CN102107897A - Method for controlling precipitation of crystal alkali in evaporator - Google Patents
Method for controlling precipitation of crystal alkali in evaporator Download PDFInfo
- Publication number
- CN102107897A CN102107897A CN2009103120752A CN200910312075A CN102107897A CN 102107897 A CN102107897 A CN 102107897A CN 2009103120752 A CN2009103120752 A CN 2009103120752A CN 200910312075 A CN200910312075 A CN 200910312075A CN 102107897 A CN102107897 A CN 102107897A
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- Prior art keywords
- evaporator
- evaporation
- carbonate
- alkali
- vaporizer
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- 238000000034 method Methods 0.000 title claims abstract description 39
- 239000003513 alkali Substances 0.000 title claims abstract description 13
- 238000001556 precipitation Methods 0.000 title abstract description 7
- 239000013078 crystal Substances 0.000 title abstract 5
- 238000001704 evaporation Methods 0.000 claims abstract description 37
- 230000008020 evaporation Effects 0.000 claims abstract description 35
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims abstract description 17
- 239000006200 vaporizer Substances 0.000 claims description 24
- 239000007788 liquid Substances 0.000 claims description 23
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 abstract description 56
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 abstract description 29
- 229910000029 sodium carbonate Inorganic materials 0.000 abstract description 28
- 229910052938 sodium sulfate Inorganic materials 0.000 abstract description 27
- 235000011152 sodium sulphate Nutrition 0.000 abstract description 27
- 238000010438 heat treatment Methods 0.000 abstract description 8
- 238000004519 manufacturing process Methods 0.000 abstract description 8
- 238000005406 washing Methods 0.000 abstract description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 5
- 238000009835 boiling Methods 0.000 abstract description 3
- 239000010413 mother solution Substances 0.000 abstract 4
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 abstract 3
- 239000011552 falling film Substances 0.000 abstract 1
- 230000002035 prolonged effect Effects 0.000 abstract 1
- 230000002277 temperature effect Effects 0.000 abstract 1
- 235000017550 sodium carbonate Nutrition 0.000 description 26
- 238000002425 crystallisation Methods 0.000 description 12
- 230000008025 crystallization Effects 0.000 description 12
- 239000012452 mother liquor Substances 0.000 description 10
- 230000008016 vaporization Effects 0.000 description 9
- 238000009834 vaporization Methods 0.000 description 7
- 230000002411 adverse Effects 0.000 description 3
- 230000004087 circulation Effects 0.000 description 3
- 239000012141 concentrate Substances 0.000 description 3
- 238000004131 Bayer process Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
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- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
Abstract
The invention discloses a method for controlling precipitation of crystal alkali in an evaporator. The evaporation mother solution after carbonate and sulfate are precipitated and separated is partially returned to one of final three-effect evaporators in the evaporation process to reduce the crystal precipitation amount of the carbonate and the sulfate in the final three effects. The method can be used for the countercurrent flow operation of the evaporation process. The evaporation mother solution is partially returned into the three-effect evaporators in the evaporation process to reduce the crystal precipitation amount of the carbonate and the sulfate in the final three effects. The ratio of the part of the evaporation mother solution returned to the evaporation process to the total amount of the evaporation mother solution is 0.5-1.5: 3. The method is suitable for a plate type falling film evaporator, and also suitable for an external heating type natural circulating evaporator. After the method is adopted, compared with the prior art, the precipitation amount of the crystal alkali on the heating surface of the evaporator is remarkably reduced, the scaling speed of sodium carbonate and sodium sulfate on the high temperature effect heating surface is slowed down, and the period of washing a boiling tank is prolonged so that washing water entering the production flow is reduced and the consumption of steam is reduced. Because the scales of the sodium carbonate and the sodium sulfate on the heating surface of the evaporator are reduced, the evaporation efficiency is greatly improved, and the average productivity of the evaporator is improved by 10 to 15 percent compared with the prior art.
Description
Technical field
The invention belongs to metallurgical every profession and trade technical field of alumina production, the method that particularly a kind of evaporization process control vaporizer intercrystalline alkali is separated out.
Background technology:
Produce in the process of aluminum oxide at alkaline process, carbonate that ore and lime are brought into and sulfide react the partial sodium carbonate and the sodium sulfate that generate with caustic alkali and accumulate gradually in (stripping) process of leaching, when yellow soda ash, sodium sulfate run up to a certain content through some circulations in the decomposition nut liquid, with this mother liquid evaporation during to the concentration that requires, then oversaturated yellow soda ash and sodium sulfate promptly begin crystallization separates out, till the balanced contents that reaches under this concentration.The quantity that enters (ore and fuel bring) in yellow soda ash of separating out and sodium sulfate quantity and each circulation in evaporative process equates, so yellow soda ash and sodium sulphate content keep constant in the solution, no longer accumulates.Yellow soda ash and the sodium sulfate solubility with temperature in mother liquor raises and increases.Temperature is low, and the yellow soda ash and the sodium sulfate of separating out are many.A part of monohydrated sodium carbonate and sodium sulfate that crystallization is separated out form fouling on the vaporizer hot face, had a strong impact on vaporization efficiency, and increase steam consumption.In order to eliminate the fouling that monohydrated sodium carbonate and sodium sulfate form on the vaporizer hot face, to reduce steam consumption, improve the vaporizer production capacity, general at present employing water-boiling method is eliminated this type of fouling, promptly when evaporator effectiveness drops to a certain degree, just boil fouling, it is dissolved toward the interior water filling heating of vaporizer.But the time cycle that this method can be kept is lacked (general about 3 days even shorter), and poach is frequent, and the water after boiling enters Production Flow Chart, also needs to steam with vaporizer to get rid of, thereby causes the steam consumption height, and cost increases.
Summary of the invention:
The technical problem that will solve of the present invention is:
A kind of method that vaporizer intercrystalline alkali is separated out of controlling is provided,, has a strong impact on vaporization efficiency, the technical problem of increase steam consumption to solve in the prior art because crystalline alkali is separated out and caused fouling on the vaporizer hot face.
The present invention takes following technical scheme:
Mother liquid evaporation behind settlement separate carbonate and the vitriol is partly returned in the evaporization process in one of last 3 single-effect evaporators, to reduce carbonate and vitriol 3 crystallization amounts of separating out in imitating in the end.Because the solubleness of carbonate and vitriol is to reduce with the reduction of temperature and the rising of mother liquid evaporation concentration, in last 3 single-effect evaporators of evaporization process, particularly 1 of vaporizer imitate in (discharging effect), mother liquid evaporation concentration is higher, thereby carbonate and the decline of vitriol solubleness, carbonate and vitriol begin mass crystallization and separate out.At this moment from the mother liquid evaporation of the 3rd single-effect evaporator adding behind settlement separate carbonate and vitriol, can reduce its degree of supersaturation, the yellow soda ash on the hot face and the crystallization speed of separating out of sodium sulfate are slowed down, a jar cycle stretch-out is boiled in washing, thereby reduced wash water and entered Production Flow Chart, reduce steam consumption, improved vaporization efficiency.
Evaporization process adopts countercurrent flow operation technique flow process.In the adverse current work flow, the mother liquid concentration in 1～3 single-effect evaporator is raising gradually, thereby the solubleness of yellow soda ash and sodium sulfate improves, and minimizing is separated out in its crystallization.Thereby, the solubleness of yellow soda ash and sodium sulfate descends, its degree of supersaturation increases, the crystallization amount of separating out of yellow soda ash and sodium sulfate increases gradually, at this moment add the mother liquid evaporation behind settlement separate carbonate and vitriol in the 3rd single-effect evaporator, can reduce its degree of supersaturation, the yellow soda ash on the hot face and the crystallization speed of separating out of sodium sulfate are slowed down.
Described mother liquid evaporation is partly returned in the 3rd single-effect evaporator of adverse current operation vaporizer, to reduce carbonate and crystallization the separate out amount of vitriol in 1～3 single-effect evaporator.In the adverse current work flow, mother liquid concentration in 1～3 single-effect evaporator is raising gradually, thereby, the solubleness of yellow soda ash and sodium sulfate descends, its degree of supersaturation increases, and the crystallization amount of separating out of yellow soda ash and sodium sulfate increases gradually, at this moment adds the mother liquid evaporation behind settlement separate carbonate and vitriol, can reduce the degree of supersaturation of carbonate and vitriol in the mother liquid evaporation effectively, thereby the yellow soda ash on the hot face and the crystallization speed of separating out of sodium sulfate are slowed down.A jar cycle stretch-out is boiled in washing, enters Production Flow Chart thereby reduced wash water, has reduced steam consumption, improves vaporization efficiency.
The ratio that described mother liquid evaporation returns evaporization process part and mother liquid evaporation total amount is 0.5～1.5: 3, and its optimal way is 1: 3.
This method is applicable in the plate-type down-film evaporator.
This method is equally applicable to the external heating type natural-circulation evaporator.
The present invention compared with prior art has following advantage:
1, carbonate and the vitriol crystallization amount of separating out on the hot face of vaporizer compared with prior art has remarkable reduction, yellow soda ash and sodium sulfate scale velocity that high temperature is imitated on the hot face slow down, a jar cycle stretch-out (boiled 1 time to extend to boil more than 5 days 1 time by 3 days of prior art) is boiled in washing, enter Production Flow Chart thereby reduced wash water, reduced steam consumption.
2, because yellow soda ash on the vaporizer hot face and sodium sulfate fouling reduce, and vaporization efficiency improves greatly than prior art, the average production capacity of vaporizer has improved 10～15% than prior art.
Description of drawings:
Fig. 1 is used for the process flow diagram of plate-type down-film evaporator for the present invention.
Fig. 2 is used for the process flow diagram of external heating type natural-circulation evaporator for the present invention.
Embodiment:
Embodiment one:
Imitating 4 grades of self-evaporating plate-type down-film evaporators of operation with countercurrent flow 6 is example.
As shown in Figure 1: 6 effects and 5 that vaporizing raw liquor (seed precipitation solution) is delivered to vaporizer 2 respectively by concentrate pump 1 are imitated interior evaporation, and ceaselessly play circulation cloth film evaporation by recycle pump 3, solution after by punishment in advance pump 4 corresponding levels being evaporated then is transported in the next stage vaporizer and evaporates, like this, solution is after through 6 grades of evaporations, process is in the pressure mode enters 1～4 grade of flash-pot 5 in 1 single-effect evaporator, doing further self-evaporatint n. concentrates, after 4 grades of self-evaporatint n., solution carries out separating of carbonate and vitriol in discharging pump 6 is sent into mother liquor subsider 7, overflow after the separation (mother liquid evaporation) enters in the overflow groove 8, then 1/3 overflow (mother liquid evaporation) is prepared burden with mother liquor pumping Bayer process, all the other are transported in vaporizer 3 effects by returning mother liquor pump 9, saturation ratio with mother liquor yellow soda ash and sodium sulfate in the reduction vaporizer, thereby suppress yellow soda ash and sodium sulfate separating out in a large number in 1～3 single-effect evaporator, yellow soda ash and the sodium sulfate scale velocity that high temperature is imitated on the hot face slowed down, vaporization efficiency is improved, and a jar cycle stretch-out is boiled in washing.
Embodiment two:
Imitating 1 grade of self-evaporating external heating type natural-circulation evaporator of operation with countercurrent flow 4 is that example is illustrated.
As shown in drawings: vaporizing raw liquor (seed precipitation solution) is transported to the 4th by concentrate pump 1 and imitates in the preheater 2, after the preheater preheating, enter evaporation in the 4th single-effect evaporator 3 again, solution after by line pump 4 corresponding levels being evaporated then is transported to 3 and imitates in the preheaters, after the preheater preheating, enter again in 3 single-effect evaporators and evaporate, solution after by line pump the corresponding levels being evaporated then is transported to 2 and imitates in the preheaters, after the preheater preheating, enter again in 2 single-effect evaporators and evaporate, and then by line pump the solution after the corresponding levels evaporations is transported to 1 and imitates in the preheater, after the preheater preheating, enter again in 1 single-effect evaporator and evaporate, solution after the evaporation carries out self-evaporatint n. by compressing into flash-pot 5 certainly, solution after the self-evaporatint n. enters by pressure mode certainly and carries out the settlement separate of yellow soda ash and sodium sulfate in the mother liquor subsider 6, overflow after the separation (mother liquid evaporation) is sent Bayer process batching by mother liquor pump 8 with 2/3 mother liquor through overflow groove 7,1/3 returns and carries out double evaporation-cooling in 3 single-effect evaporators through returning mother liquor pump 9, saturation ratio with mother liquor yellow soda ash and sodium sulfate in the reduction vaporizer, thereby suppress yellow soda ash and sodium sulfate separating out in a large number in 1～3 single-effect evaporator, yellow soda ash and the sodium sulfate scale velocity that high temperature is imitated on the hot face slowed down, vaporization efficiency is improved, and a jar cycle stretch-out is boiled in washing.
Claims (5)
1. control the method that vaporizer intercrystalline alkali is separated out for one kind, it is characterized in that: the mother liquid evaporation behind settlement separate carbonate and the vitriol is partly returned in the evaporization process in one of last 3 single-effect evaporators.
2. according to the described a kind of method that vaporizer intercrystalline alkali is separated out of controlling of claim 1, it is characterized in that: evaporization process adopts the countercurrent flow operation.
3. according to the described a kind of method that vaporizer intercrystalline alkali is separated out of controlling of claim 1, it is characterized in that: described mother liquid evaporation is partly returned in the evaporization process in 3 single-effect evaporators.
4. according to claim 1 or 2 described a kind of methods that vaporizer intercrystalline alkali is separated out of controlling, it is characterized in that: the ratio that described mother liquid evaporation returns evaporization process part and mother liquid evaporation total amount is 0.5～1.5: 3.
5. according to the described a kind of method that vaporizer intercrystalline alkali is separated out of controlling of claim 4, it is characterized in that: the ratio that described mother liquid evaporation returns evaporization process part and mother liquid evaporation total amount is 1: 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910312075.2A CN102107897B (en) | 2009-12-23 | 2009-12-23 | Method for controlling precipitation of crystal alkali in evaporator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910312075.2A CN102107897B (en) | 2009-12-23 | 2009-12-23 | Method for controlling precipitation of crystal alkali in evaporator |
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| Publication Number | Publication Date |
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| CN102107897A true CN102107897A (en) | 2011-06-29 |
| CN102107897B CN102107897B (en) | 2014-08-13 |
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| CN200910312075.2A Active CN102107897B (en) | 2009-12-23 | 2009-12-23 | Method for controlling precipitation of crystal alkali in evaporator |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103007554A (en) * | 2012-12-14 | 2013-04-03 | 中国铝业股份有限公司 | Operation method for eliminating scaling of reinforced film evaporator |
| CN103130256A (en) * | 2011-12-05 | 2013-06-05 | 贵阳铝镁设计研究院有限公司 | Dissolving self-evaporation process |
| EA036045B1 (en) * | 2018-11-12 | 2020-09-17 | Общество с ограниченной ответственностью "Баромембранная технология" (ООО "БМТ") | Method for evaporating water from saline solutions in a film evaporator |
| RU2775695C1 (en) * | 2018-02-12 | 2022-07-06 | Общество с ограниченной ответственностью "Баромембранная технология" | Method for washing tubes in film evaporator from sediments formed as a result of water evaporation from saline solution |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85103681A (en) * | 1985-05-06 | 1986-11-12 | 贵阳铝镁设计研究院 | The method of prevention evaporimeter heating tube fouling in the alumina producing |
| CN1387931A (en) * | 2002-01-22 | 2003-01-01 | 兰州节能环保工程有限责任公司 | Multi-effect self-descending membrane-pipe type alumina liquid evaporating process |
| CN101234771A (en) * | 2007-01-31 | 2008-08-06 | 中国铝业股份有限公司 | Mother liquid evaporation desalting technique in aluminum oxide production |
-
2009
- 2009-12-23 CN CN200910312075.2A patent/CN102107897B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85103681A (en) * | 1985-05-06 | 1986-11-12 | 贵阳铝镁设计研究院 | The method of prevention evaporimeter heating tube fouling in the alumina producing |
| CN1387931A (en) * | 2002-01-22 | 2003-01-01 | 兰州节能环保工程有限责任公司 | Multi-effect self-descending membrane-pipe type alumina liquid evaporating process |
| CN101234771A (en) * | 2007-01-31 | 2008-08-06 | 中国铝业股份有限公司 | Mother liquid evaporation desalting technique in aluminum oxide production |
Non-Patent Citations (1)
| Title |
|---|
| 赵清法等: "种分母液蒸发浓度与结晶碱析出关系探讨", 《有色冶炼》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103130256A (en) * | 2011-12-05 | 2013-06-05 | 贵阳铝镁设计研究院有限公司 | Dissolving self-evaporation process |
| CN103007554A (en) * | 2012-12-14 | 2013-04-03 | 中国铝业股份有限公司 | Operation method for eliminating scaling of reinforced film evaporator |
| CN103007554B (en) * | 2012-12-14 | 2014-10-22 | 中国铝业股份有限公司 | Operation method for eliminating scaling of reinforced film evaporator |
| RU2775695C1 (en) * | 2018-02-12 | 2022-07-06 | Общество с ограниченной ответственностью "Баромембранная технология" | Method for washing tubes in film evaporator from sediments formed as a result of water evaporation from saline solution |
| EA036045B1 (en) * | 2018-11-12 | 2020-09-17 | Общество с ограниченной ответственностью "Баромембранная технология" (ООО "БМТ") | Method for evaporating water from saline solutions in a film evaporator |
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| Publication number | Publication date |
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| CN102107897B (en) | 2014-08-13 |
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