CN112299630A - Device and method for recovering sodium chloride from wastewater generated in preparation of bonded permanent magnetic ferrite magnetic powder - Google Patents

Device and method for recovering sodium chloride from wastewater generated in preparation of bonded permanent magnetic ferrite magnetic powder Download PDF

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CN112299630A
CN112299630A CN201910898377.6A CN201910898377A CN112299630A CN 112299630 A CN112299630 A CN 112299630A CN 201910898377 A CN201910898377 A CN 201910898377A CN 112299630 A CN112299630 A CN 112299630A
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wastewater
outlet
salt
permanent magnetic
bonded permanent
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刘荣明
耿赵文
张鹏杰
胡国辉
周超
黄可淼
李志宏
贾立颖
王倩
李炳山
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Bgrimm Technology Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D3/00—Halides of sodium, potassium or alkali metals in general
    • C01D3/04—Chlorides
    • C01D3/06—Preparation by working up brines; seawater or spent lyes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D3/00—Halides of sodium, potassium or alkali metals in general
    • C01D3/14—Purification
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C02F1/048—Purification of waste water by evaporation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Heat Treatment Of Water, Waste Water Or Sewage (AREA)
  • Separation Of Suspended Particles By Flocculating Agents (AREA)

Abstract

The invention belongs to the technical field of wastewater treatment, and particularly relates to a device and a method for recovering sodium chloride from wastewater for preparing bonded permanent magnetic ferrite magnetic powder. The device and the method provided by the invention utilize the heat generated in the process of preparing the bonded permanent magnetic ferrite magnetic powder to crystallize and concentrate the wastewater, and can separate the salt in the wastewater to obtain the available sodium chloride, thereby improving the resource utilization rate.

Description

Device and method for recovering sodium chloride from wastewater generated in preparation of bonded permanent magnetic ferrite magnetic powder
Technical Field
The invention belongs to the technical field of wastewater treatment, and particularly relates to a device and a method for recovering sodium chloride from wastewater for preparing bonded permanent magnetic ferrite magnetic powder.
Background
The permanent ferrite pre-sintering material is iron oxide red (Fe)2O3) Steel rolling mill scale (Fe)3O4) With strontium carbonate (SrCO)3) Adding strontium chloride (SrCl) as main material2) Silicon oxide (SiO)2) Alumina (Al)2O3) The permanent magnetic material prepared by pre-burning the additives in a rotary kiln can be sintered and molded or bonded to prepare permanent magnetic ferrite device products.
The permanent magnetic ferrite material for bonding molding is ultrafine magnetic powder produced by taking a permanent magnetic ferrite pre-sintered material as a raw material through complex processes of fine grinding, acid washing, water washing, drying and the like, the magnetic powder has a high added value, but a large amount of wastewater with high salt content is generated in the production process. This is because there are three sources of chloride in the permanent magnetic ferrite material for binding molding: raw materials of iron oxide red and strontium chloride contain chlorine radicals, hydrochloric acid is used in the acid washing process to introduce the chlorine radicals, caustic soda flakes and quicklime are added in the subsequent water washing process to carry out acid-base neutralization, and sodium chloride or calcium chloride is generated after reaction, so that salt-containing wastewater with high sodium chloride concentration is formed. If these waste waters are directly evaporated and crystallized to produce miscellaneous salts, which are discharged as waste, they will bring a large burden to the environment, and the evaporation and crystallization efficiency is very low, and the recovery rate of miscellaneous salts is also very low.
Disclosure of Invention
The invention aims to provide a device and a method for recovering sodium chloride from wastewater generated in the preparation of bonded permanent magnetic ferrite magnetic powder.
In order to achieve the above purpose, the invention provides the following technical scheme:
the invention provides a device for recovering sodium chloride from wastewater for preparing bonded permanent magnetic ferrite magnetic powder, which is constructed by relying on a preparation device for bonded permanent magnetic ferrite magnetic powder; according to the wastewater flow direction, the device comprises a filtering-nanofiltration system 1, a concentration system 2 and an evaporative crystallization system 3 which are connected in sequence;
the filtering-nanofiltration system 1 comprises an I-th wastewater inlet 1-1, and the I-th wastewater inlet 1-1 is connected with a wastewater outlet of the bonded permanent magnetic ferrite magnetic powder preparation device;
the filtering-nanofiltration system 1 comprises a salt mud outlet 1-2, a clear water outlet 1-3 and a salt-containing wastewater outlet 1-4; the salt-containing wastewater outlet 1-4 is connected with the concentration system 2;
the concentration system 2 comprises a II-th wastewater inlet 2-1 and a heat source inlet 2-2 for concentration, and the II-th wastewater inlet 2-1 is connected with the salt-containing wastewater outlet 1-4; the heat source inlet 2-2 for concentration is connected with the I heat source outlet of the bonded permanent magnetic ferrite powder preparation device;
the concentration system 2 comprises a concentrated saline wastewater outlet 2-3 and a concentrated condensed water outlet 2-4, and the concentrated saline wastewater outlet 2-3 is connected with the evaporative crystallization system 3;
the evaporative crystallization system 3 comprises a III wastewater inlet 3-1 and a heat source inlet 3-2 for crystallization, and the III wastewater inlet 3-1 is connected with the concentrated salt-containing wastewater outlet 2-3; the heat source inlet 3-2 for crystallization is connected with a heat source outlet II of the bonded permanent magnetic ferrite powder preparation device;
the evaporative crystallization system 3 comprises a sodium chloride outlet 3-3 and a crystallization condensate outlet 3-4.
Preferably, the preparation device for the bonded permanent magnetic ferrite magnetic powder comprises a rotary kiln L1, a ball cooling cylinder L2, a ball milling system L3, an acid washing system L4, a water washing system L5, a powder drying system L6 and a powder packaging system L7 which are connected in sequence.
Preferably, the ball material cooling cylinder L2 is provided with a cooling pipeline for introducing cooling water; and the water outlet of the cooling pipeline is connected with a heat source inlet 3-2 for crystallization of the evaporative crystallization system 3 and is used for realizing waste heat utilization.
Preferably, the powder drying system L6 has a heat channel for introducing heat required for drying the powder; the outlet of the heat channel is connected with a heat source inlet 2-2 for concentration of the concentration system 2, and the heat channel is used for realizing waste heat utilization.
Preferably, the ith wastewater inlet 1-1 of the filtration-nanofiltration system 1 is connected with a water discharge port of a water washing system L5.
Preferably, the clear water outlet 1-3, the condensed water outlet 2-4 and the crystallized condensed water outlet 3-4 are respectively connected with an acid washing system L4 in the bonded permanent magnetic ferrite magnetic powder preparation device, so as to realize the recycling of water.
The invention also provides a method for recovering sodium chloride from the wastewater for preparing the bonded permanent magnetic ferrite magnetic powder, which takes the wastewater generated by preparing the bonded permanent magnetic ferrite magnetic powder as a salt source and comprises the following steps:
(1) filtering and nano-filtering the wastewater to obtain salt mud, clear water and salt-containing wastewater;
(2) evaporating and concentrating the salt-containing wastewater obtained in the step (1) to obtain concentrated salt-containing wastewater and concentrated condensate water;
(3) evaporating and crystallizing the concentrated salt-containing wastewater obtained in the step (3) to obtain recyclable sodium chloride and crystallization condensate water;
recycling the clean water obtained in the step (1), the concentrated condensate water obtained in the step (2) and the crystallized condensate water obtained in the step (3) to the preparation process of the bonded permanent magnetic ferrite magnetic powder;
the heat for evaporation and concentration in the step (2) and evaporation and crystallization in the step (3) comes from the residual heat in the preparation process of the bonded permanent magnetic ferrite magnetic powder.
Preferably, the filtration-nanofiltration treatment comprises filtration and nanofiltration which are sequentially carried out; the filtration may include microfiltration and/or activated carbon filtration.
Preferably, the pore of the microfiltration membrane can retain particles of 0.1-1 μm; the granularity of the active carbon for filtering the active carbon is 10 +/-5 mu m;
the aperture of the nanofiltration membrane for nanofiltration is 1-2 nm.
Preferably, the filtration-nanofiltration treatment is performed under pressure, and the applied pressure is 0.3 to 7 bar.
The device provided by the invention utilizes the heat generated in the process of preparing the bonded permanent magnetic ferrite magnetic powder to crystallize and concentrate the wastewater, and can separate the salt in the wastewater to obtain the available sodium chloride, thereby improving the resource utilization rate.
The device provided by the invention can also recycle the purified water generated in the wastewater treatment process, thereby improving the utilization rate of water resources.
Drawings
FIG. 1 is a schematic structural diagram of an apparatus for recovering sodium chloride from wastewater from the preparation of bonded permanent magnetic ferrite powder according to the present invention;
in the figure, 1 is a filtration-nanofiltration system, 2 is a concentration system, 3 is an evaporative crystallization system, 1-1 is a wastewater I inlet, 1-2 is a salty mud outlet, 1-3 is a clear water outlet, 1-4 is a salty wastewater outlet, 2-1 is a wastewater II inlet, 2-2 is a heat source inlet for concentration, 2-3 is a concentrated salty wastewater outlet, 2-4 is a concentrated condensed water outlet, 3-1 is a wastewater III inlet, 3-2 is a heat source inlet for crystallization, 3-3 is a sodium chloride outlet, 3-4 is a condensed water outlet for crystallization, L1 is a rotary kiln, L2 is a ball cooling cylinder, L3 is a ball milling system, L4 is an acid washing system, L5 is a water washing system, L6 is a powder drying system, and L7 is a powder packaging system.
Detailed Description
The invention provides a device for recovering sodium chloride from wastewater for preparing bonded permanent magnetic ferrite magnetic powder, which is constructed by relying on a preparation device for bonded permanent magnetic ferrite magnetic powder; according to the wastewater flow direction, the device comprises a filtering-nanofiltration system 1, a concentration system 2 and an evaporative crystallization system 3 which are connected in sequence;
the filtering-nanofiltration system 1 comprises an I-th wastewater inlet 1-1, and the I-th wastewater inlet 1-1 is connected with a wastewater outlet of the bonded permanent magnetic ferrite magnetic powder preparation device;
the filtering-nanofiltration system 1 comprises a salt mud outlet 1-2, a clear water outlet 1-3 and a salt-containing wastewater outlet 1-4; the salt-containing wastewater outlets 1 to 4 are connected with the concentration system 2;
the concentration system 2 comprises a II-th wastewater inlet 2-1 and a heat source inlet 2-2 for concentration, and the II-th wastewater inlet 2-1 is connected with the salt-containing wastewater outlet 1-4; the heat source inlet 2-2 for concentration is connected with the I heat source outlet of the bonded permanent magnetic ferrite powder preparation device;
the concentration system 2 comprises a concentrated saline wastewater outlet 2-3 and a concentrated condensed water outlet 2-4, and the concentrated saline wastewater outlet 2-3 is connected with the evaporative crystallization system 3;
the evaporative crystallization system 3 comprises a III wastewater inlet 3-1 and a heat source inlet 3-2 for crystallization, and the III wastewater inlet 3-1 is connected with the concentrated salt-containing wastewater outlet 2-3; the heat source inlet 3-2 for crystallization is connected with a heat source outlet II of the bonded permanent magnetic ferrite powder preparation device;
the evaporative crystallization system 3 comprises a sodium chloride outlet 3-3 and a crystallization condensate outlet 3-4.
The device for recovering the sodium chloride from the wastewater for preparing the bonded permanent magnetic ferrite magnetic powder is constructed by depending on the preparation device of the bonded permanent magnetic ferrite magnetic powder. In the invention, as shown in fig. 1, the preparation device of the bonded permanent magnetic ferrite magnetic powder comprises a rotary kiln L1, a pellet cooling cylinder L2, a ball milling system L3, an acid washing system L4, a water washing system L5, a powder drying system L6 and a powder packaging system L7 which are connected in sequence.
In the invention, the rotary kiln L1 is used for pre-burning materials including iron oxide red/steel rolling iron scale, strontium carbonate, strontium chloride, silicon oxide, aluminum oxide and the like to obtain a permanent magnetic ferrite pre-burning material;
the material ball cooling cylinder L2 is preferably provided with a cooling pipeline for introducing cooling water to cool the pre-sintering material treated by the rotary kiln; in the cooling process, the cooling water absorbs the heat on the surface of the material ball cooling cylinder, the temperature is increased, and the material ball cooling cylinder can be used as a heat source of an evaporative crystallization system. In the invention, the water outlet of the cooling pipeline is a heat source outlet II which is connected with the evaporative crystallization system 3 to realize the cyclic utilization of the heat source;
the ball milling system L3 is used for refining the pre-sintering material to obtain superfine magnetic powder;
the acid washing system L4 is used for adding hydrochloric acid into the superfine magnetic powder obtained after ball milling to remove substances such as residual iron red, strontium carbonate and the like in the superfine magnetic powder;
the water washing system L5 is used for adding alkaline materials into the acidified materials to remove residual hydrochloric acid, so that the pH of the feed liquid is adjusted to about 7; the alkaline material comprises flake caustic soda and/or quicklime; in the water washing system, a large amount of waste water containing chlorine salts, preferably including ferrous chloride, sodium chloride, calcium chloride, strontium chloride, and the like, is generated. The invention preferably arranges a wastewater discharge port on the water washing system, and the wastewater discharge port is connected with the I-th wastewater inlet 1-1 of the filtering-nanofiltration system 1;
the material powder drying system L6 is preferably provided with a heat supply pipeline for introducing a heat supply medium required by the dried material powder to remove moisture in the washed superfine magnetic powder; the heat transfer between the heat supply medium and the superfine magnetic powder occurs during the drying process, the temperature of the heat supply medium is reduced to a certain extent, but the temperature is still kept at a higher temperature, and the heat supply medium can be used as a heat source for concentration. In the invention, the outlet of the heat supply pipeline (i.e. the I-th heat source outlet) in the powder drying system is preferably connected with the concentration system 2 so as to realize the utilization of waste heat;
the powder packaging system is used for packaging the superfine magnetic powder.
In the invention, a ball cooling cylinder L2, an acid washing system L4, a water washing system L5 and a powder drying system L6 in the preparation device for the bonded permanent magnetic ferrite magnetic powder are the construction basis of the device for recovering sodium chloride from the wastewater for preparing the bonded permanent magnetic ferrite magnetic powder. The structure of the apparatus of the present invention will be described below in terms of the direction of wastewater flow:
as shown in fig. 1, the apparatus for recovering sodium chloride from wastewater generated in the preparation of bonded permanent magnetic ferrite magnetic powder according to the present invention comprises a filtration-nanofiltration system 1, a concentration system 2, and an evaporative crystallization system 3, which are connected in sequence.
In the present invention, the filtration-nanofiltration system 1 preferably comprises a filtration unit and a nanofiltration unit connected in sequence, wherein the filtration unit preferably employs a microfiltration membrane and/or an activated carbon filtration layer for filtration; the pores of the microfiltration membrane are preferably capable of intercepting particles with the particle size of 0.1-1 mu m; the particle size of the activated carbon in the activated carbon filter layer is preferably 10 +/-5 microns. According to the invention, large-particle impurities in the wastewater are preferably removed through a filtering device to form salt mud; the filtered liquid material enters a subsequent nanofiltration component; the nanofiltration component is preferably provided with a nanofiltration membrane, and the aperture of the nanofiltration membrane is preferably 1-2 nm, and more preferably 2 nm. According to the invention, the filtered liquid is preferably separated by nanofiltration to obtain clear water and salt-containing wastewater, wherein the salt-containing wastewater refers to wastewater containing salts of monovalent ions, namely wastewater containing sodium chloride.
In the invention, the filtering-nanofiltration system 1 comprises an I-th wastewater inlet 1-1, wherein the I-th wastewater inlet 1-1 is connected with a wastewater outlet of a bonded permanent magnetic ferrite magnetic powder preparation device, in particular to a water outlet of a water washing system L5, and is used for guiding wastewater into a recovery device; the filtering-nanofiltration system 1 comprises a salt mud outlet 1-2, a clear water outlet 1-3 and a salt-containing wastewater outlet 1-4; the salt-containing wastewater outlet 1-4 is connected with the concentration system 2 and is used for conveying salt-containing wastewater obtained after nanofiltration; the salt mud outlet 1-2 is preferably connected with a salt mud receiving device and used for collecting and separating the obtained salt mud; the clear water outlet 1-3 is preferably connected with an acid washing system L4, so that the recycling of clear water obtained after nanofiltration is realized.
In the invention, the concentration system 2 comprises a II-th wastewater inlet 2-1 and a concentration heat source inlet 2-2, wherein the II-th wastewater inlet 2-1 is connected with the salt-containing wastewater outlet 1-4; the heat source inlet 2-2 for concentration is connected with the I-th heat source outlet of the bonded permanent magnetic ferrite powder preparation device, residual heat in the process of preparing the bonded permanent magnetic ferrite powder is transferred to evaporation concentration, part of water in the salt-containing wastewater is heated and evaporated, and water condensed by evaporated escaping water vapor is concentrated condensate water which can be reused; and the residual materials after concentration are concentrated salt-containing wastewater, and the concentration of the concentrated salt-containing wastewater is increased to be high salt-containing wastewater.
In the invention, the heat source inlet 2-2 for concentration is connected with the I-th heat source outlet of the material powder drying system L6 and is used for recycling residual heat in the preparation process of the bonded permanent magnetic ferrite magnetic powder.
In the invention, the concentration system 2 comprises a concentrated salt-containing wastewater outlet 2-3 and a concentrated condensed water outlet 2-4, and the concentrated salt-containing wastewater outlet 2-3 is connected with the evaporative crystallization system 3, so that the concentrated salt-containing wastewater enters the next evaporative crystallization step to obtain sodium chloride. In the invention, the concentrated condensed water outlet 2-4 is preferably connected with an acid washing system L4, and is used for recycling the concentrated and recovered waste water for the acid washing step, so that the water can be recycled.
In the invention, the evaporative crystallization system 3 comprises a III wastewater inlet 3-1 and a heat source inlet 3-2 for crystallization, wherein the III wastewater inlet 3-1 is connected with the concentrated saline wastewater outlet 2-3 and is used for conveying the concentrated saline wastewater into the evaporative crystallization system 3; and the heat source inlet 3-2 for crystallization is connected with a heat source outlet II of the bonded permanent magnetic ferrite powder preparation device and is used for guiding high-temperature cooling water obtained after the pre-sintered material is cooled into an evaporative crystallization system so as to realize waste heat utilization.
In the invention, the evaporative crystallization system 3 comprises a sodium chloride outlet 3-3 and a crystallization condensed water outlet 3-4; the sodium chloride outlet 3-3 is used for discharging sodium chloride precipitated by evaporation and crystallization, and the sodium chloride can be recycled; the crystallization condensed water outlet 3-4 is used for discharging condensed water after evaporation and crystallization, and the crystallization condensed water outlet 3-4 is preferably connected with an acid washing system L4 so that the crystallization condensed water can be recycled.
In the invention, a crystallizer is preferably arranged in the evaporative crystallization system, and the structure of the crystallizer preferably comprises an external supply steam type or a mechanical steam compression type; in one embodiment of the invention, the crystallizer is preferably a forced circulation crystallizer or a DTB crystallizer (draft tube plus baffle evaporative crystallizer).
In the present invention, the filtration-nanofiltration system 1, the concentration system 2 and the evaporative crystallization system 3 are preferably connected by pipes, and pressure pumps are preferably provided so that wastewater can circulate between the respective systems. The invention has no special requirements on the setting position and the setting mode of the pressure pump, and the waste water and different materials generated in each step can normally circulate by adopting a mode well known by the technical personnel in the field.
In the invention, the connecting pipelines among the filtering-nanofiltration system 1, the concentration system 2, the evaporative crystallization system 3 and the preparation device of the bonded permanent magnetic ferrite powder are preferably provided with valves for realizing the flowing and collection of all materials in the wastewater treatment process. The invention has no special requirements on the setting position and the setting number of the valves, and the method is well known by the technical personnel in the field.
The invention provides a method for recovering sodium chloride from wastewater generated in the preparation of bonded permanent magnetic ferrite magnetic powder, which treats the wastewater by taking the wastewater generated in the preparation of the bonded permanent magnetic ferrite magnetic powder as a salt source, and the treatment comprises the following steps:
(1) filtering and nano-filtering the wastewater to obtain salt mud, clear water and salt-containing wastewater;
(2) evaporating and concentrating the salt-containing wastewater obtained in the step (1) to obtain concentrated salt-containing wastewater and concentrated condensate water;
(3) evaporating and crystallizing the concentrated salt-containing wastewater obtained in the step (3) to obtain recyclable sodium chloride and crystallization condensate water;
recycling the clean water obtained in the step (1), the concentrated condensate water obtained in the step (2) and the crystallized condensate water obtained in the step (3) to the preparation process of the bonded permanent magnetic ferrite magnetic powder;
the heat for evaporation and concentration in the step (2) and evaporation and crystallization in the step (3) comes from the residual heat in the preparation process of the bonded permanent magnetic ferrite magnetic powder.
The invention carries out filtration-nanofiltration treatment on the wastewater to obtain salt mud, clear water and salt-containing wastewater. In the invention, the wastewater is generated by preparing bonded permanent magnetic ferrite magnetic powder, and the chemical components contained in the wastewater preferably comprise ferrous chloride, sodium chloride, calcium chloride and strontium chloride. The invention has no special requirement on the chemical content of each component in the wastewater, and the chemical content can be any concentration.
In the present invention, the filtration-nanofiltration treatment includes filtration and nanofiltration performed in this order; the filtration preferably comprises microfiltration and/or active carbon filtration, and the pores of the microfiltration membrane for microfiltration preferably can retain 0.1-1 μm of particles, and more preferably 0.2-0.8 μm, so as to remove large particle impurities; the granularity of the active carbon for filtering the active carbon is 10 +/-5 mu m so as to fully absorb particle impurities in the wastewater.
In the invention, the aperture of the nanofiltration membrane is preferably 1-2 nm. In the specific implementation of the invention, the nanofiltration membrane is preferably a Delauer RS series RS8-C, a Tim Amestec commercial HSX-NF6 or HSX-NF7XX nanofiltration unit from Tim Amestec, Inc., of Tim separation technologies, or a Coriolis, Inc., USA
Figure BDA0002211011800000081
-S series
Figure BDA0002211011800000082
-SR100 series nanofiltration membranes.
In the present invention, the filtration-nanofiltration treatment is preferably performed under pressure, and the applied pressure is preferably 0.3 to 7bar, and more preferably 1 to 5 bar.
In the invention, after the wastewater is subjected to filtration-nanofiltration treatment, salt mud, clear water and salt-containing wastewater are separated; the salt mud is directly discharged; the clean water is preferably used for the pickling step in the process of preparing the bonded permanent magnetic ferrite magnetic powder.
After the salt-containing wastewater is obtained, the salt-containing wastewater is evaporated and concentrated to obtain concentrated salt-containing wastewater and concentrated condensate water. In the invention, the heat for evaporation concentration comes from the residual heat in the preparation process of the bonded permanent magnetic ferrite powder, in particular from the residual heat after the powder is dried in the preparation process of the bonded permanent magnetic ferrite powder. According to the invention, through evaporation concentration, part of water in the salt-containing wastewater is evaporated and removed, and the evaporated water vapor is condensed to obtain concentrated condensate water, wherein the concentrated condensate water is preferably used for an acid washing step in the process of preparing the bonded permanent magnetic ferrite magnetic powder; and the residual material after evaporation is concentrated salt-containing wastewater.
After the concentrated salt-containing wastewater is obtained, the concentrated salt-containing wastewater is subjected to evaporative crystallization to obtain recyclable sodium chloride and crystallization condensate water. In the invention, the heat for evaporative crystallization comes from the waste heat in the preparation process of the bonded permanent magnetic ferrite powder, in particular from the heat of the pre-sintered material absorbed by the ball material cooling cylinder used in the preparation process of the bonded permanent magnetic ferrite powder (the surface temperature of the ball material cooling cylinder reaches 900 ℃).
In the invention, after the concentrated salt-containing wastewater is heated, sodium chloride solid is separated out, and the sodium chloride can be recycled. In the invention, the concentrated salt-containing wastewater is heated to obtain water vapor, the evaporated water vapor is condensed to obtain crystallized condensate water, and the crystallized condensate water is preferably used for the acid washing step in the process of preparing the bonded permanent magnetic ferrite magnetic powder.
Although the present invention has been described in detail with reference to the above embodiments, it is only a part of the embodiments of the present invention, not all of the embodiments, and one can also obtain other embodiments without inventive step according to the embodiments, and these embodiments are all included in the scope of the present invention.

Claims (10)

1. A device for recovering sodium chloride from wastewater of preparing bonded permanent magnetic ferrite magnetic powder is characterized in that the device is constructed by depending on a preparation device of the bonded permanent magnetic ferrite magnetic powder; according to the wastewater flow direction, the device comprises a filtering-nanofiltration system (1), a concentration system (2) and an evaporative crystallization system (3) which are connected in sequence;
the filtering-nanofiltration system (1) comprises an I-th wastewater inlet (1-1), and the I-th wastewater inlet (1-1) is connected with a wastewater outlet of the bonded permanent magnetic ferrite magnetic powder preparation device;
the filtering-nanofiltration system (1) comprises a salt mud outlet (1-2), a clear water outlet (1-3) and a salt-containing wastewater outlet (1-4); the salt-containing wastewater outlet (1-4) is connected with the concentration system (2);
the concentration system (2) comprises a II-th wastewater inlet (2-1) and a heat source inlet (2-2) for concentration, and the II-th wastewater inlet (2-1) is connected with the salt-containing wastewater outlet (1-4); the heat source inlet (2-2) for concentration is connected with an I heat source outlet of the bonded permanent magnetic ferrite magnetic powder preparation device;
the concentration system (2) comprises a concentrated saline wastewater outlet (2-3) and a concentrated condensed water outlet (2-4), and the concentrated saline wastewater outlet (2-3) is connected with the evaporative crystallization system (3);
the evaporative crystallization system (3) comprises a III wastewater inlet (3-1) and a heat source inlet (3-2) for crystallization, wherein the III wastewater inlet (3-1) is connected with the concentrated salt-containing wastewater outlet (2-3); the heat source inlet (3-2) for crystallization is connected with a heat source outlet II of the bonded permanent magnetic ferrite magnetic powder preparation device;
the evaporative crystallization system (3) comprises a sodium chloride outlet (3-3) and a crystallization condensed water outlet (3-4).
2. The apparatus according to claim 1, wherein the apparatus for preparing bonded permanent magnetic ferrite powder comprises a rotary kiln (L1), a pellet cooling cylinder (L2), a ball milling system (L3), an acid pickling system (L4), a water washing system (L5), a powder drying system (L6) and a powder packaging system (L7) which are connected in sequence.
3. The apparatus according to claim 2, wherein said pellet cooling cylinder (L2) has a cooling pipe for introducing cooling water; and a water outlet of the cooling pipeline is connected with a heat source inlet (3-2) for crystallization of the evaporative crystallization system (3) and is used for realizing waste heat utilization.
4. The apparatus according to claim 2 or 3, characterized in that the powder drying system (L6) has a heat channel for introducing the heat required for drying the powder; the outlet of the heat channel is connected with a heat source inlet (2-2) for concentration of the concentration system (2) and used for realizing waste heat utilization.
5. The apparatus according to claim 2, wherein the I-th wastewater inlet (1-1) of the filtration-nanofiltration system (1) is connected to a drain of a water washing system (L5).
6. The apparatus according to claim 2 or 5, wherein the clear water outlet (1-3), the condensed water outlet (2-4) and the crystallized condensed water outlet (3-4) are respectively connected with an acid washing system (L4) in the bonded permanent magnetic ferrite magnetic powder preparation apparatus for realizing water recycling.
7. A method for recovering sodium chloride from wastewater generated in the preparation of bonded permanent magnetic ferrite magnetic powder takes the wastewater generated in the preparation of the bonded permanent magnetic ferrite magnetic powder as a salt source, and the treatment of the wastewater comprises the following steps:
(1) filtering and nano-filtering the wastewater to obtain salt mud, clear water and salt-containing wastewater;
(2) evaporating and concentrating the salt-containing wastewater obtained in the step (1) to obtain concentrated salt-containing wastewater and concentrated condensate water;
(3) evaporating and crystallizing the concentrated salt-containing wastewater obtained in the step (3) to obtain recyclable sodium chloride and crystallization condensate water;
recycling the clean water obtained in the step (1), the concentrated condensate water obtained in the step (2) and the crystallized condensate water obtained in the step (3) to the preparation process of the bonded permanent magnetic ferrite magnetic powder;
the heat for evaporation and concentration in the step (2) and evaporation and crystallization in the step (3) comes from the residual heat in the preparation process of the bonded permanent magnetic ferrite magnetic powder.
8. The method of claim 7, wherein the filtration-nanofiltration treatment comprises filtration and nanofiltration performed in sequence; the filtration may include microfiltration and/or activated carbon filtration.
9. The method of claim 8, wherein the microfiltration membrane has pores capable of retaining 0.1 to 1 μm particles; the granularity of the active carbon for filtering the active carbon is 10 +/-5 mu m;
the aperture of the nanofiltration membrane for nanofiltration is 1-2 nm.
10. The method of claim 7, wherein the filtering-nanofiltration treatment is performed under pressure, and the applied pressure is 0.3 to 7 bar.
CN201910898377.6A 2019-09-23 2019-09-23 Device and method for recovering sodium chloride from wastewater generated in preparation of bonded permanent magnetic ferrite magnetic powder Pending CN112299630A (en)

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