CN117303453A - A continuous refining method and device for titanium dioxide by-product ferrous sulfate - Google Patents
A continuous refining method and device for titanium dioxide by-product ferrous sulfate Download PDFInfo
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- CN117303453A CN117303453A CN202311044983.4A CN202311044983A CN117303453A CN 117303453 A CN117303453 A CN 117303453A CN 202311044983 A CN202311044983 A CN 202311044983A CN 117303453 A CN117303453 A CN 117303453A
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/14—Sulfates
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D25/00—Filters formed by clamping together several filtering elements or parts of such elements
- B01D25/12—Filter presses, i.e. of the plate or plate and frame type
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D36/00—Filter circuits or combinations of filters with other separating devices
- B01D36/04—Combinations of filters with settling tanks
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F21/00—Dissolving
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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Abstract
The invention provides a continuous refining method and a device of titanium white byproduct ferrous sulfate, comprising the following steps: s1: the raw materials are sent to a dissolving tank, hot water is introduced into the bottom of the dissolving tank, the ferrous sulfate solution enters a buffer tank through a baffle tank of the dissolving tank, and water is added into the baffle tank to dilute the ferrous sulfate solution; s2: the ferrous sulfate solution in the buffer tank enters a impurity removal tank through a pump, the solution at the top of the iron sheet impurity removal tank is added into the impurity removal tank and overflows to a ground sedimentation tank, clear liquid at the top of the sedimentation tank overflows to a metal film filtering system, and the clear liquid after metal film filtering is used as a product and sent to a ferrous sulfate storage tank; s3: the concentrated liquid discharged by the metal film filtering system and the impurity removing tank is reversely fed into the buffer ground tank of the filter press, the pump sends the liquid in the ground tank to the compressor, and the clear liquid in the filter press is returned to the clear liquid buffer tank. The invention has the beneficial effects that: the method solves the problem that ferrous sulfate cannot be continuously refined in ferric phosphate production enterprises, reduces manual operation, and saves investment and occupied area.
Description
Technical Field
The invention belongs to the field of inorganic material and battery material preparation, and particularly relates to a continuous refining method and device of titanium white byproduct ferrous sulfate.
Background
The ferric phosphate is a precursor of lithium iron phosphate which is a new energy source anode material. Currently, as the demand of lithium iron phosphate bursts, the demand of raw material ferric phosphate is continuously increasing, and the method for producing ferric phosphate on a large scale in the market at present mainly comprises the steps of oxidizing ferrous sulfate solution by hydrogen peroxide and then reacting with phosphoric acid (salt) for precipitation. At present, the main production processes of ferric phosphate include an iron dissolving method and a ferrous sulfate method (sodium method and ammonia method). Ferrous sulfate method (ammonia method) is the main stream direction of the present ferric phosphate process, the ferrous sulfate raw material of the method is mainly titanium white byproduct ferrous sulfate crystal, contains various metal impurities and hydrolyzed titanium sulfate impurities, and needs to be refined to meet the purity requirement of ferric phosphate production. The industry adopts an intermittent method to refine ferrous sulfate, and a plurality of filter presses are used for filter pressing to obtain clear ferrous sulfate liquid, so that the clear filter pressing liquid of the filter presses can not completely remove impurities and can not be discharged continuously. In order to maintain the continuity of the downstream feeding, a plurality of large storage tanks are required to be arranged for storage, the storage tanks are kept still for about 7 to 11 days, and the green and transparent ferrous sulfate solution can be used as the downstream raw material after the PH is between 2 and 4.
The existing refining method of the byproduct ferrous sulfate of the traditional titanium dioxide comprises the following steps:
according to the downstream yield requirement, a plurality of underground dissolving tanks are arranged, water is added, stirring is carried out to dissolve ferrous sulfate crystals, after stirring is carried out uniformly, the solution is pumped to a refining tank, naOH solution is added to adjust PH for removing impurities, and oxidized Fe is removed 3+ Reacts with alkali to form Fe (OH) 3 And (3) precipitating, pumping the slurry to a buffer tank of a filter press after the precipitation is completed, and pumping the slurry to a plurality of filter presses. The filter presses are operated in sequence,the flow is as follows: feeding the materials into a filter chamber to be full, squeezing and discharging. The clear liquid of the filter press is intermittently produced and contains a plurality of floccule impurities, particularly the content of Ti is higher, the clear liquid needs to enter a storage tank to be settled for about 8 to 12 days, the PH returns to 2 to 4, and the green and transparent ferrous sulfate solution can be used as a downstream raw material.
In view of the characteristics of the filter press, the whole process cannot realize continuous production, has low filtering precision, has a large amount of work for manually cleaning the underground dissolving tank and the finished product storage tank, has a large number of finished product storage tanks, occupies large space and has high investment. The ferrous sulfate solution is in an acidic environment in the process, has strong corrosiveness, and is particularly environment-friendly due to a plurality of large underground dissolving tanks.
Disclosure of Invention
In view of the above, the invention aims to provide a continuous refining method and a continuous refining device for titanium white byproduct ferrous sulfate, which are used for solving the problems that continuous production cannot be realized, the filtering precision is low, a large amount of work for manually cleaning an underground dissolving tank and a finished product storage tank is needed, the finished product storage tank is large in occupied area, and the investment is high.
In order to achieve the above purpose, the technical scheme of the invention is realized as follows:
a continuous refining method of titanium white byproduct ferrous sulfate is characterized in that: the method comprises the following steps:
s1: the raw materials are sent to a dissolving tank, hot water is introduced into the bottom of the dissolving tank, the ferrous sulfate solution enters a buffer tank through a baffle tank of the dissolving tank, and water is added into the baffle tank to dilute the ferrous sulfate solution;
s2: the ferrous sulfate solution in the buffer tank enters a impurity removal tank through a pump, the solution at the top of the iron sheet impurity removal tank is added into the impurity removal tank and overflows to a ground sedimentation tank, clear liquid at the top of the sedimentation tank overflows to a metal film filtering system, and the clear liquid after metal film filtering is used as a product and sent to a ferrous sulfate storage tank;
s3: the concentrated liquid discharged by the metal film filtering system and the impurity removing tank is reversely fed into the buffer ground tank of the filter press, the pump sends the liquid in the ground tank to the compressor, and the clear liquid in the filter press is returned to the clear liquid buffer tank.
Further, the raw material in the step S1 is ferrous sulfate heptahydrate; the temperature of hot water introduced into the dissolving tank in the step S1 is 60-90 ℃; the salt layer height of the dissolving tank is 2-4.5 m.
Further, the flow rate of the diversion trench in the step S1 needs to be controlled to be 0.1-0.3 m/S, the temperature of the ferrous sulfate solution of the diversion trench is at least 50-70 ℃, and the ferrous sulfate concentration of the diversion trench is 20-23%.
Further, the metal film filtering systems in the step S2 and the step S3 are cross-flow filtering, the aperture of the metal film is 30-100 nm, and the metal film is 316L metal powder sintered felt;
and in the step S2, a patch is added to control the PH of the ferrous sulfate solution to be 2-4.
Preferably, the metal membrane filtration system adopts a two-stage series or three-stage series filtration mode, and the membrane surface flow velocity is 1-5 m/s.
The device comprises a dissolving tank, a buffer tank, a impurity removal tank, a settling tank, a metal film filtering system and a finished product tank;
the dissolving tank is connected with the buffer tank through the diversion trench, the buffer tank is connected with the impurity removal tank through a first pipeline, the top of the impurity removal tank is connected with the sedimentation tank through a first overflow pipe, the top of the sedimentation tank is connected with the metal film filtering system through a second overflow pipe, the metal film filtering system is connected with Chen Pinguan through a pipeline, and the bottoms of the metal film filtering system and the sedimentation tank are connected with the filter press assembly.
Further, the dissolving tank is a semi-underground dissolving tank, the bottom of the dissolving tank is provided with a plurality of water outlet pipelines and a main pipeline, the water outlet pipelines are sequentially arranged on the main pipeline, and the water outlet pipelines are provided with a plurality of spray heads;
the two ends of the diversion trench are respectively communicated with the dissolution tank and the buffer tank, a plurality of baffle plates which are arranged in a staggered way are arranged in the diversion trench, and the preferable interval between the baffle plates is 300-600 mm;
a concentration meter is arranged in the diversion trench, a water inlet pipe is arranged at the top of the diversion trench, and a regulating valve is arranged on the water inlet pipe;
the flow speed of the diversion trench is controlled to be 0.1-0.3 m/s, the temperature of ferrous sulfate solution of the diversion trench is not lower than 50-70 ℃, and the ferrous sulfate concentration of the diversion trench is 20-23%.
Further, the solution buffer tank is of a semi-underground concrete structure, a stirrer is arranged in the solution buffer tank, preferably, the stirring speed of the stirrer is 10-30 rpm, an automatic weighing feeder is arranged at the top of the impurity removal tank, the automatic weighing feeder is provided with iron sheets, preferably, the iron sheets are iron sheets in irregular shapes of automobile cold rolling;
a pH tester is arranged in the impurity removal tank, and the pH of ferrous sulfate solution in the impurity removal tank is controlled to be 2-4 by controlling the amount of the added iron sheet;
the first pipeline is provided with a first axial flow pump.
Further, the top of the impurity removal tank is provided with a plurality of first overflow ports which are uniformly distributed, a backflow pipeline is arranged at the first overflow ports, the first overflow pipeline is arranged on the backflow pipeline, and the other end of the first overflow pipe is connected with the sedimentation tank;
the reflux pipeline is provided with a second axial flow pump and a first valve, and the feeding amount of the second axial flow pump type first axial flow pump is 20-50 times;
an eccentric stirrer is arranged in the top of the impurity removal tank, the stirring speed of the eccentric stirrer is 10-30 rpm, and the eccentric stirrer is a blade stirrer;
the bottom of the drop tank is provided with a bottom mud raking machine, and the rotating speed is 0.03-0.06 rpm.
Further, the metal film filtering system comprises a clear liquid buffer tank and a metal film filter, the settling tank is connected with the clear liquid buffer tank through a second overflow pipeline, the clear liquid buffer tank is connected with the metal film filter through a third pipeline, a third axial flow pump is arranged on the third pipeline, and clear liquid filtered by the metal film filter flows into a finished product tank through a fourth pipeline; and (5) introducing nitrogen into the finished product tank.
The bottom of the sedimentation tank is connected with the filter press assembly through a fifth pipeline, and a second valve is arranged on the fifth pipeline;
the bottom of the metal film filter is connected with the filter press component through a pipeline;
the aperture of the metal film is 30-100 nm, and the metal film is 316L metal powder sintered felt; the flux of the membrane can be restored to 90-100% by back flushing of the clear liquid. The metal film is easy to regenerate and the time is short. The continuous operation of the process is ensured, and the production efficiency is greatly improved. And (5) taking the membrane filtration clear liquid as a product to enter a ferrous sulfate storage tank.
Preferably, the metal membrane filtration system adopts a two-stage series or three-stage series filtration mode, and the membrane surface flow velocity is 1-5 m/s.
Further, the filter press assembly comprises a filter press buffering ground groove and a filter press machine, the bottom of the sedimentation groove is connected with the filter press buffering ground groove through a fifth pipeline, the filter press buffering ground groove is connected with the filter press machine through a sixth pipeline, a filter press feeding pump is arranged on the sixth pipeline, filtrate of the filter press is connected with the clear liquid buffering groove through a seventh pipeline, and a filter residue conveying belt is arranged at the bottom of the filter press;
the filter press has a squeezing function, and the filtering precision of the filter cloth is 1-20 microns. The metal film discharges the concentrate, the concentrate discharged from the bottom of the impurity removing tank returns to the buffer ground tank of the filter press, the concentrate is pumped to the filter press, the filter press has the squeezing function, and the clear liquid of the filter press returns to the feeding buffer tank of the metal film system. The discharged filter cake is conveyed to a warehouse by a belt.
Compared with the prior art, the continuous refining method and device for the titanium white byproduct ferrous sulfate have the following advantages:
according to the invention, the iron sheet is added into the impurity removal tank, and ferric iron is reduced by iron, so that the product yield is improved, and the floccule content is reduced. The impurity removal tank and the sedimentation tank are reasonably designed, so that the floccule content of the metal film is reduced, and the stable operation of a metal film system is improved. And a metal film with high filtering precision is selected, and the filtered clear liquid can meet the quality requirement of ferrous sulfate of battery-grade ferric phosphate. The last slurry is filtered by a filter press, so that the series of problems that the slurry returns to the dissolving tank are solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:
FIG. 1 is a schematic diagram of a continuous refining apparatus for titanium white byproduct ferrous sulfate according to an embodiment of the invention;
FIG. 2 is a process for preparing a titanium white byproduct ferrous sulfate in the prior art.
Reference numerals illustrate:
1. a dissolution tank; 2. a buffer tank; 3. a impurity removing tank; 4. a settling tank; 5. a finished product tank; 6. a first pipe; 7. a first axial flow pump; 8. a first valve; 9. a filter residue conveying belt; 10. a return line; 11. a first overflow pipe; 12. a second axial flow pump; 13. a clear liquid buffer tank; 14. a metal membrane filter; 15. a second overflow pipe; 16. a third conduit; 17. a third axial flow pump; 18. a fourth conduit; 19. a fifth pipe; 20. a second valve; 21. a buffer ground groove of the filter press; 22. a filter press machine; 23. a sixth conduit; 24. a filter press feed pump; 25. and a seventh pipeline.
Detailed Description
It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art in a specific case.
The invention will be described in detail below with reference to the drawings in connection with embodiments.
A continuous refining method of titanium white byproduct ferrous sulfate is characterized in that: the method comprises the following steps: s1: the raw materials are sent to a dissolution tank 1, hot water is introduced into the bottom of the dissolution tank 1, ferrous sulfate solution enters a buffer tank 2 through a baffle tank of the dissolution tank 1, and water is added into the baffle tank to dilute the ferrous sulfate solution; s2: the ferrous sulfate solution in the buffer tank 2 enters the impurity removal tank 3 through a pump, the solution at the top of the iron sheet impurity removal tank 3 is added into the impurity removal tank 3 and overflows to the overground sedimentation tank 4, the clear liquid at the top of the sedimentation tank 4 overflows to a metal film filtering system, and the clear liquid after metal film filtering is used as a product and sent to a ferrous sulfate storage tank; s3: the concentrate discharged from the metal membrane filtration system and the impurity removal tank 3 is returned to the filter press buffer floor 21, the pump sends the floor liquid to the compressor, and the clear liquid in the filter press is returned to the clear liquid buffer 13.
The raw material in the step S1 is ferrous sulfate heptahydrate; the temperature of hot water introduced into the dissolving tank 1 in the step S1 is 60-90 ℃; the salt layer height of the dissolution tank 1 is 2-4.5 m. The flow speed of the diversion trench in the step S1 needs to be controlled to be 0.1-0.3 m/S, the temperature of ferrous sulfate solution of the diversion trench is at least 50-70 ℃, and the ferrous sulfate concentration of the diversion trench is 20-23%.
The metal film filtering systems in the step S2 and the step S3 are cross-flow filtering, the aperture of the metal film is 30-100 nm, and the metal film is 316L metal powder sintered felt; and step S2, adding a patch to control the PH of the ferrous sulfate solution to be 2-4.
In the specific implementation, the metal membrane filtration system adopts a two-stage series or three-stage series filtration mode, and the membrane surface flow velocity is 1-5 m/s.
The device for the continuous refining method of the titanium white byproduct ferrous sulfate comprises a dissolving tank 1, a buffer tank 2, a impurity removal tank 3, a settling tank 4, a metal film filtering system and a finished product tank 5; the dissolving tank 1 is connected with the buffer tank 2 through a diversion trench, the buffer tank 2 is connected with the impurity removal tank 3 through a first pipeline 6, the top of the impurity removal tank 3 is connected with the sedimentation tank 4 through a first overflow pipe, the top of the sedimentation tank 4 is connected with a metal film filtering system through a second overflow pipe, the metal film filtering system is connected with Chen Pinguan through a pipeline, and the bottoms of the metal film filtering system and the sedimentation tank 4 are connected with a filter press assembly.
The dissolution tank 1 is a semi-underground dissolution tank 1, the bottom of the dissolution tank 1 is provided with a plurality of water outlet pipelines and a main pipeline, the water outlet pipelines are sequentially arranged on the main pipeline, and the water outlet pipelines are provided with a plurality of spray heads; the two ends of the diversion trench are respectively communicated with the dissolution tank 1 and the buffer tank, a plurality of baffle plates which are arranged in a staggered way are arranged in the diversion trench, and the preferable interval between the baffle plates is 300-600 mm; a concentration meter is arranged in the diversion trench, a water inlet pipe is arranged at the top of the diversion trench, and a regulating valve is arranged on the water inlet pipe; the flow speed of the diversion trench is controlled to be 0.1-0.3 m/s, the temperature of ferrous sulfate solution of the diversion trench is not lower than 50-70 ℃, and the ferrous sulfate concentration of the diversion trench is 20-23%.
The solution buffer tank 2 is of a semi-underground concrete structure, a stirrer is arranged in the solution buffer tank 2, preferably, the stirring speed of the stirrer is 10-30 rpm, the top of the impurity removal tank 3 is provided with an automatic weighing feeder, the automatic weighing feeder is provided with iron sheets, preferably, the iron sheets are iron sheets in irregular shapes of automobile cold rolling; a pH tester is arranged in the impurity removal tank 3, and the pH of the ferrous sulfate solution in the impurity removal tank 3 is controlled to be 2-4 by controlling the amount of the added iron sheet; the first pipe 6 is provided with a first axial flow pump 7.
The top of the impurity removal tank 3 is provided with a plurality of first overflow ports which are uniformly distributed, a reflux pipeline 10 is arranged at the first overflow ports, a first overflow pipeline 11 is arranged on the reflux pipeline 10, and the other end of the first overflow pipe is connected with the sedimentation tank 4; the reflux pipeline 10 is provided with a second axial flow pump 12 and a first valve 8, and the feeding amount of the second axial flow pump 12 type first axial flow pump 7 is 20-50 times; an eccentric stirrer is arranged in the top of the impurity removal tank 3, the stirring speed of the eccentric stirrer is 10-30 rpm, and the eccentric stirrer is a blade stirrer; the bottom of the drop tank is provided with a bottom mud raking machine, and the rotating speed is 0.03-0.06 rpm.
The metal film filtering system comprises a clear liquid buffer tank 13 and a metal film filter 14, the sedimentation tank 4 is connected with the clear liquid buffer tank 13 through a second overflow pipeline 15, the clear liquid buffer tank 13 is connected with the metal film filter 14 through a third pipeline 16, a third axial flow pump 17 is arranged on the third pipeline 16, and clear liquid filtered by the metal film filter 14 flows into the finished product tank 5 through a fourth pipeline 18; nitrogen is introduced into the final tank 5. The bottom of the sedimentation tank 4 is connected with a filter press assembly through a fifth pipeline 19, and a second valve 20 is arranged on the fifth pipeline 19; the bottom of the metal film filter 14 is connected with the filter press assembly through a pipeline;
the aperture of the metal film is 30-100 nm, and the metal film is 316L metal powder sintered felt; the flux of the membrane can be restored to 90-100% by back flushing of the clear liquid. The metal film is easy to regenerate and the time is short. The continuous operation of the process is ensured, and the production efficiency is greatly improved. And (5) taking the membrane filtration clear liquid as a product to enter a ferrous sulfate storage tank.
Preferably, the metal membrane filtration system adopts a two-stage series or three-stage series filtration mode, and the membrane surface flow velocity is 1-5 m/s.
The filter press assembly comprises a filter press buffering ground tank 21 and a filter press machine 22, wherein the bottom of the sedimentation tank 4 is connected with the filter press buffering ground tank 21 through a fifth pipeline 19, the filter press buffering ground tank 21 is connected with the filter press machine 22 through a sixth pipeline 23, a filter press feeding pump 24 is arranged on the sixth pipeline 23, filtrate of the filter press is connected with the clear solution buffering tank 13 through a seventh pipeline 25, and a filter residue conveying belt 9 is arranged at the bottom of the filter press; the filter press has a squeezing function, and the filtering precision of the filter cloth is 1-20 microns. The metal film discharges the concentrate, the concentrate discharged from the bottom of the impurity removal tank 3 returns to the buffer ground 21 of the filter press, the concentrate is pumped to the filter press, the filter press has the squeezing function, and the clear liquid of the filter press returns to the feeding buffer tank 2 of the metal film system. The discharged filter cake is conveyed to a warehouse by a belt.
Example 1:
as shown in fig. 1, the ferrous sulfate heptahydrate forklift is sent to a dissolving tank which is in a concrete structure, the height of a salt layer is 4.5m, hot water at 70 ℃ is uniformly dissolved into ferrous sulfate heptahydrate from bottom to top through a distributor and a spray nozzle, and ferrous sulfate solution enters a solution buffer tank through a baffling tank. The water is added into the baffle tank to dilute ferrous sulfate solution, a concentration meter is arranged in the baffle tank, and a water adding regulating valve is automatically controlled to ensure that the concentration of the ferrous sulfate is 22% (wt). The groove body of the diversion trench is hollow, is provided with a cover plate, and the inner wall of the bottom is provided with baffle plates in a left-right staggered way, and the interval is 400mm. The flow speed of the diversion trench is controlled to be 0.2m/s, the temperature of ferrous sulfate solution in the diversion trench is not lower than 68 ℃, and the ferrous sulfate concentration in the diversion trench is 22%.
The solution buffer tank is in the form of a semi-underground concrete structure, and is provided with a stirrer, the speed of which is preferably 20rpm. The stirred solution is pumped to an above-ground impurity removal tank. The upper part of the impurity removing tank is weighed by an automatic lifter, and iron sheets are added, and are in irregular shapes for cold rolling of automobiles. The impurity removing tank adopts a circulating axial flow pump to carry out back mixing, so that the floccules are prevented from being deposited on the iron sheet, and the reaction speed is further influenced. A plurality of overflow ports are uniformly distributed at the top of the impurity removal tank, and a main pipe enters an axial flow pump after collection and enters the bottom of the impurity removal tank after pressure lifting. The flow rate of the axial flow pump is preferably 50 times of the feeding amount of the impurity removing tank.
The PH of the ferrous sulfate solution in the impurity removal tank is controlled at 3 by controlling the adding amount of the iron sheet.
The top solution of the impurity removal tank overflows to an above-ground settling tank. The settling velocity of the floc in the settling tank was 0.1 m/s. The settling tank is provided with a bottom mud raking machine, and the rotating speed of the bottom mud raking machine is controlled to be 0.03rpm.
The supernatant in the top of the sedimentation tank overflows to a feeding circulation tank of the metal film system, and the incoming material of the circulation tank is mixed with the circulating concentrated solution discharged by the metal film and is conveyed into the metal film for filtering by a pump. The metal membrane filtration is cross-flow filtration, the pore diameter of the metal membrane is 20nm, and the metal membrane is 316L metal powder sintered felt. The metal film adopts a two-stage series or three-stage series filtration mode, and the flow rate of the film surface is 5m/s. The metal film has automatic back flushing and on-line chemical cleaning functions. The flux of the membrane can be restored to 99% by backwashing of the clear liquid. And sending the clear solution obtained by membrane filtration to a ferrous sulfate storage tank as a product.
The metal film discharges the concentrate, the bottom of the impurity removing tank discharges the concentrate and returns to the buffer ground tank of the filter press, the concentrate is pumped to the filter press, the filter press has the squeezing function, the filtering precision of the filter cloth is 10 microns, and the clear liquid of the filter press returns to the feeding buffer tank of the metal film system. The discharged filter cake is conveyed to a warehouse by a belt.
The principle of the invention is explained:
compared with the traditional old technology
Dissolution optimization
The old process adopts a batch method to dissolve solid FeSO 4 ·7H 2 O raw materials are directly discharged into a dissolving tank, corresponding condensate is introduced according to the adding amount of the raw materials for dissolving, the dissolving tank is required to be provided with a stirrer for stirring, and after the raw materials are completely dissolved, the dissolving liquid in the tank is conveyed to the downstream by a pump. The process has obvious defects that firstly, continuous operation cannot be performed, the raw materials in the whole dissolving tank can be sent out only after the raw materials are completely dissolved, and a large amount of manpower and a plurality of large-capacity dissolving tanks are required to realize batch discharging; secondly, the fluctuation of the composition of the raw materials is large, the addition of the raw material amount and the water amount is difficult to finely control, and the dissolution tank is large, so that the partial undissolved condition can occur, and the reject ratio of the product is high.
The invention adopts a continuous method for dissolution, firstly, proper FeSO is added into a dissolution tank 4 ·7H 2 The O raw material forms a salt layer with a certain height, the condensate is introduced into the bottom of the salt layer, passes through the salt layer from bottom to top, overflows from the top of the tank to the downstream, and after the height of the salt layer is ensured, the overflowed salt solution is saturated solution, and then water is quantitatively added to dilute to the required concentration according to concentration calculation. The process can realize continuous operation, has simple equipment, does not need more personnel to operate, and can accurately regulate and control the concentration of the product.
Impurity removal optimization
Fe 2+ Formation of Fe which is extremely easily oxidized in air 3+ The old technology adds NaOH to make Fe 3+ Formation of Fe (OH) 3 The precipitate is pumped to a filter press and removed by filter pressing. On the one hand, similar to the dissolution section, only batch adjustment of pH can be performed, continuous operation can not be realized, and a large amount of manpower is required to be consumed; on the other hand, fe 3+ By forming Fe (OH) 3 Precipitation removal results in a significant portion of the material being lost, largeThe utilization rate of raw materials is greatly reduced; in addition, a large amount of precipitates are easy to cause the blockage of a pipeline system, increase the overhauling frequency, and can also cause the application of more filter pressing equipment and the generation of more filter residue solid wastes. After the filter press filtrate enters the finished product tank, the filter press filtrate still needs to stand for 7 to 11 days to be sent to the downstream.
According to the invention, by adding the iron sheet for impurity removal, the full contact and the enough reaction time between the solution and the iron sheet are ensured in the impurity removal tank, the top solution of the impurity removal tank overflows to the above-ground sedimentation tank, and the overflow of the top clear solution of the sedimentation tank flows into the metal film for filtration. And (5) delivering the concentrated solution at the bottom of the impurity removal tank to a filter press for treatment. The whole process runs continuously, so that the production efficiency is greatly improved, and the loss of raw materials is avoided; in addition, the precipitation amount is greatly reduced, and the use of a filter press and the generation of solid waste are reduced; the aperture of the metal film is 20nm, the filtering precision is far higher than that of a filter press, and the filtrate can be directly sent to the downstream without long-time standing.
The process comparison is as follows:
the foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Claims (10)
1. A continuous refining method of titanium white byproduct ferrous sulfate is characterized in that: the method comprises the following steps:
s1: the raw materials are sent to a dissolving tank, hot water is introduced into the bottom of the dissolving tank, the ferrous sulfate solution enters a buffer tank through a baffle tank of the dissolving tank, and water is added into the baffle tank to dilute the ferrous sulfate solution;
s2: the ferrous sulfate solution in the buffer tank enters a impurity removal tank through a pump, the solution at the top of the iron sheet impurity removal tank is added into the impurity removal tank and overflows to a ground sedimentation tank, clear liquid at the top of the sedimentation tank overflows to a metal film filtering system, and the clear liquid after metal film filtering is used as a product and sent to a ferrous sulfate storage tank;
s3: the concentrated liquid discharged by the metal film filtering system and the impurity removing tank is reversely fed into the buffer ground tank of the filter press, the pump sends the liquid in the ground tank to the compressor, and the clear liquid in the filter press is returned to the clear liquid buffer tank.
2. The continuous refining method of titanium white byproduct ferrous sulfate according to claim 1, which is characterized in that: the raw material in the step S1 is ferrous sulfate heptahydrate;
the temperature of the hot water introduced into the dissolving tank in the step S1 is 60-90 ℃; the salt layer height of the dissolving tank is 2-4.5 m.
3. The continuous refining method of titanium white byproduct ferrous sulfate according to claim 1, which is characterized in that: the flow speed of the diversion trench in the step S1 needs to be controlled to be 0.1-0.3 m/S, the temperature of the ferrous sulfate solution of the diversion trench is at least 50-70 ℃, and the ferrous sulfate concentration of the diversion trench is 20-23%.
4. The continuous refining method of titanium white byproduct ferrous sulfate according to claim 1, which is characterized in that: the metal film filtering systems in the step S2 and the step S3 are cross-flow filtering, the aperture of the metal film is 30-100 nm, and the metal film is 316L metal powder sintered felt;
in the step S2, a patch is added to control the PH of ferrous sulfate solution to be 2-4;
preferably, the metal membrane filtration system adopts a two-stage series or three-stage series filtration mode, and the membrane surface flow velocity is 1-5 m/s.
5. An apparatus for use in a continuous refining method of titanium dioxide by-product ferrous sulfate as claimed in any one of claims 1 to 4, characterized in that: comprises a dissolving tank, a buffer tank, a impurity removal tank, a settling tank, a metal film filtering system and a finished product tank;
the dissolving tank is connected with the buffer tank through the diversion trench, the buffer tank is connected with the impurity removal tank through a first pipeline, the top of the impurity removal tank is connected with the sedimentation tank through a first overflow pipe, the top of the sedimentation tank is connected with the metal film filtering system through a second overflow pipe, the metal film filtering system is connected with Chen Pinguan through a pipeline, and the bottoms of the metal film filtering system and the sedimentation tank are connected with the filter press assembly.
6. The continuous refining apparatus for titanium white byproduct ferrous sulfate according to claim 5, wherein: the dissolving tank is a semi-underground dissolving tank;
the bottom of the dissolving tank is provided with a plurality of water outlet pipelines and a main pipeline, the water outlet pipelines are sequentially arranged on the main pipeline, and the water outlet pipelines are provided with a plurality of spray heads;
the two ends of the diversion trench are respectively communicated with the dissolution tank and the buffer tank, a plurality of baffle plates which are arranged in a staggered way are arranged in the diversion trench, and the preferable interval between the baffle plates is 300-600 mm;
a concentration meter is arranged in the diversion trench, a water inlet pipe is arranged at the top of the diversion trench, and a regulating valve is arranged on the water inlet pipe;
the flow speed of the diversion trench is controlled to be 0.1-0.3 m/s, the temperature of ferrous sulfate solution of the diversion trench is not lower than 50-70 ℃, and the ferrous sulfate concentration of the diversion trench is 20-23%.
7. The continuous refining apparatus for titanium white byproduct ferrous sulfate according to claim 5, wherein: the solution buffer tank is of a semi-underground concrete structure, a stirrer is arranged in the solution buffer tank, preferably, the stirring speed of the stirrer is 10-30 rpm, the top of the impurity removal tank is provided with an automatic weighing feeder, the automatic weighing feeder is provided with iron sheets, preferably, the iron sheets are iron sheets in irregular shapes of automobile cold rolling;
a pH tester is arranged in the impurity removal tank, and the pH of ferrous sulfate solution in the impurity removal tank is controlled to be 2-4 by controlling the amount of the added iron sheet;
the first pipeline is provided with a first axial flow pump.
8. The continuous refining apparatus for titanium white byproduct ferrous sulfate according to claim 7, wherein: the top of the impurity removal tank is provided with a plurality of first overflow ports which are uniformly distributed, a reflux pipeline is arranged at the first overflow ports, the first overflow pipeline is arranged on the reflux pipeline, and the other end of the first overflow pipe is connected with the sedimentation tank;
the reflux pipeline is provided with a second axial flow pump and a first valve, and the feeding amount of the second axial flow pump type first axial flow pump is 20-50 times;
an eccentric stirrer is arranged in the top of the impurity removal tank, the stirring speed of the eccentric stirrer is 10-30 rpm, and the eccentric stirrer is a blade stirrer;
the bottom of the drop tank is provided with a bottom mud raking machine, and the rotating speed is 0.03-0.06 rpm.
9. The continuous refining apparatus for titanium white byproduct ferrous sulfate according to claim 5, wherein: the metal film filtering system comprises a clear liquid buffer tank and a metal film filter, wherein the settling tank is connected with the clear liquid buffer tank through a second overflow pipeline, the clear liquid buffer tank is connected with the metal film filter through a third pipeline, a third axial flow pump is arranged on the third pipeline, and clear liquid filtered by the metal film filter flows into a finished product tank through a fourth pipeline;
the bottom of the sedimentation tank is connected with the filter press assembly through a fifth pipeline, and a second valve is arranged on the fifth pipeline;
the bottom of the metal film filter is connected with the filter press component through a pipeline;
the aperture of the metal film is 30-100 nm, and the metal film is 316L metal powder sintered felt;
preferably, the metal membrane filtration system adopts a two-stage series or three-stage series filtration mode, and the membrane surface flow velocity is 1-5 m/s.
10. The continuous refining apparatus for titanium white byproduct ferrous sulfate according to claim 5, wherein: the filter press assembly comprises a filter press buffering ground groove and a filter press machine, wherein the bottom of the sedimentation groove is connected with the filter press buffering ground groove through a fifth pipeline, the filter press buffering ground groove is connected with the filter press machine through a sixth pipeline, a filter press feeding pump is arranged on the sixth pipeline, filtrate of the filter press is connected with the clear liquid buffering groove through a seventh pipeline, and a filter residue conveying belt is arranged at the bottom of the filter press;
the filter press has a squeezing function, and the filtering precision of the filter cloth is 1-20 microns.
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| CN202311044983.4A CN117303453A (en) | 2023-08-18 | 2023-08-18 | A continuous refining method and device for titanium dioxide by-product ferrous sulfate |
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| CN202311044983.4A CN117303453A (en) | 2023-08-18 | 2023-08-18 | A continuous refining method and device for titanium dioxide by-product ferrous sulfate |
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| CN105152271A (en) * | 2015-07-31 | 2015-12-16 | 上海安赐机械设备有限公司 | Titanium dioxide white water reuse process and system thereof |
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| CN115974123A (en) * | 2022-12-09 | 2023-04-18 | 四川大学 | Recovery and Utilization Method of Sulfuric Acid and Valuable Metals in Titanium White Waste Acid |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105152271A (en) * | 2015-07-31 | 2015-12-16 | 上海安赐机械设备有限公司 | Titanium dioxide white water reuse process and system thereof |
| CN105293588A (en) * | 2015-11-26 | 2016-02-03 | 湖北万润新能源科技发展有限公司 | Preparation method for battery grade ferrous sulfate heptahydrate crystal |
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