CN1057819A - Production process for solid sodium cyanide - Google Patents
Production process for solid sodium cyanide Download PDFInfo
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- CN1057819A CN1057819A CN 90103439 CN90103439A CN1057819A CN 1057819 A CN1057819 A CN 1057819A CN 90103439 CN90103439 CN 90103439 CN 90103439 A CN90103439 A CN 90103439A CN 1057819 A CN1057819 A CN 1057819A
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Abstract
It is with the liquid sodium cyanide decrease temperature crystalline that a kind of reduction temperature of producing solid sodium cyanide is separated out the crystallization curing process, gets the hydrate (NaCN2H of sodium cyanide after centrifugation
2O) crystal, isolate mother liquor, at 100 ℃ to 150 ℃, pressure is 0 to-0.093MPa dry 1 to 3 minute down with crystal, again after granulation with 80 ℃ to 170 ℃ air direct heating 30 to 60 minutes, can obtain sodium cyanide content 96% or more highly purified granular sodium cyanide finished product.This technology continuous production does not produce cyanide wastewater substantially.
Description
The present invention relates to a kind of technology of producing solid sodium cyanide.
Producing sodium cyanide at present both at home and abroad all adopts hydrocyanic acid and liquid caustic soda neutralization to make liquid sodium cyanide.Again through evaporation, crystallization, centrifugation.Operations such as drying and moulding are made solid sodium cyanide.
Reaction equation:
Make solid sodium cyanide from liquid sodium cyanide and generally adopt evaporation technology.Strict to material purity.Domestic liquid sodium cyanide purity height, the foreign matter content that has only minority large chemical complex to adopt purified liquid hydrocyanic acid and caustic soda neutralization to make is low, and be just high with its solid sodium cyanide purity that makes.And domestic most of producer all is the furnace gas that contains prussic acid that adopts light oil cracking method to generate, and wherein still contains not cracked ammonia and other gaseous impurities.Relatively poor with this furnace gas synthetic fluid sodium cyanide purity, impurity is more, adopt evaporation technology to make solid sodium cyanide again after product purity relatively poor.And it is strict to operational condition, processing parameter.Sodium cyanide generates sodium formiate quickening hydrolysis more than 60 ℃.
Reaction equation:
Therefore evaporation technology requires temperature to carry out at (general about 45 ℃) below 60 ℃.Tackling vacuum tightness mutually requires very high.Yet domestic most of Sodium Cyanide Production producer does not all have such favourable condition, generally all adopts mechanical pump to vacuumize, because evaporative process has a large amount of water vapors to extract out.So vacuum tightness is difficult to reach requirement.Have to suitably improve vaporization temperature, generally at 65 ℃ to 75 ℃.Like this, hydrolysis can take place in the evaporative process form a large amount of sodium formiates, influence the purity of product, generally can only reach sodium cyanide content 85% to 90%.And there is more foam to take out of in the evaporative process with vacuumizing.Thereby produce a large amount of cyanide wastewater, and seriously surpassing emission standard, contaminate environment strengthens control expense, in evaporation technology, can influence centrifugal separating effect if the iron ion content of liquid sodium cyanide is high.Make technology interruption and complicated.Therefore all curing apparatus and pipeline need to use the stainless steel manufacturing, and facility investment is big.
For solving and avoid existing various disadvantages in the evaporation technology.Thereby invented by the reduction temperature of liquid sodium cyanide system solid sodium cyanide and separated out the crystallization curing process.
The present invention reduces temperature, and to separate out the basis of crystallization curing process be that the solubility with temperature of sodium cyanide changes and to have than big-difference.Reduce the hydrate (NaCN.2H that the sodium cyanide solution temperature is easy to separate out sodium cyanide
2O).It consists of, and NaCN accounts for 55%, H
2O accounts for 45%, does not contain other impurity.This hydrate can lose crystal water at 34.7 ℃, for slough crystal water and reduce the sodium cyanide hydrolysis, direct hydrate (NaCN.2H with prussiate as far as possible
2O) carry out moment vacuum-drying, can slough part (about 30%) moisture content, content is 85% sodium cyanide.For preventing that meal from producing a large amount of dust in drying process, will carry out the degree of depth (secondary) drying behind its extruder grain more earlier, be higher than 96% granular sodium cyanide thereby make purity.
Technical process:
In the decrease temperature crystalline operation,, generally can about 5 ℃ to-20 ℃, make the hydrate (NaCN.2H that separates out sodium cyanide with the liquid sodium cyanide cooling
2O) crystallization, after centrifugation, crystal enters moment vacuum-drying operation, mother liquor rework solution cyanogen generate in and operation, as: is content about 40%, temperature is 35 ℃ a liquid sodium cyanide (A point in the accompanying drawing), and after cooling is handled (B point in the accompanying drawing), centrifugation obtains the hydrate (NaCN.2H of sodium cyanide again
2O) mother liquor (C point in the accompanying drawing) is isolated in crystallization, and heats up and to add liquid caustic soda (NaOH) (D point in the accompanying drawing), feeds the sodium cyanide-containing furnace gases down at 35 ℃ and is neutralized to the A point once more.So repeatedly circulation when impurity increases to when being not suitable for recrystallize, is discharged the mother liquor in the technological process and is sold as liquid sodium cyanide.In moment vacuum-drying operation, the hydrate (NaCN.2H of sodium cyanide
2O) crystal is in 100 ℃ to 150 ℃, and pressure is under 0 to-0.093MPa the condition, to stop 1 to 3 minute in moisture eliminator, can obtain moisture 11% to 13% sodium cyanide, enters the secondary drying device after granulation, with 80 ℃ to 170 ℃ air direct heating materials.In the secondary drying device, stopped 30 minutes to 60 minutes, can obtain content 96% or more highly purified granular sodium cyanide finished product.
Reduce temperature and separate out the shortcoming that the crystallization curing process has overcome evaporation technology.This technology is less demanding to material purity, is specially adapted to adopt the enterprise of light oil, ammonia cracking production technique, and with the solid sodium cyanide purity height that this technology makes, its product quality indicator is as follows:
Sodium cyanide content 〉=96%; Sodium hydrate content≤0.5%
Carbonate content≤1.2% sodium formiate content≤1.8%
Water content≤1%
Reduce temperature and separate out the crystallization curing process owing to adopt the reduction temperature to separate out crystallization solidified method.Recycling Mother Solution is used.Substantially do not produce cyanide wastewater in the technological process, drying process adopts vacuum-drying and air stream drying.The air-flow of discharging can wash through water wash column.And reaching finite concentration, washing water can be used to dilute caustic soda.Therefore do not produce pollution problem yet.Reduce temperature and separate out the equipment that the crystallization curing process overcome evaporation technology and need use stainless steel, the shortcoming that cost is high, equipment all adopts the carbon steel manufacturing, and high pressure steam that need not be a large amount of, can reduce investment cost significantly.
Embodiment:
(wherein NaCN content 38.71%, NaOH content 1.46%, NaCO 35 ℃ of liquid sodium cyanide raw materials
2Content 0.68%), centrifugation again after cooling is handled.Obtain the hydrate (NaCN2H of sodium cyanide
2O) mother liquor is isolated in crystallization, and crystal is sent into moment vacuum-drying, carries out redrying after the granulation, thereby makes granular sodium cyanide finished product, and concrete parameter divides each operation to list.
1, decrease temperature crystalline operation:
| Sequence number | Cooling | NaCN·2H 2O | Mother liquor | ||||
| Tc ℃ | NaCN ％ | NaOH ％ | Na 2CO 3％ | NaCN ％ | NaOH ％ | Na 2CO 3％ | |
| 1 | －7 | 56.7 | 0.13 | Do not have | 29.5 | 2.4 | 1.09 |
| 2 | －10 | 55.3 | 0.12 | 0.1 | 25.5 | 2.5 | 1.36 |
| 3 | －13 | 55.1 | 0.17 | 0.13 | 24.6 | 2.60 | 1.42 |
2, moment vacuum-drying operation:
| Sequence number | NaCN·2H 2O | Moment vacuum-drying condition | Dry back group easily | ||||||||
| NaCN ％ | NaOH ％ | Na 2CO 3％ | Temperature ℃ | Pressure Mpa | Time minute | NaCN ％ | NaOH ％ | Na 2CO 3％ | HCOONa ％ | H 2O ％ | |
| 1 | 55.3 | 0.12 | 0.1 | 150 | 0 | 1 | 86.14 | 0.22 | 1.37 | 11.71 | |
| 2 | 55.3 | 0.12 | 0.1 | 150 | －0.053 | 1 | 90.97 | 0.22 | 0.93 | 8.57 | |
| 3 | 55.3 | 0.12 | 0.1 | 120 | －0.080 | 2 | 87.2 | 0.11 | Trace | 0.80 | 11.7 |
3, redrying operation after the granulation
| Sequence number 1 | Form % NaCN86.14 NaOH 0.22 Na before entering redrying 2CO 3HCOONa?1.37 H 2O?11.71 | The redrying condition | Solid sodium cyanide finished product | ||||||
| Temperature ℃ | |||||||||
| 80 | Pressure Mpa 0 | |
NaCN ％ 96.1 | NaOH ％ 0.16 | Na 2CO 3％ 0.54 | HCOONa ％ 1.8 | H 2O ％ | ||
| 2 | 100 | 0 | 60 | 96.2 | 0.16 | 0.93 | 1.79 | ||
| 3 | 110 | －0.053 | 30 | 96.5 | 0.16 | 0.8 | 1.8 | ||
Claims (3)
1, a kind of production solid sodium cyanide technology, it is characterized by this technology is the temperature that reduces liquid sodium cyanide, separates out the hydrate (NaCN.2H of sodium cyanide
2O) crystallization, the technology of dry solidification again.Its technical process reduces temperature by liquid sodium cyanide and separates out crystallization.The centrifugation of crystal and mother liquor, crystalline moment vacuum-drying, granulation, the dry several operations of the degree of depth (secondary) are formed.
2, moment vacuum-drying operation as claimed in claim 1 is characterized by drying temperature by 100 ℃ to 150 ℃, and pressure is by 0 to-0.093MPa, and the residence time is 1 to 3 minute.
3, the degree of depth as claimed in claim 1 (secondary) drying process is characterized by drying temperature by 80 ℃ to 170 ℃, and the residence time is 30 to 60 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 90103439 CN1022750C (en) | 1990-07-06 | 1990-07-06 | Production process for solid sodium cyanide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 90103439 CN1022750C (en) | 1990-07-06 | 1990-07-06 | Production process for solid sodium cyanide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1057819A true CN1057819A (en) | 1992-01-15 |
| CN1022750C CN1022750C (en) | 1993-11-17 |
Family
ID=4878067
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 90103439 Expired - Fee Related CN1022750C (en) | 1990-07-06 | 1990-07-06 | Production process for solid sodium cyanide |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1022750C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106629878A (en) * | 2016-10-20 | 2017-05-10 | 安庆市长虹化工有限公司 | High-cyanide-content wastewater treatment system and treatment method |
| CN107750234A (en) * | 2015-06-18 | 2018-03-02 | Epc工程与技术有限公司 | The method for preparing Cymag |
-
1990
- 1990-07-06 CN CN 90103439 patent/CN1022750C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107750234A (en) * | 2015-06-18 | 2018-03-02 | Epc工程与技术有限公司 | The method for preparing Cymag |
| CN107750234B (en) * | 2015-06-18 | 2021-12-24 | 赛普有限公司 | Process for the preparation of sodium cyanide |
| CN106629878A (en) * | 2016-10-20 | 2017-05-10 | 安庆市长虹化工有限公司 | High-cyanide-content wastewater treatment system and treatment method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1022750C (en) | 1993-11-17 |
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