A treatment process for circulating water in potassium fluoride concentration section and internal filtration reactor

Abstract

The invention discloses a treatment process for circulating water in a potassium fluoride concentration section and an internal filtering reactor. In the process of producing potassium fluoride and synchronously producing white carbon black, circulating water in the potassium fluoride concentration section and washing water in the white carbon black are synchronously treated, and circulating water and washing water are subjected to different classification treatments through an internal filtering system. Washing water adopts a separate filtering channel, does not occupy purification resources of circulating water in the potassium fluoride concentration section, and reduces waste of purification resources. The circulating water is cooled, classified, internally filtered, reversely osmotic, and then recovered for internal circulation and reuse, thereby reducing the use of fresh water or other clean water, reducing production costs and consumption of water resources, and having the advantage of saving resources.

Description

Technical Field

[0001] The invention belongs to the technical field of potassium fluoride circulating water treatment, and in particular relates to a treatment process for circulating water in a potassium fluoride concentration section and an internal filtering reactor. Background Art

[0002] Potassium fluoride is mainly used as a flux for welding of various alloys or metals, as a fluorinating agent or catalyst for the synthesis of organic matter, as an absorbent for absorbing hydrogen fluoride and water, and in the production of sodium fluoroacetate and fluoroacetamide pesticides.

[0003] The concentration section is an important link in the potassium fluoride production process. It is used to concentrate the potassium fluoride solution in the dilute solution to the required concentration. For the concentration section, in order to ensure the normal operating temperature of the evaporator, water is used as a cooling medium to absorb and take away the heat released by the evaporator, while stabilizing the pressure of the evaporator, which helps to improve the stability of the production process and the consistency of product quality.

[0004] In order to reduce the impact on the environment and the waste of water resources, and comply with the requirements of environmental protection and sustainable development, the method of circulating water is often adopted. The use of circulating water can reduce the use of fresh water or other clean water, reduce production costs and the consumption of water resources, and has the advantage of saving resources.

[0005] At present, the simultaneous production of white carbon black in the production process of potassium fluoride has been initially realized. However, in the production process of white carbon black, it also goes through a washing step, and when another water source is introduced to wash it, it will cause additional water waste. At the same time, compared with the circulating water in the potassium fluoride concentration section, the washing step of white carbon black has slightly fewer impurities. If it is directly introduced into the purification process of circulating water, it will cause a waste of resources. Therefore, it is necessary to consider adding a treatment function for the washing water used in the simultaneous processing of white carbon black to the traditional circulating water treatment process. Summary of the invention

[0006] In view of the above defects, the present invention provides a treatment process for circulating water in a potassium fluoride concentration section and an internal filtration reactor. The treatment process for circulating water in a potassium fluoride concentration section comprises the following steps:

[0007] S1, cooling stage: After solid-liquid separation, the circulating water in the potassium fluoride concentration stage is transported to the inside of the raw water tank A and the raw water tank B through the potassium fluoride pipeline and the white carbon black pipeline respectively. The raw water tank A and the raw water tank B respectively transport the circulating water in their respective tanks to the inside of the connected cooling tower I and cooling tower II through pumps;

[0008] S2, internal filtration stage: the circulating water inside cooling tower I and cooling tower II is respectively transported to the internal filtration reactor through booster pumps for graded filtration;

[0009] S2-1, the circulating water transported by cooling tower I is subjected to heavy metal filtration, fluoride filtration and membrane separation treatment in sequence;

[0010] S2-2, perform internal secondary filtration on the circulating water delivered by cooling tower II;

[0011] S2-3, the circulating water treated in step S2-1 and step S2-2 is combined and subjected to biological treatment;

[0012] S3, reverse osmosis stage: the circulating water after biological treatment in step S2-3 is subjected to primary reverse osmosis and secondary reverse osmosis treatment in sequence;

[0013] S4, recycling stage: the circulating water after reverse osmosis treatment in step S3 is finely filtered again, and then transported to the potassium fluoride concentration section through a lift pump for circulation;

[0014] The inner filtration reactor comprises a reactor body, wherein the interior of the reactor body is provided with a multi-layer filtration mechanism for communicating with a cooling tower I and a particle landslide for communicating with a cooling tower II;

[0015] The multi-layer filtering mechanism comprises a heavy metal filtering layer for filtering heavy metals, a fluoride filtering layer for filtering fluorides, and a membrane separation layer for membrane separation treatment;

[0016] The particle landslide is spiral, and the inner ring of the particle landslide is sleeved on the outer wall of the multi-layer filtering mechanism, and the outer ring is fixed to the inner wall of the kettle body;

[0017] The bottom of the multi-layer filtering mechanism and the particle landslide is provided with a confluence bucket, and the bottom of the confluence bucket is respectively connected with the inlet pipe of the biological treatment tank and the inlet pipe of the primary reverse osmosis through a diverter valve.

[0018] Furthermore, the solid-liquid separation includes filtration treatment and sedimentation treatment. The filtration treatment is to use a rotary vacuum filter to filter solid particles, and the sedimentation treatment is to add flocculant I to promote the solid particles suspended in the water to quickly coagulate into larger agglomerates to form precipitates.

[0019] Furthermore, a pH control system for detecting the pH value of circulating water is installed inside the raw water tank A and the raw water tank B, and the pH value is neutralized to between 7.0 and 8.5 by acid-base neutralization.

[0020] Furthermore, the pump in step S1 is a combination of a centrifugal pump and a filter.

[0021] Furthermore, the membrane components inside the primary reverse osmosis and the secondary reverse osmosis are polyamide membranes.

[0022] Furthermore, the heavy metal filter layer includes a plurality of filter element groups arranged in an annular shape, the filter element groups include an external pressure activated carbon filter element group, an external pressure ceramic filter element group and an external pressure ion exchange resin filter element group, which are arranged in sequence from top to bottom, and the clean water outlets of the filter element groups at the top are all located outside the clean water outlets of the filter element groups at the bottom, and the filter elements in two adjacent filter element groups are arranged crosswise along the intervals;

[0023] A flocculant II is provided inside the fluoride filter layer, and the flocculant II is replenished through an automatic feeding device;

[0024] The membrane separation layer is a double-layer polyetheretherketone-based ceramic composite membrane structure.

[0025] Furthermore, the particle landslide is filtered through a plurality of filter holes opened on the bottom surface, the diameters of the filter holes decrease successively along the downward direction of the spiral, and the output end of the particle landslide passes through the kettle body and is connected to a solids bin arranged externally.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] In the process of producing white carbon black while producing potassium fluoride, the circulating water used in the potassium fluoride concentration stage and the water washed in the white carbon black production stage are comprehensively treated at the same time:

[0028] 1. For the treatment of potassium fluoride concentration section, the use of circulating water is reduced, the use of fresh water or other clean water is reduced, the production cost and the consumption of water resources are reduced, and it has the advantage of saving resources. At the same time, the circulating water is subjected to a series of purification treatments, and is cooled, classified, internally filtered, reverse osmosis, and then recycled for internal recycling;

[0029] 2. For the wastewater used for washing in the production stage of white carbon black, it is introduced in the same way as the circulating water of the potassium fluoride concentration section to reduce the complicated operation of additional drainage. At the same time, since it does not have the complex impurities of the potassium fluoride concentration section, a separate filtration channel is used during the subsequent purification, which does not occupy the purification resources of the circulating water of the potassium fluoride concentration section and reduces the waste of purification resources;

[0030] 3. Compared with the direct confluence of two sections of circulating water from the initial stage of water treatment, the silicate in the white carbon black circulating water will not form insoluble precipitation with the fluoride in the potassium fluoride circulating water, affecting the removal efficiency of fluoride, and there is no need for more precise control and adjustment to adapt to different water quality changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a process flow chart of the present invention.

[0032] Figure 2 It is a schematic diagram of the multi-layer filtering mechanism in the present invention.

[0033] Figure 3 It is a schematic diagram of the particle landslide in the present invention.

[0034] Figure 4 Schematic diagram of the internal distribution of the heavy metal filter layer in the present invention.

[0035] Figure 5 It is a three-dimensional schematic diagram of the heavy metal filtering layer in the present invention.

[0036] In the figure: 1. Raw water tank A; 2. Raw water tank B; 3. Cooling tower I; 4. Cooling tower II; 5. Internal filtration reactor; 6. Multi-layer filtration mechanism; 61. Heavy metal filtration layer; 62. Fluoride filtration layer; 63. Membrane separation layer; 7. Particle landslide. DETAILED DESCRIPTION

[0037] In order to facilitate the understanding of the present invention, the device of the present invention will be described more fully below with reference to the relevant drawings. Embodiments of the device are given in the drawings. However, the device can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "set" should be understood in a broad sense, for example, they can be fixedly connected or set, or detachably connected or set, or integrally connected or set. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] Example

[0040] like Figure 1 As shown, this embodiment provides a treatment process for circulating water in a potassium fluoride concentration stage, wherein potassium carbonate is prepared into a 35% to 40% solution, and then water / mother liquor is used as a base, and fluorosilicic acid and potassium carbonate solution are added at the same time, and after reacting for 0.5 to 1 hour, potassium fluorosilicate ointment and mother liquor A are obtained by filtration; calcium hydroxide is added to the mother liquor A for reaction, and the precipitate is removed by filtration, and potassium carbonate is added to the filtrate to remove excess calcium hydroxide, and mother liquor B is obtained by filtration; the potassium fluorosilicate ointment obtained in the step is mixed with the obtained mother liquor B; to obtain potassium fluorosilicate slurry; to add a certain amount of white carbon black seed crystals to the obtained potassium fluorosilicate slurry, and then add a certain amount of 35% to 40% potassium carbonate solution under stirring for alkaline hydrolysis reaction for 30 minutes, and then slowly add 25% to 30% potassium hydroxide solution, adjust the pH value of the reaction solution to 7.5 to 8, continue to react for 1 hour, and then filter to obtain potassium fluoride solution and white carbon black ointment, and concentrate the potassium fluoride solution to a concentration of 40% to 50%, and spray dry to obtain high-quality potassium fluoride;

[0041] According to the ratio of the molar ratio of fluorosilicic acid to potassium carbonate of 1:3, potassium carbonate solution is quickly added to fluorosilicic acid, and the reaction is stirred for 10 minutes at a reaction temperature of 40°C. After the reaction, white carbon black seed is obtained. White carbon black seed is added to the potassium fluorosilicate slurry obtained in the process of potassium fluoride production (the amount added is based on the percentage of the theoretical mass of the generated white carbon black product), and then 35% potassium carbonate solution is added, and the molar ratio of potassium carbonate to potassium fluorosilicate is 2:1. After stirring and reacting at 90°C for 30 minutes, 30% potassium hydroxide solution is slowly added, and the pH value of the reaction solution is adjusted to 7.5-8. The reaction is continued for 1 hour, and the white carbon black ointment is obtained by filtration, and the white carbon black product is obtained by washing and drying.

[0042] In the above production process, the circulating water and white carbon black wastewater in the potassium fluoride concentration stage are separated into solid and liquid, and then cooled, classified, internally filtered, reverse osmosis, and then recycled for internal recycling. The specific process steps are as follows:

[0043] S1, cooling stage:

[0044] S1-1, subjecting the circulating water in the potassium fluoride concentration stage to solid-liquid separation, wherein the solid-liquid separation includes filtration treatment and precipitation treatment, wherein the filtration treatment is to use a rotary vacuum filter to filter solid particles, and the precipitation treatment is to add flocculant I to cause the solid particles suspended in the water to quickly condense into larger agglomerates to form precipitates;

[0045] S1-2, then transport the circulating water in the above step to the raw water tank A1 and the raw water tank B2 through the potassium fluoride pipeline and the white carbon black pipeline respectively, and neutralize the pH value to between 7.0 and 8.5 by acid-base neutralization;

[0046] In detail, a built-in pH control system for detecting the pH value of circulating water can be used for automatic detection. The pH control system includes a pH sensor installed inside the raw water tank A1 and the raw water tank B2. The pH value of the aqueous solution is measured by an electrode or other technology, and these data are sent to an external controller. The difference between the measured pH value and the preset pH value is fed back to the acid and alkali liquid storage tanks set outside the raw water tank A1 and the raw water tank B2 through a feedback loop, and the metering valve is automatically controlled to realize the function of automatically adjusting the internal circulating water and wastewater acid-base neutralization. Data recording and alarm functions can also be added, which will not be described in detail here;

[0047] S1-3, raw water tank A1 and raw water tank B2 respectively transport the circulating water in their respective tanks to the connected cooling tower I3 and cooling tower II4 for cooling through pumps (composed of a centrifugal pump and a filter, with good secondary filtration function). At the same time, the heat exchangers in cooling towers I3 and II4 recover the heat and transport it to the white carbon black production process (stirring reaction process of potassium carbonate and potassium fluorosilicate substances) to achieve heat reuse;

[0048] S2, internal filtration stage: The circulating water inside the cooling tower I3 and the cooling tower II4 is respectively transported to the internal filtration reactor through a booster pump for graded filtration, such as Figure 2-5 As shown, the inner filtration reactor is an inner filtration reactor 5 including a reactor body;

[0049] S2-1, the circulating water transported by the cooling tower 13 is subjected to heavy metal filtration, fluoride filtration and membrane separation treatment in sequence, which is completed by the multi-layer filtration mechanism 6 inside the kettle body, specifically:

[0050] The circulating water first passes through the heavy metal filter layer 61 located at the top, which includes several groups of filter element groups arranged in a ring shape, and the filter element groups include an external pressure type activated carbon filter element group, an external pressure type ceramic filter element group and an external pressure type ion exchange resin filter element group, which are arranged in sequence from top to bottom, and the clean water outlets of the filter element groups located at the top are all located on the outside of the clean water outlet of the filter element group at the bottom, and the filter elements in the two adjacent filter element groups are arranged crosswise along the interval, that is, the external pressure type activated carbon filter element group passes the circulating water flowing in from the outside to the inside for filtration, and discharges circulating water I from its clean water outlet, enters from the outside of the external pressure type ceramic filter element group at the bottom and circulates to the inside for filtration, and discharges circulating water II from its clean water outlet, and then enters from the outside of the external pressure type ion exchange resin filter element group at the bottom and circulates to the inside for filtration, and discharges circulating water III from its clean water outlet (such as Figure 5 As shown). The heavy metal filter layer 61 can not only filter out the lead, chromium and copper produced by corrosion in the pipes during use (although the pipes are made of corrosion-resistant materials, the circulating water will still carry some of the above substances when it is injected from the external water source), but also filter out other heavy metals produced during the production process to achieve internal primary purification treatment;

[0051] Then, a secondary purification treatment is carried out through the fluoride filter layer 62 located in the middle, in which a flocculant II is arranged, and the flocculant II is supplemented by an automatic feeding device, and the automatic feeding can be achieved by a timed feeding method. It should be noted that the flocculants I and II are polyaluminum chloride flocculants and polyaluminum silicate flocculants, respectively. Since the flocculant I needs to treat the washing water when producing white carbon black, which is mixed with potassium carbonate and potassium hydroxide, the polyferric chloride flocculant is suitable for treating solid particles and impurities in potassium carbonate and potassium fluorosilicate wastewater. It can quickly form flocs, which helps to improve the efficiency of subsequent treatment. When the polyaluminum silicate flocculant treats the circulating water of the potassium fluoride concentration section, since it combines elements such as aluminum, silicon and chlorine, aluminum, silicon and chlorine, etc., the elements usually have little effect on fluoride, so it is more suitable for treating circulating water containing potassium carbonate and potassium fluorosilicate.

[0052] Finally, the membrane separation layer 63 at the bottom is used for a three-stage purification process, wherein the membrane separation layer 63 is a double-layer polyetheretherketone-based ceramic composite membrane structure, which has a better membrane separation effect;

[0053] This stage completes the treatment of the circulating water in the potassium fluoride concentration section;

[0054] S2-2, internal secondary filtration of circulating water delivered by cooling tower II4:

[0055] A particle landslide 7 connected to the cooling tower II4 is also fixed inside the kettle body for treating white carbon black washing water. Since the washing water has a different function from the circulating water in the potassium fluoride concentration section, it only plays a washing role on white carbon black, and therefore contains a large amount of impurities and particles. A simple filtering method can be used without wasting the resources in step S2-1. Specifically, the particle landslide 7 is spiral, and the inner ring of the particle landslide 7 is sleeved on the outer wall of the multi-layer filtering mechanism 6, and the outer ring is fixed to the inner wall of the kettle body to ensure the sealing of the side and prevent leakage. The particle landslide 7 completes the filtration through a number of filter holes opened on the bottom surface, and the diameter of the filter holes decreases successively in the downward direction of the spiral, which has the effect of gradually increasing the filtration fineness. The output end of the particle landslide 7 passes through the kettle body and is connected to an external solid bin for storing impurities and particles.

[0056] S2-3, the circulating water treated in step S2-1 and step S2-2 is combined and biologically treated. It should be noted that in the production process of potassium fluoride and white carbon black, the two can be directly combined and enter the reverse osmosis stage. The biological treatment stage is used after the overall production process is completed. At this time, there is no need to use the circulating water. This stage requires static reaction, so it should be carried out in the non-production stage;

[0057] S3, reverse osmosis stage: the circulating water after biological treatment in step S2-3 is subjected to primary reverse osmosis and secondary reverse osmosis treatment in sequence. It should be noted that the membrane assembly is made of polyamide membrane material, which can not only separate potassium carbonate mixed with potassium hydroxide in the production process of white carbon black, but also separate potassium fluoride, and has the characteristics of both at the same time;

[0058] S4, recovery cycle stage: the circulating water after reverse osmosis treatment in step S3 is finely filtered again, and then transported to the potassium fluoride concentration section (if white carbon black is produced, it is simultaneously transported for washing operation) for circulation, wherein the fine filtration is the common microporous filtration (such as microporous membrane filter or deep filter) or filter cloth filter for final filtration.

[0059] It should be noted that the structure described in the present invention can be implemented in a variety of different forms and is not limited to the described embodiments. Any equivalent transformations made by ordinary technicians in this field using the contents of the present invention description and drawings, or directly or indirectly applied to other related technical fields, such as the loading and unloading of other items, are included in the protection scope of the present invention.

Claims

1. A process for treating circulating water in a potassium fluoride concentration stage, characterized in that: The following steps are involved: S1, cooling stage: the circulating water in the potassium fluoride concentration stage and the white carbon black circulating water produced by washing in the white carbon black production stage are transported to the inside of the raw water tank A and the raw water tank B through the potassium fluoride pipeline and the white carbon black pipeline respectively, and the raw water tank A and the raw water tank B respectively transport the circulating water in their respective tanks to the inside of the connected cooling tower I and cooling tower II through pumps; S2, internal filtration stage: the circulating water inside cooling tower I and cooling tower II is respectively transported to the internal filtration reactor through booster pumps for graded filtration; S2-1, the circulating water transported by cooling tower I is subjected to heavy metal filtration, fluoride filtration and membrane separation treatment in sequence; S2-2, perform internal secondary filtration on the circulating water delivered by cooling tower II; S2-3, the circulating water treated in step S2-1 and step S2-2 is combined and subjected to biological treatment; S3, reverse osmosis stage: the circulating water after biological treatment in step S2-3 is subjected to primary reverse osmosis and secondary reverse osmosis treatment in sequence; S4, recycling stage: the circulating water after reverse osmosis treatment in step S3 is finely filtered again, and then transported to the potassium fluoride concentration section through a lift pump for circulation; The inner filtration reactor comprises a reactor body, wherein the interior of the reactor body is provided with a multi-layer filtration mechanism for communicating with a cooling tower I and a particle landslide for communicating with a cooling tower II; The multi-layer filtering mechanism comprises a heavy metal filtering layer for filtering heavy metals, a fluoride filtering layer for filtering fluorides, and a membrane separation layer for membrane separation treatment; The particle landslide is spiral-shaped, and the inner ring of the particle landslide is sleeved on the outer wall of the multi-layer filtering mechanism, and the outer ring is fixed to the inner wall of the kettle body. The particle landslide completes filtering through a plurality of filter holes opened on the bottom surface, and the diameter of the filter holes decreases in sequence along the downward direction of the spiral. The output end of the particle landslide passes through the kettle body and is connected to the solid matter bin arranged outside; The bottom of the multi-layer filtering mechanism and the particle landslide is provided with a confluence bucket, and the bottom of the confluence bucket is respectively connected with the inlet pipe of the biological treatment tank and the inlet pipe of the primary reverse osmosis through a diverter valve.

2. A process for treating circulating water in a potassium fluoride concentration stage as claimed in claim 1, characterized in that: The solid-liquid separation includes filtration treatment and sedimentation treatment. The filtration treatment is to use a rotary vacuum filter to filter solid particles, and the sedimentation treatment is to add flocculant I to promote the solid particles suspended in the water to quickly coagulate into larger agglomerates to form precipitates.

3. A process for treating circulating water in a potassium fluoride concentration stage as claimed in claim 1, characterized in that: The raw water tank A and the raw water tank B are both equipped with a pH control system for detecting the pH value of the circulating water, and the pH value is neutralized to between 7.0 and 8.5 by acid-base neutralization.

4. A process for treating circulating water in a potassium fluoride concentration stage as claimed in claim 1, characterized in that: The pump in step S1 is a combination of a centrifugal pump and a filter.

5. A process for treating circulating water in a potassium fluoride concentration stage as claimed in claim 1, characterized in that: The membrane components inside the primary reverse osmosis and the secondary reverse osmosis are polyamide membranes.

6. An internal filtration reactor for treating the circulating water of the potassium fluoride concentration stage according to any one of claims 1 to 5, characterized in that: The inner filtration reactor comprises a reactor body, wherein the interior of the reactor body is provided with a multi-layer filtration mechanism for communicating with a cooling tower I and a particle landslide for communicating with a cooling tower II; The multi-layer filtering mechanism comprises a heavy metal filtering layer for filtering heavy metals, a fluoride filtering layer for filtering fluorides, and a membrane separation layer for membrane separation treatment; The particle landslide is spiral-shaped, and the inner ring of the particle landslide is sleeved on the outer wall of the multi-layer filtering mechanism, and the outer ring is fixed to the inner wall of the kettle body. The particle landslide completes filtering through a plurality of filter holes opened on the bottom surface, and the diameter of the filter holes decreases in sequence along the downward direction of the spiral. The output end of the particle landslide passes through the kettle body and is connected to the solid matter bin arranged outside; The bottom of the multi-layer filtering mechanism and the particle landslide is provided with a confluence bucket, and the bottom of the confluence bucket is respectively connected with the inlet pipe of the biological treatment tank and the inlet pipe of the primary reverse osmosis through a diverter valve.

7. An internal filtration reactor as claimed in claim 6, characterized in that: The heavy metal filter layer includes a plurality of filter element groups arranged in an annular shape, the filter element groups include an external pressure activated carbon filter element group, an external pressure ceramic filter element group and an external pressure ion exchange resin filter element group, which are arranged in sequence from top to bottom, and the clean water outlets of the filter element groups at the top are all located outside the clean water outlets of the filter element groups at the bottom, and the filter elements in two adjacent filter element groups are arranged crosswise along the intervals; A flocculant II is provided inside the fluoride filter layer, and the flocculant II is replenished through an automatic feeding device; The membrane separation layer is a double-layer polyetheretherketone-based ceramic composite membrane structure.

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