Device for continuously producing sodium fluosilicate by utilizing low-grade fluosilicic acid

Abstract

The utility model provides a device for continuously producing sodium fluosilicate by utilizing low-grade fluosilicic acid, which realizes the flowing type continuous production of the produced sodium fluosilicate through a thickener, a scraper centrifuge and a dryer which are arranged in sequence, and meets the requirement that the low-grade fluosilicic acid is continuously converted into a sodium fluosilicate product. In addition, the thickener and the scraper centrifugal machine are communicated to the filter press II, so that mother liquor components are recycled to the salt dissolving tank, and the negative influence of mother liquor wastewater on the environment is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to sodium fluorosilicate production technical field, specifically for a kind of device for continuous production of sodium fluorosilicate using low-grade fluorosilicic acid. BACKGROUND

[0002] Low-grade fluorosilicic acid is a common byproduct, such as in the production process of wet-process phosphoric acid, part of the fluorine will be converted into fluorosilicic acid. Traditionally, the treatment method of low-grade fluorosilicic acid includes chemical method and biological method. Chemical treatment is mainly converted into fluorosilicate or fluoride salt through neutralization reaction; biological treatment method is to degrade and convert harmful substances into harmless or less toxic substances by using specific strains or microbial communities, but this treatment method is high in cost, and the economic value of fluorosilicic acid is not fully utilized.

[0003] For the preparation of fluorosilicate by chemical method, the current preparation device is basically intermittent, and the production efficiency is difficult to guarantee, and improper treatment of mother liquor and wastewater may also cause negative impact on the environment, limiting the conversion and application range of low-grade fluorosilicic acid.

[0004] Therefore, it is necessary to design a device for continuous production of sodium fluorosilicate using low-grade fluorosilicic acid, which can continuously convert low-grade fluorosilicic acid into sodium fluorosilicate product while reducing the negative impact on the environment. UTILITY MODEL CONTENT

[0005] The utility model provides a kind of device for continuous production of sodium fluorosilicate using low-grade fluorosilicic acid, which can continuously convert low-grade fluorosilicic acid into sodium fluorosilicate product while reducing the negative impact on the environment.

[0006] The technical scheme of the utility model is as follows:

[0007] A device for continuous production of sodium fluorosilicate using low-grade fluorosilicic acid, comprising a reactor, a thickener, a scraper centrifuge, a dryer and a packaging system connected in series; the reactor is connected to a hydrogen fluoride supply line and a sodium sulfate supply line at the feed end; the hydrogen fluoride supply line is connected to a filter press one, and the sodium sulfate supply line is connected to a salt dissolving tank; the liquid outlet of each of the thickener and the scraper centrifuge is connected to the salt dissolving tank through a filter press two.

[0008] Further, the reactor, thickener, dryer and packaging system are respectively connected to an exhaust gas washing tower for absorbing the exhaust gas generated by the reactor, thickener, dryer and packaging system respectively.

[0009] Further, the reactor comprises reactor one and reactor two connected in series, the hydrogen fluoride supply line is connected to reactor one, and the sodium sulfate supply line is connected to reactor one and reactor two respectively.

[0010] Further, the output end of the filter press one is communicated with the pump one, the buffer tank one and the pump two in sequence on the hydrogen fluoride supply pipeline; the output end of the pump two is communicated to the reactor feed end.

[0011] Further, the thickener comprises the thickener one and the thickener two in sequence, and the output end of the thickener one is communicated to the feed end of the thickener two through the pump three.

[0012] Further, the buffer tank two is communicated between the thickener and the scraper centrifuge.

[0013] Further, the liquid outlet ends of the thickener and the scraper centrifuge are respectively communicated to the underground tank; the underground tank is communicated to the salt dissolving tank through the filter press two and the pump four in sequence.

[0014] Compared with the prior art, the device has the following beneficial effects:

[0015] The preparation device comprises the thickener, the scraper centrifuge and the dryer arranged in sequence, realizes the flow type continuous production of sodium fluorosilicate, and meets the continuous conversion of low-grade fluorosilicic acid into sodium fluorosilicate product; in addition, the thickener and the scraper centrifuge are communicated to the filter press two to realize the recycling of mother liquor components to the salt dissolving tank, and the negative influence of mother liquor wastewater on the environment is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description, and obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0017] Figure 1 It is a device schematic diagram for continuously producing sodium fluorosilicate by using low-grade fluorosilicic acid.

[0018] In the drawings, the reference signs are as follows:

[0019] A1, tail gas washing tower; C1, scraper centrifuge; D1, dryer; F1, filter press one; F2, filter press two; L1, hydrogen fluoride supply pipeline; L2, sodium sulfate supply pipeline; P1, pump one; P2, pump two; P3, pump three; PS1, packaging system; R1, synthesis tank one; R2, synthesis tank two; ST1, salt dissolving tank; T1, thickener one; T2, thickener two; V1, buffer tank one; V2, buffer tank two; V3, underground tank. DETAILED DESCRIPTION

[0020] The technical scheme of the utility model will be described clearly and completely in conjunction with the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by the ordinary skilled in the art without creative labor belong to the protection scope of the utility model.

[0021] Referring to Figure 1 In one embodiment, a device for continuous production of sodium fluosilicate by using low-grade fluosilicic acid is provided, comprising a reactor, a thickener, a scraper centrifuge C1, a dryer D1 and a packaging system PS1 connected in series; the reactor is connected with a hydrogen fluoride supply pipeline L1 and a sodium sulfate supply pipeline L2 at the feeding end; the hydrogen fluoride supply pipeline L1 is connected with a filter press F1, and the sodium sulfate supply pipeline L2 is connected with a salt dissolving tank ST1; the liquid outlet of the thickener and the scraper centrifuge C1 is connected to the salt dissolving tank ST1 through a filter press F2.

[0022] In the above embodiment, the by-product hydrogen fluoride generated from the phosphoric acid device is filtered to remove impurities through the filter press F1, and then enters the reactor through the hydrogen fluoride supply pipeline L1 and the salt dissolving tank ST1 for dissolving solid sodium sulfate through the sodium sulfate supply pipeline L2. The hydrogen fluoride and sodium sulfate react in the reactor to generate sodium fluosilicate. The generated sodium fluosilicate enters the thickener for thickening to realize pre-crystallization, and then enters the dryer D1 for drying to obtain the finished product in the packaging system PS1. In this process, the thickener and the scraper centrifuge C1 are connected to the filter press F2 to realize pressure filtration of the mother liquor composition, and then the mother liquor composition is recovered to the salt dissolving tank ST1 for continuous use. The above process meets the continuous conversion of low-grade fluosilicic acid into sodium fluosilicate product, and reduces the negative impact of mother liquor wastewater on the environment.

[0023] In a preferred embodiment, the reactor, the thickener, the dryer D1 and the packaging system PS1 are respectively connected to an off-gas washing tower A1. An absorption liquid is introduced into the off-gas washing tower A1 to absorb the off-gas generated by the reactor, the thickener, the dryer D1 and the packaging system PS1, respectively.

[0024] In an optional embodiment, the feeding end of the dryer D1 can be fed by a belt conveyor, and the dryer D1 can be a continuous feeding dryer, including but not limited to one of a tunnel dryer, a belt dryer, a disc dryer, a continuous microwave dryer, a continuous fluidized bed dryer and a continuous air flow dryer. The packaging system PS1 can be a closed automatic packaging system to avoid escape of harmful gas.

[0025] In the preferred embodiment, in order to improve the reaction efficiency, the reactor comprises reactor one R1 and reactor two R2 in series, the hydrofluoric acid supply pipeline L1 is communicated to reactor one R1, and the sodium sulfate supply pipeline is respectively communicated to reactor one R1 and reactor two R2.

[0026] In the preferred embodiment, in order to improve the stability of the supply, on the hydrofluoric acid supply pipeline L1, the output end of the filter press one F1 is sequentially communicated to the pump one P1, the buffer tank one V1 and the pump two P2; the output end of the pump two P2 is communicated to the reactor feed end.

[0027] In the preferred embodiment, in order to improve the efficiency and product yield, the thickener comprises thickener one T1 and thickener two T2 in series, the discharge end of the thickener one T1 is provided with a pump three P3 communicated to the feed end of the thickener two T2.

[0028] In the optional embodiment, the thickener one T1 and the thickener two T2 are common conical-bottom cylindrical thickeners, the suspension flows in from the central liquid feeding groove, the suspended solids are concentrated by gravity settling to achieve steady-state material balance. The solids are continuously discharged mainly in the underflow, while also added at the same rate from the raw material stream, and the clear liquid is discharged from the periphery overflow through the outflow groove, thereby achieving the purpose of continuous thickening.

[0029] In the above embodiment, by providing two reactors in series, the reaction efficiency and conversion rate are improved; by providing two thickeners in series, the product purity is improved, and finally the high-purity sodium fluorosilicate product is obtained.

[0030] In the preferred embodiment, the thickener is communicated with the scraper centrifuge C1 through a buffer tank two V2 for storing and settling the thickened product. The liquid discharge ends of the thickener, the buffer tank two V2 and the scraper centrifuge C1 are respectively communicated to an underground tank V3; specifically, the waste liquid generated in the upper part of the thickener and the upper part of the buffer tank two V2 overflows to the underground tank V3 for recovery, and the mother liquor generated by centrifugation in the scraper centrifuge C1 is also recovered into the underground tank V3, and the underground tank V3 is sequentially communicated to a filter press two F2 and a pump four P4 communicated to the salt dissolving tank ST1, thereby realizing the recycling of a small amount of unreacted product or product.

[0031] In the above embodiment, the device is also provided with instruments and meters or valves on the pipeline or operation unit, such as thermometers, flowmeters, etc., which all belong to the conventional design in the field, and the person skilled in the art can add and set them as needed, which will not be repeated here.

[0032] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A device for continuously producing sodium fluosilicate using low-grade fluosilicic acid, characterized by, The system comprises a reactor, a thickener, a scraper centrifuge (C1), a dryer (D1) and a packaging system (PS1); the reactor is connected with a hydrogen fluoride supply pipeline and a sodium sulfate supply pipeline; the hydrogen fluoride supply pipeline is connected with a filter press (F1); the sodium sulfate supply pipeline is connected with a salt dissolving tank (ST1); the liquid outlet of the thickener and the scraper centrifuge (C1) is connected with the salt dissolving tank (ST1) through a filter press (F2).

2. The apparatus of claim 1, wherein, The reactor, the thickener, the dryer (D1) and the packaging system (PS1) are respectively connected with an exhaust gas washing tower (A1) for absorbing the exhaust gas generated by the reactor, the thickener, the dryer (D1) and the packaging system (PS1) respectively.

3. The apparatus of claim 1, wherein, The reactor comprises a reactor one (R1) and a reactor two (R2) connected in series; the hydrogen fluoride supply pipeline is connected with the reactor one (R1); the sodium sulfate supply pipeline is connected with the reactor one (R1) and the reactor two (R2) respectively.

4. The apparatus of claim 1, wherein, The output end of the filter press (F1) is connected with a pump one (P1), a buffer tank one (V1) and a pump two (P2) in sequence; the output end of the pump two (P2) is connected with the reactor.

5. The apparatus of claim 1, wherein, The thickener comprises a thickener one (T1) and a thickener two (T2) connected in series; the output end of the thickener one (T1) is connected with the input end of the thickener two (T2) through a pump three (P3).

6. The apparatus of claim 1, wherein, The thickener is connected with a buffer tank two (V2) and the scraper centrifuge (C1).

7. The apparatus of claim 1, wherein, The liquid outlet of the thickener and the scraper centrifuge (C1) is connected with an underground tank (V3) respectively; the underground tank (V3) is connected with the salt dissolving tank (ST1) through a filter press (F2) and a pump four (P4) in sequence.

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