CN108439448B - Natural alkali sodium bicarbonate mother liquor resource utilization system and treatment method thereof - Google Patents

Natural alkali sodium bicarbonate mother liquor resource utilization system and treatment method thereof Download PDF

Info

Publication number
CN108439448B
CN108439448B CN201810448729.3A CN201810448729A CN108439448B CN 108439448 B CN108439448 B CN 108439448B CN 201810448729 A CN201810448729 A CN 201810448729A CN 108439448 B CN108439448 B CN 108439448B
Authority
CN
China
Prior art keywords
unit
calcium carbonate
inlet
outlet
caustic soda
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201810448729.3A
Other languages
Chinese (zh)
Other versions
CN108439448A (en
Inventor
肖炘
王云山
安学斌
包炜军
宋菲
朱闽
杨仁春
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Institute of Process Engineering of CAS
Original Assignee
Institute of Process Engineering of CAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Institute of Process Engineering of CAS filed Critical Institute of Process Engineering of CAS
Priority to CN201810448729.3A priority Critical patent/CN108439448B/en
Publication of CN108439448A publication Critical patent/CN108439448A/en
Application granted granted Critical
Publication of CN108439448B publication Critical patent/CN108439448B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • C01F11/18—Carbonates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D1/00—Oxides or hydroxides of sodium, potassium or alkali metals in general
    • C01D1/04—Hydroxides
    • C01D1/20—Preparation by reacting oxides or hydroxides with alkali metal salts
    • C01D1/22—Preparation by reacting oxides or hydroxides with alkali metal salts with carbonates or bicarbonates
    • 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
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/60—Optical properties, e.g. expressed in CIELAB-values
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/141—Feedstock

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Abstract

The invention discloses a natural alkali sodium bicarbonate mother liquor resource utilization system and a treatment method thereof. The system comprises a lime slaking unit, a causticizing reaction unit, a slurry separation unit, a calcium carbonate whole grain carbonation unit, a calcium carbonate separation and drying unit, a caustic soda evaporation unit and a crystallization separation unit; the lime slaking unit is respectively connected with the quicklime feeding pipeline and the causticizing reaction unit; the causticization reaction unit is respectively connected with a trona sodium bicarbonate mother liquor feeding pipeline, a lime digestion unit and a slurry separation unit; the slurry separation unit is respectively connected with the causticization reaction unit, the calcium carbonate whole grain carbonation unit and the caustic soda evaporation unit; the calcium carbonate whole grain carbonation unit is respectively connected with the water feeding pipeline, the carbon dioxide feeding pipeline, the slurry separation unit and the calcium carbonate separation and drying unit; and the caustic soda evaporation unit is respectively connected with the slurry separation unit and the crystallization separation unit. The invention does not produce solid waste, and is a clean production technology of the mother solution of the sodium bicarbonate of natural alkali.

Description

Natural alkali sodium bicarbonate mother liquor resource utilization system and treatment method thereof
Technical Field
The invention belongs to the technical field of comprehensive utilization of trona, and relates to a trona baking soda mother liquor resource utilization system and a treatment method thereof.
Background
Trona contains various impurities, such as sodium sulfate, sodium chloride, etc., and in order to produce the desired pure alkaline product, it is necessary to first prepare the lye, then process the lye, by which method and process the finished product is soda ash, baking soda or caustic soda, depending on the content of the components in the lye. In the process, the mother liquor is recycled, and is reinjected to a mining area after the product is extracted to dissolve the trona. The salt in the natural alkali does not react with carbon dioxide chemically and remains in the alkali filtering mother liquor, and the mother liquor returns to dissolve alkali, so that the salt is accumulated in the mother liquor circularly. On one hand, due to the influence and unbalance problem of the mutual solubility of the salts, the concentration of the alkali liquor is difficult to reach the control index of the total alkali concentration, and the yield of the natural alkali product is influenced; on the other hand, the total salt content of the alkali liquor is too high, so that the content of soluble impurities is high, the amount of mother liquor carried in the crystals is increased, and the product quality is influenced.
The high-salt content of the trona reduces the solubility of the product in the actual production, and simultaneously precipitates together with the trona product in the evaporation concentration process as a result of the accumulation of sodium chloride in the system, so that the concentration of the sodium chloride must be controlled in the production, and part of the circulating mother liquor must be discharged.
The high salt content affects many aspects of trona production from mining to processing, as follows:
1. the quality of the high-salt-content trona product has no competitive advantage.
2. Sodium chloride is continuously accumulated in the recycling of mother liquor, and the normal operation of the production process is finally influenced, so that the yield is reduced year by year.
3. The high-salt mother liquor reinjection in the solution mining method pollutes the original trona ore, so that the grade of the trona is reduced.
4. Sodium chloride itself can accelerate corrosion and fouling of process equipment.
The random discharge of waste high-salt-content waste alkali liquor has adverse effects on local agriculture and environment.
The high salt content in the natural alkali causes great obstacles to the development of alkali industry in China. Therefore, the separation of salt from the system or the separation of salt and alkali from the waste liquid produced in the production process of trona is a difficult problem to be solved in the trona industry.
In order to solve the problems, the related technology of the saline-alkali separation gradually receives attention and research of people, and the basic principle of the mainstream method of the saline-alkali separation in China at present is to utilize the characteristic that the solubility of inorganic salt changes along with the temperature to carry out the saline-alkali separation, specifically to utilize a phase diagram of a saline-alkali liquor system to select better parameters to carry out the saline-alkali separation according to the solubility difference of sodium carbonate, sodium bicarbonate and sodium chloride at different temperatures. However, the main production area of the natural alkali in China is the south-yang area of Henan, is not the production area of coal and the like, and additionally, the conditions for establishing a salt pan are not provided, so that the mother liquor generated in the final section of baking soda production in the utilization of the natural alkali is utilized, and the first problem which troubles the utilization of the natural alkali is solved.
Dongypeng (experimental research on membrane separation in recycling of sodium bicarbonate mother liquor [ D ], beijing university of chemical industry, 2013) discloses a method for separating sodium bicarbonate mother liquor by using a membrane, wherein a nanofiltration membrane is used for carrying out salt and alkali separation on the sodium bicarbonate mother liquor, but the membrane needs to be replaced after being used for a period of time, so that not only waste is generated, but also the operating cost is increased.
Therefore, it would be of great interest in the art to develop a low cost, waste-free system and process for clean utilization of baking soda mother liquor.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a system for recycling soda ash mother liquor and a treatment method thereof. The system and the treatment method provided by the invention do not generate solid waste, and provide a way for the clean production technology of the soda mother liquor of the trona and the comprehensive utilization of the trona. The sodium bicarbonate mother liquor of trona in the invention refers to mother liquor generated in the process of producing sodium carbonate or sodium bicarbonate by trona.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides a trona baking soda mother liquor resource utilization system, which comprises: the device comprises a lime slaking unit, a causticizing reaction unit, a slurry separation unit, a calcium carbonate whole grain carbonation unit, a calcium carbonate separation and drying unit, a caustic soda evaporation unit and a crystallization separation unit;
the lime slaking unit is respectively connected with the quicklime feeding pipeline and the causticizing reaction unit;
the causticization reaction unit is respectively connected with the trona sodium bicarbonate mother liquor feeding pipeline, the lime digestion unit and the slurry separation unit;
the slurry separation unit is respectively connected with the causticization reaction unit, the calcium carbonate whole grain carbonation unit and the caustic soda evaporation unit;
the calcium carbonate whole grain carbonation unit is respectively connected with the water feeding pipeline, the carbon dioxide feeding pipeline, the slurry separation unit and the calcium carbonate separation and drying unit;
and the caustic soda evaporation unit is respectively connected with the slurry separation unit and the crystallization separation unit.
In the natural alkali sodium bicarbonate mother liquor resource utilization system provided by the invention, the lime digestion unit is used for carrying out digestion reaction to prepare lime milk; the causticizing reaction unit uses lime milk to carry out causticizing reaction on the mother liquor of the sodium bicarbonate of the trona to be treated to obtain mixed slurry consisting of light calcium carbonate intermediate products and a solution containing salt caustic soda; the slurry separation unit is used for carrying out solid-liquid separation on the mixed slurry obtained by the causticization reaction unit, the solid phase enters the calcium carbonate whole grain carbonation unit, and the liquid phase enters the caustic soda evaporation unit; the calcium carbonate whole grain carbonation unit carries out carbonation reaction and grinding shaping on the light calcium carbonate intermediate product obtained by separation, and the light calcium carbonate is sent to a subsequent calcium carbonate separation and drying unit to finally obtain the light calcium carbonate (the light calcium carbonate is also called precipitated calcium carbonate, is calcium carbonate prepared by a chemical processing method, and is called as the light calcium carbonate because the precipitation volume of the light calcium carbonate is larger than that of heavy calcium carbonate produced by a mechanical method); and the caustic soda evaporation unit is used for concentrating the separated salt-containing caustic soda solution and sending the concentrated salt-containing caustic soda solution into a subsequent crystallization separation unit for separation, so that the caustic soda solution and the salt-containing solid are finally obtained.
In the trona sodium bicarbonate mother liquor resource utilization system provided by the invention, the related main reaction formula is as follows:
CaO+H2O＝Ca(OH)2(1)
Ca(OH)2+Na2CO3＝CaCO3+2NaOH (2)
Ca(OH)2+NaHCO3＝CaCO3+NaOH+H2O (3)
wherein the reaction formula (1) is a reaction formula of lime slaking, and the reaction formulas (2) and (3) are reaction formulas of causticization reaction.
The following is a preferred technical solution of the present invention, but not a limitation to the technical solution provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solution.
As a preferable technical scheme of the invention, the lime slaking unit comprises a quicklime slaker and a lime milk vibrating screen, an inlet of the quicklime slaker is connected with a quicklime feeding pipeline, an outlet of the quicklime slaker is connected with an inlet of the lime milk vibrating screen, and an outlet of the lime milk vibrating screen is connected with the causticization reaction unit.
Preferably, the causticizing reaction unit comprises a causticizer, wherein an inlet of the causticizer is connected with an outlet of the lime milk vibrating screen, and an outlet of the causticizer is connected with the slurry separation unit.
In the invention, the lime milk vibrating screen can eliminate undigested impurities in the lime milk.
Preferably, a lye pump is arranged on a pipeline between the outlet of the causticizer and the slurry separation unit.
Preferably, the slurry separation unit comprises a belt vacuum filter, a material inlet of the belt vacuum filter is connected with an outlet of the causticizer, a solid outlet of the belt vacuum filter is connected with the calcium carbonate whole grain carbonation unit, and an alkali liquor outlet of the belt vacuum filter is connected with the caustic soda evaporation unit.
Preferably, the belt vacuum filter is sequentially distributed with a first-stage washing inlet, a second-stage washing inlet and a third-stage washing inlet along the direction far away from the material inlet, the first-stage washing inlet is connected with the first-stage washing liquid outlet, the second-stage washing inlet is connected with the second-stage washing liquid outlet, and the third-stage washing inlet is connected with the third-stage washing liquid outlet.
Preferably, a third-level washing liquid outlet of the belt type vacuum filter is connected with a second-level washing inlet, and a second-level washing pump is arranged on a pipeline between the third-level washing liquid outlet and the second-level washing inlet.
Preferably, a second-stage washing liquid outlet of the belt type vacuum filter is connected with a first-stage washing inlet, and a first-stage washing pump is arranged on a pipeline between the second-stage washing liquid outlet and the first-stage washing inlet.
Preferably, the primary washing liquid outlet of the belt type vacuum filter is connected with the inlet of the quicklime slaker.
Preferably, the belt vacuum filter is a moving disc belt vacuum filter.
As a preferable technical scheme of the invention, the calcium carbonate pelletizing carbonation unit comprises a pelletizing carbonation reactor, an inlet of the pelletizing carbonation reactor is respectively connected with a solid outlet of the belt vacuum filter, a water feeding pipeline and a carbon dioxide feeding pipeline, and an outlet of the pelletizing carbonation reactor is connected with the calcium carbonate separating and drying unit.
In the invention, the whole grain carbonation reactor can complete the pH value adjustment of the produced light calcium carbonate particles and the washing of sodium ions in filter cakes.
Preferably, the whole grain carbonation reactor contains grinding aid particles. The grinding-aid particles enable the whole-grain carbonation reactor to finish the shaping of the light calcium carbonate particles.
Preferably, the grinding aid particles are zirconia microspheres.
Preferably, a slurry pump is arranged on a pipeline between the outlet of the whole grain carbonation reactor and the calcium carbonate separation and drying unit.
Preferably, the calcium carbonate separation and drying unit comprises a filter press and a light calcium carbonate dryer, wherein an inlet of the filter press is connected with an outlet of the whole grain carbonation reactor, and a solid outlet of the filter press is connected with an inlet of the light calcium carbonate dryer.
Preferably, the liquid outlet of the filter press is connected to the tertiary wash inlet of the belt vacuum filter.
Preferably, a conveyor is arranged between the solid outlet of the filter press and the inlet of the light calcium carbonate dryer.
In the invention, the belt type vacuum filter, the filter press and the whole grain carbonation reactor are combined to form a set of system for washing, grain shaping and pH value adjustment, thereby realizing the functions of three times of in-situ washing and one time of slurry washing.
As the preferred technical scheme of the invention, the caustic soda evaporation unit comprises a mechanical compression steam preheater, a mechanical compression steam heater, a mechanical compression steam evaporation chamber and a four-effect evaporator, wherein a material inlet of the mechanical compression steam preheater is connected with an alkali liquor outlet of a belt type vacuum filter, a material outlet of the mechanical compression steam preheater is connected with a material inlet of the mechanical compression steam heater, a material outlet of the mechanical compression steam heater is connected with an inlet of the mechanical compression steam evaporation chamber, a liquid outlet of the mechanical compression steam evaporation chamber is connected with an inlet of the four-effect evaporator, an outlet of the four-effect evaporator is connected with a crystallization separation unit, and the four-effect evaporator is connected with a steam feeding pipeline.
Mechanical vapor compression (MVR) technology converts mechanical energy into heat energy, and efficiency is higher. In the invention, an MVR system comprising a mechanical compression steam preheater (MVR preheater), a mechanical compression steam heater (MVR heater) and a mechanical compression steam evaporation chamber (MVR evaporation chamber) is a key energy-saving device, so that the evaporation energy consumption can be greatly reduced. And in the four-effect evaporator, steam is efficiently utilized.
Preferably, the gas outlet of the mechanical compression steam evaporation chamber is connected with the heat exchange medium inlet of the mechanical compression steam heater.
Preferably, a mechanical compression vapor compressor (MVR compressor) is arranged between the gas outlet of the mechanical compression vapor evaporation chamber and the heat exchange medium inlet of the mechanical compression vapor heater.
Preferably, the heat exchange medium outlet of the mechanical compressed steam heater is connected with the heat exchange medium inlet of the mechanical compressed steam preheater.
Preferably, a mechanical compression steam circulating pump (MVR circulating pump) is arranged between the material outlet of the mechanical compression steam preheater and the material inlet of the mechanical compression steam heater.
Preferably, the liquid outlet of the mechanical compression steam evaporation chamber is also connected with the material inlet of the mechanical compression steam heater.
Preferably, a mechanical compression steam circulating pump (MVR circulating pump) is arranged between the liquid outlet of the mechanical compression steam evaporation chamber and the material inlet of the mechanical compression steam heater.
Preferably, the crystallization separation unit comprises a cooling crystallizer, and a material inlet of the cooling crystallizer is connected with an outlet of the four-effect evaporator.
Preferably, the cooling crystallizer is provided with a circulating cooling water inlet and a circulating cooling water outlet.
The natural alkali sodium bicarbonate mother liquor resource utilization system provided by the invention performs low-temperature causticization reaction on quick lime and natural alkali sodium bicarbonate mother liquor, and controls the reaction temperature and the reaction time to obtain a light calcium carbonate intermediate product and a caustic soda solution containing salt and sodium carbonate; carrying out slurrying washing on a filter cake generated by the belt type vacuum filter, grinding and shaping by utilizing grinding-aid particles in a whole grain carbonation reactor, introducing carbon dioxide for carbonation reaction, adjusting the pH value of a light calcium carbonate product, using the generated washing liquid for in-situ washing, and drying the generated filter cake to obtain the light calcium carbonate product; the method comprises the steps of firstly carrying out primary concentration on the caustic soda solution by utilizing the principle that the concentration of the caustic soda solution is increased and sodium chloride is crystallized and separated out, then further carrying out evaporation concentration on the caustic soda solution by utilizing a multi-effect evaporator to reach the mass concentration of about 40 wt%, thus obtaining the high-added-value product caustic soda, and simultaneously, crystallizing and separating out sodium chloride and sodium carbonate, thus being capable of being used as a high-quality raw material in the chlor-alkali industry.
The natural soda baking soda mother liquor resource utilization system provided by the invention is applied to the process for producing sodium carbonate or baking soda in the natural soda industry.
In a second aspect, the invention provides a treatment method of the trona baking soda mother liquor resource utilization system, which comprises the following steps:
(1) carrying out a digestion reaction on the raw material of the quicklime to obtain lime milk;
(2) mixing the lime milk obtained in the step (1) and the soda mother liquor of trona for causticization reaction to obtain mixed slurry consisting of a light calcium carbonate intermediate product and a salt-containing caustic soda solution;
(3) separating the mixed slurry consisting of the light calcium carbonate intermediate product and the salt-containing caustic soda solution in the step (2) into the light calcium carbonate intermediate product and the salt-containing caustic soda solution;
(4) mixing the light calcium carbonate intermediate product obtained in the step (3) with water and carbon dioxide, carrying out carbonation reaction, grinding and shaping simultaneously, and then separating and drying to obtain light calcium carbonate;
(5) and (4) evaporating, crystallizing and separating the salt-containing caustic soda solution obtained in the step (3) to obtain caustic soda solution and salt solid.
The treatment method provided by the invention has the advantages of simple process, easiness in operation and low cost, and is suitable for industrial production.
In the treatment method provided by the invention, the water in the step (4) mainly has the functions of pulping and washing, removing impurities and providing a solution environment for carbonation; the carbon dioxide can perform carbonation reaction with the intermediate product of the light calcium carbonate and also can play a role in adjusting the pH value of the light calcium carbonate product.
In a preferred embodiment of the present invention, in the step (1), the quicklime raw material has a quicklime mass fraction of 90 to 95 wt%, for example, 90%, 91%, 92%, 93%, 94%, or 95%, but not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.
Preferably, in step (1), the digestion reaction time is 1.5-2h, such as 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2.0h, but not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, step (1) further comprises: and after the digestion reaction, vibrating the lime milk to remove impurities.
Preferably, in step (2), the concentration of sodium bicarbonate in the trona sodium bicarbonate mother liquor is 45-60g/L, such as 45g/L, 50g/L, 52g/L, 54g/L, 56g/L, 58g/L or 60g/L, but not limited to the recited values, and other non-recited values within the range are equally applicable; the sodium carbonate concentration in the mother liquor of the sodium bicarbonate trona is 20-30g/L, such as 20g/L, 22g/L, 24g/L, 26g/L, 28g/L or 30g/L, etc., but the concentration is not limited to the recited values, and other values not recited in the numerical range are also applicable; the sodium chloride concentration in the mother liquor of the sodium bicarbonate is 60-90g/L, such as 60g/L, 65g/L, 70g/L, 75g/L, 80g/L, 85g/L or 90g/L, but the concentration is not limited to the recited values, and other values not recited in the numerical range are also applicable.
Preferably, in step (2), the causticizing reaction temperature is 35-60 ℃, for example, 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃ or 60 ℃, but not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, in the salt-containing caustic soda solution in the step (2), the concentration of caustic soda is 35-40g/L, such as 35g/L, 36g/L, 37g/L, 38g/L, 39g/L or 40g/L, etc., but not limited to the enumerated values, and other non-enumerated values in the numerical range are also applicable; the concentration of sodium carbonate in the solution containing salt caustic soda is 4-5g/L, such as 4g/L, 4.2g/L, 4.4g/L, 4.6g/L, 4.8g/L or 5g/L, etc., but is not limited to the recited values, and other non-recited values in the range of the values are also applicable; the concentration of sodium chloride in the solution containing salt of caustic soda is 55-65g/L, such as 55g/L, 57g/L, 59g/L, 61g/L, 63g/L or 65g/L, but is not limited to the recited values, and other values not recited in the range of values are also applicable.
As a preferable technical scheme of the invention, in the step (3), the separation is filtration separation by a belt type vacuum filter.
Preferably, the belt vacuum filter is a moving disc belt vacuum filter.
Preferably, the primary washing liquid of the belt vacuum filter is refluxed to the operation of the digestion reaction in the step (1).
As a preferable technical scheme of the invention, in the step (4), the temperature of the water is 20-30 ℃, namely the water temperature is normal temperature.
Preferably, in step (4), the mass ratio of water to the precipitated calcium carbonate intermediate product is (2-3):1, for example, 2.0:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1 or 3.0:1, but not limited to the recited values, and other values not recited in the numerical range are also applicable.
Preferably, in the step (4), the grinding and shaping are grinding and shaping under the action of grinding aid particles.
Preferably, in step (4), the separation is a filter press filtration separation.
Preferably, in the step (4), the liquid obtained by the separation is returned to the separation in the step (3) as a tertiary washing liquid.
Preferably, in the step (4), the drying is dryer drying.
Preferably, in step (4), the dry heat source comprises hot air and/or steam. In the present invention, the hot air and/or steam may be hot air, steam, or a combination of hot air and steam.
Preferably, in step (4), the drying temperature is 110-.
In the preferred technical scheme of the invention, in the step (5), the evaporation comprises mechanical compression steam system evaporation and four-effect evaporation.
Preferably, the operating pressure of the mechanical compression vapor system is negative pressure.
Preferably, the mechanical compression vapor system is operated at an absolute pressure of 60 to 70kPa, such as 60kPa, 62kPa, 65kPa, or 70kPa, but not limited to the recited values, and other values not recited in this range are equally applicable.
Preferably, the temperature of the input steam for the four-effect evaporation is 150-.
Preferably, the input steam pressure of the four-way evaporation is 0.6-0.8MPa, such as 0.6MPa, 0.65MPa, 0.7MPa, 0.75MPa or 0.8MPa, but not limited to the values listed, and other values not listed in this range are equally applicable.
Preferably, the input steam of the four-effect evaporation is saturated steam.
Preferably, in step (5), the temperature at which the crystals are isolated is in the range of 15 to 35 ℃, such as 15 ℃,20 ℃, 25 ℃, 30 ℃ or 35 ℃, but is not limited to the recited values, and other values not recited within this range are equally applicable.
Preferably, in the step (5), the cooling medium for crystallization separation is circulating cooling water.
Preferably, in the step (5), the mass fraction of the caustic soda in the caustic soda solution is 40 wt%.
Preferably, in step (5), the salt solid is alkali-containing sodium chloride.
As a further preferred technical solution of the method of the present invention, the method comprises the steps of:
(1) carrying out a digestion reaction on the raw material of the quicklime for 1.5-2h, and vibrating and removing impurities from the lime milk after the digestion reaction to obtain the lime milk;
wherein the mass fraction of the quicklime raw material is 90-95 wt%;
(2) mixing the lime milk obtained in the step (1) with soda mother liquor of natural alkali, and carrying out causticization reaction at 35-60 ℃ to obtain mixed slurry consisting of a light calcium carbonate intermediate product and a salt-containing caustic soda solution;
wherein, in the mother liquor of the sodium bicarbonate of the trona, the concentration of sodium bicarbonate is 45-60g/L, the concentration of sodium carbonate is 20-30g/L, and the concentration of sodium chloride is 60-90 g/L;
(3) filtering and separating the mixed slurry consisting of the light calcium carbonate intermediate product and the salt-containing caustic soda solution in the step (2) into the light calcium carbonate intermediate product and the salt-containing caustic soda solution by using a moving disc belt type vacuum filter, and refluxing a primary washing liquid to the digestion reaction operation in the step (1);
(4) mixing the light calcium carbonate intermediate product obtained in the step (3) with water and carbon dioxide, carrying out carbonation reaction, grinding and shaping simultaneously, filtering and separating by using a filter press, and drying at the temperature of 110-;
wherein the mass ratio of the water to the light calcium carbonate intermediate product is (2-3) to 1, the liquid obtained by filtering and separating by the filter press is returned to the moving disc belt type vacuum filter in the step (3) for filtering and separating as a third-level washing liquid, and the heat source for drying comprises hot air and/or steam;
(5) and (4) performing mechanical compression steam system evaporation and four-effect evaporation on the salt-containing caustic soda solution obtained in the step (3), and then performing crystallization separation at 15-35 ℃ by using circulating cooling water as a cooling medium to obtain 40 wt% of caustic soda solution and alkali-containing sodium chloride.
Wherein the absolute pressure of the mechanical compression steam system is 60-70Kpa, and the input steam of the four-effect evaporation is 150-180 ℃ saturated steam with gauge pressure of 0.6-0.8 Mpa.
Compared with the prior art, the invention has the following beneficial effects:
(1) the natural alkali sodium bicarbonate mother liquor resource utilization system provided by the invention prepares the natural alkali sodium bicarbonate mother liquor into caustic soda solution and light calcium carbonate products, does not generate solid waste and liquid waste, and realizes clean utilization of the natural alkali sodium bicarbonate mother liquor; the mass concentration of the caustic soda solution reaches 40 wt%, the sedimentation volume of the light calcium carbonate product is 2.5-2.9mL/g, the pH value is 7-8.5, and the sodium ion content is 0.1-0.15 wt%;
(2) the treatment method provided by the invention has the advantages of simple process, easiness in operation and low cost, and is suitable for industrial production.
Drawings
FIG. 1 is a schematic view of a trona baking soda mother liquor resource utilization system in example 1 of the present invention;
wherein, 1-quicklime slaker; 2-lime milk vibrating screen; 3-a causticizer; 4-lye pump; 5-a belt vacuum filter; 6-granulation carbonation reactor; 7-a secondary washing pump; 8-first-stage washing pump; 9-pulping pump; 10-a filter press; 11-a conveyor; 12-light calcium drier; 13-mechanical compression steam preheater; 14-mechanical compression steam heater; 15-a mechanical compression vapor compressor; 16-a mechanically compressed vapor evaporation chamber; 17-mechanically compressing the vapor circulation pump; 18-four effect evaporators; 19-cooling the crystallizer;
fig. 2 is a schematic flow chart of a treatment method of a trona baking soda mother liquor resource utilization system in embodiment 1 of the invention.
Detailed Description
In order to better illustrate the present invention and facilitate the understanding of the technical solutions of the present invention, the present invention is further described in detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.
The mother liquor of sodium bicarbonate and quicklime used in the embodiment of the invention are both from Anhuzhen town of Tubai county of south-Yang city of Henan province.
The light calcium carbonate prepared by the embodiment of the invention refers to the chemical industry standard HG/T2226-2010 of common industrial precipitated calcium carbonate, and the specific indexes of the standard are shown in Table 1.
TABLE 1
Figure BDA0001657903810000131
The following are typical but non-limiting examples of the invention:
example 1
A natural alkali sodium bicarbonate mother liquor resource utilization system is shown in figure 1, and comprises a lime digestion unit, a causticization reaction unit, a slurry separation unit, a calcium carbonate whole grain carbonation unit, a calcium carbonate separation and drying unit, a caustic soda evaporation unit and a crystallization separation unit.
The lime slaking unit comprises a quick lime slaker 1 and a lime milk vibrating screen 2, an inlet of the quick lime slaker 1 is connected with a quick lime feeding pipeline, an outlet of the quick lime slaker 1 is connected with an inlet of the lime milk vibrating screen 2, and an outlet of the lime milk vibrating screen 2 is connected with the causticization reaction unit.
The causticizing reaction unit comprises a causticizer 3, wherein an inlet of the causticizer 3 is connected with an outlet of the lime milk vibrating screen 2, and an outlet of the causticizer 3 is connected with the slurry separation unit; and an alkali liquid pump 4 is arranged on a pipeline between the outlet of the causticizer 3 and the slurry separation unit.
The slurry separation unit comprises a belt type vacuum filter 5, a material inlet of the belt type vacuum filter 5 is connected with an outlet of the causticizer 3, a solid outlet of the belt type vacuum filter 5 is connected with the calcium carbonate whole grain carbonation unit, and an alkali liquor outlet of the belt type vacuum filter 5 is connected with the caustic soda evaporation unit; the belt type vacuum filter 5 is sequentially provided with a first-stage washing inlet, a second-stage washing inlet and a third-stage washing inlet along the direction far away from the material inlet, the first-stage washing inlet is connected with the first-stage washing liquid outlet, the second-stage washing inlet is connected with the second-stage washing liquid outlet, and the third-stage washing inlet is connected with the third-stage washing liquid outlet; a third-level washing liquid outlet of the belt type vacuum filter 5 is connected with a second-level washing inlet, and a second-level washing pump 7 is arranged on a pipeline between the third-level washing liquid outlet and the second-level washing inlet; a secondary washing liquid outlet of the belt type vacuum filter 5 is connected with a primary washing inlet, and a primary washing pump 8 is arranged on a pipeline between the secondary washing liquid outlet and the primary washing inlet; the first-stage washing liquid outlet of the belt type vacuum filter 5 is connected with the inlet of the quicklime slaker 1; the belt type vacuum filter 5 is a movable disc belt type vacuum filter.
The calcium carbonate pelletizing carbonation unit comprises a pelletizing carbonation reactor 6, an inlet of the pelletizing carbonation reactor 6 is respectively connected with a solid outlet of the belt type vacuum filter 5, a water feeding pipeline and a carbon dioxide feeding pipeline, and an outlet of the pelletizing carbonation reactor 6 is connected with the calcium carbonate separation and drying unit; the whole grain carbonation reactor 6 contains zirconia microspheres grinding aid particles; and a pulping pump 9 is arranged on a pipeline between the outlet of the whole grain carbonation reactor 6 and the calcium carbonate separation and drying unit.
The calcium carbonate separation and drying unit comprises a filter press 10 and a light calcium carbonate dryer 12, wherein the inlet of the filter press 10 is connected with the outlet of the whole grain carbonation reactor 6, and the solid outlet of the filter press 10 is connected with the inlet of the light calcium carbonate dryer 12; the liquid outlet of the filter press 10 is connected with the three-stage washing inlet of the belt vacuum filter 5; a conveyor 11 is arranged between the solid outlet of the filter press 10 and the inlet of the light calcium carbonate dryer 12.
The caustic soda evaporation unit comprises a mechanical compression steam preheater 13, a mechanical compression steam heater 14, a mechanical compression steam evaporation chamber 16 and a four-effect evaporator 18, wherein a material inlet of the mechanical compression steam preheater 13 is connected with an alkali liquor outlet of the belt type vacuum filter 5, a material outlet of the mechanical compression steam preheater 13 is connected with a material inlet of the mechanical compression steam heater 14, a material outlet of the mechanical compression steam heater 14 is connected with an inlet of the mechanical compression steam evaporation chamber 16, a liquid outlet of the mechanical compression steam evaporation chamber 16 is connected with a material inlet of the four-effect evaporator 18, a material outlet of the four-effect evaporator 18 is connected with a crystallization separation unit, a steam inlet of the four-effect evaporator 18 is connected with a steam feeding pipeline, and the four-effect evaporator 18 is also provided with a condensate outlet; the gas outlet of the mechanical compression steam evaporation chamber 16 is connected with the heat exchange medium inlet of the mechanical compression steam heater 14; a mechanical compression steam compressor 15 is arranged between a gas outlet of the mechanical compression steam evaporation chamber 16 and a heat exchange medium inlet of the mechanical compression steam heater 14; the outlet of the heat exchange medium of the mechanical compression steam heater 14 is connected with the inlet of the heat exchange medium of the mechanical compression steam preheater 13; a mechanical compression steam circulating pump 17 is arranged between the material outlet of the mechanical compression steam preheater 13 and the material inlet of the mechanical compression steam heater 14; the mechanical compression steam preheater 13 is also provided with a condensate outlet; the liquid outlet of the mechanical compression vapor evaporation chamber 16 is also connected to the material inlet of the mechanical compression vapor heater 14.
In this embodiment, the mechanical compression steam preheater 13, the mechanical compression steam heater 14, the mechanical compression steam compressor 15, the mechanical compression steam evaporation chamber 16, and the mechanical compression steam circulation pump 17 constitute an MVR system.
The crystallization separation unit comprises a cooling crystallizer 19, and a material inlet of the cooling crystallizer 19 is connected with an outlet of the four-effect evaporator 18; the cooling crystallizer 19 is provided with a circulating cooling water inlet and a circulating cooling water outlet.
The treatment method of the trona sodium bicarbonate mother liquor resource utilization system provided by the embodiment comprises the following steps:
(1) firstly, adding 90 wt% of quicklime 45Kg into a quicklime slaker, adding 140Kg of first-stage washing liquid, slaking for 1.5h, and then passing the slaked material through a lime milk vibrating screen to remove undigested impurities to obtain pure lime milk;
(2) adding sodium bicarbonate mother liquor of trona 1m into causticizer3In which NaHCO3The mass concentration is 45g/L and Na2CO3The mass concentration is 20g/L, and the NaCl mass concentration is 60 g/L; slowly adding the lime milk into a causticizer, and carrying out causticization reaction under stirring, wherein the causticization temperature is 35 ℃;
(3) performing three-stage countercurrent washing on the causticized material on a belt type vacuum filter, wherein three-stage washing water is from filter liquor of a plate and frame filter press, second-stage washing water is third-stage washing filter liquor, first-stage washing water is second-stage washing filter liquor, and the obtained first-stage washing liquid is used for slaking next batch of quicklime; filtering to obtain a water-containing filter cake (a light calcium carbonate intermediate product) and feeding the water-containing filter cake into a whole grain carbonation reactor; the mass concentration of NaOH in the solution containing salt caustic soda obtained by the vacuum filter is 35g/L, Na2CO3The mass concentration is 4g/L, and the mass concentration of NaCl is 55 g/L; the saline caustic soda solution enters an MVR system;
(4) adding fresh water into the whole grain carbonation reactor to carry out pulping washing on the water-containing filter cake obtained in the step (3), wherein the mass ratio of washing water to the filter cake is 2.0:1, the washing water temperature is normal temperature, carbon dioxide is introduced for carbonation, and zirconium oxide microspheres serving as grinding aid particles are added into the whole grain carbonation reactor to carry out grinding and shaping on calcium carbonate; the material in the slurry dissolving tank is pumped to a plate-and-frame filter press for filtration, the filtrate is used as the three-stage washing water of a vacuum filter, the filter cake is conveyed to a dryer by a conveyor, hot air is used as a heat source, and the drying is carried out at the temperature of 150 ℃ to obtain 75Kg of light calcium carbonate product;
(5) the saline caustic soda solution enters an MVR system and is evaporated under the absolute pressure of 60Kpa, so that the mass concentration of NaOH in the solution reaches 150 g/L; the solution after MVR evaporation enters a four-effect evaporator, and is evaporated under the conditions that the gauge pressure is 0.6Mpa and the steam temperature is 150 ℃, so that the mass concentration of NaOH in the solution reaches 40 wt%; and (3) feeding the evaporated material into a cooling crystallizer, taking circulating cooling water as a cooling medium, cooling and crystallizing at 15 ℃, and performing centrifugal separation to obtain 95.2Kg of caustic soda solution and 68.5Kg of sodium chloride with the mass concentration of 40.1 wt%, wherein the mass percentage of the alkali in the NaCl is 9.9 wt%, and the mass percentage of the sodium chloride is 90.1%.
The flow schematic diagram of the treatment method of the trona baking soda mother liquor resource utilization system of the embodiment is shown in fig. 2.
The precipitated calcium carbonate product prepared in this example substantially meets the first-class standard specifications, and the composition thereof is shown in table 2.
Example 2
The natural soda mother liquor resource utilization system is the same as that in the embodiment 1.
The treatment method of the trona sodium bicarbonate mother liquor resource utilization system provided by the embodiment comprises the following steps:
(1) adding 48Kg of quicklime with the mass percentage of 93 wt% into a quicklime slaker, adding 145Kg of first-stage washing liquid, slaking for 1.8h, and then passing the slaked material through a lime milk vibrating screen to remove undigested impurities to obtain pure lime milk;
(2) adding sodium bicarbonate mother liquor of trona 1m into causticizer3In which NaHCO3The mass concentration is 50g/L, Na2CO3The mass concentration is 25g/L, and the NaCl mass concentration is 75 g/L; slowly adding the lime milk into a causticizer, and carrying out causticization reaction under stirring, wherein the causticization temperature is 50 ℃;
(3) performing three-stage countercurrent washing on the causticized material on a belt type vacuum filter, wherein three-stage washing water is from filter liquor of a plate and frame filter press, second-stage washing water is third-stage washing filter liquor, first-stage washing water is second-stage washing filter liquor, and the obtained first-stage washing liquid is used for slaking next batch of quicklime; filtering to obtain a water-containing filter cake (a light calcium carbonate intermediate product) and feeding the water-containing filter cake into a whole grain carbonation reactor; the mass concentration of NaOH in the solution containing salt caustic soda obtained by the vacuum filter is 38g/L, Na2CO3The mass concentration is 4.5g/L, and the mass concentration of NaCl is 60 g/L; the saline caustic soda solution enters an MVR system;
(4) adding fresh water into the whole grain carbonation reactor to carry out pulping washing on the water-containing filter cake obtained in the step (3), wherein the mass ratio of washing water to the filter cake is 2.5:1, the washing water temperature is normal temperature, carbon dioxide is introduced for carbonation, and zirconium oxide microspheres serving as grinding aid particles are added into the whole grain carbonation reactor to carry out grinding and shaping on calcium carbonate; the material in the slurry dissolving tank is pumped to a plate-and-frame filter press for filtration, the filtrate is used as the three-stage washing water of a vacuum filter, the filter cake is conveyed to a dryer by a conveyor, and the filter cake is dried at 110 ℃ by taking steam as a heat source to obtain 78Kg of light calcium carbonate product;
(5) the saline caustic soda solution enters an MVR system and is evaporated under the absolute pressure of 65Kpa, so that the mass concentration of NaOH in the solution reaches 150 g/L; the solution after MVR evaporation enters a four-effect evaporator, and is evaporated under the conditions that the gauge pressure is 0.7Mpa and the steam temperature is 170 ℃, so that the mass concentration of NaOH in the solution reaches 40 wt%; and (3) feeding the evaporated material into a cooling crystallizer, taking circulating cooling water as a cooling medium, cooling and crystallizing at 25 ℃, and performing centrifugal separation to obtain 94.9Kg of caustic soda solution and 68.2Kg of sodium chloride with the mass concentration of 40.2 wt%, wherein the mass percentage of the alkali in the NaCl is 10.1 wt%, and the mass percentage of the sodium chloride is 89.9%.
The precipitated calcium carbonate product prepared in this example substantially meets the first-class standard specifications, and the composition thereof is shown in table 2.
Example 3
The natural soda mother liquor resource utilization system is the same as that in the embodiment 1.
The treatment method of the trona sodium bicarbonate mother liquor resource utilization system provided by the embodiment comprises the following steps:
(1) adding 50Kg of quicklime with the mass percentage of 95 wt% into a quicklime slaker, adding 150Kg of first-level washing liquid, slaking for 2 hours, and then passing the slaked material through a lime milk vibrating screen to remove undigested impurities to obtain pure lime milk;
(2) adding sodium bicarbonate mother liquor of trona 1m into causticizer3In which NaHCO3The mass concentration is 60g/L, Na2CO3The mass concentration is 30g/L, and the NaCl mass concentration is 90 g/L; slowly adding the lime milk into a causticizer, and carrying out causticization reaction under stirring, wherein the causticization temperature is 60 ℃;
(3) performing three-stage countercurrent washing on the causticized material on a belt type vacuum filter, wherein three-stage washing water is from filter liquor of a plate and frame filter press, second-stage washing water is third-stage washing filter liquor, first-stage washing water is second-stage washing filter liquor, and the obtained first-stage washing liquid is used for slaking next batch of quicklime; filtering to obtain a water-containing filter cake (a light calcium carbonate intermediate product) and feeding the water-containing filter cake into a whole grain carbonation reactor; the mass concentration of NaOH in the salt-containing caustic soda solution obtained by the vacuum filter is 40g/L,Na2CO3the mass concentration is 5g/L, and the mass concentration of NaCl is 65 g/L; the saline caustic soda solution enters an MVR system;
(4) adding fresh water into the whole grain carbonation reactor to carry out pulping washing on the water-containing filter cake obtained in the step (3), wherein the mass ratio of washing water to the filter cake is 3:1, the washing water temperature is normal temperature, carbon dioxide is introduced for carbonation, and zirconium oxide microspheres are added into the whole grain carbonation reactor as grinding aid particles to carry out grinding and shaping on calcium carbonate; the material in the slurry dissolving tank is pumped to a plate-and-frame filter press for filtration, the filtrate is used as the three-stage washing water of a vacuum filter, the filter cake is conveyed to a dryer by a conveyor, and the filter cake is dried at 130 ℃ by taking steam as a heat source to obtain 85Kg of light calcium carbonate product;
(5) the saline caustic soda solution enters an MVR system and is evaporated under the absolute pressure of 70Kpa, so that the mass concentration of NaOH in the solution reaches 150 g/L; the solution after MVR evaporation enters a four-effect evaporator, and is evaporated under the conditions that the gauge pressure is 0.8Mpa and the steam temperature is 180 ℃, so that the mass concentration of NaOH in the solution reaches 40 wt%; the evaporated material enters a cooling crystallizer, circulating cooling water is used as a cooling medium, cooling crystallization is carried out at 35 ℃, and 95.1Kg of caustic soda solution with the mass concentration of 40.0 wt% and 68.0Kg of sodium chloride are obtained through centrifugal separation, wherein the mass percentage of the alkali in the NaCl is 10.0 wt%, and the mass percentage of the sodium chloride is 90.0%.
The precipitated calcium carbonate product prepared in this example substantially meets the first-class standard specifications, and the composition thereof is shown in table 2.
Comparative example 1
The trona baking soda mother liquor resource utilization system of this comparative example is referenced to example 1 with the difference that the calcium carbonate trim carbonation unit, i.e. the trim carbonation reactor 6, is not included.
Referring to example 1, the difference is that in step (3), the water-containing filter cake obtained by filtration does not enter the whole grain carbonation reactor, but directly enters the plate and frame filter press after being mixed with water; in the step (4), the filter cake containing water is directly filtered in a plate-and-frame filter press, the filtrate is used as the three-stage washing water of a vacuum filter, the filter cake is conveyed to a dryer by a conveyor, and the filter cake is dried at the temperature of 150 ℃ by taking hot air as a heat source.
The results of this comparative example are a reduction in purity, a higher pH, a reduction in the sediment volume, and a reduction in the whiteness of the calcium carbonate product; this is because the formation and concentration of caustic soda in the causticization reaction inhibit the conversion of calcium hydroxide, and the causticization reaction is difficult to complete.
The composition of the precipitated calcium carbonate product obtained in this comparative example is shown in Table 2.
TABLE 2 light calcium carbonate product characterization data Table for examples and comparative examples
Figure BDA0001657903810000201
It can be known from the synthesis of the above examples and comparative examples that the trona sodium bicarbonate mother liquor resource utilization system provided by the invention does not generate solid waste and liquid waste, realizes the clean utilization of the trona sodium bicarbonate mother liquor, and the quality of the prepared caustic soda solution and light calcium carbonate product is good. In the treatment method of the trona sodium bicarbonate mother liquor resource utilization system, the pH value of the system can be reduced in the whole grain carbonation process, so that the reaction is more thorough, the grain diameter and the appearance of the product can be improved by the whole grain function, the increase of the sedimentation volume and the reduction of the impurity content are promoted, and the whiteness is increased. The comparative example did not adopt the scheme of the present invention, and thus the effects of the present invention could not be obtained.
The applicant states that the present invention is illustrated by the above examples to show the detailed process equipment and process flow of the present invention, but the present invention is not limited to the above detailed process equipment and process flow, i.e. it does not mean that the present invention must rely on the above detailed process equipment and process flow to be implemented. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims (51)

1. A method for resource utilization of sodium bicarbonate mother liquor of trona is characterized by comprising the following steps:
(1) carrying out a digestion reaction on the raw material of the quicklime to obtain lime milk;
(2) mixing the lime milk obtained in the step (1) and the soda mother liquor of trona for causticization reaction to obtain mixed slurry consisting of a light calcium carbonate intermediate product and a salt-containing caustic soda solution;
(3) separating the mixed slurry consisting of the light calcium carbonate intermediate product and the salt-containing caustic soda solution in the step (2) into the light calcium carbonate intermediate product and the salt-containing caustic soda solution;
(4) mixing the light calcium carbonate intermediate product obtained in the step (3) with water and carbon dioxide, carrying out carbonation reaction, grinding and shaping simultaneously, and then separating and drying to obtain light calcium carbonate;
(5) evaporating, crystallizing and separating the salt-containing caustic soda solution obtained in the step (3) to obtain caustic soda solution and salt solid;
in the step (2), the concentration of sodium bicarbonate in the mother liquor of the sodium bicarbonate is 45-60g/L, the concentration of sodium carbonate is 20-30g/L, and the concentration of sodium chloride is 60-90 g/L;
in the step (3), the separation is the filtration and separation of a belt type vacuum filter (5);
in the step (5), the evaporation comprises mechanical compression steam system evaporation and four-effect evaporation;
the method is processed by a system comprising: the device comprises a lime slaking unit, a causticizing reaction unit, a slurry separation unit, a calcium carbonate whole grain carbonation unit, a calcium carbonate separation and drying unit, a caustic soda evaporation unit and a crystallization separation unit;
the lime slaking unit is respectively connected with the quicklime feeding pipeline and the causticizing reaction unit;
the causticization reaction unit is respectively connected with the trona sodium bicarbonate mother liquor feeding pipeline, the lime digestion unit and the slurry separation unit;
the slurry separation unit is respectively connected with the causticization reaction unit, the calcium carbonate whole grain carbonation unit and the caustic soda evaporation unit;
the calcium carbonate whole grain carbonation unit is respectively connected with the water feeding pipeline, the carbon dioxide feeding pipeline, the slurry separation unit and the calcium carbonate separation and drying unit;
the caustic soda evaporation unit is respectively connected with the slurry separation unit and the crystallization separation unit;
the slurry separation unit comprises a belt type vacuum filter (5), and the caustic soda evaporation unit comprises a mechanical compression steam preheater (13), a mechanical compression steam heater (14), a mechanical compression steam evaporation chamber (16) and a four-effect evaporator (18).
2. The method according to claim 1, characterized in that the lime slaking unit comprises a quicklime slaker (1) and a lime milk vibrating screen (2), the inlet of the quicklime slaker (1) is connected with a quicklime feeding pipeline, the outlet of the quicklime slaker (1) is connected with the inlet of the lime milk vibrating screen (2), and the outlet of the lime milk vibrating screen (2) is connected with the causticizing reaction unit.
3. A method according to claim 2, characterized in that the causticizing reaction unit comprises a causticizer (3), the inlet of which causticizer (3) is connected to the outlet of a lime milk vibrating screen (2), and the outlet of the causticizer (3) is connected to a slurry separation unit.
4. A method according to claim 3, characterized in that a lye pump (4) is provided in the line between the outlet of the causticizer (3) and the slurry separation unit.
5. The method according to claim 3, characterized in that the slurry separation unit comprises a belt vacuum filter (5), the material inlet of the belt vacuum filter (5) is connected to the outlet of the causticizer (3), the solids outlet of the belt vacuum filter (5) is connected to the calcium carbonate granulation carbonation unit, and the lye outlet of the belt vacuum filter (5) is connected to the caustic soda evaporation unit.
6. The method according to claim 5, characterized in that the belt vacuum filter (5) is provided with a primary washing inlet, a secondary washing inlet and a tertiary washing inlet in sequence along the direction far away from the material inlet, wherein the primary washing inlet is connected with the primary washing liquid outlet, the secondary washing inlet is connected with the secondary washing liquid outlet, and the tertiary washing inlet is connected with the tertiary washing liquid outlet.
7. A method according to claim 5, characterized in that the belt vacuum filter (5) is provided with a tertiary washing liquid outlet connected to a secondary washing inlet, and a secondary washing pump (7) is provided in the pipe between the tertiary washing liquid outlet and the secondary washing inlet.
8. A method according to claim 5, characterized in that the belt vacuum filter (5) is provided with a secondary washing liquid outlet connected to the primary washing inlet, and a primary washing pump (8) is provided in the pipe between the secondary washing liquid outlet and the primary washing inlet.
9. A method according to claim 6, characterized in that the primary washing liquid outlet of the belt vacuum filter (5) is connected to the inlet of the slaker of burnt lime (1).
10. The method according to claim 5, wherein the belt vacuum filter (5) is a moving tray belt vacuum filter.
11. The method according to claim 5, characterized in that the calcium carbonate pelletizing carbonation unit comprises a pelletizing carbonation reactor (6), the inlet of the pelletizing carbonation reactor (6) being connected to the solids outlet of the belt vacuum filter (5), the water feed line and the carbon dioxide feed line, respectively, and the outlet of the carbonation pelletizing reactor (6) being connected to the calcium carbonate separation drying unit.
12. The method according to claim 11, characterized in that grinding aid particles are contained in the whole grain carbonation reactor (6).
13. The method of claim 12 wherein the grinding aid particles are zirconia microspheres.
14. The method according to claim 11, characterized in that a slurry pump (9) is provided on the piping between the outlet of the granular carbonation reactor (6) and the calcium carbonate separation and drying unit.
15. The method according to claim 11, characterized in that the calcium carbonate separation drying unit comprises a filter press (10) and a light calcium carbonate dryer (12), the inlet of the filter press (10) being connected to the outlet of the whole grain carbonation reactor (6), the solids outlet of the filter press (10) being connected to the inlet of the light calcium carbonate dryer (12).
16. The method according to claim 15, characterized in that the liquid outlet of the filter press (10) is connected to the three-stage washing inlet of the belt vacuum filter (5).
17. The method according to claim 15, characterized in that a conveyor (11) is provided between the solids outlet of the filter press (10) and the inlet of the light calcium dryer (12).
18. The method according to claim 5, characterized in that the caustic soda evaporation unit comprises a mechanical compression steam preheater (13), a mechanical compression steam heater (14), a mechanical compression steam evaporation chamber (16) and a four-effect evaporator (18), the material inlet of the mechanical compression steam preheater (13) is connected with the alkali liquor outlet of the belt type vacuum filter (5), the material outlet of the mechanical compression steam preheater (13) is connected with the material inlet of the mechanical compression steam heater (14), the material outlet of the mechanical compression steam heater (14) is connected with the inlet of the mechanical compression steam evaporation chamber (16), the liquid outlet of the mechanical compression steam evaporation chamber (16) is connected with the inlet of the four-effect evaporator (18), the outlet of the four-effect evaporator (18) is connected with the crystallization separation unit, and the four-effect evaporator (18) is connected with the steam feeding pipeline.
19. Method according to claim 18, characterized in that the gas outlet of the mechanical compression vapour evaporation chamber (16) is connected to the heat exchange medium inlet of the mechanical compression vapour heater (14).
20. Method according to claim 18, characterized in that a mechanical compression vapour compressor (15) is arranged between the gas outlet of the mechanical compression vapour evaporation chamber (16) and the heat exchange medium inlet of the mechanical compression vapour heater (14).
21. Method according to claim 18, characterized in that the heat exchange medium outlet of the mechanical compressed steam heater (14) is connected to the heat exchange medium inlet of the mechanical compressed steam preheater (13).
22. Method according to claim 18, characterized in that a mechanical compressed steam circulation pump (17) is provided between the material outlet of the mechanical compressed steam preheater (13) and the material inlet of the mechanical compressed steam heater (14).
23. The method of claim 18, wherein the liquid outlet of the mechanical compression vapor evaporation chamber (16) is further connected to the feed inlet of the mechanical compression vapor heater (14).
24. Method according to claim 18, characterized in that a mechanical compressed vapor circulation pump (17) is provided between the liquid outlet of the mechanical compressed vapor evaporation chamber (16) and the feed inlet of the mechanical compressed vapor heater (14).
25. The method according to claim 18, wherein the crystallization separation unit comprises a cooling crystallizer (19), and a material inlet of the cooling crystallizer (19) is connected with an outlet of the four-effect evaporator (18).
26. Method according to claim 25, characterized in that the cooling crystallizer (19) is provided with a circulating cooling water inlet and a circulating cooling water outlet.
27. The method as claimed in claim 1, wherein in the step (1), the quicklime mass fraction of the quicklime raw material is 90-95 wt%.
28. The method according to claim 1, wherein in the step (1), the digestion reaction time is 1.5-2 h.
29. The method of claim 1, wherein step (1) further comprises: and after the digestion reaction, vibrating the lime milk to remove impurities.
30. The method of claim 1, wherein in step (2), the causticizing reaction temperature is 35-60 ℃.
31. The method according to claim 1, wherein in the step (2), the concentration of the caustic soda in the solution containing the salt of caustic soda is 35-40g/L, the concentration of the sodium carbonate is 4-5g/L, and the concentration of the sodium chloride is 55-65 g/L.
32. The method according to claim 1, wherein the belt vacuum filter (5) is a moving tray belt vacuum filter.
33. The method according to claim 1, characterized in that the primary washing liquid of the belt vacuum filter (5) is refluxed to the operation of the digestion reaction of step (1).
34. The method according to claim 1, wherein the temperature of the water in the step (4) is 20-30 ℃.
35. The method according to claim 1, wherein in the step (4), the mass ratio of the water to the light calcium carbonate intermediate product is (2-3): 1.
36. The method of claim 1, wherein in step (4), the grinding and shaping are grinding and shaping under the action of grinding aid particles.
37. The method of claim 1, wherein in step (4), the separation is a filter press separation.
38. The method according to claim 1, wherein in step (4), the separated liquid is returned to step (3) as a tertiary wash.
39. The method of claim 1, wherein in step (4), the drying is dryer drying.
40. The method of claim 1, wherein in step (4), the dry heat source comprises hot air and/or steam.
41. The method as claimed in claim 1, wherein the drying temperature in step (4) is 110-150 ℃.
42. The method of claim 1, wherein the operating pressure of the mechanical compression vapor system is negative pressure.
43. The method of claim 1, wherein the mechanical compression vapor system operates at an absolute pressure of 60-70 kpa.
44. The method as claimed in claim 1, wherein the temperature of the input steam of the four-effect evaporation is 150-180 ℃.
45. The method of claim 1, wherein the input steam to the quadruple effect evaporation has a gauge pressure of 0.6-0.8 Mpa.
46. The method of claim 1, wherein the input steam for the four-effect evaporation is saturated steam.
47. The method according to claim 1, wherein in step (5), the temperature of the crystallization separation is 15-35 ℃.
48. The method according to claim 1, wherein in the step (5), the cooling medium for crystallization separation is circulating cooling water.
49. The method according to claim 1, wherein in the step (5), the mass fraction of the caustic soda in the caustic soda solution is 40 wt%.
50. The method of claim 1, wherein in step (5), the salt solid is alkali-containing sodium chloride.
51. Method according to claim 1, characterized in that it comprises the following steps:
(1) carrying out a digestion reaction on the raw material of the quicklime for 1.5-2h, and vibrating and removing impurities from the lime milk after the digestion reaction to obtain the lime milk;
wherein the mass fraction of the quicklime raw material is 90-95 wt%;
(2) mixing the lime milk obtained in the step (1) with soda mother liquor of natural alkali, and carrying out causticization reaction at 35-60 ℃ to obtain mixed slurry consisting of a light calcium carbonate intermediate product and a salt-containing caustic soda solution;
wherein, in the mother liquor of the sodium bicarbonate of the trona, the concentration of sodium bicarbonate is 45-60g/L, the concentration of sodium carbonate is 20-30g/L, and the concentration of sodium chloride is 60-90 g/L;
(3) filtering and separating the mixed slurry consisting of the light calcium carbonate intermediate product and the salt-containing caustic soda solution in the step (2) into the light calcium carbonate intermediate product and the salt-containing caustic soda solution by using a moving disc belt type vacuum filter, and refluxing a primary washing liquid to the digestion reaction operation in the step (1);
(4) mixing the light calcium carbonate intermediate product obtained in the step (3) with water and carbon dioxide, carrying out carbonation reaction, grinding and shaping simultaneously, filtering and separating by using a filter press, and drying at the temperature of 110-;
wherein the mass ratio of the water to the light calcium carbonate intermediate product is (2-3) to 1, the liquid obtained by filtering and separating by the filter press is returned to the moving disc belt type vacuum filter in the step (3) for filtering and separating as a third-level washing liquid, and the heat source for drying comprises hot air and/or steam;
(5) performing mechanical compression steam system evaporation and four-effect evaporation on the salt-containing caustic soda solution obtained in the step (3), and then performing crystallization separation at 15-35 ℃ by using circulating cooling water as a cooling medium to obtain 40 wt% of caustic soda solution and alkali-containing sodium chloride;
wherein the absolute pressure of the mechanical compression steam system is 60-70Kpa, and the input steam of the four-effect evaporation is 150-180 ℃ saturated steam with gauge pressure of 0.6-0.8 Mpa.
CN201810448729.3A 2018-05-11 2018-05-11 Natural alkali sodium bicarbonate mother liquor resource utilization system and treatment method thereof Active CN108439448B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810448729.3A CN108439448B (en) 2018-05-11 2018-05-11 Natural alkali sodium bicarbonate mother liquor resource utilization system and treatment method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201810448729.3A CN108439448B (en) 2018-05-11 2018-05-11 Natural alkali sodium bicarbonate mother liquor resource utilization system and treatment method thereof

Publications (2)

Publication Number Publication Date
CN108439448A CN108439448A (en) 2018-08-24
CN108439448B true CN108439448B (en) 2020-08-14

Family

ID=63203581

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201810448729.3A Active CN108439448B (en) 2018-05-11 2018-05-11 Natural alkali sodium bicarbonate mother liquor resource utilization system and treatment method thereof

Country Status (1)

Country Link
CN (1) CN108439448B (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109850922B (en) * 2019-03-11 2023-10-03 东方电气集团东方锅炉股份有限公司 Method and device for recycling baking soda desulfurization ash
CN110092395B (en) * 2019-05-28 2021-09-10 江西吉尔化工科技有限公司 Sodium hydroxide production method
CN111362290A (en) * 2020-05-05 2020-07-03 湖南诺兰蒂尔环保科技有限公司 Causticizing process and device for sodium carbonate in sodium aluminate solution
CN112079373A (en) * 2020-09-10 2020-12-15 浙江浙能嘉华发电有限公司 Device and process for preparing micron-sized homogeneous calcium carbonate through causticization reaction
CN114854457B (en) * 2022-01-20 2023-04-18 中国中煤能源集团有限公司 Decarbonization and desulfurization method for mixed gas containing combustible gas
CN114772626A (en) * 2022-06-02 2022-07-22 武汉华德环保工程技术有限公司 Method for co-producing sodium sulfate and calcium carbonate from sodium bicarbonate desulfurized fly ash

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1037319A (en) * 1988-05-07 1989-11-22 山西省师范大学 The method of comprehensive utilization of urao
CN1039780A (en) * 1988-07-26 1990-02-21 郭湘泗 The method of caustic soda made by trona
CN1148028A (en) * 1995-10-18 1997-04-23 孙世宁 Process for preparing caustic soda from natural soda
CN102079536B (en) * 2010-12-03 2012-10-10 桐柏兴源化工有限公司 Method for producing caustic soda and papermaking filler calcium carbonate by using natural alkali liquor

Also Published As

Publication number Publication date
CN108439448A (en) 2018-08-24

Similar Documents

Publication Publication Date Title
CN108439448B (en) Natural alkali sodium bicarbonate mother liquor resource utilization system and treatment method thereof
CN102060408B (en) Wastewater evaporating process and device system
CN111960445B (en) Method for preparing battery-grade lithium carbonate by using lithium sulfate coarse ore and recycling by-products
CN107934996A (en) A kind of technique using triamine End gas production sodium bicarbonate and ammonium chloride
CN103588225A (en) Method for producing food-grade potassium chloride through multistage flash evaporation, cooling and continuous crystallization
CN112047547A (en) Continuous washing energy-saving treatment device and process for waste incineration fly ash or fly ash after hydrochloric acid washing
CN110937612B (en) Process for preparing high-quality heavy soda ash by using crude sodium bicarbonate
CN101428827A (en) Method for producing ultrafine-grain special mirabilite
CN114162837A (en) Waste salt recycling treatment system and treatment method thereof
CN113522934B (en) System and method for waste incineration flue gas purification and fly ash desalination
CN102264644A (en) Process for joint production of sodium carbonate and sodium bicarbonate
CN112758959A (en) Preparation method of sodium bicarbonate
CN213887551U (en) Continuous washing energy-saving treatment device for waste incineration fly ash or fly ash after hydrochloric acid washing
US3653848A (en) Crystallization process
CN112279277A (en) System and method for high-end resource utilization of flue gas desulfurization by magnesium method
CN114956618B (en) Cement kiln co-treatment fly ash system
CN113998715A (en) Method for extracting lithium from high-calcium lithium-containing raw material
CN101428828A (en) Method for producing coarse-grain special mirabilite
CN108455636A (en) A kind of production method of magnesium sulfate monohydrate
CN103991851A (en) New process for green and cyclic production of hydrazine hydrate
CN108862329B (en) Recovery method for preparing edible-grade potassium chloride salt-containing mother liquor
RU91530U1 (en) PLANT FOR PRODUCING CAUSTIC SODA FROM ELECTROLYTIC ALKALI
CN221027728U (en) System for utilize crude calcium nitrate liquid preparation fused salt level sodium nitrate
CN110510645A (en) A kind of method and system cleaning loop production magnesium hydroxide
CN110980765A (en) Process for preparing ammonium chloride

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant