Device and method for preparing high-purity ferric trichloride water purifying agent

Abstract

The invention belongs to the technical field of synthesis and purification of ferric trichloride, and particularly relates to a preparation method of a high-purity ferric trichloride water purifier, which comprises the following steps: S1, adding a titanium dioxide byproduct ferrous sulfate and desalted water into a reaction kettle, then adding ammonium dihydrogen phosphate, and stirring for reaction to form a solution a; s2, stirring the solution a, dropwise adding hydrogen peroxide, and dropwise adding ammonia water after oxidation is completed to form a solution b; and S3, when the pH value of the solution b is less than 5, discharging and filtering to obtain a ferric hydroxide filter cake. The high-purity ferric trichloride water purifying agent preparation device comprises a reaction kettle, an evaporator and a freezing crystallizer, the reaction kettle is used for preparing a ferric trichloride solution, the evaporator is used for evaporating and concentrating the ferric trichloride solution, and the evaporated and concentrated ferric trichloride solution is added into the freezing crystallizer for recrystallization. And waste can be turned into wealth, so that the problem that the byproduct ferrous sulfate is discharged to rivers, lakes and seas to cause environmental pollution is solved, and raw materials are saved.

Description

Technical Field

[0001] The present invention relates to the technical field of ferric chloride synthesis and purification, and specifically to a device and method for preparing a high-purity ferric chloride water purifier. Background Art

[0002] Ferric chloride, also known as ferric chloride, is a covalent inorganic compound with the chemical formula FeCl 3 It is a covalent compound. It is a black-brown crystal, or a thin flake, with a melting point of 306°C and a boiling point of 316°C. It is easily soluble in water and has strong water absorption, and can absorb moisture in the air and deliquesce. FeCl 3 When precipitated from aqueous solution, it contains six crystal waters as FeCl 3· 6H 2 O, ferric chloride hexahydrate is orange-yellow crystals. Ferric chloride is a very important iron salt. Ferric chloride is a flocculant widely used in water purification treatment. It separates and removes impurities in water by flocculating, and is also used in the corrosion of circuit boards. The preparation of ferric chloride in the prior art is mostly prepared by the chlorination reaction of ferrous chloride and chlorine. Chlorine is a highly toxic and dangerous substance. If it leaks during the production process, it is harmful to the human body. Therefore, the sealing requirements of the production equipment are extremely high; secondly, the price of chlorine is relatively high, and the production cost is relatively large. Thirdly, most of the ferric chloride prepared by the prior art can only be used for sewage purification due to its relatively low purity and the presence of impermissible impurities, but cannot be used in the purification of drinking water such as tap water.

[0003] The invention patent with application number 200910184059.X discloses a method for preparing ferric chloride, which uses natural iron ore with a mesh size of 40 or more as the iron-containing raw material, and hydrochloric acid with a molar ratio of 10 wt% or more, and the hydrochloric acid is equivalent or slightly excessive according to the molar ratio of ferric chloride molecules, so that the reaction is carried out in the liquid phase. Compared with the prior art, the method has the following advantages: safe reaction, preparation and production, undemanding process conditions, low requirements on production equipment, easy availability of raw materials, low preparation cost, and the iron ore basically does not contain harmful impurities, impurities in the iron ore are easily separated by precipitation, and purification is simple. The obtained product fully meets the standard of drinking water treatment by water treatment agent ferric chloride, has a low heavy metal content, can be directly used for drinking water purification, and the obtained product can be used for drinking water purification.

[0004] The above technology uses iron ore as a reaction raw material for preparing ferric chloride. Although iron ore can be obtained through mining, its mining and smelting processes are relatively complicated. In addition, in the actual manufacturing process, many reactions generate by-products containing iron ions. If these by-products can be used as reaction raw materials, the loss of iron ore will be reduced.

[0005] The domestic production capacity of ferrous sulfate, a byproduct of titanium dioxide production, is huge, and the output ratio of titanium dioxide to ferrous sulfate is usually about 1:3. Therefore, sulfuric acid-based titanium dioxide production enterprises produce a large amount of byproduct ferrous sulfate heptahydrate, but due to the poor crystal form of ferrous sulfate, the purity of ferrous sulfate is generally less than 90%, and it contains many impurities, mainly Ti, Mn, Mg, Al, Si, etc., and cannot be sold directly as a commodity. Most of the byproduct ferrous sulfate is treated as waste and piled up for a long time or discharged into rivers, lakes and seas, which not only wastes resources but also causes great harm to the environment.

[0006] Ferrous sulfate produced as a byproduct of titanium dioxide contains abundant iron resources and has the advantages of being easily soluble and easy to handle. It can be used as a basic raw material for the production of high value-added products such as water treatment agents, iron oxide industrial pigments, iron oxide for soft ferrites, iron phosphate for batteries, and ferrous sulfate for feed after systematic purification. In the past 10 years, the resource utilization of ferrous sulfate produced as a byproduct of titanium dioxide has become a key research object. Now a technology is needed to produce ferric chloride water purifier based on ferrous sulfate produced as a byproduct of titanium dioxide as an iron source, so as to solve the problem of byproduct ferrous sulfate being discharged into rivers, lakes and seas, causing environmental pollution, and to achieve waste-to-treasure and save raw materials. Summary of the invention

[0007] The purpose of this scheme is to provide a high-purity ferric chloride water purifier preparation device and method to solve the problem of by-product ferrous sulfate being discharged into rivers, lakes and seas, causing environmental pollution.

[0008] In order to achieve the above object, the present invention provides a method for preparing a high-purity ferric chloride water purifier, comprising the following steps:

[0009] S1: Put the titanium dioxide byproduct ferrous sulfate and desalted water into a reactor, then add ammonium dihydrogen phosphate and stir to react to form solution a;

[0010] S2: Stir solution a, add hydrogen peroxide, and then add ammonia water after oxidation to form solution b;

[0011] S3: When the pH value of solution b is less than 5, the material is filtered to obtain an iron hydroxide filter cake;

[0012] S4: adding the iron hydroxide filter cake in step S3 to a reaction kettle, and then adding industrial by-product hydrochloric acid, stirring, to obtain a ferric chloride solution;

[0013] S5: taking the ferric chloride solution and adding it into a forced evaporator device, and performing forced evaporation and concentration under negative pressure, and after the ferric chloride solution reaches saturation, entering into a freezing crystallizer for recrystallization;

[0014] S6: The recrystallized crystals are separated by filter pressing in a centrifugal separator to obtain primary recrystallized ferric chloride and primary recrystallization mother liquor, respectively.

[0015] Furthermore, in step S1, the weight ratio of desalted water to ferrous sulfate is in the range of 1:1 to 3:1, and the content of ferrous sulfate produced as a byproduct of titanium dioxide is in the range of 80 to 92%; in step S2, the molar ratio of hydrogen peroxide to iron ions is in the range of 0.5:1 to 0.65:1, and the molar ratio of ammonia water to iron ions is in the range of 3.0:1 to 3.3:1. The stirring speed of step S2 is in the range of 50 to 500 rpm, the temperature is in the range of 20 to 60°C, the reaction time is in the range of 1 to 5 hours, and the pH value adjusted at the endpoint is in the range of 2.0 to 5.0.

[0016] Further, in step S4, the molar ratio of hydrochloric acid to ferric hydroxide is in the range of 3:1 to 3.3:1, the concentration of hydrochloric acid is in the range of 15% to 32%, the speed is in the range of 50 to 500 rpm, the temperature is in the range of 20 to 60° C., and the reaction time is in the range of 1 to 5 hours;

[0017] Furthermore, in step S5, the temperature range of the forced evaporation concentration is 90-100° C., the speed range is 50-500 rpm, the temperature range of the recrystallization is 0-15° C., and the time range of the recrystallization is 0.5-5 h.

[0018] Beneficial effects of this solution: In the present invention, extremely cheap titanium dioxide by-product ferrous sulfate is used as the iron source, and industrial by-product hydrochloric acid is effectively used as the chlorine source, making full use of two cheap by-products of the industrial system as the main reaction raw materials, greatly reducing the cost. At the same time, the use of vacuum distillation technology fully reduces energy consumption, and the use of secondary recrystallization technology greatly improves product purity. The whole process has low raw material cost, low energy consumption, and high product added value. It provides an important solution for the digestion and direction of titanium dioxide by-product ferrous sulfate and a large amount of by-product hydrochloric acid in my country's chemical production field, turning waste into treasure, which is of great significance.

[0019] Using ferrous sulfate, a byproduct of titanium dioxide enterprises, as an iron source and industrial byproduct hydrochloric acid as a chlorine source, the resource utilization of industrial byproducts is realized, waste emissions are reduced, and environmental pollution is reduced. Using cheap industrial byproducts as raw materials greatly reduces production costs. At the same time, because the raw materials are easily available, the sustainability of production is guaranteed. Through a series of process steps such as oxidation, pH adjustment, chlorination, forced evaporation concentration and freezing recrystallization, a high-purity ferric chloride water purifier is prepared. The purity of ferric chloride is as high as more than 99%, meeting the high standard water quality treatment requirements. Among them, the addition of ammonium dihydrogen phosphate is to remove impurities such as Zn, Pb and Cr, which is conducive to improving the purity of the final product; the use of vacuum distillation technology reduces energy consumption in the production process and improves energy efficiency. The secondary recrystallization technology is used to further improve the product purity and ensure the high quality of the final product.

[0020] A high-purity ferric chloride water purifier preparation device comprises a reactor, an evaporator and a freezing crystallizer. The reactor is used to prepare a ferric chloride solution. The evaporator is used to evaporate and concentrate the ferric chloride solution. The evaporated and concentrated ferric chloride solution is added to the freezing crystallizer for recrystallization.

[0021] Furthermore, the freezing crystallizer includes a crystallization box, a discharge port is provided at the bottom of the crystallization box, a solenoid valve for controlling the opening and closing of the discharge port is installed at the discharge port, the bottom of the crystallization box is in a constricted shape, a first airbag is fixed on the side wall of the crystallization box at the constricted portion, the upper end of the first airbag is a platform, a plurality of evenly spaced second airbags are provided on the platform, the bottom of the second airbag is connected to the first airbag, the elastic modulus of the first airbag is lower than the elastic modulus of the second airbag, the first airbag is connected to an air pump, after the second airbag is inflated, it extends toward the top of the crystallization box, and after the first airbag is inflated, it extends vertically toward the axial direction of the crystallization box.

[0022] The basic principle and beneficial effects of this scheme: the saturated ferric chloride solution after evaporation and concentration is added to the crystallization box, and then the refrigerator is started to transfer the frozen water to the crystallization box, and the solution in the crystallization box is cooled to reach the temperature of freezing crystallization to complete the crystallization work; after adding the saturated ferric chloride solution to the crystallization box, the air pump is started to inflate the first airbag and the second airbag, the first airbag forms a platform, the second airbag extends upward in a columnar shape, and the second airbag stands in the solution. As the temperature decreases, crystallization begins to appear; the crystallization process includes nucleation and growth. Nucleation is the first stage of crystal formation, and a starting point or "fulcrum" is required to start the growth of crystals. In the solution, this "fulcrum" may be the wall of the container, suspended impurities or other solid surfaces. This scheme uses several second airbags as fulcrums for crystallization to provide a plane for crystallization to start growth. Once crystals begin to form, they will continue to grow until they reach equilibrium or the solute in the solution is exhausted.

[0023] Since the crystals grow by adhering to the second airbag, the probability of growing against the inner wall of the crystallization box is reduced, and the probability of cleaning the inner wall of the crystallization box in the later stage is reduced; at the same time, since multiple second airbags produce crystals at the same time, the crystallization rate is accelerated. After crystallization, the weight of the second airbag increases, and the center of gravity of the second airbag is unstable, and it swings, that is, the crystals on different second airbags are reduced to grow into a whole; the crystal block is prevented from being too large and blocking the discharge port. The air pressure in the first airbag can be adjusted to control the load-bearing capacity of the second airbag. The second airbag that reaches the upper limit of the load-bearing capacity will tilt toward the platform of the first airbag, so that other second airbags can crystallize faster; the weight control of each crystal block is completed. After the crystallization is completed, the first airbag and the second airbag are deflated, and the second airbag and the second airbag are reduced, that is, the airbag is separated from the inside of the crystal, so that the crystal becomes a free individual. The first airbag only releases part of the gas, and the remaining gas makes the first airbag form a smooth inclined surface, which is convenient for the crystal to slide out. When the discharge port is opened, the crystal is prevented from remaining at the bottom of the crystallization box.

[0024] Furthermore, a counterweight is arranged inside the top of the second airbag.

[0025] Beneficial effect: The setting of the counterweight block can make the top of the second airbag appear as a pit. During the crystallization process, the pit is filled with saturated ferric chloride solution, and the surface contacted by the ferric chloride solution in the pit is the inner wall of the pit, that is, there are more contact surfaces, which makes it easier to form crystal nuclei, and it is convenient for the crystal to grow from here. The counterweight block also plays a resetting role. During the process of deflating the airbag, since the elastic modulus of the first airbag is lower than that of the second airbag, that is, under the same air pressure, the first airbag will expand larger. In addition, the use of the counterweight block can make the expansion degree of the second airbag very small, that is, only a small convex point is formed on the first airbag, which can provide a buffering effect in the subsequent crystal sliding process to prevent the crystal from sliding too fast and causing violent collisions.

[0026] Furthermore, a filter tank is arranged at the lower end of the solenoid valve, a collecting tank is fixed below the filter tank, and a filter screen is fixed between the filter tank and the collecting tank.

[0027] Beneficial effect: The filter can intercept large crystals coming out of the discharge port, and some smaller crystals enter the centrifugal separator together with the filtrate for separation.

[0028] Further, the evaporator and the freezing crystallizer are combined in the same evaporation crystallization tank to complete evaporation concentration and recrystallization, and the evaporation crystallization tank includes:

[0029] A tank body, wherein a feed pipe, a compressed air inlet pipe and a water vapor extraction unit are arranged on the top of the tank body, a liquid discharge pipe and a crystal discharge pipe are arranged on the bottom of the tank body, and a precision filter screen is arranged at the inlet of the liquid discharge pipe;

[0030] A jacket, the jacket is arranged outside the tank body and is equipped with an inlet superheated steam pipe, an outlet superheated steam pipe, an inlet chilled water pipe and an outlet chilled water pipe;

[0031] A stirrer, the stirrer is rotatably disposed in the tank;

[0032] A regulating valve is provided on each of the feed pipe, the compressed air inlet pipe, the liquid discharge pipe, the crystal discharge pipe, the superheated steam inlet pipe, the superheated steam outlet pipe, the chilled water inlet pipe and the chilled water outlet pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention is a flow chart of a method for preparing a high-purity ferric chloride water purifier;

[0034] Figure 2 It is a step diagram of recrystallization of high-purity ferric chloride;

[0035] Figure 3 It is a schematic diagram of the device used for recrystallization of high-purity ferric chloride;

[0036] Figure 4 It is a structural schematic diagram of a freezing crystallizer (freezer omitted);

[0037] Figure 5 for Figure 4 The enlarged schematic diagram of point A in the middle;

[0038] Figure 6 for Figure 5 Another state diagram of ;

[0039] Figure 7 It is a structural schematic diagram of the evaporation crystallization tank.

[0040] The following is further described in detail through specific implementation methods:

[0041] The marks in the drawings of the specification include: crystallization box 1, filter tank 2, filter screen 3, collection tank 4, solenoid valve 5, first air bag 6, second air bag 7, counterweight block 8, tank body 9, jacket 10, agitator 11, feed pipe 12, compressed air inlet pipe 13, liquid discharge pipe 14, crystallization discharge pipe 15, precision filter screen 16, superheated steam inlet pipe 17, superheated steam outlet pipe 18, chilled water inlet pipe 19, chilled water outlet pipe 20, steam outlet pipe 21, condenser 22, condensed water storage tank 23, vacuum pump 23, pressure relief pipe 25. DETAILED DESCRIPTION

[0042] A method for preparing a high-purity ferric chloride water purifier, as shown in the following Figure 1 As shown, the following steps are included:

[0043] S1: putting titanium dioxide byproduct ferrous sulfate and desalted water into a reactor, and then adding monoammonium dihydrogen phosphate to stir and react to form solution a; the weight ratio of desalted water to ferrous sulfate is in the range of 1:1 to 3:1, and the content of titanium dioxide byproduct ferrous sulfate is in the range of 80 to 92%; in step S2, the molar ratio of hydrogen peroxide to iron ions is in the range of 0.5:1 to 0.65:1, and the molar ratio of ammonia water to iron ions is in the range of 3.0:1 to 3.3:1, the stirring speed of step S2 is in the range of 50 to 500 rpm, the temperature is in the range of 20 to 60°C, the reaction time is in the range of 1 to 5 hours, and the pH value adjusted at the end point is in the range of 2.0 to 5.0.

[0044] S2: Stir solution a, add hydrogen peroxide, and then add ammonia water after oxidation to form solution b;

[0045] S3: When the pH value of solution b is less than 5, the material is filtered to obtain an iron hydroxide filter cake;

[0046] S4: adding the iron hydroxide filter cake in step S3 to a reaction kettle, and then adding industrial by-product hydrochloric acid, stirring, to obtain a ferric chloride solution; the molar ratio of hydrochloric acid to ferric hydroxide is in the range of 3:1 to 3.3:1, the concentration of hydrochloric acid is in the range of 15% to 32%, the speed is in the range of 50 to 500 rpm, the temperature is in the range of 20 to 60° C., and the reaction time is in the range of 1 to 5 hours;

[0047] S5: taking a ferric chloride solution and adding it to a forced evaporator device, performing forced evaporation and concentration under negative pressure, and entering a freezing crystallizer for recrystallization after the ferric chloride solution reaches saturation; in step S5, the molar ratio of hydrochloric acid to ferric hydroxide is in the range of 3:1 to 3.3:1, the concentration of hydrochloric acid is in the range of 15% to 32%, the speed is in the range of 50 to 500 rpm, the temperature is in the range of 20 to 60°C, and the reaction time is in the range of 1 to 5h; the temperature range of the forced evaporation and concentration is in the range of 90 to 100°C, the speed range is in the range of 50 to 500 rpm; the temperature range of recrystallization is in the range of 0 to 15°C, and the time range of recrystallization is in the range of 0.5 to 5h;

[0048] S6: The recrystallized crystals are separated by filter pressing in a centrifugal separator to obtain primary recrystallized ferric chloride and primary recrystallization mother liquor, respectively.

[0049] A high-purity ferric chloride water purifier preparation device suitable for the above method: as shown in the attached Figure 2-3 As shown, it includes a reactor, an evaporator, and a freezing crystallizer. The reactor is used to prepare a ferric chloride solution. The evaporator is used to evaporate and concentrate the ferric chloride solution. The evaporated and concentrated ferric chloride solution is added to the freezing crystallizer for recrystallization. Figure 4-6As shown, the freezing crystallizer includes a crystallization box 1, a discharge port is provided at the bottom of the crystallization box 1, a solenoid valve 5 for controlling the opening and closing of the discharge port is installed at the discharge port, the bottom of the crystallization box 1 is in a constricted shape, a first airbag 6 is fixed on the side wall of the crystallization box 1 at the constricted port, the upper end of the first airbag 6 is a platform, a number of evenly spaced second airbags 7 are arranged on the platform, the bottom of the second airbag 7 is connected to the first airbag 6, the elastic modulus of the first airbag 6 is lower than the elastic modulus of the second airbag 7, the first airbag 6 is connected to the air pump, the second airbag 7 expands and extends to the top of the crystallization box 1, and the first airbag 6 expands and extends vertically toward the axis direction of the crystallization box 1. A counterweight 8 is arranged inside the top of the second airbag 7. A filter tank 2 is arranged at the lower end of the solenoid valve 5, a collection tank 4 is fixed below the filter tank 2, and a filter screen 3 is fixed between the filter tank 2 and the collection tank 4.

[0050] The saturated ferric chloride solution after evaporation and concentration is added to the crystallization box 1, and then the refrigerator is started to transfer the frozen water to the crystallization box 1, and the solution in the crystallization box 1 is cooled to reach the temperature of freezing crystallization to complete the crystallization work; after adding the saturated ferric chloride solution to the crystallization box 1, the air pump is started to inflate the first airbag 6 and the second airbag 7, the first airbag 6 forms a platform, the second airbag 7 extends upward in a columnar shape, and the second airbag 7 stands in the solution. As the temperature decreases, crystallization begins to appear; the crystallization process includes nucleation and growth. Nucleation is the first stage of crystal formation, and a starting point or "fulcrum" is required to start the growth of crystals. In the solution, this "fulcrum" may be the wall of the container, suspended impurities or other solid surfaces. This scheme uses a number of second airbags 7 as the fulcrum of crystallization to provide a plane for crystallization to start growth. Once crystals begin to form, they will continue to grow until they reach equilibrium or the solute in the solution is exhausted.

[0051] Since the crystals grow by adhering to the second airbags 7, the probability of growing against the inner wall of the crystallization box 1 is reduced, that is, the probability of cleaning the inner wall of the crystallization box 1 in the later stage is reduced; at the same time, since multiple second airbags 7 produce crystals at the same time, the crystallization rate is accelerated. After crystallization, the weight of the second airbags 7 increases, and the center of gravity of the second airbags 7 becomes unstable and swings, that is, the crystals on different second airbags 7 are reduced from growing into a whole; to prevent the crystal block from being too large and blocking the discharge port, the air pressure in the first airbag 6 can be adjusted to control the second airbag 7. The second airbag 7 that reaches the upper limit of the load-bearing capacity will tilt toward the platform of the first airbag 6, so that the other second airbags 7 can crystallize faster; the weight control of each crystal block is completed. After the crystallization is completed, the first airbag 6 and the second airbag 7 are deflated, and the second airbag 7 and the second airbag 7 become smaller, that is, the airbags are separated from the inside of the crystal, so that the crystal becomes a free individual. The first airbag 6 only releases part of the gas, and the remaining gas makes the first airbag 6 form a smooth inclined surface, which is convenient for the crystal to slide out, and when the discharge port is opened, it prevents the crystal from remaining at the bottom of the crystallization box 1.

[0052] The setting of the counterweight 8 can make the top of the second airbag 7 appear as a pit. During the crystallization process, the pit is filled with saturated ferric chloride solution, and the surface contacted by the ferric chloride solution in the pit is the inner wall of the pit, that is, there are more contact surfaces, it is easier to form a crystal nucleus, and it is convenient for the crystal to grow from here, and the counterweight 8 also plays a resetting role. In the process of deflating the airbag, since the elastic modulus of the first airbag 6 is lower than the elastic modulus of the second airbag 7, that is, under the same air pressure, the first airbag 6 will expand larger, and the use of the counterweight 8 can make the expansion degree of the second airbag 7 very small, that is, only a small convex point is formed on the first airbag 6, which can provide a buffering effect in the subsequent crystal sliding process to prevent the crystal from sliding too fast, causing violent collisions, and breaking into too small fragments, and entering the centrifuge with the filtrate.

[0053] By the above method, the following embodiments are obtained:

[0054] Embodiment 1:

[0055] A high-purity ferric chloride water purifier preparation device and method, 204.18g of titanium dioxide by-product ferrous sulfate (mass fraction of 80%) and 400.24g of desalted water are added into a reactor, heated at 60°C to dissolve, 2g of ammonium dihydrogen phosphate (mass fraction of 99%, the following percentages are all mass fractions) is added, stirred for reaction for 1h, and after the reaction is completed, ferrous sulfate solution is obtained by filtering (pH=1.3, the control of this pH value is to ensure that ammonium dihydrogen phosphate does not react with titanium dioxide by-product ferrous sulfate). 150mL of ferrous sulfate liquid was placed in a reactor and oxidized with 60.935g of hydrogen peroxide (30%) and 20.3g of industrial ammonia (15%) was added. During the reaction, the reaction temperature was controlled to be 20°C and stirred at a stirring speed of 50 rev / min. The pH in the solution was 2. After reacting for 5h, the ferric hydroxide colloid was filtered to obtain the ferric hydroxide colloid. The ferric hydroxide colloid was placed in a 105°C drying oven for 5h to obtain 23.35g of ferric hydroxide. The ferric hydroxide was dissolved by 119.65g of industrial by-product hydrochloric acid (20%) at room temperature and at a stirring speed of 50 rev / min for 2h to obtain ferric chloride liquid. The ferric chloride liquid was stirred and distilled at 90°C and at a speed of 500 rev / min until the ferric chloride liquid was saturated. The ferric chloride liquid was frozen and recrystallized for 5h under the condition of 15°C. After the recrystallization was completed, it was separated by filtration to obtain high-purity ferric chloride.

[0056] Table 1 shows the impurity content of each step in the preparation of high-purity ferric chloride according to GB / T 4482-2018 water treatment agent in Example 1.

[0057] Table 1 Impurity content changes in Example 1 during the preparation of ferric chloride

[0058]

[0059] Embodiment 2:

[0060] A high-purity ferric chloride water purifier preparation device and method, 201.18g of titanium dioxide by-product ferrous sulfate (mass fraction of 86%) and 400.14g of desalted water are added into a reactor, heated at 60°C to dissolve, 2g of ammonium dihydrogen phosphate (mass fraction of 99%) is added, stirred for reaction for 1h, and after the reaction is completed, ferrous sulfate solution (pH=1.3) is obtained by filtering. 150mL of ferrous sulfate liquid was placed in a reactor and oxidized with 79.19g of hydrogen peroxide (30%) and 22.35g of industrial ammonia (15%) was added. During the reaction temperature was controlled to be 60°C and stirred at a stirring speed of 500 rev / min. The pH in the solution was 4.2. After reacting for 1h, filtration was performed to obtain ferric hydroxide colloid. The ferric hydroxide colloid was placed in a 105°C drying oven for 5h to obtain 24.12g of ferric hydroxide. The ferric hydroxide was dissolved by 123.57g of industrial by-product hydrochloric acid (32%) at 60°C and at a stirring speed of 500 rev / min for 1h to obtain ferric chloride liquid. The ferric chloride liquid was stirred and distilled at 90°C and at a rotating speed of 350 rev / min until the ferric chloride liquid was saturated. The ferric chloride liquid was frozen and recrystallized for 30min under the condition of 15°C. After the recrystallization was completed, high-purity ferric chloride was obtained by separation by filtration.

[0061] Table 2 shows the impurity content in each step of preparing high-purity ferric chloride according to GB / T 4482-2018 water treatment agent in Example 2.

[0062] Table 2 Impurity content changes in Example 2 during the preparation of ferric chloride

[0063]

[0064] Embodiment 3:

[0065] A device and method for preparing a high-purity ferric chloride water purifier comprises the following steps: adding 204.18 g of titanium dioxide byproduct ferrous sulfate (mass fraction of 88%) and 400.24 g of desalted water into a reactor, heating at 60° C. to dissolve, adding 2 g of ammonium dihydrogen phosphate (mass fraction of 99%), stirring for reaction for 1 hour, and filtering to obtain a ferrous sulfate solution (pH=1.3) after the reaction is completed. 150mL of ferrous sulfate liquid was placed in a reactor and oxidized with 70.67g of hydrogen peroxide (30%) and 21g of industrial ammonia (15%) was added. During the reaction temperature was controlled to be 40°C and stirred at a stirring speed of 260 rev / min. The pH in the solution was 5. After reacting for 3h, filtration was performed to obtain ferric hydroxide colloid. The ferric hydroxide colloid was placed in a 105°C drying oven for 5h to obtain 25.04g of ferric hydroxide. The ferric hydroxide was dissolved by 128.28g of industrial by-product hydrochloric acid (15%) at 45°C and at a stirring speed of 320 rev / min for 2.8h to obtain ferric chloride liquid. The ferric chloride liquid was stirred and distilled at 90°C and at a rotating speed of 200 rev / min until the ferric chloride liquid was saturated. The ferric chloride liquid was frozen and recrystallized for 2.5h under 15°C. After the recrystallization ended, it was separated by filtration to obtain high-purity ferric chloride.

[0066] Table 3 shows the impurity content in each step of preparing high-purity ferric chloride according to GB / T 4482-2018 water treatment agent in Example 3.

[0067] Table 3 Impurity content changes in Example 3 during the preparation of ferric chloride

[0068]

[0069] Embodiment 4:

[0070] A high-purity ferric chloride water purifier preparation device and method, 204.18g of titanium dioxide by-product ferrous sulfate (mass fraction of 92%) and 400.24g of desalted water are added into a reactor, heated at 60°C to dissolve, 2g of ammonium dihydrogen phosphate (mass fraction of 99%) is added, stirred for reaction for 1h, and after the reaction is completed, ferrous sulfate solution (pH=1.3) is obtained by filtering. 150mL of ferrous sulfate liquid was placed in a reactor and oxidized by 60.94g of hydrogen peroxide (30%) and 20.3g of industrial ammonia (15%) was added. During the reaction temperature was controlled to be 20°C and stirred at a stirring speed of 50 rev / min. The pH in the solution was 3.2. After reacting for 5h, the ferric hydroxide colloid was filtered to obtain the ferric hydroxide colloid. The ferric hydroxide colloid was placed in a 105°C drying oven for 5h to obtain 24.42g of ferric hydroxide. The ferric hydroxide was dissolved by 125.10g of industrial by-product hydrochloric acid (25%) at 30°C and at a stirring speed of 100 rev / min for 4h to obtain ferric chloride liquid. The ferric chloride liquid was stirred and distilled at 95°C and at a speed of 250 rev / min until the ferric chloride liquid was saturated. It was controlled to be frozen and recrystallized for 30min under 5°C. After the recrystallization ended, it was separated by filtration to obtain high-purity ferric chloride.

[0071] Table 4 shows the impurity content in each step of preparing high-purity ferric chloride according to GB / T 4482-2018 water treatment agent in Example 4.

[0072] Table 4: Changes in impurity content in the process of preparing ferric chloride in Example 4

[0073]

[0074] Embodiment 5:

[0075] A device and method for preparing a high-purity ferric chloride water purifier comprises the following steps: adding 204.18 g of titanium dioxide byproduct ferrous sulfate (mass fraction is 80%) and 400.24 g of desalted water into a reactor, heating at 60° C. to dissolve, adding 2 g of ammonium dihydrogen phosphate (mass fraction is 99%), stirring to react for 1 hour, and filtering to obtain a ferrous sulfate solution (pH=1.3) after the reaction is completed. 150mL of ferrous sulfate liquid was placed in a reactor and oxidized with 60.31g of hydrogen peroxide (30%) and 21g of industrial ammonia (15%) was added. During the reaction, the reaction temperature was controlled to be 35°C and stirred at a stirring speed of 150 rev / min. The pH in the solution was 3.2. After reacting for 5h, filtration was performed to obtain ferric hydroxide colloid. The ferric hydroxide colloid was placed in a 105°C drying oven for 5h to obtain 23.89g of ferric hydroxide. The ferric hydroxide was dissolved by 122.39g of industrial by-product hydrochloric acid (20%) at 50°C and at a stirring speed of 300 rev / min for 1.5h to obtain ferric chloride liquid. The ferric chloride liquid was stirred and distilled at 95°C and at a rotating speed of 300 rev / min until the ferric chloride liquid was saturated. The ferric chloride liquid was frozen and recrystallized for 30min under 10°C. After the recrystallization was completed, high-purity ferric chloride was obtained by separation by filtration.

[0076] Table 5 shows the impurity content in each step of preparing high-purity ferric chloride according to GB / T 4482-2018 water treatment agent in Example 5.

[0077] Table 5: Changes in impurity content in the process of preparing ferric chloride in Example 5

[0078]

[0079] Embodiment 6:

[0080] A device and method for preparing a high-purity ferric chloride water purifier comprises the following steps: adding 204.18 g of titanium dioxide byproduct ferrous sulfate (mass fraction is 80%) and 400.24 g of desalted water into a reactor, heating at 60° C. to dissolve, adding 2 g of ammonium dihydrogen phosphate (mass fraction is 99%), stirring to react for 1 hour, and filtering to obtain a ferrous sulfate solution (pH=1.3) after the reaction is completed. 150mL of ferrous sulfate liquid was placed in a reactor and oxidized with 60.06g of hydrogen peroxide (30%) and 21.3g of industrial ammonia (15%) was added. During the reaction temperature was controlled to be 40°C and stirred at a stirring speed of 180 rev / min. The pH in the solution was 3.2. After reacting for 2.8h, ferric hydroxide colloid was obtained by filtration. The ferric hydroxide colloid was placed in a 105°C drying oven for 5h to obtain 25.14g of ferric hydroxide. The ferric hydroxide was dissolved by 128.79g of industrial by-product hydrochloric acid (20%) at 28°C and at a stirring speed of 400 rev / min for 2h to obtain ferric chloride liquid. The ferric chloride liquid was stirred and distilled at 95°C and at a rotating speed of 400 rev / min until the ferric chloride liquid was saturated. The reaction was controlled to be frozen and recrystallized for 30min under 5°C. After the recrystallization finished, high-purity ferric chloride was obtained by separation by filtration.

[0081] Table 6 shows the impurity content in each step of preparing high-purity ferric chloride according to GB / T 4482-2018 water treatment agent in Example 6.

[0082] Table 6 Impurity content changes in Example 6 during the preparation of ferric chloride

[0083]

[0084]

[0085] Embodiment 7:

[0086] A device and method for preparing a high-purity ferric chloride water purifier comprises the following steps: adding 204.18 g of titanium dioxide byproduct ferrous sulfate (mass fraction is 80%) and 400.24 g of desalted water into a reactor, heating at 60° C. to dissolve, adding 2 g of ammonium dihydrogen phosphate (mass fraction is 99%), stirring to react for 1 hour, and filtering to obtain a ferrous sulfate solution (pH=1.3) after the reaction is completed. 150mL of ferrous sulfate liquid was placed in a reactor and oxidized with 60.21g of hydrogen peroxide (30%) and 21.4g of industrial ammonia (15%) was added. During the reaction, the reaction temperature was controlled to be 25°C and stirred at a stirring speed of 320 rev / min. The pH in the solution was 3.2. After reacting for 3.5h, ferric hydroxide colloid was obtained by filtration. The ferric hydroxide colloid was placed in a 105°C drying oven for 5h to obtain 24.78g of ferric hydroxide. The ferric hydroxide was dissolved by 126.95g of industrial by-product hydrochloric acid (20%) at 30°C and at a stirring speed of 300 rev / min for 3h to obtain ferric chloride liquid. The ferric chloride liquid was stirred and distilled at 95°C and at a rotating speed of 300 rev / min until the ferric chloride liquid was saturated. The ferric chloride liquid was controlled to be frozen and recrystallized for 30min under 10°C. After the recrystallization finished, it was separated by filtration to obtain high-purity ferric chloride.

[0087] Table 7 shows the impurity content in each step of preparing high-purity ferric chloride according to GB / T 4482-2018 water treatment agent in Example 7.

[0088] Table 7 Impurity content changes in Example 7 during the preparation of ferric chloride

[0089]

[0090]

[0091] Embodiment 8:

[0092] A device and method for preparing a high-purity ferric chloride water purifier comprises the following steps: adding 204.18 g of titanium dioxide byproduct ferrous sulfate (mass fraction is 80%) and 400.24 g of desalted water into a reactor, heating at 60° C. to dissolve, adding 2 g of ammonium dihydrogen phosphate (mass fraction is 99%), stirring to react for 1 hour, and filtering to obtain a ferrous sulfate solution (pH=1.3) after the reaction is completed. 150mL of ferrous sulfate liquid was placed in a reactor and oxidized with 60.2g of hydrogen peroxide (30%) and 21.25g of industrial ammonia (15%) was added. During the reaction temperature was controlled to be 40°C and stirred at a stirring speed of 230 rev / min. The pH in the solution was 3.2. After reacting for 4h, filtration was performed to obtain ferric hydroxide colloid. The ferric hydroxide colloid was placed in a 105°C drying oven for 5h to obtain 25.98g of ferric hydroxide. The ferric hydroxide was dissolved by 133.10g of industrial by-product hydrochloric acid (20%) at 20°C and at a stirring speed of 360 rev / min for 2h to obtain ferric chloride liquid. The ferric chloride liquid was stirred and distilled at 100°C and at a rotating speed of 50 rev / min until the ferric chloride liquid was saturated. The ferric chloride liquid was frozen and recrystallized for 30min under 5°C. After the recrystallization was completed, high-purity ferric chloride was obtained by separation by filtration.

[0093] Table 8 shows the impurity content in each step of preparing high-purity ferric chloride according to GB / T 4482-2018 water treatment agent in Example 8.

[0094] Table 8 Impurity content changes in Example 8 during the preparation of ferric chloride

[0095]

[0096] Embodiment 9:

[0097] A device and method for preparing a high-purity ferric chloride water purifier comprises the following steps: adding 204.18 g of titanium dioxide byproduct ferrous sulfate (mass fraction is 80%) and 400.24 g of desalted water into a reactor, heating at 60° C. to dissolve, adding 2 g of ammonium dihydrogen phosphate (mass fraction is 99%), stirring to react for 1 hour, and filtering to obtain a ferrous sulfate solution (pH=1.3) after the reaction is completed. 150mL of ferrous sulfate liquid was placed in a reactor and oxidized with 60.2g of hydrogen peroxide (30%) and 21.4g of industrial ammonia (15%) was added. During the reaction temperature was controlled to be 30°C and stirred at a stirring speed of 280 rev / min. The pH in the solution was 5. After reacting for 3.8h, filtration was performed to obtain ferric hydroxide colloid. The ferric hydroxide colloid was placed in a 105°C drying oven for 5h to obtain 25.68g of ferric hydroxide. The ferric hydroxide was dissolved by 131.56g of industrial by-product hydrochloric acid (20%) at room temperature and at a stirring speed of 360 rev / min for 2h to obtain ferric chloride liquid. The ferric chloride liquid was stirred and distilled at 100°C and at a rotating speed of 100 rev / min until the ferric chloride liquid was saturated. The ferric chloride liquid was frozen and recrystallized for 30min under the condition of 10°C. After the recrystallization was completed, high-purity ferric chloride was obtained by separation by filtration.

[0098] Table 9 shows the impurity content in each step of preparing high-purity ferric chloride according to GB / T 4482-2018 water treatment agent in Example 9.

[0099] Table 9: Changes in impurity content during the preparation of ferric chloride in Example 9

[0100]

[0101] Comparative Example 1

[0102] The only difference from Example 9 is that no ammonium dihydrogen phosphate is added.

[0103] Table 10 shows the impurity content in each step of the preparation of high-purity ferric chloride in Comparative Example 1 according to the water treatment agent GB / T 4482-2018.

[0104] Table 10 Impurity content changes in comparative example 1 during the preparation of ferric chloride

[0105]

[0106] Table 11 compares the impurity content of high-purity ferric chloride prepared in 9 embodiments and 1 comparative example with the water treatment agent GB / T 4482-2018.

[0107] Table 11 Impurity content and purity of ferric chloride prepared in Examples 1-9 and Comparative Example 1

[0108]

[0109]

[0110] According to Table 11, it can be known that: relative to the industry standard of high-purity ferric chloride water treatment agent GB / T 4482-2018, the impurity content of the high-purity ferric chloride product prepared in Examples 1-9 of the present application is within the scope of industry standards, and the arsenic, lead, mercury, and cadmium element contents in the raw material are removed during the preparation of the product. It can be known from the impurity content of the product in Example 1-9 that the core factor affecting the impurity content of its product during the preparation of the high-purity ferric chloride product is the regulation of the pH of the ferric hydroxide colloid generation and the recrystallization temperature of the ferric chloride liquid, and the impurity content of the generated product increases with the increase of the pH of the synthesis of the ferric hydroxide colloid, and its core reason is that the increase of the pH of the synthesis of the ferric hydroxide will cause other elements to precipitate in this precipitation interval range, and the heavy metal elements in the free state will be adsorbed on the surface of the ferric hydroxide colloid. Meanwhile, the impurity content of the generated product will also increase as the recrystallization temperature decreases, and the reason is that the lower the recrystallization temperature, when the solution reaches saturation, more elements will be precipitated at low temperatures, and the heavy metal elements in the free state will be adsorbed on the surface of the ferric chloride crystal.

[0111] The difference from the above structure is that the evaporator and the freezing crystallizer are combined in the same evaporation crystallization tank to complete evaporation concentration and recrystallization. Figure 7 The evaporation crystallization tank includes a tank body 9, a jacket 10, an agitator 11 and a regulating valve. A feed pipe 12, a compressed air inlet pipe 13 and a water vapor extraction unit are arranged on the top of the tank body 9, and a liquid discharge pipe 14 and a crystallization discharge pipe 15 are arranged at the bottom of the tank body 9. A precision filter 16 is arranged at the inlet of the liquid discharge pipe 14; the jacket 10 is sleeved outside the tank body 9 and the jacket 10 is matched with an inlet superheated steam pipe 17, an outlet superheated steam pipe 18, an inlet chilled water pipe 19 and an outlet chilled water pipe 20; the agitator 11 is rotatably arranged in the tank body 9; the regulating valve is arranged on the feed pipe 12, the compressed air inlet pipe 13, the liquid discharge pipe 14, the crystallization discharge pipe 15, the inlet superheated steam pipe 17, the outlet superheated steam pipe 18, the inlet chilled water pipe 19 and the outlet chilled water pipe 20.

[0112] In this embodiment, the agitator 11 includes a stirring paddle rotatably arranged in the tank body 9 and a stirring motor arranged at the top outside the tank body 9 and connected to the stirring paddle; the water vapor extraction unit includes a water vapor outlet pipe 21 arranged at the top of the tank body 9 and a condenser 22 and a condensed water storage tank 23 connected to the water vapor outlet pipe 21 in sequence, and the regulating valve is arranged on the water vapor outlet pipe 21.

[0113] When in use, the regulating valves on the feed pipe 12, the inlet superheated steam pipe 17, the outlet superheated steam pipe 18 and the water vapor outlet pipe 21 are opened, and the other regulating valves are closed. The feed pipe 12 introduces the ferric chloride solution into the tank body 91, and then the regulating valve on the feed pipe 12 is closed; the inlet superheated steam pipe 17 introduces 160°C superheated steam into the jacket 10, and the flow rates of the inlet superheated steam pipe 17 and the outlet superheated steam pipe 18 are controlled to control the temperature in the tank body 9 to be 90°C-100°C, and at the same time, the stirring motor is started, and the stirring paddle is rotated at a speed of 50-500 rpm to evaporate and concentrate the ferric chloride solution, and the water vapor generated by evaporation and concentration is discharged from the water vapor outlet pipe 21 and enters the condenser 22 for condensation to form condensed water, and the condensed water enters the condensed water storage tank 23 for storage. In order to improve the efficiency of evaporation and concentration, a vacuum pump 23 is also provided between the condenser 22 and the condensed water storage tank 23. The vacuum pump 23 is started to form a vacuum effect to achieve a pressure of -0.05MPa to -0.1MPa. Reduced pressure distillation can increase the distillation speed.

[0114] When the ferric chloride solution completes evaporation and concentration to form a saturated ferric chloride solution, close the regulating valves on the superheated steam inlet pipe 17, the superheated steam outlet pipe 18 and the steam outlet pipe 21, open the regulating valves on the chilled water inlet pipe 19 and the chilled water outlet pipe 20, and the chilled water inlet pipe 19 introduces 4-10°C chilled water into the jacket 10, and control the flow of the chilled water inlet pipe 19 and the chilled water outlet pipe 20 to control the temperature in the tank body 9 to 0-15°C, and cooperate with the stirring paddle to rotate at a speed of 50-500 rpm. The freezing time in the tank body 9 is 0.5h-5h to complete the freezing recrystallization.

[0115] After completing the frozen recrystallization, close the regulating valves on the frozen water inlet pipe 19 and the frozen water outlet pipe 20, open the regulating valves on the compressed air inlet pipe 13 and the liquid discharge pipe 14, and the compressed air inlet pipe 13 introduces 0.1MPa~0.3MPa compressed air into the tank body 9 to squeeze out the liquid remaining in the frozen recrystallized ferric chloride. The liquid passes through the precision filter 16 and is discharged from the liquid discharge pipe 14. When the residual liquid in the frozen recrystallized ferric chloride is squeezed and discharged, close the regulating valve on the liquid discharge pipe 14, open the regulating valve on the crystallization discharge pipe 15, discharge the frozen recrystallized ferric chloride from the crystallization discharge pipe 15, and collect it to obtain the product.

[0116] Furthermore, a pressure relief pipe 25 is provided on the top of the tank body 9, and a pressure relief valve is installed on the pressure relief pipe 25 to avoid safety problems caused by overpressure in the tank body 9 during use.

[0117] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing a high-purity ferric chloride water purifier, characterized in that: The following steps are involved: S1: Put the titanium dioxide byproduct ferrous sulfate and desalted water into a reactor, then add ammonium dihydrogen phosphate and stir to react to form solution a; S2: Stir solution a, add hydrogen peroxide, and then add ammonia water after oxidation to form solution b; S3: When the pH value of solution b is less than 5, the material is filtered to obtain an iron hydroxide filter cake; S4: adding the iron hydroxide filter cake in step S3 to a reaction kettle, and then adding industrial by-product hydrochloric acid, stirring, to obtain a ferric chloride solution; S5: taking the ferric chloride solution and adding it into a forced evaporator device, and performing forced evaporation and concentration under negative pressure, and after the ferric chloride solution reaches saturation, entering into a freezing crystallizer for recrystallization; S6: The recrystallized crystals are separated by filter pressing in a centrifugal separator to obtain primary recrystallized ferric chloride and primary recrystallization mother liquor, respectively.

2. A method for preparing a high-purity ferric chloride water purifier according to claim 1, characterized in that: In step S1, the weight ratio of desalted water to ferrous sulfate is in the range of 1:1-3:1, and the content of ferrous sulfate produced as a byproduct of titanium dioxide is in the range of 80-92%; in step S2, the molar ratio of hydrogen peroxide to iron ions is in the range of 0.5:1-0.65:1, and the molar ratio of ammonia water to iron ions is in the range of 3.0:1-3.3:

1. The stirring speed of step S2 is in the range of 50-500 rpm, the temperature is in the range of 20-60°C, the reaction time is in the range of 1-5h, and the pH value adjusted at the end point is in the range of 2.0-5.

0.

3. A method for preparing a high-purity ferric chloride water purifier according to claim 1, characterized in that: In step S4, the molar ratio of hydrochloric acid to ferric hydroxide is in the range of 3:1 to 3.3:1, the concentration of hydrochloric acid is in the range of 15% to 32%, the speed is in the range of 50 to 500 rpm, the temperature is in the range of 20 to 60° C., and the reaction time is in the range of 1 to 5 hours.

4. A method for preparing a high-purity ferric chloride water purifier according to claim 1, characterized in that: In step S5, the temperature range of the forced evaporation concentration is 90-100° C., the speed range is 50-500 rpm, the temperature range of the recrystallization is 0-15° C., and the time range of the recrystallization is 0.5-5 h.

5. A high-purity ferric chloride water purifier preparation device, suitable for a high-purity ferric chloride water purifier preparation method according to any one of claims 1 to 4, characterized in that: The invention comprises a reaction kettle, an evaporator and a freezing crystallizer. The reaction kettle is used to prepare a ferric chloride solution. The evaporator is used to evaporate and concentrate the ferric chloride solution. The evaporated and concentrated ferric chloride solution is added into the freezing crystallizer for recrystallization.

6. A high-purity ferric chloride water purifier preparation device according to claim 5, characterized in that: The freezing crystallizer includes a crystallization box, a discharge port is provided at the bottom of the crystallization box, a solenoid valve for controlling the opening and closing of the discharge port is installed at the discharge port, the bottom of the crystallization box is in a constricted shape, a first airbag is fixed on the side wall of the crystallization box at the constricted portion, the upper end of the first airbag is a platform, a plurality of second airbags with even intervals are arranged on the platform, the bottom of the second airbag is connected to the first airbag, the elastic modulus of the first airbag is lower than the elastic modulus of the second airbag, the first airbag is connected to an air pump, after the second airbag is expanded, it extends toward the top of the crystallization box, and after the first airbag is expanded, it extends vertically toward the axis direction of the crystallization box.

7. A high-purity ferric chloride water purifier preparation device according to claim 6, characterized in that: A counterweight is arranged inside the top of the second airbag.

8. A high-purity ferric chloride water purifier preparation device according to claim 6 or 7, characterized in that: A filter tank is arranged at the lower end of the solenoid valve, a collecting tank is fixed below the filter tank, and a filter screen is fixed between the filter tank and the collecting tank.

9. A high-purity ferric chloride water purifier preparation device according to claim 5, characterized in that: The evaporator and the freezing crystallizer are combined in the same evaporation crystallization tank to complete evaporation concentration and recrystallization. The evaporation crystallization tank includes: A tank body, wherein a feed pipe, a compressed air inlet pipe and a water vapor extraction unit are arranged on the top of the tank body, a liquid discharge pipe and a crystal discharge pipe are arranged on the bottom of the tank body, and a precision filter screen is arranged at the inlet of the liquid discharge pipe; A jacket, the jacket is arranged outside the tank body and is equipped with an inlet superheated steam pipe, an outlet superheated steam pipe, an inlet chilled water pipe and an outlet chilled water pipe; A stirrer, the stirrer is rotatably disposed in the tank; A regulating valve is provided on each of the feed pipe, the compressed air inlet pipe, the liquid discharge pipe, the crystal discharge pipe, the superheated steam inlet pipe, the superheated steam outlet pipe, the chilled water inlet pipe and the chilled water outlet pipe.

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