CN111392746A - Resourceful treatment system and method for mixed salt solution - Google Patents

Resourceful treatment system and method for mixed salt solution Download PDF

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Publication number
CN111392746A
CN111392746A CN202010234955.9A CN202010234955A CN111392746A CN 111392746 A CN111392746 A CN 111392746A CN 202010234955 A CN202010234955 A CN 202010234955A CN 111392746 A CN111392746 A CN 111392746A
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reaction
ammonia
sodium chloride
solution
unit
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CN111392746B (en
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王云山
杨刚
安学斌
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Institute of Process Engineering of CAS
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Institute of Process Engineering of CAS
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/46—Sulfates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
    • C01C1/00—Ammonia; Compounds thereof
    • C01C1/16—Halides of ammonium
    • C01C1/164—Ammonium chloride
    • 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
    • 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
    • C01D7/00—Carbonates of sodium, potassium or alkali metals in general
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D7/00—Carbonates of sodium, potassium or alkali metals in general
    • C01D7/12—Preparation of carbonates from bicarbonates or bicarbonate-containing product

Abstract

The invention provides a resource treatment system and a resource treatment method of a mixed salt solution, wherein the resource treatment system comprises a gypsum synthesis unit, an evaporation unit and a reaction unit which are sequentially connected along a material flow direction, the resource treatment system also comprises a calcination unit, an ammonia distillation unit and a salting-out unit which are respectively connected with an outlet of the reaction unit, the outlet of the calcination unit and the outlet of the ammonia distillation unit are combined into one path and then connected into the reaction unit, the ammonia distillation unit is also connected with the gypsum synthesis unit, and the salting-out unit is circularly connected with the evaporation unit.

Description

Resourceful treatment system and method for mixed salt solution
Technical Field
The invention belongs to the technical field of mixed salt solution treatment, relates to a treatment system and a treatment method for mixed salt solution, and particularly relates to a resource treatment system and a resource treatment method for mixed salt solution.
Background
High salt wastewater refers to wastewater containing organic matter and at least 3.5% by weight of total dissolved solids. Such waste waters often contain Cl in addition to a large amount of organic contaminants－、SO4 2－、Na+、Ca2 +And the like soluble inorganic salt ions. Firstly, the high-salinity wastewater generated in the process of directly utilizing seawater is mainly generated in coastal cities as production water or cooling water in industries such as electric power, chemical engineering, machinery and the like; secondly, the high-salinity wastewater generated in the chemical production process mainly comprises the processes of pharmacy, dye, paper making, refining, food processing, coal chemical industry and the like; and thirdly, high-salinity wastewater generated by groundwater abnormity and permeation of salt-containing seawater in certain special areas. The high-salt wastewater is widely generated and has larger and larger quantity, if the high-salt wastewater is directly discharged without being treated, the salinization of the water quality of rivers is intensified, the available quantity of surface groundwater such as domestic water, domestic fresh water and the like is greatly reduced, and very serious pollution to soil and water quality is necessarily brought. The high-salinity wastewater zero-discharge crystallization salt recycling method generally comprises the processes of pretreatment, nanofiltration salt separation, membrane concentration, evaporative crystallization and the like. Removing impurities such as organic matters by flocculation sedimentation, chemical precipitation, oxidation and the like, then performing nanofiltration to separate salt, performing membrane concentration after salt separation, recycling the obtained water, and performing evaporation concentration on the concentrated solution to respectively obtain sodium chloride, sodium sulfate and the like. However, with the requirement of zero discharge of wastewater in various industries, a large amount of sodium chloride and sodium sulfate which cannot be utilized are inevitably generated, and most of the sodium chloride and the sodium sulfate can only be stockpiled. The largest outlet of sodium chloride is the chlor-alkali and soda ash industries, wherein the chlor-alkali industry uses ionic membrane electrolysis, the requirement on sodium chloride is extremely high, the waste salt generated by waste water evaporation is difficult to use as a raw material, and the soda ash industry has large scale and is arranged coastal or needs to be arrangedThe method needs large synthetic ammonia and is limited in use. Sodium sulfate has certain application in the fields of dye, medicine and the like, but millions of tons of sodium sulfate are produced every year, and the support of a large industry is urgently needed.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a recycling treatment system and a recycling treatment method for a mixed salt solution, and provides a sodium chloride and sodium sulfate mixed salt solution system and a method by organically coupling the technologies of synthesizing α -semi-hydrated high-strength gypsum from sodium sulfate and calcium chloride in a normal-pressure sodium chloride solution, preparing sodium carbonate by reacting sodium chloride and ammonium bicarbonate, preparing ammonium chloride by freezing and salting out in a combined alkali method and the like.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides a resource treatment system for a mixed salt solution, which comprises a gypsum synthesis unit, an evaporation unit and a reaction unit which are sequentially connected along a material flow direction.
The resource treatment system also comprises a calcining unit, an ammonia distilling unit and a salting-out unit which are respectively connected with the outlet of the reaction unit, wherein the outlet of the calcining unit and the outlet of the ammonia distilling unit are merged into one path and then are connected into the reaction unit, the ammonia distilling unit is also connected with a gypsum synthesis unit, and the salting-out unit is circularly connected with the evaporation unit.
The invention provides a recycling system and a recycling method for a mixed salt solution of sodium chloride and sodium sulfate by organically coupling technologies of synthesizing α -semi-hydrated high-strength gypsum from sodium sulfate and calcium chloride in a normal-pressure sodium chloride solution, preparing soda ash by reacting sodium chloride and ammonium bicarbonate, preparing ammonium chloride by freezing and salting out in a combined alkali method and the like aiming at the characteristics of the mixed salt solution of sodium chloride and sodium sulfate.
As a preferred technical scheme of the invention, the gypsum synthesis unit comprises a gypsum synthesis device and a gypsum filtering device which are sequentially connected, the mixed salt solution and calcium chloride are introduced into the gypsum synthesis device to react to generate calcium sulfate, and the reaction solution is filtered to remove gypsum in the reaction solution through the gypsum filtering device.
In the invention, the gypsum filtering device can be selected as a plate-and-frame filter press or a vacuum filter.
Preferably, a gypsum slurry pump is arranged on a connecting pipeline between the gypsum synthesis device and the gypsum filtering device.
Preferably, the mixed salt solution comprises sodium chloride and sodium sulfate.
Preferably, the gypsum synthesis device comprises a reaction shell and a steam jacket sleeved outside the reaction shell.
Preferably, the steam jacket is externally connected with a steam source, and the steam source introduces steam into the steam jacket to indirectly heat the reaction raw materials in the reaction shell.
Preferably, a stirring device is arranged in the gypsum synthesis device.
Preferably, the evaporation unit includes MVR evaporation plant, MVR evaporation plant's inlet is connected gypsum filter equipment's liquid outlet, and gypsum filter equipment exhaust reaction liquid gets into MVR evaporation plant, evaporates and separates out the sodium chloride crystal wherein.
Preferably, the reaction unit comprises a reaction device and a separation device which are connected in sequence, a liquid inlet of the reaction device is connected with a liquid outlet of the MVR evaporation device, reaction liquid discharged by the MVR evaporation device enters the reaction device, and the reaction liquid reacts with ammonium bicarbonate introduced from the outside in the reaction device to generate sodium bicarbonate and ammonium chloride.
Preferably, the outlet of the separation device is divided into a liquid outlet and a discharge outlet, the reaction liquid discharged from the reaction device enters the separation device to separate sodium bicarbonate, the separated sodium bicarbonate is discharged from the discharge outlet of the separation device, and the rest of the reaction liquid is discharged from the liquid outlet of the separation device.
In a preferred embodiment of the present invention, the calcination unit includes a calcination device.
Preferably, a feed inlet of the calcining device is in butt joint with a discharge outlet of the separating device, sodium bicarbonate separated by the separating device is discharged from the discharge outlet of the separating device and enters the calcining device, calcined at high temperature is carried out to generate soda and carbon dioxide, and the soda is discharged outside.
Preferably, the separation device is a centrifuge.
Preferably, the ammonia distillation unit comprises an ammonia distillation device, an ammonia concentration device and a silica residue filtering device, wherein an air outlet of the ammonia distillation device is connected with an air inlet of the ammonia concentration device, and a liquid outlet of the ammonia distillation device is connected with a liquid inlet of the silica residue filtering device.
Preferably, a first discharge pump is arranged on a connecting pipeline of the ammonia still device and the silicon slag filtering device.
Preferably, an ammonia condensing device is arranged at the top of the ammonia concentrating device, and the ammonia condensing device is circularly connected with the ammonia concentrating device.
Preferably, the liquid outlet of the ammonia concentration device is connected with the liquid inlet of the recovery device, the gas outlet of the calcining device is connected with the gas inlet of the recovery device, the liquid outlet of the recovery device is connected with the liquid inlet of the reaction device, ammonia water discharged from the top of the ammonia concentration device reacts with carbon dioxide discharged from the calcining device in the recovery device to generate ammonium bicarbonate, and the generated ammonium bicarbonate is introduced into the reaction device to participate in the reaction.
Preferably, a second discharge pump is arranged on a connecting pipeline of the recovery device and the reaction device.
Preferably, a liquid outlet of the silica slag filtering device is connected with a liquid inlet of the gypsum synthesis device.
Preferably, the salting-out unit comprises a freezing device and a salting-out device which are sequentially connected along the material flow direction, a feed inlet of the salting-out device is connected with a discharge outlet of the MVR evaporation device, a liquid outlet of the salting-out device is connected with a liquid inlet of the MVR evaporation device, sodium chloride crystals evaporated and precipitated by the MVR evaporation device enter the salting-out device to participate in salting-out of the ammonium chloride solution, the ammonium chloride crystals are separated out through crystallization and obtain the sodium chloride solution, and the sodium chloride solution flows back to the MVR evaporation device to be evaporated and crystallized.
Preferably, the discharge port of the salting-out device is connected with a drying device, and ammonium chloride crystals discharged by the salting-out device enter the drying device.
Preferably, the discharge hole of the MVR evaporation device is connected to the feed inlet of the salting-out device through a lifting device.
Preferably, the liquid outlet of the separation device is divided into two paths, one path is connected with the ammonia distillation device, the other path is sequentially connected with the freezing device and the salting-out device along the material flow direction, the reaction liquid discharged by the separation device is divided into two parts, one part enters the ammonia distillation device to be mixed with the lime milk for ammonia distillation, and the other part is introduced into the salting-out device after being frozen by the freezing device to be mixed with the sodium chloride crystal discharged by the MVR evaporation device for salting out, so that ammonium chloride crystal and sodium chloride solution are obtained.
As a preferable technical scheme of the invention, the resourceful treatment system further comprises a lime milk supply unit, and an outlet of the lime milk supply unit is connected with an inlet of the ammonia distillation unit.
Preferably, the lime milk supply unit comprises a quick lime bin, a weighing device, a conveying device and a pulping device which are sequentially connected, wherein the pulping device is connected with an ammonia distillation device, and lime milk prepared in the pulping device is conveyed into the ammonia distillation device to be mixed with an ammonium chloride solution for ammonia distillation.
In a second aspect, the present invention provides a method for recycling a mixed salt solution, in which the recycling system of the first aspect is adopted to perform recycling treatment on the mixed salt solution, and the recycling treatment method specifically includes the following steps:
(1) the mixed salt solution reacts with a calcium chloride solution in a gypsum synthesis unit to generate gypsum and a sodium chloride solution, and the sodium chloride solution enters an evaporation unit to separate out partial sodium chloride crystals;
(2) the sodium chloride solution separated out of the sodium chloride crystals enters a reaction unit to react with the ammonium bicarbonate solution to generate sodium bicarbonate and ammonium chloride solution, and the sodium bicarbonate enters a calcining unit to be calcined to obtain sodium carbonate and carbon dioxide;
(3) the ammonium chloride solution is divided into two parts, one part enters a salting-out unit, and is mixed with sodium chloride crystals discharged from the evaporation unit in the step (1) for salting out, ammonium chloride crystals are separated out and sodium chloride solution is obtained, and the sodium chloride solution flows back to the evaporation unit; the other part of the calcium carbonate enters an ammonia distillation unit, is mixed with lime milk to distill ammonia to obtain calcium chloride and ammonia water, the ammonia water is combined with carbon dioxide discharged from a calcining unit to generate ammonium bicarbonate, the ammonium bicarbonate flows back to a reaction unit, and the calcium chloride flows back to a gypsum synthesis unit to supplement reaction raw materials.
As a preferred technical solution of the present invention, the recycling treatment method specifically includes the steps of:
the method comprises the following steps of (I) reacting a mixed salt solution with a calcium chloride solution in a gypsum synthesis device to generate calcium sulfate and sodium chloride, filtering the calcium sulfate by a gypsum filtering device to obtain gypsum, and allowing the sodium chloride solution to enter an MVR evaporation device for evaporation and concentration to separate out partial sodium chloride crystals;
(II) allowing the sodium chloride solution with the sodium chloride crystals separated out to enter a reaction device to react with an ammonium bicarbonate solution to generate a sodium bicarbonate solution and an ammonium chloride solution, allowing the reaction solution to enter a separation device to separate sodium bicarbonate out, and introducing the sodium bicarbonate into a calcination device to perform steam calcination to obtain sodium carbonate and carbon dioxide;
(III) separating the reaction liquid of the sodium bicarbonate separated in the step (II) into two parts, putting one part into a salting-out device, adding the sodium chloride crystals separated out in the step (I) into the salting-out device, crystallizing and separating out ammonium chloride crystals and obtaining a sodium chloride solution, drying the ammonium chloride crystals to obtain an ammonium chloride product, and refluxing the sodium chloride solution to an MVR evaporation device;
(IV) the other part of the reaction liquid in the step (III) enters an ammonia distillation device to carry out ammonia distillation reaction with lime milk to obtain ammonia-containing steam and a calcium chloride solution; wherein, ammonia-containing steam enters an ammonia concentration device to prepare ammonia water, and the ammonia water and carbon dioxide obtained by calcining the steam in the step (II) are subjected to gas-liquid contact reaction in a recovery device to generate ammonium bicarbonate solution required by the step (II); and (3) filtering the calcium chloride solution, and then refluxing to a gypsum synthesis device to be used as a reaction raw material in the step (I).
In a preferred embodiment of the present invention, in step (i), the mixed salt solution comprises sodium chloride and sodium sulfate.
Preferably, the total content of sodium chloride and sodium sulfate in the mixed salt solution is 240 g/L, such as 120 g/L, 130 g/L0, 140 g/L1, 150 g/L2, 160 g/L3, 170 g/L4, 180 g/L, 190 g/L, 200 g/L, 210 g/L, 220 g/L, 230 g/L or 240 g/L, but not limited to the enumerated values, and other non-enumerated values in the range of values are also applicable, and further preferably, the total content of sodium chloride and sodium sulfate in the mixed salt solution is 160-200 g/L.
Preferably, the temperature of the mixed salt solution entering the gypsum synthesizer is 30 to 60 ℃, for example, 30 ℃, 32 ℃, 34 ℃, 36 ℃, 38 ℃, 40 ℃, 42 ℃, 44 ℃, 46 ℃, 48 ℃, 50 ℃, 52 ℃, 54 ℃, 56 ℃, 58 ℃ or 60 ℃, but not limited to the listed values, and other values not listed in the numerical range are also applicable, and more preferably, the temperature of the mixed salt solution entering the gypsum synthesizer is 40 to 50 ℃.
Preferably, a crystal transformation agent is added in the reaction process of the mixed salt solution and the calcium chloride.
Preferably, the crystal transformation agent comprises any one or a combination of at least two of citric acid, citrate or aluminate.
Preferably, the added mass of the crystal transformation agent is 0.1-0.25 wt% of the total mass of the reaction raw materials, for example, 0.1 wt%, 0.11 wt%, 0.12 wt%, 0.13 wt%, 0.14 wt%, 0.15 wt%, 0.16 wt%, 0.17 wt%, 0.18 wt%, 0.19 wt%, 0.20 wt%, 0.21 wt%, 0.22 wt%, 0.23 wt%, 0.24 wt%, 0.25 wt%, but not limited to the enumerated values, and other non-enumerated values in the numerical range are also applicable, and further preferably, the added mass of the crystal transformation agent is 0.15-0.2 wt% of the total mass of the reaction raw materials.
Preferably, the concentration of the calcium chloride solution is 150-230 g/L, for example, 150 g/L, 160 g/L0, 170 g/L, 180 g/L, 190 g/L, 200 g/L, 210 g/L, 220 g/L or 230 g/L, but not limited to the recited values, and other unrecited values within the range of the values are also applicable, and more preferably, the concentration of the calcium chloride solution is 180-200 g/L.
Preferably, the reaction temperature of the mixed salt solution and the calcium chloride solution is 95 to 110 ℃, for example, 95 ℃, 96 ℃, 97 ℃, 98 ℃, 99 ℃, 100 ℃, 101 ℃, 102 ℃, 103 ℃, 104 ℃, 105 ℃, 106 ℃, 107 ℃, 108 ℃, 109 ℃ or 110 ℃, but not limited to the cited values, and other values not listed in the numerical range are also applicable, and more preferably, the reaction temperature of the mixed salt solution and the calcium chloride solution is 100 to 105 ℃.
Preferably, the reaction time of the mixed salt solution and the calcium chloride solution is 1 to 2.5 hours, for example, 1.0 hour, 1.1 hour, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, 2.0 hours, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours or 2.5 hours, but not limited to the enumerated values, and other non-enumerated values in the numerical range are also applicable, and more preferably, the reaction time of the mixed salt solution and the calcium chloride solution is 1.5 to 2 hours.
Preferably, the gypsum obtained by filtration is α -hemihydrate high strength gypsum.
Preferably, the evaporative concentration is vacuum evaporation.
Preferably, the temperature of the evaporation concentration is 60 to 90 ℃, for example, 60 ℃, 62 ℃, 64 ℃, 66 ℃, 68 ℃, 70 ℃, 72 ℃, 74 ℃, 76 ℃, 78 ℃, 80 ℃, 82 ℃, 84 ℃, 86 ℃, 88 ℃ or 90 ℃, but not limited to the recited values, and other values not recited in the range of the values are also applicable, and more preferably, the temperature of the evaporation concentration is 70 to 80 ℃.
In a preferred embodiment of the present invention, in the step (II), the sodium chloride content in the sodium chloride solution after the precipitation of sodium chloride crystals is 250 to 330 g/L, for example, 250 g/L, 260 g/L, 270 g/L, 280 g/L, 290 g/L, 300 g/L, 310 g/L, 320 g/L or 330 g/L, but not limited to the above-mentioned values, and other values not listed in the above-mentioned range are also applicable.
Preferably, the content of sodium chloride in the sodium chloride solution after the sodium chloride crystals are precipitated is 280-300 g/L.
Preferably, the concentration of the ammonium bicarbonate solution is 300-380 g/L, such as 300 g/L, 310 g/L0, 320 g/L, 330 g/L, 340 g/L, 350 g/L, 360 g/L, 370 g/L or 380 g/L, but not limited to the recited values, and other unrecited values within the range of the values are also applicable, and more preferably, the concentration of the ammonium bicarbonate solution is 320-360 g/L.
Preferably, the reaction temperature of the sodium chloride solution and the ammonium bicarbonate solution is 25 to 40 ℃, for example, 25 ℃, 26 ℃, 27 ℃, 28 ℃, 29 ℃, 30 ℃, 31 ℃, 32 ℃, 33 ℃, 34 ℃, 35 ℃, 36 ℃, 37 ℃, 38 ℃, 39 ℃ or 40 ℃, but not limited to the listed values, and other non-listed values within the range of the values are also applicable, and more preferably, the reaction temperature of the sodium chloride solution and the ammonium bicarbonate solution is 30 to 35 ℃.
Preferably, the reaction time of the sodium chloride solution and the ammonium bicarbonate solution is 1 to 2.5 hours, such as 1.0 hour, 1.1 hour, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, 2.0 hours, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours or 2.5 hours, but not limited to the listed values, and other values in the range of the values are also applicable, and further preferably, the reaction time of the sodium chloride solution and the ammonium bicarbonate solution is 1.5 to 2 hours.
Preferably, the steam calcination temperature is 90 to 120 ℃, for example, 90 ℃, 92 ℃, 94 ℃, 96 ℃, 98 ℃, 100 ℃, 102 ℃, 104 ℃, 106 ℃, 108 ℃, 110 ℃, 112 ℃, 114 ℃, 116 ℃, 118 ℃ or 120 ℃, but not limited to the recited values, and other values not recited in the range of the values are also applicable, and more preferably, the steam calcination temperature is 100 to 110 ℃.
Preferably, the calcination time of the steam calcination is 50 to 80min, for example, 50min, 52min, 54min, 56min, 58min, 60min, 62min, 64min, 66min, 68min, 70min, 72min, 74min, 76min, 78min or 80min, but not limited to the enumerated values, and other non-enumerated values in the numerical range are also applicable, and further preferably, the calcination time of the steam calcination is 60 to 70 min.
In the step (III), the reaction solution from which the sodium bicarbonate is separated is frozen and then enters a salting-out device.
Preferably, the freezing temperature is 0 to 15 ℃, for example, 0 ℃, 1 ℃, 2 ℃, 3 ℃, 4 ℃, 5 ℃, 6 ℃, 7 ℃, 8 ℃, 9 ℃, 10 ℃, 11 ℃, 12 ℃, 13 ℃, 14 ℃ or 15 ℃, but is not limited to the recited values, and other values not recited in the range of the values are also applicable, and more preferably, the freezing temperature is 5 to 10 ℃.
Preferably, the temperature of the salting-out device is 5 to 20 ℃, for example, 5 ℃, 6 ℃, 7 ℃, 8 ℃, 9 ℃, 10 ℃, 11 ℃, 12 ℃, 13 ℃, 14 ℃, 15 ℃, 16 ℃, 17 ℃, 18 ℃, 19 ℃ or 20 ℃, but not limited to the enumerated values, and other non-enumerated values within the numerical range are also applicable, and more preferably, the temperature of the salting-out device is 10 to 15 ℃.
Preferably, the sodium chloride crystals are added to the salting-out device in an amount that satisfies the crystallization requirement of ammonium chloride.
Preferably, the amount of sodium chloride crystals added to the salting-out apparatus is 7 to 15% in excess based on the requirement for ammonium chloride crystallization, for example, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%, but is not limited to the recited values, and other values not recited in the above range are also applicable, and more preferably, the amount of sodium chloride crystals added to the salting-out apparatus is 10 to 12% in excess based on the requirement for ammonium chloride crystallization.
Preferably, the sodium chloride content of the ammonium chloride solution obtained after crystallization of ammonium chloride crystals is 60 to 120 g/L, for example, 60 g/L, 65 g/L0, 70 g/L1, 75 g/L2, 80 g/L3, 85 g/L4, 90 g/L, 95 g/L, 100 g/L, 105 g/L, 110 g/L, 115 g/L, or 120 g/L, but not limited to the above-mentioned values, and other values not mentioned within the above-mentioned range are also applicable, and more preferably, the sodium chloride content of the ammonium chloride solution obtained after crystallization of ammonium chloride crystals is 80 to 100 g/L.
In a preferred embodiment of the present invention, in the step (iv), the number of moles of ammonium ions contained in the partial reaction solution introduced into the ammonia still is 0.45 to 0.6, for example, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, or 0.60, based on the number of moles of sulfate groups in the mixed salt solution, but the number is not limited to the above-mentioned values, and other values not listed in the above-mentioned range are also applicable.
Preferably, the number of moles of ammonium ions contained in the partial reaction solution introduced into the ammonia still is 0.5 to 0.55, for example, 0.50, 0.51, 0.52, 0.53, 0.54 or 0.55, based on the number of moles of sulfate groups in the mixed salt solution, but the number is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.
Preferably, the reaction temperature of the ammonia distillation reaction is 95 to 110 ℃, for example, 95 ℃, 96 ℃, 97 ℃, 98 ℃, 99 ℃, 100 ℃, 101 ℃, 102 ℃, 103 ℃, 104 ℃, 105 ℃, 106 ℃, 107 ℃, 108 ℃, 109 ℃ or 110 ℃, but not limited to the cited values, and other values not listed in the numerical range are also applicable, and more preferably, the reaction temperature of the ammonia distillation reaction is 100 to 105 ℃.
Preferably, the reaction time of the ammonia distillation reaction is 50 to 80min, for example, 50min, 52min, 54min, 56min, 58min, 60min, 62min, 64min, 66min, 68min, 70min, 72min, 74min, 76min, 78min or 80min, but is not limited to the values listed, and other values not listed in the range of the values are also applicable, and more preferably, the reaction time of the ammonia distillation reaction is 60 to 70 min.
Preferably, the ammonia content of the ammonia-containing steam obtained by the ammonia distillation reaction is 10-15 wt%, for example, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt% or 15 wt%, but not limited to the recited values, and other values not recited in the range of the recited values are also applicable.
The mass concentration of the produced aqueous ammonia is preferably 23 to 26 wt%, and may be 23 wt%, 24 wt%, 25 wt%, or 26 wt%, for example, and the mass concentration of the produced aqueous ammonia is more preferably 24 to 25%. But not limited to, the recited values and other values not recited within the range of values are equally applicable.
Preferably, the ammonium bicarbonate solution has a mass concentration of 20 to 25 wt%, such as 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt% or 25 wt%, but not limited to the recited values, and other values not recited in the range of the recited values are also applicable.
Preferably, the concentration of the calcium chloride solution obtained by the ammonia distillation reaction is 150-200 g/L, such as 150 g/L, 155 g/L0, 160 g/L1, 165 g/L, 170 g/L, 175 g/L, 180 g/L, 185 g/L, 190 g/L, 195 g/L or 200 g/L, but the invention is not limited to the recited values, and other values not recited in the range of the values are also applicable.
The system refers to an equipment system, or a production equipment.
Compared with the prior art, the invention has the beneficial effects that:
(1) the invention provides a recycling system and a recycling method for a mixed salt solution of sodium chloride and sodium sulfate by organically coupling technologies of synthesizing α -semi-hydrated high-strength gypsum from sodium sulfate and calcium chloride in a normal-pressure sodium chloride solution, preparing soda ash by reacting sodium chloride and ammonium bicarbonate, preparing ammonium chloride by freezing and salting out in a combined alkali method and the like aiming at the characteristics of the mixed salt solution of sodium chloride and sodium sulfate.
(2) The resource utilization process provided by the invention has no wastewater and waste gas, is clean and environment-friendly in process, and provides a new way and a research direction for resource utilization of the mixed salt solution of sodium chloride and sodium sulfate.
Drawings
FIG. 1 is a schematic diagram of a recycling system according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a recycling system according to an embodiment of the present invention;
fig. 3 is a process flow diagram of the recycling treatment according to an embodiment of the present invention.
Wherein, 1-a gypsum synthesis device; 2-a gypsum slurry pump; 3-a gypsum filtration unit; 4-MVR evaporation apparatus; 5-a lifting device; 6-salting out device; 7-a drying device; 8-a reaction device; 9-a separation device; 10-a freezing device; 11-a calcination apparatus; 12-quicklime bin; 13-a weighing device; 14-a conveying device; 15-a pulping device; 16-an ammonia still; 17-a first discharge pump; 18-a silica fume filtration unit; 19-an ammonia concentration unit; 20-an ammonia condensing unit; 21-a recovery unit; 22-second discharge pump.
Detailed Description
It is to be understood that in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be taken as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
It should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "disposed," "connected" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected 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 through specific situations.
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.
In one embodiment, the invention provides a resource treatment system of a mixed salt solution, which comprises a gypsum synthesis unit, an evaporation unit and a reaction unit which are connected in sequence along a material flow direction as shown in fig. 1. The resource treatment system also comprises a calcining unit, an ammonia distilling unit and a salting-out unit which are respectively connected with the outlet of the reaction unit, wherein the outlet of the calcining unit and the outlet of the ammonia distilling unit are combined into one path and then connected into the reaction unit, the ammonia distilling unit is also connected with a gypsum synthesis unit, and the salting-out unit is circularly connected with the evaporation unit.
In another embodiment, the invention provides a resource treatment system of a mixed salt solution, which comprises a gypsum synthesis unit, an evaporation unit and a reaction unit which are connected in sequence along a material flow direction as shown in fig. 2. The resource treatment system also comprises a calcining unit, an ammonia distilling unit and a salting-out unit which are respectively connected with the outlet of the reaction unit, wherein the outlet of the calcining unit and the outlet of the ammonia distilling unit are combined into one path and then connected into the reaction unit, the ammonia distilling unit is also connected with a gypsum synthesis unit, and the salting-out unit is circularly connected with the evaporation unit.
The gypsum synthesis unit comprises a gypsum synthesis device 1 and a gypsum filtering device 3 which are sequentially connected, the mixed salt solution and calcium chloride are introduced into the gypsum synthesis device 1 to react to generate calcium sulfate, and the reaction solution is filtered to remove gypsum in the gypsum through the gypsum filtering device 3. A gypsum slurry pump 2 is arranged on a connecting pipeline between the gypsum synthesis device 1 and the gypsum filtering device 3. The mixed salt solution comprises sodium chloride and sodium sulfate. The gypsum synthesis device 1 comprises a reaction shell and a steam jacket sleeved outside the reaction shell, wherein the steam jacket is externally connected with a steam source, and the steam source introduces steam into the steam jacket to indirectly heat reaction raw materials in the reaction shell. The gypsum synthesis apparatus 1 is provided with a stirring device therein.
The evaporation unit includes MVR evaporation plant 4, and the liquid outlet of gypsum filter equipment 3 is connected to MVR evaporation plant 4's inlet, and gypsum filter equipment 3 exhaust reaction liquid gets into MVR evaporation plant 4, and the sodium chloride crystal wherein is appeared in the evaporation.
The reaction unit comprises a reaction device 8 and a separation device 9 which are connected in sequence, a liquid inlet of the reaction device 8 is connected with a liquid outlet of the MVR evaporation device 4, reaction liquid discharged from the MVR evaporation device 4 enters the reaction device 8, and the reaction liquid reacts with ammonium bicarbonate introduced from the outside in the reaction device 8 to generate sodium bicarbonate and ammonium chloride. The outlet of the separation device 9 is divided into a liquid outlet and a discharge outlet, the reaction liquid discharged from the reaction device 8 enters the separation device 9 to separate sodium bicarbonate therein, the separated sodium bicarbonate is discharged from the discharge outlet of the separation device 9, and the rest of the reaction liquid is discharged from the liquid outlet of the separation device 9. Specifically, in the present embodiment, the separation device 9 may be selected as a centrifuge.
The calcining unit comprises a calcining device 11, a feed inlet of the calcining device 11 is in butt joint with a discharge outlet of the separating device 9, sodium bicarbonate separated by the separating device 9 is discharged from the discharge outlet of the separating device 9 and enters the calcining device 11, calcined at high temperature to generate soda and carbon dioxide, and the soda is discharged outside.
The ammonia distillation unit comprises an ammonia distillation device 16, an ammonia concentration device 19 and a silica residue filtering device 18, wherein an air outlet of the ammonia distillation device 16 is connected with an air inlet of the ammonia concentration device 19, and a liquid outlet of the ammonia distillation device 16 is connected with a liquid inlet of the silica residue filtering device 18. A first discharging pump 17 is arranged on a connecting pipeline of the ammonia still 16 and the silicon slag filtering device 18. An ammonia condensing device 20 is arranged at the top of the ammonia concentrating device 19, and the ammonia condensing device 20 is circularly connected with the ammonia concentrating device 19. The liquid outlet of ammonia enrichment facility 19 is connected the inlet of recovery unit 21, and the air inlet of recovery unit 21 is connected to calcining device 11's gas outlet, and the liquid outlet of recovery unit 21 is connected reaction unit 8's inlet, and 19 top exhaust aqueous ammonia of ammonia enrichment facility and calcining device 11 exhaust carbon dioxide react in recovery unit 21 and generate ammonium bicarbonate, and the ammonium bicarbonate that generates lets in reaction unit 8 and participates in the reaction. A second discharge pump 22 is provided in a connection line between the recovery unit 21 and the reaction unit 8. The liquid outlet of the silica residue filtering device 18 is connected with the liquid inlet of the gypsum synthesis device 1.
The unit of salting out is including the refrigerating plant 10 and the device 6 of salting out that connect gradually along the material flow direction, and the discharge gate of MVR evaporation plant 4 is connected to the feed inlet of the device 6 of salting out, and the inlet of MVR evaporation plant 4 is connected to the liquid outlet of the device 6 of salting out, and the sodium chloride crystal that MVR evaporation plant 4 evaporation was precipitated gets into the salting out that salting out device 6 participated in the ammonium chloride solution, and the ammonium chloride crystal is precipitated and obtain the sodium chloride solution to the crystallization of MVR evaporation plant 4 back flow. The discharge port of the salting-out device 6 is connected with a drying device 7, and ammonium chloride crystals discharged by the salting-out device 6 enter the drying device 7. The discharge hole of the MVR evaporation device 4 is connected to the feed inlet of the salting-out device 6 through a lifting device 5.
The liquid outlet of the separator 9 is divided into two paths, one path is connected with the ammonia distiller 16, the other path is connected with the freezer 10 and the salting-out device 6 in sequence along the material flow direction, the reaction liquid discharged by the separator 9 is divided into two parts, one part enters the ammonia distiller 16 to be mixed with the lime milk for distilling ammonia, and the other part is introduced into the salting-out device 6 after being frozen by the freezer 10 to be mixed with the sodium chloride crystal discharged by the MVR evaporator 4 for salting out, so that ammonium chloride crystal and sodium chloride solution are obtained.
The resourceful treatment system also comprises a lime milk supply unit, and an outlet of the lime milk supply unit is connected with an inlet of the ammonia distillation unit. The lime milk supply unit comprises a lime bin 12, a weighing device 13, a conveying device 14 and a pulping device 15 which are sequentially connected, wherein the pulping device 15 is connected with an ammonia distillation device 16, and lime milk prepared in the pulping device 15 is sent into the ammonia distillation device 16 to be mixed with ammonium chloride solution for ammonia distillation.
In another specific embodiment, the invention provides a resource treatment method of a mixed salt solution, which is shown in fig. 3 and specifically includes the following steps:
(1) adding a mixed salt solution with the total content of sodium chloride and sodium sulfate of 120-240 g/L into a gypsum synthesis device 1, wherein the feeding temperature is 30-60 ℃, the mixed salt solution and calcium chloride after ammonia evaporation or calcium chloride supplemented additionally are subjected to high-temperature synthesis reaction, the concentration of the calcium chloride solution is 150-23 g/L, the reaction temperature of the high-temperature synthesis reaction is 95-110 ℃, the reaction time of the high-temperature synthesis reaction is 1-2.5 h, a crystal transformation agent is added in the reaction process, the crystal transformation agent comprises one or a combination of at least two of citric acid, citrate or aluminate, the addition amount of the crystal transformation agent is 0.1-0.25 wt% of the total mass of reaction raw materials, calcium sulfate and sodium chloride solution are obtained after the reaction is finished, calcium sulfate is filtered through gypsum to obtain α -semi-hydrated high-strength gypsum, the sodium chloride solution enters an MVR evaporation device 4 to be evaporated and concentrated, part of sodium chloride crystals are separated out, and evaporated and concentrated to be vacuum evaporation, and the evaporation temperature is 60-90;
(2) the sodium chloride solution for separating out sodium chloride crystals contains 250-330 g/L sodium chloride, the sodium chloride solution enters a reaction device 8 to react with an ammonium bicarbonate solution to generate sodium bicarbonate and ammonium chloride, the concentration of the ammonium bicarbonate solution is 300-380 g/L, the reaction temperature is 25-40 ℃, the reaction time is 1-2.5 hours, the reaction liquid enters a separation device 9 to separate out the sodium bicarbonate, the sodium bicarbonate is introduced into a calcination device 11 to be calcined and decomposed by steam to obtain soda products and carbon dioxide, the calcination temperature is 90-120 ℃, and the calcination time is 50-80 min;
(3) separating the reaction liquid for separating the sodium bicarbonate in the step (1) into two parts, freezing one part of the reaction liquid, then entering a salting-out device 6, adding the sodium chloride crystals precipitated in the step (1) into the salting-out device 6 for salting-out crystallization, wherein the freezing temperature is 0-15 ℃, the crystallization temperature of the salting-out device 6 is 5-20 ℃, the addition amount of the sodium chloride crystals meets the requirement of ammonium chloride crystallization and is 7-15% excessive, crystallizing and precipitating ammonium chloride crystals to obtain a sodium chloride solution, centrifugally separating the ammonium chloride crystals to obtain an ammonium chloride product, converting chloride ions in the mixed salt solution into ammonium chloride, discharging the sodium chloride solution from the salting-out device 6 to obtain the sodium chloride product with the sodium chloride content of 60-120 g/L, and refluxing the ammonium chloride product into the MVR evaporation device 4 in the step (1) for evaporation and concentration;
(4) and (3) feeding the other part of the reaction liquid obtained in the step (III) into an ammonia distillation device 16, wherein the mole number of ammonium ions contained in the part of the reaction liquid is 0.45-0.6 of the mole number of sulfate radicals in a mixed salt solution, performing ammonia distillation reaction on the reaction liquid and prepared lime milk to obtain ammonia-containing steam and a calcium chloride solution, wherein the ammonia distillation reaction temperature is 95-110 ℃, the ammonia distillation time is 50-80 min, the ammonia content of the obtained ammonia-containing steam is 10-15 wt%, feeding the ammonia-containing steam into an ammonia concentration device 19 to prepare ammonia water, the mass concentration of the prepared ammonia water is 23-26 wt%, performing gas-liquid contact on the ammonia water and carbon dioxide generated by calcining and decomposing sodium bicarbonate in the step (2) in a recovery device 21 to obtain an ammonium bicarbonate solution required in the step (2), the mass concentration of the ammonium bicarbonate solution is 20-25 wt%, the concentration of the calcium chloride solution obtained by ammonia distillation is 150-200 g/L, and refluxing the calcium chloride solution to a gypsum synthesis device 1 after filtering silicon residues to be used.
Example 1
The resource treatment system provided by the specific embodiment is adopted to carry out resource treatment on the mixed salt solution, and the specific treatment process comprises the following steps:
(1) at 1m3The mixed solution containing sodium chloride and sodium sulfate is calculated as standard, the sodium chloride content is 60 g/L, the sodium sulfate content is 100 g/L, the total content of the two is 160 g/L, and the specific gravity of the mixed salt solution is 1100kg/m3Adding the mixed salt solution into the gypsum synthesizer 1, wherein the feeding temperature is 40 ℃, and the feeding temperature is 0.42m3Performing high-temperature synthesis reaction on calcium chloride solution, wherein the concentration of the calcium chloride solution is 200 g/L, and the specific gravity of the calcium chloride solution is 1155Kg/m3The total amount of the mixed salt solution and the calcium chloride solution is 1585kg, the reaction temperature of the high-temperature synthesis reaction is 100 ℃, the reaction time of the high-temperature synthesis reaction is 2 hours, 2.4kg of citric acid is added as a crystal transformation agent in the reaction process, the addition amount of the crystal transformation agent is 0.15 wt% of the total mass of the reaction raw materials, calcium sulfate and sodium chloride solution is obtained after the reaction is finished, the mass of the sodium chloride solution is 1465kg, and the calcium sulfate is filtered out after the calcium sulfate is filtered by gypsum to obtain 122kg of α -hemihydrate high-strength gypsum containing free water;
the sodium chloride solution enters an MVR evaporation device 4 for evaporation concentration, the evaporation concentration is vacuum evaporation, the evaporation temperature is 80 ℃, 50kg of sodium chloride crystals are separated out, and the rest of the sodium chloride solution is 0.35m3；
(2) The sodium chloride solution from which the sodium chloride crystals are separated out has a sodium chloride content of 280 g/L and enters a reaction device 8 with a particle size of 0.37m3Reacting 360 g/L mass concentration ammonium bicarbonate solution to generate sodium bicarbonate and ammonium chloride, wherein the reaction temperature is 30 ℃, and the reaction time is 2 hours;
the reaction liquid enters a separation device 9 to be separated out to obtain 140kg of sodium bicarbonate crystals, the sodium bicarbonate crystals are introduced into a calcining device 11 to be calcined and decomposed by steam to obtain a soda product and carbon dioxide, the calcining temperature is 100 ℃, the calcining time is 70min, and the mass of the obtained soda product is 88 kg;
(3) separating the reaction liquid of sodium bicarbonate separated in the step (1) into two parts, freezing one part of the reaction liquid, entering a salting-out device 6, adding 50kg of sodium chloride crystals separated out in the step (1) into the salting-out device 6, carrying out salting-out crystallization, wherein the freezing temperature is 5 ℃, the crystallization temperature of the salting-out device 6 is 10 ℃, the addition amount of the sodium chloride crystals meets the requirement of ammonium chloride crystallization and is excessive by 12%, all chloride ions in the mixed salt solution are required to be converted into ammonium chloride, crystallizing and separating out the ammonium chloride crystals to obtain a sodium chloride solution, carrying out centrifugal separation on the ammonium chloride crystals to obtain 55kg of ammonium chloride products, wherein the ammonium chloride crystallization amount is that all chloride ions in the mixed salt solution are converted into ammonium chloride, the sodium chloride content in the sodium chloride solution discharged from the salting-out device 6 is 80 g/L, and refluxing to the MVR evaporation device 4 in the step (1) for evaporation and concentration;
(4) the other part of the reaction liquid in the step (3) enters an ammonia still 16, and the mole number of ammonium ions contained in the part of the reaction liquid is 378 moles which is 0.5 of the mole number of sulfate radicals in the mixed salt solution;
the method comprises the following steps that external quicklime powder enters a quicklime bin 12, is metered by a weighing device 13, is conveyed into a pulping device 15 through a conveying device 14, is added with water to prepare lime milk, and the prepared lime milk is conveyed into an ammonia still 16;
and (2) carrying out ammonia distillation reaction on the reaction liquid and prepared lime milk to obtain ammonia-containing steam and a calcium chloride solution, wherein the ammonia distillation reaction temperature is 100 ℃, the ammonia distillation time is 70min, the ammonia content of the obtained ammonia-containing steam is 10 wt%, the ammonia-containing steam enters an ammonia concentration device 19 to prepare ammonia water, the mass concentration of the prepared ammonia water is 24 wt%, the ammonia water is in gas-liquid contact with carbon dioxide generated by calcining and decomposing sodium bicarbonate in the step (2) in a recovery device 21 to obtain the ammonium bicarbonate solution required in the step (2), the mass concentration of the ammonium bicarbonate solution is 20 wt%, the concentration of the calcium chloride solution obtained by ammonia distillation is 180 g/L, and the calcium chloride solution is filtered to remove silicon residues and then flows back to a gypsum synthesis device 1 to serve as a reaction raw material in the step (1).
Example 2
The resource treatment system provided by the specific embodiment is adopted to carry out resource treatment on the mixed salt solution, and the specific treatment process comprises the following steps:
(1) at 1m3The mixed solution containing sodium chloride and sodium sulfate is calculated by taking the mixed solution as a reference, the sodium chloride content is 80 g/L, the sodium sulfate content is 120 g/L, the total content of the sodium chloride and the sodium sulfate is 200 g/L, and the mixed salt solutionThe specific gravity of the liquid is 1130kg/m3Adding the mixed salt solution into the gypsum synthesizer 1, wherein the feeding temperature is 50 ℃, and the feeding temperature is 0.56m3Performing high-temperature synthesis reaction on calcium chloride, wherein the concentration of calcium chloride solution is 180 g/L, and the specific gravity of 180 g/L calcium chloride solution is 1138kg/m3The total amount of the mixed salt solution and the calcium chloride solution is 1767kg, the reaction temperature of the high-temperature synthesis reaction is 105 ℃, the reaction time of the high-temperature synthesis reaction is 1.5h, 3.5kg of sodium citrate is added as a crystal transformation agent in the reaction process, the addition amount of the crystal transformation agent is 0.2 wt% of the total mass of the reaction raw materials, calcium sulfate and sodium chloride solution are obtained after the reaction is finished, the mass of the sodium chloride solution is 1624kg, and after the calcium sulfate is filtered, 146kg of α -hemihydrate high-strength gypsum containing free water is obtained;
the sodium chloride solution enters an MVR evaporation device 4 for evaporation concentration, the evaporation concentration is vacuum evaporation, the evaporation temperature is 70 ℃, 60kg of sodium chloride crystals are separated out, and the rest of the sodium chloride solution is 0.43m3；
(2) The sodium chloride solution from which the sodium chloride crystals are separated out has a sodium chloride content of 300 g/L, and enters a reaction device 8 and a reaction time of 0.54m3Reacting 320 g/L mass concentration ammonium bicarbonate solution to generate sodium bicarbonate and ammonium chloride, wherein the reaction temperature is 35 ℃, and the reaction time is 1.5 h;
the reaction liquid enters a separation device 9 to be separated out to obtain 180kg of sodium bicarbonate crystals, the sodium bicarbonate crystals are introduced into a calcining device 11 to be calcined and decomposed by steam to obtain a soda product and carbon dioxide, the calcining temperature is 110 ℃, the calcining time is 60min, and the mass of the obtained soda product is 113 kg;
(3) separating the reaction liquid of sodium bicarbonate separated in the step (1) into two parts, freezing one part of the reaction liquid, entering a salting-out device 6, adding 60kg of sodium chloride crystals separated out in the step (1) into the salting-out device 6, carrying out salting-out crystallization, wherein the freezing temperature is 10 ℃, the crystallization temperature of the salting-out device 6 is 15 ℃, the addition amount of the sodium chloride crystals meets the requirement of ammonium chloride crystallization and is excessive by 10%, all chloride ions in the mixed salt solution are required to be converted into ammonium chloride, crystallizing and separating out the ammonium chloride crystals to obtain a sodium chloride solution, carrying out centrifugal separation on the ammonium chloride crystals to obtain 73kg of ammonium chloride products, wherein the ammonium chloride crystallization amount is that all chloride ions in the mixed salt solution are converted into ammonium chloride, the sodium chloride content in the sodium chloride solution discharged from the salting-out device 6 is 100 g/L, and refluxing to the MVR evaporation device 4 in the step (1) for evaporation and concentration;
(4) the other part of the reaction liquid in the step (III) enters an ammonia still 16, and the mole number of ammonium ions contained in the part of the reaction liquid is 500 moles and is 0.55 of the mole number of sulfate radicals in the mixed salt solution;
the method comprises the following steps that external quicklime powder enters a quicklime bin 12, is metered by a weighing device 13, is conveyed into a pulping device 15 through a conveying device 14, is added with water to prepare lime milk, and the prepared lime milk is conveyed into an ammonia still 16;
and (2) carrying out ammonia distillation reaction on the reaction liquid and prepared lime milk to obtain ammonia-containing steam and a calcium chloride solution, wherein the ammonia distillation reaction temperature is 105 ℃, the ammonia distillation time is 60min, the ammonia content of the obtained ammonia-containing steam is 15 wt%, the ammonia-containing steam enters an ammonia concentration device 19 to prepare ammonia water, the mass concentration of the prepared ammonia water is 25 wt%, the ammonia water is in gas-liquid contact with carbon dioxide generated by calcining and decomposing sodium bicarbonate in the step (2) in a recovery device 21 to obtain the ammonium bicarbonate solution required in the step (2), the mass concentration of the ammonium bicarbonate solution is 25 wt%, the concentration of the calcium chloride solution obtained by ammonia distillation is 160 g/L, and the calcium chloride solution is filtered to remove silicon residues and then flows back to a gypsum synthesis device 1 to serve as a reaction raw material in the step (1).
Example 3
The resource treatment system provided by the specific embodiment is adopted to carry out resource treatment on the mixed salt solution, and the specific treatment process comprises the following steps:
(1) at 1m3The mixed solution containing sodium chloride and sodium sulfate is calculated as reference, the sodium chloride content is 100 g/L, the sodium sulfate content is 80 g/L, the total content of the sodium chloride and the sodium sulfate is 180 g/L, and the specific gravity of the mixed salt solution is 1118kg/m3Adding the mixed salt solution into the gypsum synthesizer 1, wherein the feeding temperature is 42 ℃, and the feeding temperature is 0.42m3Performing high-temperature synthesis reaction on calcium chloride, wherein the concentration of the calcium chloride solution is 160 g/L, and the specific gravity of the 160 g/L calcium chloride solution is 1125kg/m3The total amount of the mixed salt solution and the calcium chloride solution is 1590kg, the reaction temperature of the high-temperature synthesis reaction is 103 ℃, and the high-temperature synthesis is carried outThe reaction time is 1.6h, 3.2kg of citric acid is added as a crystal modifier in the reaction process, the addition amount of the crystal modifier is 0.2 wt% of the total mass of the reaction raw materials, calcium sulfate and sodium chloride solution are obtained after the reaction is finished, the mass of the sodium chloride solution is 1497kg, and 96kg of α -hemihydrate high-strength gypsum containing free water is obtained by filtering calcium sulfate through gypsum;
the sodium chloride solution enters an MVR evaporation device 4 for evaporation concentration, the evaporation concentration is vacuum evaporation, the evaporation temperature is 72 ℃, 57kg of sodium chloride crystals are separated out, and the rest of the sodium chloride solution is 0.4m3；
(2) The sodium chloride solution from which sodium chloride crystals are separated out has a sodium chloride content of 285 g/L, and enters a reaction device 8 and a reaction time of 0.46m3The ammonium bicarbonate solution with the mass concentration of 330 g/L reacts to generate sodium bicarbonate and ammonium chloride, the reaction temperature is 32 ℃, and the reaction time is 1.8 h;
separating and separating out 163kg of sodium bicarbonate crystals by feeding the reaction liquid into a separation device 9, introducing the sodium bicarbonate crystals into a calcining device 11 for steam calcining and decomposing to obtain a soda product and carbon dioxide, wherein the calcining temperature is 108 ℃, the calcining time is 62min, and the mass of the obtained soda product is 102 kg;
(3) separating the reaction liquid of sodium bicarbonate separated in the step (1) into two parts, freezing one part of the reaction liquid, entering a salting-out device 6, adding 57kg of sodium chloride crystals separated out in the step (1) into the salting-out device 6 for salting-out crystallization, wherein the freezing temperature is 8 ℃, the crystallization temperature of the salting-out device 6 is 13 ℃, the addition amount of the sodium chloride crystals meets the requirement of ammonium chloride crystallization and is excessive by 11%, all chloride ions in the mixed salt solution are required to be converted into ammonium chloride, ammonium chloride crystals are separated out through crystallization and a sodium chloride solution is obtained, the ammonium chloride crystals are subjected to centrifugal separation to obtain 91kg of ammonium chloride products, the ammonium chloride crystallization amount is that all chloride ions in the mixed salt solution are converted into ammonium chloride, the sodium chloride content in the sodium chloride solution discharged from the salting-out device 6 is 95 g/L, and refluxing is carried out evaporation concentration in the MVR evaporation device 4 in the step (1);
(4) the other part of the reaction liquid in the step (III) enters an ammonia still 16, and the mole number of ammonium ions contained in the part of the reaction liquid is 315 moles which is 0.52 of the mole number of sulfate radicals in the mixed salt solution;
the method comprises the following steps that external quicklime powder enters a quicklime bin 12, is metered by a weighing device 13, is conveyed into a pulping device 15 through a conveying device 14, is added with water to prepare lime milk, and the prepared lime milk is conveyed into an ammonia still 16;
and (2) carrying out ammonia distillation reaction on the reaction liquid and prepared lime milk to obtain ammonia-containing steam and a calcium chloride solution, wherein the ammonia distillation reaction temperature is 103 ℃, the ammonia distillation time is 63min, the ammonia content of the obtained ammonia-containing steam is 11 wt%, the ammonia-containing steam enters an ammonia concentration device 19 to prepare ammonia water, the mass concentration of the prepared ammonia water is 21 wt%, the ammonia water is in gas-liquid contact with carbon dioxide generated by calcining and decomposing sodium bicarbonate in the step (2) in a recovery device 21 to obtain the ammonium bicarbonate solution required in the step (2), the mass concentration of the ammonium bicarbonate solution is 22 wt%, the concentration of the calcium chloride solution obtained by ammonia distillation is 150 g/L, and the calcium chloride solution is filtered to remove silicon residues and then flows back to a gypsum synthesis device 1 to serve as a reaction raw material in the step (1).
Example 4
The resource treatment system provided by the specific embodiment is adopted to carry out resource treatment on the mixed salt solution, and the specific treatment process comprises the following steps:
(1) at 1m3The mixed solution containing sodium chloride and sodium sulfate is calculated as reference, the sodium chloride content is 80 g/L, the sodium sulfate content is 90 g/L, the total content of the sodium chloride and the sodium sulfate is 170 g/L, and the specific gravity of the mixed salt solution is 1112kg/m3Adding the mixed salt solution into the gypsum synthesizer 1, wherein the feeding temperature is 45 ℃, and the feeding temperature is 0.45m3Performing high-temperature synthesis reaction on calcium chloride, wherein the concentration of the calcium chloride solution is 170 g/L, and the specific gravity of the 170 g/L calcium chloride solution is 1135kg/m3The total amount of the mixed salt solution and the calcium chloride solution is 1622kg, the reaction temperature of the high-temperature synthesis reaction is 102 ℃, the reaction time of the high-temperature synthesis reaction is 1.7h, 2.8kg of sodium citrate is added in the reaction process as a crystal transformation agent, the addition amount of the crystal transformation agent is 0.17 wt% of the total mass of the reaction raw materials, calcium sulfate and sodium chloride solution is obtained after the reaction is finished, the mass of the sodium chloride solution is 1517kg, and after the calcium sulfate is filtered, the α -hemihydrate high-strength gypsum containing free water is obtained by filtering the calcium sulfate;
sodium chloride solution intoEvaporating and concentrating in MVR evaporation device 4 at 75 deg.C to obtain 53kg sodium chloride crystal and 0.37m sodium chloride solution3；
(2) The sodium chloride solution from which the sodium chloride crystals are separated out has a sodium chloride content of 290 g/L and enters a reaction device 8 with a particle size of 0.42m3Reacting 340 g/L mass concentration ammonium bicarbonate solution to generate sodium bicarbonate and ammonium chloride, wherein the reaction temperature is 33 ℃, and the reaction time is 1.7 h;
the reaction liquid enters a separation device 9 to be separated out to obtain 153kg of sodium bicarbonate crystals, the sodium bicarbonate crystals are introduced into a calcining device 11 to be calcined and decomposed by steam to obtain a soda product and carbon dioxide, the calcining temperature is 106 ℃, the calcining time is 65min, and the mass of the obtained soda product is 96 kg;
(3) separating the reaction liquid of sodium bicarbonate separated in the step (1) into two parts, freezing one part of the reaction liquid, entering a salting-out device 6, adding 53kg of sodium chloride crystals separated out in the step (1) into the salting-out device 6 for salting-out crystallization, wherein the freezing temperature is 7 ℃, the crystallization temperature of the salting-out device 6 is 12 ℃, the addition amount of the sodium chloride crystals meets the requirement of ammonium chloride crystallization and is 10.5% excessive, all chloride ions in the mixed salt solution are required to be converted into ammonium chloride, the ammonium chloride crystals are crystallized and separated out to obtain a sodium chloride solution, the ammonium chloride crystals are centrifugally separated to obtain 73kg of ammonium chloride products, the ammonium chloride crystallization amount is that all chloride ions in the mixed salt solution are converted into ammonium chloride, the sodium chloride content in the sodium chloride solution discharged from the salting-out device 6 is 90 g/L, and refluxing to the MVR evaporation device 4 in the step (1) for evaporation and concentration;
(4) the other part of the reaction liquid in the step (III) enters an ammonia still 16, and the mole number of ammonium ions contained in the part of the reaction liquid is 360 moles which is 0.53 of the mole number of sulfate radicals in the mixed salt solution;
the method comprises the following steps that external quicklime powder enters a quicklime bin 12, is metered by a weighing device 13, is conveyed into a pulping device 15 through a conveying device 14, is added with water to prepare lime milk, and the prepared lime milk is conveyed into an ammonia still 16;
and (2) carrying out ammonia distillation reaction on the reaction liquid and prepared lime milk to obtain ammonia-containing steam and a calcium chloride solution, wherein the ammonia distillation reaction temperature is 102 ℃, the ammonia distillation time is 66min, the ammonia content of the obtained ammonia-containing steam is 13 wt%, the ammonia-containing steam enters an ammonia concentration device 19 to prepare ammonia water, the mass concentration of the prepared ammonia water is 23 wt%, the ammonia water is in gas-liquid contact with carbon dioxide generated by calcining and decomposing sodium bicarbonate in the step (2) in a recovery device 21 to obtain the ammonium bicarbonate solution required in the step (2), the mass concentration of the ammonium bicarbonate solution is 24 wt%, the concentration of the calcium chloride solution obtained by ammonia distillation is 155 g/L, and the calcium chloride solution is filtered to remove silicon residues and then flows back to a gypsum synthesis device 1 to serve as a reaction raw material in the step (1).
Example 5
The resource treatment system provided by the specific embodiment is adopted to carry out resource treatment on the mixed salt solution, and the specific treatment process comprises the following steps:
(1) at 1m3The mixed solution containing sodium chloride and sodium sulfate is calculated as reference, the sodium chloride content is 95 g/L, the sodium sulfate content is 95 g/L, the total content of the sodium chloride and the sodium sulfate is 190 g/L, and the specific gravity of the mixed salt solution is 1125kg/m3The mixed salt solution is added into the gypsum synthesizer 1, the feeding temperature is 47 ℃, and the feeding temperature is 0.42m3Performing high-temperature synthesis reaction on calcium chloride, wherein the concentration of the calcium chloride solution is 190 g/L, and the specific gravity of the 190 g/L calcium chloride solution is 1146kg/m3The total amount of the mixed salt solution and the calcium chloride solution is 1606kg, the reaction temperature of the high-temperature synthesis reaction is 101 ℃, the reaction time of the high-temperature synthesis reaction is 1.9h, 2.9kg of citric acid is added as a crystal transformation agent in the reaction process, the addition amount of the crystal transformation agent is 0.18 wt% of the total mass of the reaction raw materials, calcium sulfate and sodium chloride solution is obtained after the reaction is finished, the mass of the sodium chloride solution is 1494kg, and the calcium sulfate is filtered out after the gypsum is filtered to obtain 115kg of α -hemihydrate high-strength gypsum containing free water;
the sodium chloride solution enters an MVR evaporation device 4 for evaporation concentration, the evaporation concentration is vacuum evaporation, the evaporation temperature is 77 ℃, 60kg of sodium chloride crystals are separated out, and the rest of the sodium chloride solution is 0.4m3；
(2) The sodium chloride solution from which the sodium chloride crystals are separated out has a sodium chloride content of 295 g/L and enters a reaction device 8 with a particle size of 0.46m3Ammonium bicarbonate solution with the mass concentration of 350 g/L reacts to generate the bicarbonateSodium and ammonium chloride, the reaction temperature is 31 ℃, and the reaction time is 1.9 h;
the reaction liquid enters a separation device 9 to be separated and separated out to obtain 170kg of sodium bicarbonate crystals, the sodium bicarbonate crystals are introduced into a calcining device 11 to be calcined and decomposed by steam to obtain a soda product and carbon dioxide, the calcining temperature is 140 ℃, the calcining time is 68min, and the mass of the obtained soda product is 107 kg;
(3) separating the reaction liquid of sodium bicarbonate separated in the step (1) into two parts, freezing one part of the reaction liquid, entering a salting-out device 6, adding 60kg of sodium chloride crystals separated out in the step (1) into the salting-out device 6 for salting-out crystallization, wherein the freezing temperature is 9 ℃, the crystallization temperature of the salting-out device 6 is 14 ℃, the addition amount of the sodium chloride crystals meets the requirement of ammonium chloride crystallization and is 11.5% excessive, all chloride ions in the mixed salt solution are required to be converted into ammonium chloride, crystallizing and separating out the ammonium chloride crystals to obtain a sodium chloride solution, carrying out centrifugal separation on the ammonium chloride crystals to obtain 87kg of ammonium chloride products, wherein the ammonium chloride crystallization amount is that all chloride ions in the mixed salt solution are converted into ammonium chloride, the sodium chloride content in the sodium chloride solution discharged from the salting-out device 6 is 85 g/L, and refluxing to the MVR evaporation device 4 in the step (1) for evaporation and concentration;
(4) the other part of the reaction liquid in the step (III) enters an ammonia still 16, and the mole number of ammonium ions contained in the part of the reaction liquid is 388 mol which is 0.54 of the mole number of sulfate radicals in the mixed salt solution;
the method comprises the following steps that external quicklime powder enters a quicklime bin 12, is metered by a weighing device 13, is conveyed into a pulping device 15 through a conveying device 14, is added with water to prepare lime milk, and the prepared lime milk is conveyed into an ammonia still 16;
and (2) carrying out ammonia distillation reaction on the reaction liquid and prepared lime milk to obtain ammonia-containing steam and a calcium chloride solution, wherein the ammonia distillation reaction temperature is 101 ℃, the ammonia distillation time is 69min, the ammonia content of the obtained ammonia-containing steam is 13.5 wt%, the ammonia-containing steam enters an ammonia concentration device 19 to prepare ammonia water, the mass concentration of the prepared ammonia water is 22.5 wt%, the ammonia water is in gas-liquid contact with carbon dioxide generated by calcining and decomposing sodium bicarbonate in the step (2) in a recovery device 21 to obtain the ammonium bicarbonate solution required in the step (2), the mass concentration of the ammonium bicarbonate solution is 21.5 wt%, the concentration of the calcium chloride solution obtained by ammonia distillation is 170 g/L, and the calcium chloride solution is filtered to remove silicon slag and then flows back to a gypsum synthesis device 1 to serve as a reaction raw material in the step (1).
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.

Claims (10)

1. The resource treatment system for the mixed salt solution is characterized by comprising a gypsum synthesis unit, an evaporation unit and a reaction unit which are sequentially connected in the material flow direction;
the resource treatment system also comprises a calcining unit, an ammonia distilling unit and a salting-out unit which are respectively connected with the outlet of the reaction unit, wherein the outlet of the calcining unit and the outlet of the ammonia distilling unit are merged into one path and then are connected into the reaction unit, the ammonia distilling unit is also connected with a gypsum synthesis unit, and the salting-out unit is circularly connected with the evaporation unit.
2. The resource treatment system according to claim 1, wherein the gypsum synthesis unit comprises a gypsum synthesis device and a gypsum filtering device which are sequentially connected, the mixed salt solution and calcium chloride are introduced into the gypsum synthesis device to react to generate calcium sulfate, and the reaction solution is filtered to remove gypsum in the reaction solution through the gypsum filtering device;
preferably, a gypsum slurry pump is arranged on a connecting pipeline between the gypsum synthesis device and the gypsum filtering device;
preferably, the mixed salt solution comprises sodium chloride and sodium sulfate;
preferably, the gypsum synthesis device comprises a reaction shell and a steam jacket sleeved outside the reaction shell;
preferably, the steam jacket is externally connected with a steam source, and the steam source introduces steam into the steam jacket to indirectly heat the reaction raw materials in the reaction shell;
preferably, a stirring device is arranged in the gypsum synthesis device;
preferably, the evaporation unit comprises an MVR evaporation device, a liquid inlet of the MVR evaporation device is connected with a liquid outlet of the gypsum filtering device, and reaction liquid discharged from the gypsum filtering device enters the MVR evaporation device to evaporate and separate out sodium chloride crystals in the reaction liquid;
preferably, the reaction unit comprises a reaction device and a separation device which are connected in sequence, a liquid inlet of the reaction device is connected with a liquid outlet of the MVR evaporation device, a reaction liquid discharged by the MVR evaporation device enters the reaction device, and reacts with ammonium bicarbonate introduced from the outside in the reaction device to generate sodium bicarbonate and ammonium chloride;
preferably, the outlet of the separation device is divided into a liquid outlet and a discharge outlet, the reaction liquid discharged from the reaction device enters the separation device to separate sodium bicarbonate, the separated sodium bicarbonate is discharged from the discharge outlet of the separation device, and the rest of the reaction liquid is discharged from the liquid outlet of the separation device.
3. A resource processing system according to claim 1 or 2, characterized in that the calcination unit comprises a calcination device;
preferably, a feed port of the calcining device is in butt joint with a discharge port of the separating device, sodium bicarbonate separated by the separating device is discharged from the discharge port of the separating device and enters the calcining device, calcined at high temperature is carried out to generate soda and carbon dioxide, and the soda is discharged outside;
preferably, the separation device is a centrifuge;
preferably, the ammonia distillation unit comprises an ammonia distillation device, an ammonia concentration device and a silica residue filtering device, wherein an air outlet of the ammonia distillation device is connected with an air inlet of the ammonia concentration device, and a liquid outlet of the ammonia distillation device is connected with a liquid inlet of the silica residue filtering device;
preferably, a first discharge pump is arranged on a connecting pipeline between the ammonia still device and the silicon slag filtering device;
preferably, an ammonia condensing device is arranged at the top of the ammonia concentrating device, and the ammonia condensing device is circularly connected with the ammonia concentrating device;
preferably, a liquid outlet of the ammonia concentration device is connected with a liquid inlet of the recovery device, a gas outlet of the calcining device is connected with a gas inlet of the recovery device, a liquid outlet of the recovery device is connected with a liquid inlet of the reaction device, ammonia water discharged from the top of the ammonia concentration device and carbon dioxide discharged from the calcining device react in the recovery device to generate ammonium bicarbonate, and the generated ammonium bicarbonate is introduced into the reaction device to participate in the reaction;
preferably, a second discharge pump is arranged on a connecting pipeline of the recovery device and the reaction device;
preferably, a liquid outlet of the silica slag filtering device is connected with a liquid inlet of the gypsum synthesis device;
preferably, the salting-out unit comprises a freezing device and a salting-out device which are sequentially connected along the material flow direction, a feed inlet of the salting-out device is connected with a discharge outlet of the MVR evaporation device, a liquid outlet of the salting-out device is connected with a liquid inlet of the MVR evaporation device, sodium chloride crystals evaporated and precipitated by the MVR evaporation device enter the salting-out device to participate in salting-out of the ammonium chloride solution, the ammonium chloride crystals are crystallized and precipitated to obtain the sodium chloride solution, and the sodium chloride solution flows back to the MVR evaporation device to be evaporated and crystallized;
preferably, a discharge port of the salting-out device is connected with a drying device, and ammonium chloride crystals discharged by the salting-out device enter the drying device;
preferably, the discharge hole of the MVR evaporation device is connected to the feed inlet of the salting-out device through a lifting device;
preferably, the liquid outlet of the separation device is divided into two paths, one path is connected with the ammonia distillation device, the other path is sequentially connected with the freezing device and the salting-out device along the material flow direction, the reaction liquid discharged by the separation device is divided into two parts, one part enters the ammonia distillation device to be mixed with the lime milk for ammonia distillation, and the other part is introduced into the salting-out device after being frozen by the freezing device to be mixed with the sodium chloride crystal discharged by the MVR evaporation device for salting out, so that ammonium chloride crystal and sodium chloride solution are obtained.
4. A resource treatment system according to any one of claims 1 to 3, characterized by further comprising a lime milk supply unit, an outlet of which is connected to an inlet of the ammonia distillation unit;
preferably, the lime milk supply unit comprises a quick lime bin, a weighing device, a conveying device and a pulping device which are sequentially connected, wherein the pulping device is connected with an ammonia distillation device, and lime milk prepared in the pulping device is conveyed into the ammonia distillation device to be mixed with an ammonium chloride solution for ammonia distillation.
5. A method for recycling a mixed salt solution, characterized in that the recycling system of any one of claims 1 to 4 is used for recycling the mixed salt solution, and the method comprises the following steps:
(1) the mixed salt solution reacts with a calcium chloride solution in a gypsum synthesis unit to generate gypsum and a sodium chloride solution, and the sodium chloride solution enters an evaporation unit to separate out partial sodium chloride crystals;
(2) the sodium chloride solution separated out of the sodium chloride crystals enters a reaction unit to react with the ammonium bicarbonate solution to generate sodium bicarbonate and ammonium chloride solution, and the sodium bicarbonate enters a calcining unit to be calcined to obtain sodium carbonate and carbon dioxide;
(3) the ammonium chloride solution is divided into two parts, one part enters a salting-out unit, and is mixed with sodium chloride crystals discharged from the evaporation unit in the step (1) for salting out, ammonium chloride crystals are separated out and sodium chloride solution is obtained, and the sodium chloride solution flows back to the evaporation unit; the other part of the calcium carbonate enters an ammonia distillation unit, is mixed with lime milk to distill ammonia to obtain calcium chloride and ammonia water, the ammonia water is combined with carbon dioxide discharged from a calcining unit to generate ammonium bicarbonate, the ammonium bicarbonate flows back to a reaction unit, and the calcium chloride flows back to a gypsum synthesis unit to supplement reaction raw materials.
6. A recycling method according to claim 5, characterized in that said recycling method comprises the steps of:
the method comprises the following steps of (I) reacting a mixed salt solution with a calcium chloride solution in a gypsum synthesis device to generate calcium sulfate and sodium chloride, filtering the calcium sulfate by a gypsum filtering device to obtain gypsum, and allowing the sodium chloride solution to enter an MVR evaporation device for evaporation and concentration to separate out partial sodium chloride crystals;
(II) allowing the sodium chloride solution with the sodium chloride crystals separated out to enter a reaction device to react with an ammonium bicarbonate solution to generate sodium bicarbonate and ammonium chloride, allowing the reaction solution to enter a separation device to separate sodium bicarbonate out, and introducing the sodium bicarbonate into a calcination device to perform steam calcination to obtain sodium carbonate and carbon dioxide;
(III) separating the reaction liquid of the sodium bicarbonate separated in the step (II) into two parts, putting one part into a salting-out device, adding the sodium chloride crystals separated out in the step (I) into the salting-out device, crystallizing to separate out ammonium chloride crystals and obtain a sodium chloride solution, drying the ammonium chloride crystals to obtain an ammonium chloride product, and refluxing the sodium chloride solution to an MVR evaporation device;
(IV) the other part of the reaction liquid in the step (III) enters an ammonia distillation device to carry out ammonia distillation reaction with lime milk to obtain ammonia-containing steam and a calcium chloride solution; wherein, ammonia-containing steam enters an ammonia concentration device to prepare ammonia water, and the ammonia water and carbon dioxide obtained by calcining the steam in the step (II) are subjected to gas-liquid contact reaction in a recovery device to generate ammonium bicarbonate solution required by the step (II); and (3) filtering the calcium chloride solution, and then refluxing to a gypsum synthesis device to be used as a reaction raw material in the step (I).
7. A resource processing method as claimed in claim 6, characterized in that, in the step (I), the mixed salt solution comprises sodium chloride and sodium sulfate;
preferably, the total content of sodium chloride and sodium sulfate in the mixed salt solution is 240 g/L, and further preferably, the total content of sodium chloride and sodium sulfate in the mixed salt solution is 160-200 g/L;
preferably, the temperature of the mixed salt solution entering the gypsum synthesis device is 30-60 ℃, and further preferably, the temperature of the mixed salt solution entering the gypsum synthesis device is 40-50 ℃;
preferably, a crystal transformation agent is added in the reaction process of the mixed salt solution and calcium chloride;
preferably, the crystal transformation agent comprises any one or a combination of at least two of citric acid, citrate or aluminate;
preferably, the adding mass of the crystal transformation agent is 0.1-0.25 wt% of the total mass of the reaction raw materials, and further preferably, the adding mass of the crystal transformation agent is 0.15-0.2 wt% of the total mass of the reaction raw materials;
preferably, the concentration of the calcium chloride solution is 150-230 g/L, and further preferably, the concentration of the calcium chloride solution is 180-200 g/L;
preferably, the reaction temperature of the mixed salt solution and the calcium chloride solution is 95-110 ℃, and further preferably, the reaction temperature of the mixed salt solution and the calcium chloride solution is 100-105 ℃;
preferably, the reaction time of the mixed salt solution and the calcium chloride solution is 1-2.5 h, and further preferably, the reaction time of the mixed salt solution and the calcium chloride solution is 1.5-2 h;
preferably, the gypsum obtained by filtering is α -hemihydrate high-strength gypsum;
preferably, the evaporative concentration is vacuum evaporation;
preferably, the temperature of the evaporation concentration is 60-90 ℃, and further preferably, the temperature of the evaporation concentration is 70-80 ℃.
8. A resource treatment method according to claim 6 or 7, characterized in that in the step (II), the content of sodium chloride in the sodium chloride solution after the sodium chloride crystals are separated out is 250-330 g/L;
preferably, the content of sodium chloride in the sodium chloride solution after the sodium chloride crystals are separated out is 280-300 g/L;
preferably, the concentration of the ammonium bicarbonate solution is 300-380 g/L, and further preferably, the concentration of the ammonium bicarbonate solution is 320-360 g/L;
preferably, the reaction temperature of the sodium chloride solution and the ammonium bicarbonate solution is 25-40 ℃, and further preferably, the reaction temperature of the sodium chloride solution and the ammonium bicarbonate solution is 30-35 ℃;
preferably, the reaction time of the sodium chloride solution and the ammonium bicarbonate solution is 1-2.5 h, and further preferably, the reaction time of the sodium chloride solution and the ammonium bicarbonate solution is 1.5-2 h;
preferably, the calcination temperature of the steam calcination is 90-120 ℃, and further preferably, the calcination temperature of the steam calcination is 100-110 ℃;
preferably, the calcination time of the steam calcination is 50-80 min, and further preferably, the calcination time of the steam calcination is 60-70 min.
9. A resource treatment method according to any one of claims 6 to 8, characterized in that in the step (III), the reaction solution from which the sodium bicarbonate is separated is frozen and then fed into a salting-out device;
preferably, the freezing temperature is 0-15 ℃, and further preferably, the freezing temperature is 5-10 ℃;
preferably, the temperature of the salting-out device is 5-20 ℃, and further preferably, the temperature of the salting-out device is 10-15 ℃;
preferably, the adding amount of the sodium chloride crystals in the salting-out device meets the crystallization requirement of ammonium chloride;
preferably, the adding amount of the sodium chloride crystals in the salting-out device is 7-15% of the excessive amount based on the requirement of meeting the ammonium chloride crystallization, and further preferably, the adding amount of the sodium chloride crystals in the salting-out device is 10-12% of the excessive amount based on the requirement of meeting the ammonium chloride crystallization;
preferably, the content of sodium chloride in the ammonium chloride solution obtained after crystallization of ammonium chloride crystals is 60 to 120 g/L, and more preferably 80 to 100 g/L.
10. A resource treatment method according to any one of claims 6 to 9, characterized in that in step (IV), the mole number of ammonium ions contained in the part of the reaction solution entering the ammonia still is 0.45 to 0.6 of the mole number of sulfate radicals in the mixed salt solution;
preferably, the mole number of ammonium ions contained in part of the reaction liquid entering the ammonia still is 0.5-0.55 of the mole number of sulfate radicals in the mixed salt solution;
preferably, the reaction temperature of the ammonia distillation reaction is 95-110 ℃, and further preferably, the reaction temperature of the ammonia distillation reaction is 100-105 ℃;
preferably, the reaction time of the ammonia distillation reaction is 50-80 min, and further preferably, the reaction time of the ammonia distillation reaction is 60-70 min;
preferably, the ammonia content of the ammonia-containing steam obtained by the ammonia distillation reaction is 10-15 wt%;
preferably, the mass concentration of the prepared ammonia water is 23-26 wt%, and further preferably, the mass concentration of the prepared ammonia water is 24-25 wt%;
preferably, the mass concentration of the ammonium bicarbonate solution is 20-25 wt%;
preferably, the concentration of the calcium chloride solution obtained by the ammonia distillation reaction is 150-200 g/L.
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CN114506861A (en) * 2021-12-20 2022-05-17 广东南方碱业股份有限公司 Comprehensive utilization method of industrial sodium sulfate/sodium chloride mixed waste salt
CN115634900A (en) * 2022-11-29 2023-01-24 国能龙源环保有限公司 Method and system for recycling solid waste miscellaneous salt resources

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CN101544437A (en) * 2009-04-30 2009-09-30 河北工业大学 Process method for recovering ammonium chloride and sodium chloride from waste water containing ammonium chloride and sodium chloride
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