipelines, and the liquid collecting tank is communicated with the phosphoric acid extraction tank through a pipeline.

Preferably, the first neutralization tank and the second neutralization tank are provided with sodium carbonate feeding ports.

The utility model discloses beneficial effect:

1. the utility model discloses directly be used for the preparation of wet process phosphoric acid with the recovery of the thin sulphuric acid of fluosilicic acid byproduct, because also contain fluorine in the phosphorite, need the later stage to remove fluorine and handle, consequently the thin sulphuric acid solution does not need extra processing, can directly be used for the wet process phosphoric acid preparation in-process, reduces the sewage treatment cost.

2. When impurities in raw material phosphorite, such as fluorine, sulfur, iron, aluminum, magnesium, calcium and the like enter trisodium phosphate, iron is one of main harmful impurities, and can reduce the purity of the trisodium phosphate product and increase the content of insoluble substances, thereby reducing the quality of the product. Most impurities in the wet-process phosphoric acid are removed by sedimentation through a first filter, then, soda ash and caustic soda are used for neutralization, and the first neutralization degree is NaH₂PO 40.5-1.5 g/100ml, which is beneficial to removing impurities such as iron and the like; and neutralizing with caustic soda for the second time, and performing double-effect evaporation concentration, cooling crystallization, centrifugal separation and airflow drying to obtain the industrial trisodium phosphate.

Drawings

FIG. 1 is a schematic view of the system of the present invention;

wherein: the acidolysis tank 1, the first filter 2, the precipitation reaction tank 3, the second filter 4, the dilute sulfuric acid inlet pipe 5, the first neutralizing tank 6, the precipitation clarification tank 7, the filtration feed pump 8, the first filter 9, the second filter 10, the second neutralizing tank 11, the concentration feed pump 12, the first evaporator 13, the second evaporator 14, the crystallization tank 15, the crystal slurry tank 16, the centrifuge 17, the wet hopper 18, the wet material spiral feeder 19, the air flow drying pipe 20, the cyclone 21, the finished product conveyor 22, the finished product hopper 23, the packaging machine 24, the bag-type dust remover 25, the tail gas fan 26, the breaker 27, the hot-blast stove 28, and the liquid receiving tank 29.

Detailed Description

The invention is further described with reference to the following examples, but the scope of the invention as claimed is not limited to the scope of the examples.

Example 1

As shown in figure 1, the sewage recycling system for preparing hydrogen fluoride from fluosilicic acid comprises an acidolysis tank 1, wherein the acidolysis tank 1 is sequentially communicated with a first filter 2, a precipitation reaction tank 3 and a second filter 4 through pipelines, the precipitation reaction tank 3 is also provided with a dilute sulfuric acid inlet pipe 5, a filtrate outlet of the second filter 4 is sequentially communicated with a first neutralization tank 6, a precipitation clarification tank 7, a filtration feed pump 8, a first filter 9, a second filter 10, a second neutralization tank 11, a concentration feed pump 12, a first evaporator 13 and a second evaporator 14 through pipelines, the bottoms of the first evaporator 13 and the second evaporator 14 are sequentially communicated with a crystallization tank 15, a crystal slurry tank 16 and a centrifuge 17 through pipelines, a liquid outlet of the centrifuge 17 is communicated with the crystallization tank 15 through a pipeline, a filter residue outlet of the centrifuge 17 is also sequentially communicated with a wet material hopper 18 and a wet material spiral feeder 19 through a pipeline, the upper part of the discharge hole of the wet material spiral feeder 19 is communicated with a cyclone separator 21, a finished product conveyor 22, a finished product hopper 23 and a packing machine 24 in turn through an airflow drying pipe 20.

Preferably, the top of the cyclone separator 21 is further communicated with a bag-type dust collector 25 and a tail gas fan 26 in sequence through pipelines, and a discharge outlet at the bottom of the cyclone separator 21 is communicated with the wet material spiral feeder 19 through a pipeline.

Preferably, the bottom discharge port of the wet material screw feeder 19 is also provided with a breaker 27 and is communicated with a hot blast stove 28 through a pipeline.

Preferably, the second filter 4, the first neutralization tank 6, the sedimentation and clarification tank 7, the first filter 9, the second filter 10, the second neutralization tank 11 and the crystallization tank 15 are also communicated with a liquid collecting tank 29 through pipelines, and the liquid collecting tank 29 is communicated with the phosphoric acid extraction tank through a pipeline.

Preferably, the first neutralization tank 6 and the second neutralization tank 11 are provided with sodium carbonate feeding ports.

The utility model discloses during the use: the optimal process conditions for decomposing the phosphorite are as follows: the acidolysis tank 1 is used for carrying out primary decomposition on phosphorite, the ratio of mixed acid (nitric acid and hydrochloric acid) is 4:1, the liquid-solid ratio of the mixed acid to the phosphorite is (3.5-5) to 1, and the reaction conditions and temperatures are as follows: and (2) filtering at 40-50 ℃ for 35-45min, adding fluosilicic acid into the precipitation reaction tank 3 after entering the first filter 2 for filtration to prepare a dilute sulfuric acid solution discharged by hydrogen fluoride, wherein the volume ratio of the dilute sulfuric acid solution to the filtrate discharged by the first filter 2 is (3.5-10): 1, and entering the generated phosphoric acid into the second filter 4 for filtration to remove most of impurities in the phosphoric acid by sedimentation.

Then, the solution was neutralized with soda in the first neutralization tank 6 and with caustic soda in the second neutralization tank 11 to prepare a disodium phosphate solution. The first time is as follows: 2H₃PO₄+ Na₂CO₃ → 2NaH₂PO₄+ CO₂↑+ H₂O; the pH value is increased, so that impurities such as iron and the like can be removed; the degree of neutralization should be controlled at NaH₂PO₄0.5-1.5g/100 ml. After the first neutralization, impurities are filtered out.

The second neutralization reaction formula is: na (Na)₂HPO₄ + NaOH→ Na₃PO₄ + H₂And O, carrying out double-effect evaporation and concentration on the reaction liquid by a first evaporator 13 and a second evaporator 14, cooling and crystallizing by a crystallizing tank 15 and a crystal slurry tank 16, carrying out centrifugal separation by a centrifugal machine 17, carrying out air flow drying by an air flow drying pipe 20 and a cyclone separator 21, and the like to obtain an industrial trisodium phosphate product.

The above-mentioned embodiments only represent the preferred embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, various changes, modifications and substitutions can be made without departing from the spirit of the invention, and these are all within the scope of the invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. The utility model provides a sewage recycling system of hydrogen fluoride is prepared to fluosilicic acid, includes acidolysis pond (1), its characterized in that: the acidolysis tank (1) is communicated with the first filter (2), the precipitation reaction tank (3) and the second filter (4) in sequence through pipelines, the precipitation reaction tank (3) is also provided with a dilute sulfuric acid inlet pipe (5), a filtrate outlet of the second filter (4) is communicated with the first neutralization tank (6), the precipitation clarification tank (7), the filtration feed pump (8), the first filter (9), the second filter (10), the second neutralization tank (11), the concentration feed pump (12), the first evaporator (13) and the second evaporator (14) in sequence through pipelines, the bottoms of the first evaporator (13) and the second evaporator (14) are communicated with the crystallization tank (15), the crystal slurry tank (16) and the centrifuge (17) in sequence through pipelines, a liquid outlet of the centrifuge (17) is communicated with the crystallization tank (15) through a pipeline, a filter residue outlet of the centrifuge (17) is also communicated with the wet material spiral feeder (18) and the wet material spiral feeder (19) in sequence through pipelines, the upper part of the discharge hole of the wet material spiral feeder (19) is communicated with a cyclone separator (21), a finished product conveyor (22), a finished product hopper (23) and a packing machine (24) in sequence through an airflow drying pipe (20).

2. The sewage recycling system for preparing hydrogen fluoride from fluosilicic acid according to claim 1, which is characterized in that: the top of the cyclone separator (21) is sequentially communicated with a bag-type dust collector (25) and a tail gas fan (26) through pipelines, and a discharge outlet at the bottom of the cyclone separator (21) is communicated with a wet material spiral feeder (19) through a pipeline.

3. The sewage recycling system for preparing hydrogen fluoride from fluosilicic acid according to claim 1, which is characterized in that: a discharging port at the bottom of the wet material spiral feeder (19) is also provided with a breaker (27) and is communicated with a hot blast stove (28) through a pipeline.

4. The sewage recycling system for preparing hydrogen fluoride from fluosilicic acid according to claim 1, which is characterized in that: the second filter (4), the first neutralization tank (6), the sedimentation and clarification tank (7), the first filter (9), the second filter (10), the second neutralization tank (11) and the crystallization tank (15) are also communicated with a liquid collecting tank (29) through pipelines, and the liquid collecting tank (29) is communicated with the phosphoric acid extraction tank through a pipeline.

5. The sewage recycling system for preparing hydrogen fluoride from fluosilicic acid according to claim 1, which is characterized in that: and the first neutralizing tank (6) and the second neutralizing tank (11) are provided with sodium carbonate feeding ports.