CN114920417B - Equipment and method for deep purification treatment of phosphogypsum slag warehouse percolate - Google Patents

Equipment and method for deep purification treatment of phosphogypsum slag warehouse percolate Download PDF

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CN114920417B
CN114920417B CN202210742022.XA CN202210742022A CN114920417B CN 114920417 B CN114920417 B CN 114920417B CN 202210742022 A CN202210742022 A CN 202210742022A CN 114920417 B CN114920417 B CN 114920417B
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leachate
phosphogypsum slag
crystallization
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fluidized bed
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CN114920417A (en
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盛勇
熊柏年
陈少华
于艳敏
赵飞
耿明
王开珍
康建姣
方睿
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Sinochem Yunlong Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00Multistage treatment of water, waste water or sewage
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/48Treatment of water, waste water, or sewage with magnetic or electric fields
    • C02F1/488Treatment of water, waste water, or sewage with magnetic or electric fields for separation of magnetic materials, e.g. magnetic flocculation
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/52Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/66Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F2001/007Processes including a sedimentation step
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/52Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F2001/5218Crystallization
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/10Inorganic compounds
    • C02F2101/105Phosphorus compounds
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/10Inorganic compounds
    • C02F2101/12Halogens or halogen-containing compounds
    • C02F2101/14Fluorine or fluorine-containing compounds
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/30Organic compounds
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/06Contaminated groundwater or leachate

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  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
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Abstract

The invention discloses equipment and a method for deep purification treatment of phosphogypsum slag reservoir percolate, which are used for coupling the traditional two-section lime cream neutralization chemical precipitation treatment method, crystallization fluidized bed, magnetic coagulation and other technologies on the basis of analyzing and summarizing phosphogypsum slag reservoir percolate components and characteristics thereof, and realizing deep purification of phosphogypsum slag reservoir percolate through brand new medicament combination. The related treatment process is independent of a phosphoric acid production system, and provides a leachate deep purification treatment path with low investment and operation cost for a phosphorus chemical industry enterprise incapable of recycling phosphogypsum slag reservoir leachate to the production system. The water phase purified by the method meets the III-class surface water requirement in the surface water environment quality standard (GB 3838-2002), and simultaneously effectively reduces the phosphoric acid consumption in the calcium magnesium polyphosphate production process, thereby bringing ideal social, economic and environmental benefits for enterprises.

Description

Equipment and method for deep purification treatment of phosphogypsum slag warehouse percolate
Technical Field
The invention relates to the technical field of chemical wastewater treatment, in particular to equipment and a method for deep purification treatment of phosphogypsum slag warehouse leachate.
Background
Phosphogypsum is a byproduct in the process of producing phosphoric acid by extracting and decomposing phosphorite by sulfuric acid, and each 1 ton of phosphoric acid is produced (100 percent P 2 O 5 Calculated as a total) about 5 tons of dry phosphogypsum as a byproduct.
Because phosphogypsum contains about 10% of phosphorus, fluorine compounds, organic matters and other harmful impurities, the application way of the phosphogypsum is severely limited, and the phosphogypsum is generally treated by adopting a slag warehouse for storage.
In the piling process, because phosphogypsum contains moisture and phosphogypsum creep extrusion moisture factors, a phosphogypsum slag warehouse can generate percolate, and the main components of the phosphogypsum slag warehouse are phosphorus-containing, fluorine-containing and magnesium-containing compounds, organic matters and the like, and the phosphogypsum slag warehouse has pH of 2-3 and is acidic. The common treatment method is that percolate is collected and drained to a liquid collecting tank through a turbid water pipe and then recycled to working sections such as ore grinding, flotation and the like, for example, the treatment method of phosphogypsum slag field backwater in wet ore grinding and phosphogypsum slag field water in wet phosphoric acid production recycling process in China literature, but the percolate contains more impurities and is acidic, and the problems of equipment corrosion aggravation, impurity accumulation in phosphoric acid and the like are caused, so that the quality of subsequent products is influenced. Other treatment methods such as natural evaporation or spray evaporation by means of a liquid collecting tank have the problems that water balance is difficult to achieve due to limited evaporation capacity, and a large amount of acid percolate is stored in the liquid collecting tank for a long time, so that the leakage environment-friendly risk exists.
The Chinese patent (a tailing wastewater recycling system) (application number: 201810128375.4) is characterized in that tailing wastewater is subjected to preliminary impurity removal through a reactor, and clear liquid is returned to a part of working sections for water supplementing after being clarified through a thickener. The method adopts a flocculating agent and precipitation method to treat the tailing wastewater, the wastewater cannot be deeply purified, and the treated reuse water is used for a production section with low requirements on water hardness. The water phase treated by the method still contains impurities such as magnesium, fluorine, organic matters and the like, the quality of phosphoric acid and downstream products can be reduced in the recycling process, and on the other hand, the method is not suitable for the condition that the slag warehouse is far away from an enterprise and wastewater cannot be recycled to a production system.
The method and system for treating the phosphogypsum yard permeate in China (application number: 201811214534.9) uses alkaline matters to regulate pH in two stages and is assisted by two units of membrane treatment and biochemical treatment to remove phosphorus, fluorine and ammonia nitrogen in the permeate, so that the treated phosphogypsum yard permeate meets the relevant requirements of comprehensive sewage discharge Standard (GB 8978-1996). However, the method adopts lime to adjust pH value in a segmented manner to treat phosphorus element in the percolate, and adds polyacrylamide to ensure the SS value of suspended matters, and adopts membrane filtration to treat ammonia nitrogen, wherein all phosphorus elements in the percolate are treated by lime precipitation, so that a large amount of lime is consumed without doubt, the production cost is too high, the raw material cost is increased due to the addition of the polyacrylamide, and the membrane filtration treatment process always has the stubborn diseases of easy blockage and high operation and maintenance cost. And the indexes of the directly discharged phosphorus and fluorine treated by the method still reach 0.5mg/L and 5mg/L, so that the deep purification treatment in the true sense is difficult to realize.
The calcium magnesium polyphosphate is a novel phosphate fertilizer product which is rich in medium trace elements such as calcium, magnesium, sulfur and the like, has slow release property, slowly releases orthophosphate along with the time so as to meet the requirements of crops, and has a relatively good prospect at present. The Chinese patent (201810281139.6) discloses a calcium magnesium polyphosphate fertilizer prepared from phosphoric acid and phosphate tailings and a preparation method thereof, wherein phosphoric acid and flotation tailings are adopted as raw materials, and calcined at 200-600 ℃ to generate calcium magnesium polyphosphate, and the phosphorus source reacted with the flotation tailings in the method is derived from P 2 O 5 The content of the wet-process phosphoric acid is more than or equal to 15 percent, and the phosphoric acid with the specification can be directly prepared into an industrial grade phosphate product by adopting a two-stage neutralization method or a concentration method, so that the method disclosed by the invention also changes phases to reduce the phosphate productivity of the phosphoric acid and the downstream working section.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides equipment and a method for deeply purifying and treating phosphogypsum slag warehouse leachate.
The aim of the invention is achieved by the following technical scheme:
the phosphogypsum residue warehouse leachate deep purification treatment equipment comprises a re-slurry tank, a solid-liquid separator, a crystallization fluidized bed and a magnetic coagulation device which are sequentially connected, wherein the magnetic coagulation device comprises an alum blossom reaction zone, an acid-base regulation zone and a sedimentation separation zone which are sequentially communicated, the alum blossom reaction zone is connected with a liquid phase outlet of the crystallization fluidized bed, a clarified water outlet is arranged on the sedimentation separation zone, and a flocculation precipitation outlet is arranged at the bottom of the sedimentation separation zone.
Preferably, the crystallization fluidized bed is provided with a clarification area, a separation area and a granulation area from top to bottom in sequence, a liquid phase outlet of the solid-liquid separator is connected to the bottom of the crystallization fluidized bed, the bottom of the granulation area is also provided with a crystallization accelerator adding port, the granulation area is connected with a granular crystallization storage tank, and the liquid phase outlet is arranged on the clarification area.
Preferably, the sedimentation separation area is internally provided with a tube filler, the installation angle of the tube filler is 45-55 degrees, the arrangement area of the tube filler and the cross-sectional area ratio of the sedimentation separation area are 0.4-0.6:1, and the tube diameter phi of the tube filler is 50-80mm.
A method for deeply purifying phosphogypsum slag warehouse percolate comprises the following steps:
step A, phosphogypsum slag reservoir leachate, calcium magnesium polyphosphate raw material flotation tailings and hydrogen peroxide are placed in a reslurry tank, and after reslurry, the mixture is subjected to solid-liquid separation;
b, transferring the liquid phase obtained in the step A to a crystallization fluidized bed, and transferring the liquid phase from which crystals are removed to a magnetic coagulation device;
and C, adding a deep purifying agent and magnetic powder into the magnetic coagulation equipment, adjusting the pH value to 6.5-9.0, and then entering a sedimentation separation zone with inclined tube filler to realize solid-liquid separation, thereby obtaining clarified water.
Preferably, in the step A, the liquid-solid mass ratio is 2-6:1, and the slurry is re-pulpedThe time is 0.5-4H, the reslurry temperature is 20-80 ℃, the pH of the reslurry liquid is 4-5.5, and the percolate and H 2 O 2 The volume ratio is 950-1200:1.
Preferably, in step B, a crystallization promoter is added to the liquid phase and the pH is adjusted to 5.5-6.5 with milk of lime.
Preferably, the crystallization promoter is loess, ceramsite or diatomite, and the mass ratio of the liquid phase entering the crystallization fluidized bed to the crystallization promoter is 1400-1700:1.
Preferably, the deep purifying agent is polyaluminum chloride, polyferric sulfate or aluminum sulfate, and in the magnetic coagulation device, al: (P+F) molar ratio of 1-9:1 or Fe: the molar ratio of (P+F) is 4.5-7.5:1, the reaction time is 20-80 min, and the stirring speed is 25-40r/min.
Preferably, the mass ratio of the magnetic powder to the deep purifying agent is 1:4-1:7.
Preferably, the solid phase obtained in step B and/or step C is transferred to a reslurry tank to repeat step A.
How to effectively utilize the phosphogypsum slag reservoir percolate is always a common problem faced by phosphorus chemical enterprises, and the P in the phosphogypsum slag reservoir percolate 2 O 5 Generally below 0.5%, the phosphogypsum slag storage percolate is difficult to directly utilize by a traditional dilute acid two-stage neutralization method, and the acid concentration is reduced and the unit consumption of concentrated steam is increased when the phosphogypsum slag storage percolate is recycled to an extraction tank or a phosphoric acid concentration working section, so that most enterprises directly use the phosphogypsum slag storage percolate for ore grinding, a flotation working section or a treated solid phase to be added into a low-end phosphate fertilizer product, the water phase is directly discharged, the method is slightly analyzed, the method is not difficult to find out that the method depends on the existing phosphoric acid production system, but in practice, phosphogypsum slag fields of a plurality of phosphorus chemical enterprises are far away from the phosphoric acid production system, the phosphogypsum slag storage percolate is difficult to recycle, and as the service life of the phosphogypsum slag storage expires, the new slag field is put into use, the phosphoric acid production system is difficult to digest the old slag storage percolate, and more enterprises are used for purifying treatment of the phosphogypsum slag storage percolate or are taken as surface water supplementing water, and the deep purification of the percolate reaches the surface water supplementing standard of the phosphorus chemical enterprises is definitely the most expected to reach the effect of the surface water supplementing water of the phosphorus chemical enterprises. Therefore, many phosphorus chemical enterprises haveThe technology of the patent is provided for effectively solving the problem by seeking a phosphogypsum slag warehouse percolate treatment method which is more economical, more environment-friendly and independent of a phosphoric acid production system.
Flotation tailings are by-products of the phosphorite flotation process due to P 2 O 5 The content of% is generally between 5% and 12%, the direct utilization difficulty of the existing technology is high, and most phosphorus chemical enterprises adopt a stacking mode similar to phosphogypsum for treatment. In recent years, enterprises propose to mix flotation tailings as raw materials with phosphoric acid for reaction and then calcine the mixture to generate calcium magnesium polyphosphate, but the method consumes a large amount of phosphoric acid, and other phosphorus chemical products using the phosphoric acid as raw materials are produced in a variable phase and reduced yield. The patent adopts flotation tailings to react with phosphogypsum slag reservoir leachate repulping in advance, and CaMg (CO) in the tailings is obtained by adjusting the liquid-solid ratio, pH, reaction time and reaction temperature 3 ) 2 、CaCO 3 、MgCO 3 The alkaline matters react with phosphoric acid and fluosilicic acid in the percolate to generate precipitates such as phosphate and calcium fluoride, so that most of phosphorus and fluorine in the phosphogypsum slag reservoir percolate are purified and removed, the consumption of purifying agents for treating the percolate can be effectively reduced, and the consumption of phosphoric acid in the production process of calcium magnesium polyphosphate can be reduced. The patent points out that the phosphogypsum slag reservoir percolate is utilized to reduce the consumption of phosphoric acid in the process of producing calcium magnesium polyphosphate, but is applicable to enterprises which do not have matched calcium magnesium polyphosphate production lines and only store the flotation tailings, for example, the phosphogypsum slag reservoir percolate is directly permeated through a flotation tailing deposit or is subjected to repulping washing and solid-liquid separation, and then the flotation tailings are stored, so that the consumption cost of the subsequent purification treatment of the percolate can be greatly reduced.
Magnesium hydrogen phosphate and calcium hydrogen phosphate belong to phosphate with smaller solubility product, the optimal sedimentation pH value is 5.5-6.2, the characteristic can be used for production by adopting a precipitation method, but the indexes of phosphorus and magnesium in a water phase after solid-liquid separation can not meet the requirements of class III surface water in surface water environment quality standard (GB 3838-2002) by adopting a crystallization fluidized bed, adding a crystallization accelerator and assisting in controlling the pH value of a system, so that magnesium hydrogen phosphate is forcedly crystallized, meanwhile, supernatant fluid of the fluidized bed overflows into a transfer storage tank provided with an online phosphorus, magnesium and calcium monitor, if related indexes are not completely up to standard, the water phase returns to the bottom of the crystallization fluidized bed again for secondary crystallization, and the purpose of basically removing phosphorus, magnesium and calcium in the water phase is ensured. Compared with the traditional solid-liquid separation equipment such as a plate-and-frame filter press and a centrifugal separator, the crystallization fluidized bed has the advantages of small occupied area and less equipment and labor investment, and the granular magnesium hydrogen phosphate and calcium hydrogen phosphate discharged from the bottom of the crystallization fluidized bed can be used as raw materials for producing calcium magnesium polyphosphate after being dried, so that magnesium impurity elements are prevented from entering a phosphoric acid production system again.
The magnetic coagulation technology is a water treatment technology which is more concerned in recent years and is mainly applied to sewage treatment plants, no report on the treatment of phosphorus-containing percolate of phosphogypsum slag reservoirs is available at present, the deep purification treatment of the phosphogypsum slag reservoirs is conducted until III-class surface water meeting the quality standard of surface water environment (GB 3838-2002), the magnetic coagulation functional areas are integrated into a whole set of equipment, and the equipment has the advantages of attractive appearance, small occupied area, convenience in maintenance and the like.
The invention combines the index characteristics of phosphogypsum slag reservoir percolate with the crystallization fluidized bed and the magnetic coagulation sedimentation technology on the basis of analyzing and summarizing the existing water treatment technology, and can effectively reduce the percolate treatment cost and simultaneously reduce the phosphoric acid consumption of calcium and magnesium polyphosphate when the deep purified phosphogypsum slag reservoir percolate meets class III surface water in surface water environment quality standard (GB 3838-2002), thereby bringing ideal social, economic and environmental benefits for enterprises.
The invention has the following advantages:
1. the leachate of the phosphate paste residue warehouse is pretreated by floatation tailings, so that most of phosphorus and fluorine in the leachate can be purified and removed, the treatment cost of the traditional chemical precipitation method is greatly reduced, and the phosphoric acid consumption for producing calcium magnesium polyphosphate products is effectively reduced.
2. The invention uses the crystallization fluidized bed as a carrier to forcedly crystallize magnesium hydrogen phosphate and magnesium hydrogen phosphate, further reduces phosphorus, magnesium and calcium impurity elements in percolate, provides useful elements for producing calcium magnesium polyphosphate, and has the advantages of small occupied area, less equipment and labor investment, and the crystallization fluidized bed is equipment integrating crystallization, granulation and solid-liquid separation, and does not need to add a traditional solid-liquid separation equipment and a granulator.
3. The invention adopts the magnetic coagulation sedimentation technology to deeply purify phosphogypsum slag warehouse percolate, firstly, polymeric ferric sulfate is preferably used as a deep purification medicament, and combines the magnetic coagulation technology to increase the specific gravity of flocs, thereby achieving the effects of rapid sedimentation, strengthening alum blossom reaction and solid-liquid separation, and simultaneously, tiny magnetic powder is used as crystal nucleus to form alum blossom more easily, thereby greatly saving the medicament consumption, finally ensuring that P in a water phase is less than 0.2mg/L and F is less than 1mg/L after the magnetic coagulation treatment, and simultaneously adopting the magnetic coagulation technology does not need to newly add solid-liquid separation equipment, thereby effectively saving the production cost. The phosphogypsum slag reservoir percolate after the deep purification treatment meets the III type surface water index requirement in the surface water environment quality standard (GB 3838-2002).
4. In the application, the proper deep purifying agent is selected, the magnetic powder is added into the deep purifying agent, the particle size of the flocculated product is controlled by adjusting the dosage of the deep purifying agent and the magnetic powder, and the inclined tube filler is prevented from being blocked.
5. In order to purify the liquid phase, a crystallization accelerator, a deep purifying agent and magnetic powder are sequentially added into the reaction system, and the components are finally transferred to a calcium magnesium polyphosphate production line in whole or in part, so that calcium magnesium polyphosphate with higher average polymerization rate can be obtained with relatively lower energy consumption during the production of the calcium magnesium polyphosphate, and the slow release performance of the calcium magnesium polyphosphate in fertilizer is better.
6. The treatment process is independent of a phosphoric acid production system, avoids reintroducing organic matters, magnesium, fluorine and other impurities in the phosphogypsum slag reservoir leachate into a phosphoric acid or downstream product system, reduces the quality of the phosphogypsum slag reservoir, is more suitable for the conditions that the phosphogypsum slag reservoir is far away from an enterprise production site or the service life of the slag reservoir is expired, the enterprise can not digest any more, and the leachate needs to be treated independently, and has important reference significance for the treatment of the phosphogypsum slag reservoir leachate by vast phosphorus chemical enterprises.
Drawings
FIG. 1 is a flow chart of a method for deeply purifying and treating phosphogypsum slag reservoir percolate.
FIG. 2 is a schematic diagram of the aqueous phase process of crystallization fluidized bed treatment step A.
FIG. 3 is a schematic diagram of the water phase process of the magnetic coagulation plant treatment step B.
Wherein, 1-reslurry tank; 2-a solid-liquid separator; 3-crystallization fluidized bed; 4-magnetic coagulation equipment; 5-calcium magnesium polyphosphate production line; 31-a granulation zone; 32-a separation zone; 33-a clarification zone; 6-a wastewater regulating tank; 7, a transit storage tank; 8-a granular crystal storage tank; 41-alum blossom reaction zone; 42-acid-base regulation zone; 43-settling separation zone; 44-a recovery pump; 9-a magnetic separator; 10-screw pump; 11-regulating tank.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, based on the embodiments of the invention, which are apparent to those of ordinary skill in the art without inventive faculty, are intended to be within the scope of the invention.
In addition, the embodiments of the present invention and the features of the embodiments may be combined with each other without collision.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
Phosphogypsum slag warehouse leachate deep purification treatment in the application comprises the following steps:
A. the percolate in phosphogypsum slag warehouse overflows or is pumped into a pretreatment section of the calcium magnesium polyphosphate raw material flotation tailings, the percolate and the flotation tailings are respectively metered and then enter a repulping tank, and simultaneously H is added together 2 O 2 Removing organic matters. The liquid-solid ratio in the re-slurry process is 2-6:1, the re-slurry time is 0.5-4H, the re-slurry temperature is 20-80 ℃, the re-slurry pH is 4-5.5, and the percolate treatment capacity and H are the same as those of the water-soluble inorganic mineral powder 2 O 2 The adding amount ratio is 950-1200:1, after pulp washing, solid-liquid separation is carried out by adopting a plate-and-frame filter press or a centrifuge, the solid phase S is sent into a calcium-magnesium polyphosphate production section III and phosphoric acid to generate calcium-magnesium polyphosphate products through calcination, and the liquid phase L enters a magnesium removal procedure;
B. the liquid phase L of the step A enters a crystallization fluidized bed from the bottom through a percolate regulating tank, the crystallization accelerator enters the bottom of the crystallization fluidized bed together, and lime milk is added according to the pH value of the water phase. And B, the water phase is subjected to solid-liquid separation after passing through a granulating area and a separating area of the crystallization fluidized bed, the solid phase is a mixture of granular magnesium hydrophosphate and calcium hydrophosphate, and is discharged from the bottom of the crystallization fluidized bed, and the solid phase is directly recycled to a floatation tailing neutralization section of the step A for producing calcium magnesium polyphosphate. The liquid phase L overflows to the deep purification process via the top of the crystallization fluidized bed. The pH value of the liquid phase in the step B is 5.5-6.5 after lime cream adjustment, the crystallization accelerator adopts loess or ceramsite or diatomite, and the ratio of the water quantity entering a crystallization fluidized bed to the addition quantity of the crystallization accelerator is 1400-1700:1;
c: the liquid phase L in the step B enters a magnetic coagulation deep purification process, the process is realized by a magnetic coagulation complete set of equipment, and the complete set of equipment consists of an alum blossom reaction and magnetic powder coagulation assisting area, a sodium hydroxide pH adjusting area, a sedimentation solid-liquid separation area and a magnetic separator. Respectively adding the liquid phase and the deep purifying agent polyaluminum chloride or polymeric ferric sulfate or aluminum sulfate and magnetic powder into the alum reaction and the magnetic powder assisted coagulation, wherein Al: the molar ratio of (P+F) is controlled to be 1-9:1 or Fe: the molar ratio of (P+F) is controlled to be 1-8.5:1, the reaction time is 5-90min, and the stirring speed is 20-80r/min, wherein the magnetic powder is added, so that the reaction effect of the alum floc can be enhanced, the generated floc is adsorbed and settled at the bottom by the magnetic powder, the SS value of suspended matters is effectively reduced, the adding amount of the magnetic powder and the adding amount of polyaluminium chloride or polymeric ferric sulfate or aluminum sulfate are in a ratio of 1:2.5-1:10, the solid-liquid mixture after the reaction is regulated to pH6.5-9 by sodium hydroxide solution, and then the solid-liquid separation is realized in a settlement separation zone with inclined tube filler, wherein the inclined tube filler has an installation angle of 40-85 degrees, the material is PP or PE or PVC, the ratio of the arrangement area to the sectional area of the settlement separation zone is 0.3-0.8:1, and the pipe diameter phi of the inclined tube filler is 50-80. The liquid phase 10 overflows into a finished product water tank area to be used as surface supplementing water or used as process water to be recycled to a production process, the bottom solid phase is thick slurry C, the thick slurry C is pumped into a magnetic separator by a screw pump, recovered magnetic powder is added into a magnetic powder coagulation assisting area again, and a small amount of thick slurry C is returned to a calcium magnesium polyphosphate raw material flotation tailing neutralization section.
Example 1:
the phosphogypsum slag warehouse leachate is taken, and the relevant detection indexes are as follows:
pumping the phosphogypsum slag reservoir percolate into a floatation tailing reslurry tank by a pump, simultaneously adding floatation tailings and hydrogen peroxide, controlling the liquid-solid ratio in the reslurry process to be 2:1, reslurrying for 1H at the reslurry temperature of 25 ℃, and controlling the slurry pH to be 4, wherein the treatment capacity of the percolate and H 2 O 2 The adding amount ratio is 990:1, solid-liquid separation is carried out by adopting a plate-and-frame filter press after pulp washing, the solid phase and phosphoric acid are calcined to generate calcium magnesium polyphosphate products, and the liquid phase enters a fluidized bed crystallization process.
Repulping and washing the flotation tailingsThe latter liquid phase is combined with Ca (OH) 2 Lime milk with the mass concentration of 4% enters a percolate regulating tank, the pH value of a liquid phase is 5.9, the lime milk enters a crystallization fluidized bed from the bottom by a water inlet pump, the loess serving as a crystallization accelerator enters the bottom of the crystallization fluidized bed, and the ratio of the water quantity entering the crystallization fluidized bed to the addition quantity of the crystallization accelerator is 1400:1. The water phase added with the crystallization accelerator is subjected to solid-liquid separation after passing through a granulating area and a separating area of a crystallization fluidized bed, the solid phase is granular crystals (magnesium hydrogen phosphate and calcium hydrogen phosphate) and is discharged from the bottom of the crystallization fluidized bed, the granular crystals enter a flotation tailing neutralization section of a calcium magnesium polyphosphate raw material after passing through a storage tank, and the liquid phase overflows from the top of the crystallization fluidized bed and goes through a transfer storage tank to a deep purification process.
The water phase from the crystallization process enters an adjusting tank to ensure the stability of the index of the water phase, and then is pumped into a magnetic coagulation complete set of equipment by a water inlet pump, wherein the complete set of equipment consists of an alum blossom reaction and magnetic powder coagulation assisting area, a sodium hydroxide pH adjusting area, a sedimentation solid-liquid separation area and a magnetic separator. Adding polymeric ferric sulfate and Fe into alum blossom reaction medicament: the molar ratio of (P+F) is controlled to be 4.8:1, the reaction time is 20min, the stirring speed is 28r/min, the ratio of the magnetic powder addition amount to the polymeric ferric sulfate addition amount is 1:4, the solid-liquid mixture after the reaction is regulated to pH7.4 by sodium hydroxide, and then the solid-liquid mixture enters a sedimentation separation area with inclined tube filler to realize solid-liquid separation, wherein the inclined tube filler is 45 degrees in installation angle, the PP is used as a material, the ratio of the arrangement area to the sectional area of the sedimentation separation area is 0.4:1, and the pipe diameter phi of the inclined tube filler is 50mm. The liquid phase overflow after deep purification treatment enters a finished product water tank area to be used as surface makeup water, the bottom thick slurry is pumped into a magnetic separator by a screw pump, recovered magnetic powder is added into a magnetic powder coagulation assisting area again, and a small amount of thick slurry is returned to a calcium magnesium polyphosphate raw material flotation tailing neutralization section. The water phase is subjected to deep purification treatment by magnetic coagulation complete equipment, and the relevant detection core indexes are as follows:
example 2:
the phosphogypsum slag warehouse leachate is taken, and the relevant detection indexes are as follows:
pumping the percolate of the phosphogypsum slag reservoir into a flotation tailing reslurry tank, adding the flotation tailings and hydrogen peroxide at the same time, controlling the liquid-solid ratio in the reslurry process to be 4:1, reslurrying for 0.8H at 40 ℃, reslurrying pH5, and treating the percolate with H 2 O 2 The adding amount ratio is 1000:1, solid-liquid separation is carried out by adopting a plate-and-frame filter press after pulp washing, the solid phase and phosphoric acid are calcined to generate calcium magnesium polyphosphate products, and the liquid phase enters a fluidized bed crystallization process.
Liquid phase and Ca (OH) after repulping and washing with flotation tailings 2 Lime milk with the concentration of 5.5% enters a percolate regulating tank, the pH value of a liquid phase is 6.1, the lime milk enters a crystallization fluidized bed from the bottom by a water inlet pump, loess serving as a crystallization accelerator enters the bottom of the crystallization fluidized bed, and the ratio of the water quantity entering the crystallization fluidized bed to the addition quantity of the crystallization accelerator is 1620:1. The water phase added with the crystallization accelerator is subjected to solid-liquid separation after passing through a granulating area and a separating area of a crystallization fluidized bed, the solid phase is granular crystals (magnesium hydrogen phosphate and calcium hydrogen phosphate) and is discharged from the bottom of the crystallization fluidized bed, the granular crystals enter a flotation tailing neutralization section of a calcium magnesium polyphosphate raw material after passing through a storage tank, and the liquid phase overflows from the top of the crystallization fluidized bed and goes through a transfer storage tank to a deep purification process.
The water phase from the crystallization process enters an adjusting tank to ensure the stability of the index of the water phase, and then is pumped into a magnetic coagulation complete set of equipment by a water inlet pump, wherein the complete set of equipment consists of an alum blossom reaction and magnetic powder coagulation assisting area, a sodium hydroxide pH adjusting area, a sedimentation solid-liquid separation area and a magnetic separator. Adding polymeric ferric sulfate and Fe into alum blossom reaction medicament: the molar ratio of (P+F) is controlled to be 6:1, the reaction time is 40min, the stirring speed is 26r/min, the ratio of the magnetic powder addition amount to the polymeric ferric sulfate addition amount is 1:5, the solid-liquid mixture after the reaction is regulated to pH7.0 by sodium hydroxide, and then the solid-liquid separation is realized by entering a sedimentation separation zone with inclined tube filler, wherein the inclined tube filler is 48 degrees in installation angle, the PP is adopted as the material, the ratio of the arrangement area to the sectional area of the sedimentation separation zone is 0.5:1, and the pipe diameter phi of the inclined tube filler is 60mm. The liquid phase overflow after deep purification treatment enters a finished product water tank area to be used as surface makeup water, the bottom thick slurry is pumped into a magnetic separator by a screw pump, recovered magnetic powder is added into a magnetic powder coagulation assisting area again, and a small amount of thick slurry is returned to a calcium magnesium polyphosphate raw material flotation tailing neutralization section. The water phase is subjected to deep purification treatment by magnetic coagulation complete equipment, and the relevant detection core indexes are as follows:
example 3:
the phosphogypsum slag warehouse leachate is taken, and the relevant detection indexes are as follows:
pumping the percolate of the phosphogypsum slag reservoir into a flotation tailing reslurry tank, adding the flotation tailings and hydrogen peroxide at the same time, controlling the liquid-solid ratio in the reslurry process to be 6:1, reslurrying for 4 hours at 80 ℃, and controlling the reslurry pH to be 5.3, wherein the treatment capacity of the percolate and H 2 O 2 The adding amount ratio is 1200:1, after the slurry is washed, solid-liquid separation is carried out by adopting a plate-and-frame filter press, the solid phase and phosphoric acid (w (P2O 5) are mixed and reacted for 1h according to the mass ratio of 1:3.5), the solid phase is obtained after solid-liquid separation, the calcination is carried out for 3h at 260 ℃, the calcium magnesium polyphosphate product with the polymerization rate of 81.3% is obtained, and the liquid phase enters a fluidized bed crystallization process.
Liquid phase and Ca (OH) after repulping and washing with flotation tailings 2 Lime milk with the concentration of 8% enters a percolate regulating tank, the pH value of a liquid phase is 6.3, the lime milk enters a crystallization fluidized bed from the bottom by a water inlet pump, the loess serving as a crystallization accelerator enters the bottom of the crystallization fluidized bed, and the ratio of the water quantity entering the crystallization fluidized bed to the addition quantity of the crystallization accelerator is 1700:1. The water phase added with the crystallization accelerator is subjected to solid-liquid separation after passing through a granulating area and a separating area of a crystallization fluidized bed, the solid phase is granular crystals (magnesium hydrogen phosphate and calcium hydrogen phosphate) and is discharged from the bottom of the crystallization fluidized bed, the granular crystals enter a flotation tailing neutralization section of a calcium magnesium polyphosphate raw material after passing through a storage tank, and the liquid phase overflows from the top of the crystallization fluidized bed and goes through a transfer storage tank to a deep purification process.
The water phase from the crystallization process enters an adjusting tank to ensure the stability of the index of the water phase, and then is pumped into a magnetic coagulation complete set of equipment by a water inlet pump, wherein the complete set of equipment consists of an alum blossom reaction and magnetic powder coagulation assisting area, a sodium hydroxide pH adjusting area, a sedimentation solid-liquid separation area and a magnetic separator. Adding polymeric ferric sulfate and Fe into alum blossom reaction medicament: the molar ratio of (P+F) is controlled to 7.3:1, the reaction time is 80min, the stirring speed is 40r/min, the ratio of the magnetic powder addition amount to the polymeric ferric sulfate addition amount is 1:7, the solid-liquid mixture after the reaction is regulated to pH7.2 by sodium hydroxide, and then the solid-liquid separation is realized by entering a sedimentation separation zone with inclined tube filler, wherein the inclined tube filler has an installation angle of 55 degrees, the PP is adopted as a material, the ratio of the arrangement area to the sectional area of the sedimentation separation zone is 0.6:1, and the pipe diameter phi of the inclined tube filler is 80mm. The liquid phase overflow after deep purification treatment enters a finished product water tank area to be used as surface makeup water, the bottom thick slurry is pumped into a magnetic separator by a screw pump, recovered magnetic powder is added into a magnetic powder coagulation assisting area again, and a small amount of thick slurry is returned to a calcium magnesium polyphosphate raw material flotation tailing neutralization section. The water phase is subjected to deep purification treatment by magnetic coagulation complete equipment, and the relevant detection core indexes are as follows:
comparative example:
the difference from example 3 is that the crystallization accelerator was not added to the crystallization fluidized bed, the solid-liquid separation by a plate-and-frame filter press was performed without using a magnetic separation device, and the magnetic powder was not added in the step C, and the solid phase separated by the plate-and-frame filter press in the step a was separated from phosphoric acid (w (P 2 O 5 ) 20-25%), mixing and reacting for 1h according to the mass ratio of 1:3.5, solid-liquid separating to obtain a solid phase, and calcining at 260 ℃ for 3h to obtain the calcium magnesium polyphosphate product with the polymerization rate of 76.7%.
Although the present invention has been described with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described, or equivalents may be substituted for elements thereof, and any modifications, equivalents, improvements and changes may be made without departing from the spirit and principles of the present invention.

Claims (5)

1. The phosphogypsum slag reservoir leachate deep purification treatment method is characterized in that phosphogypsum slag reservoir leachate deep purification treatment equipment is adopted to carry out deep purification treatment on phosphogypsum slag reservoir leachate, the phosphogypsum slag reservoir leachate deep purification treatment equipment comprises a reslurry tank, a solid-liquid separator, a crystallization fluidized bed and a magnetic coagulation device which are sequentially connected, the magnetic coagulation device comprises an alum reaction zone, an acid-base regulation zone and a sedimentation separation zone which are sequentially communicated, wherein the alum reaction zone is connected with a liquid phase outlet of the crystallization fluidized bed, a clarified water outlet is arranged on the sedimentation separation zone, a flocculation precipitation outlet is arranged at the bottom of the sedimentation separation zone, and the phosphogypsum slag reservoir leachate deep purification treatment comprises the following specific steps:
step A, placing phosphogypsum slag reservoir leachate, calcium magnesium polyphosphate raw material flotation tailings and hydrogen peroxide into a reslurry tank, and carrying out solid-liquid separation on the mixture after reslurry, wherein the mass ratio of liquid to solid is 2-6:1, the reslurry time is 0.5-4H, the reslurry temperature is 20-80 ℃, the slurry pH is 4-5.5, and the leachate and H are carried out 2 O 2 The volume ratio is 950-1200:1;
b, transferring the liquid phase obtained in the step A to a crystallization fluidized bed, adding a crystallization accelerator into the liquid phase, regulating the pH to 5.5-6.5 by lime milk, and transferring the liquid phase with the crystals removed to a magnetic coagulation device, wherein the crystallization accelerator is loess, ceramsite or diatomite, and the mass ratio of the liquid phase entering the crystallization fluidized bed to the crystallization accelerator is 1400-1700:1;
adding a deep purifying agent and magnetic powder into the magnetic coagulation equipment, adjusting the pH value to 6.5-9.0, and then entering a sedimentation separation zone with inclined tube filler to realize solid-liquid separation to obtain clarified water, wherein the deep purifying agent is polyaluminium chloride, polyaluminium sulfate or aluminum sulfate, and in the magnetic coagulation equipment, al: (P+F) molar ratio of 1-9:1 or Fe: the molar ratio of (P+F) is 4.5-7.5:1, the reaction time is 20-80 min, and the stirring speed is 25-40r/min.
2. The method for deeply purifying phosphogypsum slag warehouse leachate, which is characterized in that: the crystallization fluidized bed is sequentially provided with a clarification area, a separation area and a granulation area from top to bottom, a liquid phase outlet of the solid-liquid separator is connected to the bottom of the crystallization fluidized bed, a crystallization accelerator adding port is further arranged at the bottom of the granulation area, the granulation area is connected with a granular crystal storage tank, and the liquid phase outlet is arranged on the clarification area.
3. The method for deeply purifying phosphogypsum slag warehouse leachate, which is characterized in that: the sedimentation separation area is internally provided with inclined tube filler, the installation angle of the inclined tube filler is 45-55 degrees, the arrangement area of the inclined tube filler and the cross-sectional area ratio of the sedimentation separation area are 0.4-0.6:1, and the pipe diameter phi of the inclined tube filler is 50-80mm.
4. The method for deeply purifying phosphogypsum slag warehouse leachate, which is characterized in that: the mass ratio of the magnetic powder to the deep purifying agent is 1:4-1:7.
5. The method for deeply purifying phosphogypsum slag warehouse leachate, which is characterized in that: and (3) transferring the solid phase obtained in the step (B) and/or the step (C) to a reslurry tank to repeat the step (A).
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1118122A (en) * 1978-09-21 1982-02-09 Donald E. Weiss Water clarification
CN103303884A (en) * 2013-05-27 2013-09-18 瓮福(集团)有限责任公司 Method for treating phosphorus concentrates and recovering phosphorus by using phosphogypsum slag dump pool water
CN207130082U (en) * 2017-04-26 2018-03-23 广东卓信环境科技股份有限公司 Magneto separate integrated apparatus
CN209113637U (en) * 2018-10-30 2019-07-16 中国五环工程有限公司 Gypsum stack percolation liquid treating system
CN110627177A (en) * 2019-09-26 2019-12-31 北京朗新明环保科技有限公司 Fluorine removal method for fluorine-containing wastewater and fluidized bed crystallization separator for fluorine removal
CN113336356A (en) * 2021-05-08 2021-09-03 武汉工程大学 Phosphogypsum leachate recycling treatment and utilization method

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1118122A (en) * 1978-09-21 1982-02-09 Donald E. Weiss Water clarification
CN103303884A (en) * 2013-05-27 2013-09-18 瓮福(集团)有限责任公司 Method for treating phosphorus concentrates and recovering phosphorus by using phosphogypsum slag dump pool water
CN207130082U (en) * 2017-04-26 2018-03-23 广东卓信环境科技股份有限公司 Magneto separate integrated apparatus
CN209113637U (en) * 2018-10-30 2019-07-16 中国五环工程有限公司 Gypsum stack percolation liquid treating system
CN110627177A (en) * 2019-09-26 2019-12-31 北京朗新明环保科技有限公司 Fluorine removal method for fluorine-containing wastewater and fluidized bed crystallization separator for fluorine removal
CN113336356A (en) * 2021-05-08 2021-09-03 武汉工程大学 Phosphogypsum leachate recycling treatment and utilization method

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